cairan tubuh

CAIRAN TUBUH

Cairan TubuhAir beserta

unsur-unsur

di

dalamnya

yang dibutuhkan

untuk

kesehatan

sel

Binatang

/ makhluk

1 sel

→ milieu exterieur

(cairan) → external environmentcontoh

: amoeba → terjadi

difusi

melalui

membran

: O2

, CO2

, makanan

Binatang

multisel

→ external environment : -

air

-

udarasel-nya

hidup

di

internal environment / milieu interieur

(= fluid

environment)→ mempunyai

susunan

tertentu

(konstan)

Pembagian

cairan

tubuh

:1.

Cairan

Intraselular

(ICF)

2. Cairan

Ekstraselular

(ECF) :

-

plasma darah

-

cairan

interstisiil-

limfe

3. Cairan

transel

:

-

cairan

otak

-

cairan

mata

-

cairan

sendi

-

cairan

perikard-

cairan

pleura

-

liur

pencernaan

→ cairan

ekstrasel

khusus→ seluruhnya

1 –2 liter

Tubuh

dewasa

normal : 60 % air, 18 % protein, 7 % mineral, 15 % lemakTanpa

air manusia

hanya

dapat

bertahan

beberapa

harikehilangan

20 –

22 % kematian

Cairan

Tubuh

: 60 % Total Body Weight in adult45 –

55 % Total Body Weight in older adult70 –

80 % Total Body Weight in newborn infant97 % Total Body Weight in human embryo

Adult → 60 % Total Body Weight →

40 % ICF (2/3)20 % ECF (1/3)

ECF : -

plasma 25 % ( = 5 % Total Body Weight)volume darah

total (plasma + selular

darah) = 8 % Total Body Weight-

cairan

interstisiil

75 % (= 15 % Total Body Weight)

Cairan

Tubuh

total & hubungannya

dengan

tingkat

obesitas

perbandingan

lemak

dan

air dalam

tubuh

(% dari

BB)

Cairan

Tubuh

total dari

BB & hubungannya

dengan

umur

dan

jenis

kelamin

Lemak AirGemuk 30 –

32 % 50 %BB normal 15 % 60 %Kurus 7 % 67 %

Umur Pria Wanita10 –

18 59 % 57 %18 –

40 61 % 51 %40 –

60 55 % 47 %60- 52 % 46 %

Wanita

lebih

sedikit

cairan

tubuhnya

: Higher body fat & Smaller amount of skeletal muscleAt puberty, sexual differences in body water content arise as males develop greater muscle mass.

-

Kadar air di

berbagai

organ tubuh

hampir

sama, kecuali

rangka-

KulitOtot

massa

relatif

besar

→ kadar

air terbanyakHati

Persentase

air di

jaringan

tubuh

terhadap

TBW :-

Otot

50,8

-

Otak

2,7-

Rangka

12,5

-

Paru

2,4-

Kulit

6,6

-

Jaringan

lemak

2,3-

Darah

4,7

-

Ginjal

0,6-

Intestine

3,2

-

Limpa

0,4-

Hepar

2,8

-

Sisa

bagian

tubuh

lain

11,0100,0

Composition of Body Fluids•

Water is the universal solvent

•

Solutes are broadly classified into:–

Electrolytes

–

inorganic salts, all acids and

bases, and some proteins–

Nonelectrolytes

–

examples include glucose,

lipids, creatinine, and urea•

Electrolytes have greater osmotic power than nonelectrolytes

•

Water moves according to osmotic gradients

Electrolyte Concentration

•

Expressed in milliequivalents

per liter (mEq/L), a measure of the number of electrical charges in one liter of solution

•

mEq/L = (concentration of ion in [mg/L]/the atomic weight of ion)

number of electrical

charges on one ion•

For single charged ions, 1 mEq

= 1 mOsm

•

For bivalent ions, 1 mEq

= 1/2 mOsm

Extracellular

and Intracellular Fluids•

Each fluid compartment of the body has a distinctive pattern of electrolytes

•

Extracellular

fluids are similar (except for the high protein content of plasma)–

Sodium is the chief cation

–

Chloride is the major anion•

Intracellular fluids have low sodium and chloride–

Potassium is the chief cation

–

Phosphate is the chief anion

Extracellular

and Intracellular Fluids

•

Proteins, phospholipids, cholesterol, and neutral fats account for:–

90% of the mass of solutes in plasma

–

60% of the mass of solutes in interstitial fluid–

97% of the mass of solutes in the intracellular compartment

Electrolyte Composition of Body Fluids

3 Kompartemen

cairan

tubuh

:1. Plasma darah

(Cairan

Intravaskuler)

2. Cairan

Interstisiil3. Cairan

Intrasel

Susunan

:-

Cairan

intrasel

→ berbeda, tergantung

pada

sifat

& fungsi

sel

-

Kadar elektrolit

berbeda

nyata

→-

ICF terutama

mengandung

ion K+, PO4

3-

, Mg2+

-

ECF : ion Na+, Cl

-, HCO3

–

-

Protein : -

interstisiil

→

relatif

sedikit

- plasma- intrasel

Ion Na & Cl

→ ekstraselIon K → intrasel

Fluid Compartments

Extracellular

and Intracellular Fluids

•

Compartmental exchange is regulated by osmotic and hydrostatic pressures

•

Ion fluxes are restricted and move selectively by active transport

•

Nutrients, respiratory gases, and wastes move unidirectionally

•

Plasma is the only fluid that circulates throughout the body and links external and internal environments

•

Osmolalities

of all body fluids are equal; changes in solute concentrations are quickly followed by osmotic changes

Continuous Mixing of Body Fluids

Cara menetapkan

volume cairan

tubuh

→ cara

tidak

langsung dengan

prinsip

pengenceran

-

Plasma darah

→ penyuntikan

zat

warna

→-

evans

blue (berikatan

dengan

protein plasma

-

albumin serum berlabel

yodium

radioaktif-

Cairan

ekstrasel

→ inulin

radioaktif, dsb

-

Cairan

interstisiil

→ volume ekstrasel

–

volume plasma-

Cairan

intrasel

→ Total Body Water –

cairan

ekstrasel

-

Total Body Water → D2

O (heavy water)

-

Walter Cannon → homeostasisusaha

mempertahankan

kondisi

statis

(konstan) di

dalam

internal

environment-

Claude Bernard → Fixity of milieu interieur

-

paru

mengambil

O2

yang baru

yang diperlukan

sel-

ginjal

mempertahankan

kadar

elektrolit

pada

batas

normal

-

alat

pencernaan

mengatur

absorpsi

makanan, dsb

Water Turnover→ keseimbangan

antara

water intake dan

water loss

External Fluid Exchange-

Water intake : minummakananoksidasi

jaringan-

Water loss :

-

Ginjal

→ urine-

Kulit

→ insensible perspiration- Keringat-

Paru

(udara

pernafasan

jenuh

dengan

uap

air)- Feses

Internal Fluid Exchange→ pertukaran

cairan

antara

berbagai

kompartemen

cairan

tubuh-

Sekresi

liur

pencernaan

& reabsorpsinya-

Filtrasi

di

kapiler

tubuh

& reabsorpsinya-

Filtrasi

di

kapiler

glomerulus

ginjal

+ reabsorpsinya-

Pembentukan

& absorpsi

cairan

otak

(CSF)

Water Balance and ECF Osmolality

•

Water intake sources–

Ingested fluid (60%) and solid food (30%)

–

Metabolic water or water of oxidation (10%)•

Water output–

Urine (60%) and feces (4%)

–

Insensible losses (28%), sweat (8%)•

Increases in plasma osmolality

trigger thirst

and release of antidiuretic

hormone (ADH)

GINJALTergantung

:

•

Glomerular

Filtration Rate (GFR)•

Reabsorpsi

Tubulus

•

99%

di

reabsorpsi

200 liter water + 30.000 mmol

Na+

2 liter water + 100 mmol

Na+

SALURAN CERNA

Tergantung

Sekresi:•

Saliva

•

Gaster•

Empedu

•

Pankreas•

Usus

10 liter water + 1.500 mmol

Na+

100 ml water + 15 mmol

Na+

KERINGAT DAN PERNAPASAN

Keringat

tergantung

suhu

tubuh

Pernapasan

tergantung

kecepatan

bernapas

900 ml water + 30 mmol

Na+

•

Osmoconformers–

Organisms whose internal and external environments have similar solute concentrations

–

Most marine invertebrates•

Osmoregulators–

Organisms who actively regulate their water loss or gain

–

Freshwater animals, most marine vertebrates–

All land animals

Fungsi

Cairan

Tubuh

:

-

Struktur

& Fungsi

organ / jaringan-

Transportasi

: mengedarkan

makanan, oksigen, elektrolit, hormon.-

Eksresi

: pembuangan

produk

sisa

hasil

metabolisme-

Regulasi

: pengaturan

suhu

tubuh-

Lubrikasi

: Pelumas

sendi

dan

membran-

Medium : sebagai

medium pencernaan

makanan

(reaksi

kimia

sel)

-

Tanpa

makan

→ dapat

hidup

beberapa

mingguTanpa

minum

→ beberapa

hari-

Kehilangan

air tubuh

(dehidrasi) :10 % →

berbahaya20 –

22 % →

kematian

Faktor-faktor

yang Mempengaruhi

Gerakan

Air dan

Zat

TerlarutZat

yang terlarut

di

dalam

cairan

tubuhion K, Na, Ca, Cl, HCO3

-

,PO4

protein,asam

organik

dsb→ tidak

statis→ selalu

ada

pertukaran

antara

ruang

yang satu

dengan

yang lain → dinamis

Membran→ membran

permeabel

selektifMembantu

mempertahankan

komposisi

unik

dari

setiap

kompartemen, sementara

memungkinkan

gerakan

nutrien

dari

plasma ke

sel

dan

gerakan

produk

sisa

ke

luar

dari

sel

dan

akhirnya

ke

dalam

plasma.

Meliputi

: 1. Membran

sel

; memisahkan

CIS dari

CIT (cairan

interstisial), terdiri

atas

lipid dan

protein2. Membran

kapiler

; memisahkan

CIV dari

CIT3. Membran

epitelial

; memisahkan

CIV dan

CIT dari

CTS (cairan

transelular). Contoh

: epitel

mukosa

lambung, membran

sinovial, tubulus

ginjal.

Membran

sel

→ hanya

dapat

dilewati

air

Membran

kapiler

→ pori

> dari

pori

membran

sel

→ semua bahan

ECF dapat

lewat, kecuali

protein plasma

selectively permeable (semipermeable)–

Allows some materials to pass.Water, oxygen, carbon dioxide

–

Prevents others from passing.Proteins, carbohydrates

•

Different cells may be permeable to different chemicals or substances.

Sherwood, Human Physiology, 6th

edition

•

Bilayer

→ Asimetris

→ karbohidrat

hanya

terdapat

di permukaan

luar

–

jenis

dan

jumlah

protein yang berbeda–

komposisi

lemak

sedikit

berbeda

Fungsi

Lipid Bilayer

:1. Membentuk

struktur

dasar

membran

("pagar" di

sekeliling

sel)

2. Bagian

dalamnya

yang hidrofobik

berfungsi

sebagai

sawar untuk

lewatnya

zat-zat

larut

air antara

CIS dan

CES. (Tetapi

molekul

air cukup

kecil

untuk

lewat)3. Menentukan

sifat

cair

(fluiditas) membran

Fungsi

Protein Membran

:1. Sebagian

protein yang terentang

di

dalam

membran

membentuk

jalur

atau

saluran

berisi

air yang menembus

lapid

lapis-ganda, memungkinkan

transport zat

larut

air yang cukup

kecil

(diameter

≤

0,8 nm). Bersifat

selektif

(diyakini

karena

susunan

spesifik gugus-gugus

asam

amino bermuatan

di

permukaan

interior

protein yang membentuk

dinding

saluran.2. Protein lain berfungsi

sebagai

carier molecule yang bersifat

selektif3. Banyak

protein di

permukaan

luar

berfungsi

sebagai

receptor site

4. Berfungsi

sebagai

enzim

yang terikat

ke

membran

yang mengontrol

reaksi-reaksi

kimia

tertentu

di

permukaan

dalam

atau

luar

sel.5. Sebagian

protein tersusun

dalam

suatu

jalinan

filamentosa

di

permukaan

bagian

dalam

mmbran

dan

dihubungkan

dengan unsur-unsur

protein tertentu

pada

sitoskeleton.

6. Sebagai

cell adhesion molecule (CAM), digunakan

oleh

sel

untuk saling

berpegangan

dan

untuk

melekat

ke

serat

jaringan

ikat

7. Protein khususnya

bersama

dengan

karbohidrat, penting

untuk kemampuan

sel

mengenali

"diri" (self, yaitu

sel

dari

jenis

yang

sama) dan

dalam

interaksi

sel

ke

sel

•

Fungsi

Karbohidrat

Membran

: belum

jelas

EXPRESSING

FLUID COMPOSITION

Gram Molecular

Weight

(GMW).

•

Mole

(mol) (6.02x1023

molecules).

•

Atomic

weight

in grams•

Molecules: sum

atomic

weight

individual

atoms.

Physiological

Molecular

WeightsATOMIC

SUBSTANCEGram Molecular Weight (g/mol)

MOLECULE Gram MolecularWeight (g/mol)

Sodium (Na) 22.99 Bicarbonate ( HCO3- ) 61.02

Potassium (K) 39.10 Phosphate, monobasic ( H2PO4- ) 96.99

Calcium (Ca ) 40.08 Phosphate, dibasic (HPO42- ) 95.98

Magnesium (Mg) 24.31 Phosphate (PO43- ) 94.97

Chlorine (Cl) 35.45 Ammonia ( NH3) 17.03

Phosphorous (P) 30.97 Ammonium ( NH4+ ) 18.04

Carbon (C) 12.01 Glucose ( C6 H12O6 ) 180.16

Hydrogen (H) 1.008 Urea ( H2NCONH2) 60.06

Oxygen (O) 16.00 B.U.N. ( N2 ) 28.02

Nitrogen (N) 14.01

Expressing

Fluid

Composition

•

Percentage•

Molality

•

Molarity•

Equivalence

Percent

Concentrations: (Solute

/ Solvent) x 100

•

Body solvent

is H2

O–

1 ml weighs

1 g.

•

(weight/volume) percentages

(w/v). •

(weight/weight) percentages

(w/w).

•

Clinical

chemistries: mg

% or

mg

/ dl.

Osmolalitasthe concentration of osmotically

active particles in solution

expressed in terms of osmoles

of solutes per kilogram of solvent.→ pengukuran

kemampuan

larutan

untuk

menciptakan

tekanan

osmotik

dan

dengan

demikian

mempengaruhi

gerakan

air.

Satuan

: miliosmol

(satu

per seribu

osmol) per kilogram air (mOsm/kg)1 osmol

mengandung

6 x 10 23

partikel.

Osmolaritas

→ istilah

lain yang digunakan

untuk

menggambarkan konsentrasi

larutan.

→ menunjukkan

jumlah

partikel

dalam

satu

liter larutanSatuan

: miliosmol

per liter (mOsm/L)

Osmolarity

of a solution is number of moles of “active”

solutes per liter of solvent

•

A 1 molar solution of glucose equals 1 osmolar•

A 1 molar solution of NaCl

is 2 osmolar

–

NaCl

Na+

+ Cl-

•

Symbol

“M”

means

moles/liter

not

moles.•

Physiological

concentrations

are

low.

•

millimolar

(mM) = 10-3

M•

micromolar

(M) = 10-6

M•

nanomolar

(nM) = 10-9 M

•

picomolar

(pM) = 10-12 M11

Electrochemical

Equivalence

(Eq).

•

Equivalent

--

weight

of an ionic substance

in grams

that

replaces

or

combines

with

one

gram (mole) of monovalent

H+

ions.

•

Physiological

Concentration: milliequivalent.

Electrochemical

Equivalence (Eq).

•

Monovalent

Ions

(Na+, K+, Cl-):–

One

equivalent

is equal

to

one

GMW.

–

1 milliequivalent

= 1 millimole•

Divalent

Ions

(Ca++, Mg++, and

HPO4

2-) –

One

equivalent

is equal

to

one-half

a GMW.

–

1 milliequivalent

= 0.5 millimole

Complications

in Determining Plasma

Concentrations.

•

Incomplete

dissociation

(e.g. NaCl).•

Protein binding

(e.g. Ca++)

•

Plasma

volume

is only

93% water.–

The

other

7% is protein and

lipid.

•

Hyperlipidemia•

Hyperproteinemia.

Tekanan

hidrostatik

: tekanan

yang dibuat

oleh

berat

cairanTekanan

osmotik

: tekanan

yang dibutuhkan

untuk

menghentikan

osmosis melalui

membran

semi permeabel.

Tekanan

osmotik

dipengaruhi

:-

kadar

zat

yang tidak

berdifusi

-

Ukuran

relatif

zat-

Ukuran

pori

Tekanan

onkotik

: tekanan

osmotik

yang terjadi

karena

adanya

zat koloid

dan

atau

zat

kristaloid

dalam

suatu

larutan.

(plasma → protein ; albumin)

Tonisitas

(Tonicity)→ the effective osmotic pressure equivalent→ osmolalitas

efektif

Tekanan

osmotik

(mmHg) : 19,3 x osmolaritas

(miliosmol

/ liter)

Tekanan

osmotik

total pada

suhu

37 °C :-

plasma darah

: 5453 mmHg

-

interstisial

: 5430 mmHg-

intrasel

: 5430 mmHg

Membran

antara

kedua

kompartemen

cairan

tubuh, intrasel

dan ekstrasel

adalah

semipermeabel

Proses

Transport1.

Pasif

: tidak

memerlukan

energi

2.

Aktif

: memerlukan

energi

1. Diffusion2. Osmosis3. Facilitated Diffusion4. Gated Channels5. Active Transport6. Endocytosis7. Exocytosis

Aktif

Pasif

TRANSPORT PASIFDifusi

: Gerakan

spontan

dan

acak

dari

partikel

pada

semua

arah

melalui

larutan

atau

gas.Bergerak

dari

konsentrasi

tinggi

ke

rendah

(adanya

gradien

konsentrasi)karena

random thermal motion, juga

dapat

terjadi

karena

perubahan

potensial

listrik

yang melalui

membran. Tidak membutuhkan

energi.

Partikel

cukup

kecil

dan

larut

lemak

→ tidak

tergantung substansi

pembawa

→ difusi

sederhana.

Difusi

menuruni

Gradien

Konsentrasi

(kimia)•

di

atas

suhu

nol

mutlak

semua

molekul

selalu

begerak

acak

akibat

energi

termal

(Brownian Motion)


edition


edition

Faktor-faktor

yang meningkatkan

difusi

:-

peningkatan

suhu

-

Peningkatan

konsentrasi

partikel-

Penurunan

ukuran

atau

berat

molekul

dari

partikel

-

Peningkatan

area permukaan

yang tersedia

untuk

difusi-

Penurunan

jarak

lintas

di

mana

massa

partikel

harus

berdifusi

→ faktor-faktor

yang berlawanan

akan

menurunkan

difusi

Sherwood, Fisiologi Manusia, edisi

2

Gerakan

sepanjang

Gradien

Listrik


2

Filtrasi

: Gerakan

air dan

zat

terlarut

dari

area dengan

tekanan hidrostatik

tinggi

ke

area dengan

tekanan

hidrostatik

rendah.

Osmosis

: Gerakan

air (HANYA AIR) melewati

membran semipermeabel

dari

area dengan

konsentrasi

zat

terlarut

rendah

ke

area dengan

konsentrasi

zat

terlarut

lebih

tinggi

Pertukaran

cairan

melalui

membran

sel

dengan

cara

osmosis → sangat

cepat

Sedikit

perbedaan

tekanan

osmotik

intrasel

& ekstrasel

→ segera dikoreksi

→ kembali

seimbang

Osmosis•

Difusi

netto

air menuruni

gradien

konsentrasinya

dari

daerah

dengan

konsentrasi

air tinggi

(konsentrasi

zat

terlarut

rendah) ke daerah

dengan

konsentrasi

air rendah

(konsentrasi

zat

terlarut

tinggi)


edition


edition

Sel

dalam

cairan

→-

Isotonik

→ tidak

berubah

co. larutan

NaCl

0,9 %, Glukosa

5%- Hipertonik → crenation

(keriput)

co. larutan

NaCl

3 %, Manitol-

Hipotonik

→ membengkak

co. larutan

garam

(NaCl) 0,45 % (< 0,9%)

ELECTROLYTE BALANCE•

Potassium is the chief intracellular cation

and sodium the chief extracellular cation•

Because the osmotic pressure of the interstitial space and the ICF are generally equal, water typically does not enter or leave the cell

KK++NaNa++


A change in the concentration of either electrolyte will cause water to move into or out of the cell via osmosis

•

A drop in potassium will cause fluid to leave the cell

whilst a drop in sodium will

cause fluid to enter the cell

KK++

H2 OH2 O

H2 O H2 O

H2 OH2 O

H2 O H2 O

KK++

KK++

KK++NaNa++

NaNa++

NaNa++

NaNa++

Click to see animation


A change in the concentration of either electrolyte will cause water to move into or out of the cell via osmosis

•

A drop in potassium will cause fluid to leave the cell whilst a drop in sodium will cause fluid to enter the cell

KK++

H2 OH2 O

H2 O H2 O

H2 OH2 O

H2 O H2 O

KK++

KK++

KK++NaNa++

NaNa++NaNa++

NaNa++

Click to see animation

•

Difusi

terfasilitasi

→ tergantung

substansi

pembawa

(protein carrier) → sesuai

dengan

penurunan

gradien

konsentrasi, tidak

memerlukan

energi


2

-A molecule binds to the carrier protein, which then changes shape

-

this shape shields the molecule from the lipid bilayer & is transported through

-

on the other side, the molecule is released, & protein returns to original shape

Ion Channels-

small passage ways thru membranes that transport ions

from higher conc. to lower conc.

- ions aren’t soluble in lipids, so they need a channel

- each ion uses a specific channel

- some are always open, some are gated

Gated Channels-

Open in response to different stimuli in environment

1.Stretching of cell membrane

2.Electrical signals (Voltage Gated channels): respond to differences in charges across the membrane

3.Chemicals (Chemically Gated channels): open briefly to allow certain ions to pass through

Transport Aktif

: Perpindahan

zat

terlarut

menembus

membran

sel pada

keadaan

tidak

terdapatnya

perubahan

potensial

listrik

yang mempermudah

atau

gradien

konsentrasi

→ membutuhkan

energi.

Melawan

gradien

konsentrasiMenggunakan

protein carrier & vesikel

-

transportasi

aktif

→

melawan

gradien

konsentrasi

→ memerlukan

energi

→

pompa

(contoh

pompa

Na+

- K+

ATP-ase)


2

•

sebuah

sel

saraf

mengandung

sekitar

satu

juta

pompa

Na+

- K+

yang mampu

memindahkan

sekitar

200 juta

ion/detik

Peran

Pompa

Na+

- K+

:1.

Menimbulkan

gradien

konsentrasi

Na+

dan

K+

di

kedua

sisi membran

plasma semua

sel; gradien

ini

sangat

penting

dalam

kemampuan

sel-sel

saraf

dan

otot

menghasilkan

impuls

saraf

yang penting

bagi

fungsi

sel-sel

tersebut

2. Membantu

mengatur

volume sel

dengan

mengontrol

konsentrasi

zat terlarut

di

dalam

sel

sehingga

memperkecil

efek-efek

osmotik

yang

akan

menyebabkan

pembengkakan

atau

pengerutan

sel.

3. Energi

yang digunakan

untuk

menjalankan

pompa

Na+

- K+

juga secara

tidak

langsung

berfungsi

sebagai

sumber

energi

untuk

kotransportasi

glukosa

dan

asam

amino menembus

sel-sel

ginjal dan

usus

(Na+

coupled co-transport carrier)

Animals need high conc. of Na+ inside & high conc. of K+ outside

cells


2

How Does the Na+- K+ Pump Work?

1.

3 Na+

ions bind to carrier protein on cytosol

side of memb.; a phospate

group is removed from ATP simultaneously.

2.

Phosphate group binds to carrier protein; protein changes shape.

3.

Na+

ions are forced outside cell by new shape.

4.

New shape allows 2 K+

ions bind to protein; phosphate group is released.

5.

Protein goes back to original shape, which forces K+

ions inside the cell.

- 3 Na+

ions are forced out while 2 K+

ions are forced out.

•

Transportasi

aktif

primer→ energi

diperlukan

secara

langsung

untuk

memindahkan

suatu

zat

melawan

gradien

konsentrasinya

•

Tranportasi

aktif

sekunder→

energi

diperlukan

dalam

keseluruhan

proses, tetapi

secara

tidak

langsung

dibutuhkan

untuk

menjalankan

pompa. Digunakan energi

"bekas pakai" yang disimpan

dalam

bentuk

gradien

konsentrasi

ion (contoh, gradien

Na+) untuk

memindahkan molekul

kotransportasi

melawan

gradien

konsentrasi.


2

Perbandingan

antara transpor

pasif

dan

transpor

aktif

Pada

transpor

pasif, suatu

substansi

secara

spontan

berdifusi

menuruni

gradien

konsentrasinya

tanpa

memerlukan

pengeluaran

energi

oleh

sel. Molekul

hidrofobik

dan

molekul

polar tak

bermuatan

yang berukuran

kecil

berdifusi

langsung

melintasi

membran. Substansi

hidrofilik

berdifusi

melalui

protein transpor

dalam

suatu

proses

yang disebut

difusi

yang dipermudah. Dalam

transpor

aktif, suatu

protein transpor

memindahkan

substansi

melintasi

membran

“naik

bukit”

melawan

gradien

konsentrasinya. Transpor

aktif

membutuhkan

pengeluaran

energi, yang biasanya

disediakan

oleh

ATP. Campbell & Reece, Biologi, Edisi

kelima

jilid

satu

•

transport vesikuler→ dibungkus

dalam

vesikel

bermembran

→ endositosis

(ke

dalam

sel) dan

eksositosis

(ke

luar

sel)

Endositosis

:

-

pinositosis-

fagositosis

•

zat

yang dimasukkan

endositosis

adalah

cairan

→ pinositosis

(sel minum)

•

zat

yang dimasukkan

endositosis

adalah

partikel

multimolekul besar, misalnya

sisa

sel

atau

bakteri

→ fagositosis

(sel

makan)

Net Osmotic

Force

Development

•

Semipermeable

membrane.•

Movement

some

solute

obstructed.

•

H2

O (solvent) crosses

freely.•

End

point:

–

Water

moves

until

solute

concentration

on both sides

of the

membrane

is equal.

–

OR, an opposing

force

prevents

further movement.

The Microcirculation

•

Important in the transport of nutrients to tissues.•

Site of waste product removal.

•

Over 10 billion capillaries with surface area of 500- 700 square meters perform function of solute and

fluid exchange.

Structure of Capillary Wall•

Composed of unicellular layer of endothelial cells surrounded by

a

basement membrane.

•

Diameter of capillaries is 4 to 9 microns.

•

Solute and water move across capillary wall via intercellular cleft (space between cells) or by plasmalemma vesicles.

Solute and Fluid Exchange Across Capillaries• Most important means by

which substances are transferred between plasma and interstitial fluid is by diffusion.

•

Lipid soluble substances diffuse directly through cell membrane of capillaries (CO2

, O2

).

•

Lipid insoluble substances such as H2

O, Na, Cl, glucose cross capillary walls via intercellular clefts and transcellular pathway.

•

Concentration differences across capillary enhance diffusion.

Effect of Molecular Size on Passage Through Capillary Pores

• The width of capillary intercellular slit pores is 6 to 7 nanometers.

•

The permeability of the capillary pores for different substances varies according to their molecular diameters.

Figure 16-2

The capillaries in different tissues have extreme differences in their permeabilities.

Tekanan filtrasi→ tekanan hidrostatik dalam kapiler –

tekanan hidrostatik cairan jaringan

Tekanan filtrasi dilawan oleh tekanan osmotik koloid

Normal :-

Tekanan hidrostatik jaringan : ±

1 –

2 mmHg

-

Tekanan osmotik koloid : ±

25 mmHg→ ujung arteriola kapiler → tekanan filtrasi > tekanan osmotik koloid →

cairan mengalir ke ruang interstisiil

Donnan’s

Law•

The

product

of Diffusible

Ions

is the

same

on the

two

sides

of a membrane.

33 K+

33 Cl-67 K+

50 Pr -17 Cl-Step 2

66 Osmoles 134 Osmoles

50 K+ 50 K+

50 Cl- 50 Pr -Initial

100 Osmoles 100 Osmoles

Final

33 ml 67 ml

33 K+

33 Cl-67 K+

50 Pr -17 Cl-

Total Volume100 ml

IonsMove

H2 Omoves

Starling-Landis Equation

http://www.bris.ac.uk/Depts/Physiology/Staff/DOB/teaching/lecture1/

Determinants of Net Fluid Movement Across Capillaries

•

Filtration rate = net filtration pressure (NFP) times filtration coefficient

•

Filtration coefficient (Kf) = surface area times hydraulic conductivity of membrane

NFP = (Pc

– Pif

) –

(c

–

if

)

p should be c

Forces Causing Filtration at Arteriole End of Capillary

Forces tending to move fluid outward:Capillary pressure 30Negative interstitial free fluid pressure

3

Interstitial fluid colloid osmotic pressure

8TOTAL OUTWARD FORCE

41

Forces tending to move fluid inward:Plasma colloid osmotic pressure 28

TOTAL INWARD FORCE

28

Summation of forces:Outward

41

Inward

28NET OUTWARD FORCE

13

mmHg

Forces Causing Reabsorption

at Venous End of Capillary

Forces tending to move fluid inward:Plasma colloid osmotic pressure

28

TOTAL INWARD FORCE

28Forces tending to move fluid outward:

Capillary pressure

10Negative interstitial free fluid pressure

3

Interstitial fluid colloid osmotic pressure 8TOTAL OUTWARD FORCE

21

Summation of forces:Outward

21

Inward

28NET INWARD FORCE

7

mmHg

Net Starting Forces in Capillaries

Mean forces tending to move fluid outward:Mean Capillary pressure

17.3

Negative interstitial free fluid pressure

3.0Interstitial fluid colloid osmotic pressure

8.0

TOTAL OUTWARD FORCE

28.3

Mean force tending to move fluid inward:Plasma colloid osmotic pressure

28.0

TOTAL INWARD FORCE

28.0

Summation of mean forces:Outward

28.3

Inward

28.0NET OUTWARD FORCE

0.3

mmHg

Net Starting Forces in Capillaries

Net filtration pressure of 0.3 mmHg which causes net filtration rate of 2ml/min for entire body.

Pusat

Haus

-

daerah

sepanjang

dinding

anteroventral

dari

ventrikel

ketiga

(juga

meningkatkan

pelepasan

ADH)-

Anterolateral

nukleus

preoptik

hipotalamus→ osmoreseptor

Peningkatan

rasa haus Penurunan

rasa haus

↑

Osmolalitas↓

Volume darah↓

Tekanan

darah↑

Angiotensin

II

Kekeringan

mulut

↓

Osmolalitas↑

Volume darah↑

Tekanan

darah↓

Angiotensin

II

Distensi

lambung

↑

osmolalitas CES →

dehidrasi intraselular pusat haus → rasa haus

↓

CES & tekanan darah → mungkin terjadi akibat input neural dari baroreseptor kardiopulmonar & baroreseptor arterial sistemik di dalam sirkulasi→ tidak tergantung pada jalur yang distimulasi oleh peningkatan osmolaritas plasma

Angiotensin II→ distimulasi oleh hipovolemia & tekanan darah rendah → rasa haus →

memulihkan volume darah dan tekanan darah kembali normal, bersama dengan kerjanya pada ginjal untuk menurunkan eksresi cairan.

Kekeringan pada mulut→ lega setelah minum walaupun belum diabsorpsi dari saluran cerna

Distensi lambung → penurunan rasa haus hanya berlangsung singkat

Regulation of Water Intake

•

The hypothalamic thirst center is stimulated:–

By a decline in plasma volume of 10%–15%

–

By increases in plasma osmolality

of 1–2%–

Via baroreceptor

input, angiotensin

II, and

other stimuli

Regulation of Water Intake

•

Thirst is quenched as soon as we begin to drink water

•

Feedback signals that inhibit the thirst centers include:–

Moistening of the mucosa of the mouth and throat

–

Activation of stomach and intestinal stretch receptors

Regulation of Water Intake:

Thirst Mechanism

thirst•

osmotic =concentration of 0.15M(molar)–

The area to detecting it is the OVLT (organum

vasculosum

laminae terminalis

=in 3rd

ventricle, not protected by BB barrier).

Osmotic Thirst

•

Loss of H2

O–

Perspiration, respiration, urination

•

consumption of salty or sugary food•

hypertonic extracellular

solution induces cellular dehydration

•

Osmoreceptors–

Respond to change in osmotic pressure

•

Osmotically-receptive neurons –

POA, anterior hypothalamus, supraoptic

nucleus, organum

vasculosum

of lamina terminalis

(OVLT) -

a circumventricular

organ

•

vasopressin acts to conserve water•

water consumption increases

•

reduced plasma osmolality

inhibits thirst and suppresses vasopressin release

Hypovolemic

Thirst

•

Low extracellular

volume•

by hemorrhage, excessive perspiration or menstrual bleeding–

reduced blood volume

•

hypovolemic=thirst based on low volume.–

a. baroreceptors

in blood vessels and the heart detect the

initial drop

in BP returning to heart.–

b. kidneys release renin--angiotensin

I then II--causes blood

vessels to constrict= raises BP.

•

water and salts are lost together •

water consumption induces body fluid dilution –

reduced blood osmolality

--

stop drinking?

•

requires salt to restore body fluid osmolality•

The brain activates responses such as thirst and salt hunger

Two Kinds of Thirst

Reduction in blood volume

Ambang

batas

stimulus osmolar

untuk

minum

the average osmotic threshold for thirst is approximately 295 mosmol/kg and varies among individuals.

konsentrasi

natrium

yang hanya

meningkat

sekitar

2 mEq/liter di

atas normal

Behavioral MechanismsDrinking water and eating salt is the only way the body obtains

these substances, therefore individuals who cannot do this must be assisted.

•

Drinking replaces fluid loss

–

when body osmolarity

raises above 280mOsM hypothalmic

osmoreceptors

trigger thrist.

Oropharynx

receptors are stimulated by cold drink and signal thirst quench

•

Low sodium stimulates salt appetite

–

the hypothalamus also has centers for salt appetite which trigger a response when osmolarity

is low.

•

Avoidance behaviors help prevent dehydration–

Desert animals avoid the heat

With decreased blood volume, the kidneys release the hormone renin, which reacts to form angiotensin

II.

Angiotensin

II conserves water by constricting blood vessels, increasing blood pressure,and

releasing vasopressin and

aldosterone.Angiotensin

II also affects behavior –

it acts in the brain to

trigger drinking.Circulating angiotensin

II acts in the circumventricular

organs

–

they send a signal to other brain sites.The subfornical

organ

is particularly sensitive to angiotensin

II.

Circumventricular

Organs

Regulation of ECF Volume

•

Mechanisms–

Neural

–

Renin-angiotensin- aldosterone

–

Atrial natriuretic hormone (ANH)

–

Antidiuretic hormone (ADH)

•

Increased ECF results in–

Decreased aldosterone secretion–

Increased ANH secretion–

Decreased ADH secretion–

Decreased sympathetic stimulation

•

Decreased ECF results in–

Increased aldosterone secretion–

Decreased ANH secretion–

Increased ADH secretion–

Increased sympathetic stimulation

Regulation of ECF Volume

Water Regulation -

Osmoregulation•

the regulation of water concentrations in the bloodstream, effectively controlling the amount of water available for cells to absorb.

Mechanism of Osmoregualtion•

Osmoreceptors

that are capable of detecting water

concentration are situated on the hypothalamus next to the circulatory system.

•

The hypothalamus sends chemical messages to the pituitary gland next to it.

•

The pituitary gland secretes anti-diuretic hormone (ADH), which targets the kidney that are responsible for maintaining water levels.

•

When the hormone reaches its target tissue, it alters the tubules of the kidney to become more / less permeable to water

•

If more water is required in the blood stream, high concentrations of ADH make the tubules more permeable.

•

If less water is required in the blood stream, low concentrations of ADH make the tubules less permeable.

Influence and Regulation of ADH

•

Water reabsorption

in collecting ducts is proportional to ADH release

•

Low ADH levels produce dilute urine and reduced volume of body fluids

•

High ADH levels produce concentrated urine•

Hypothalamic osmoreceptors

trigger or inhibit

ADH release•

Factors that specifically trigger ADH release include prolonged fever; excessive sweating, vomiting, or diarrhea (severe dehydration) ;

drop in

blood pressure ; severe blood loss; and traumatic burns

Mechanisms and

Consequences of ADH Release

Renin-Angiotensin System

vasokontriksi

→ meningkatkan

tekanan

darah

•

The renin-angiotensin

mechanism triggers the release of aldosterone

•

This is mediated by the juxtaglomerular apparatus, which releases renin

in response to:

–

Sympathetic nervous system stimulation–

Decreased filtrate osmolality

–

Decreased stretch (due to decreased blood pressure)

RENAL BLOOD FLOWRBF

Sekresi

RENIN

Renin-Angiotensin System

Aldosteron

dan

Tekanan

Darah

Regulation of Sodium Balance: Aldosterone

HOMEOSTASIS AIR DAN ELEKTROLITHOMEOSTASIS AIR DAN ELEKTROLIT

ADH ADH HH22 OO

AA RBFRBF

HipotalamusHipotalamus ReninRenin

BB AngiotensinAngiotensin

OsmolalitasOsmolalitas ALDOSTERONALDOSTERON

Cardiovascular System Baroreceptors

•

Baroreceptors

alert the brain of increases in blood volume (hence increased blood pressure) –

Sympathetic nervous system impulses to the kidneys decline

–

Afferent arterioles dilate–

Glomerular

filtration rate rises

–

Sodium and water output increase

Cardiovascular System Baroreceptors

•

This phenomenon, called pressure diuresis, decreases blood pressure

•

Drops in systemic blood pressure lead to opposite actions and systemic blood pressure increases

•

Since sodium ion concentration determines fluid volume, baroreceptors

can be viewed

as “sodium receptors”

Maintenance of Blood Pressure Homeostasis

Atrial

Natriuretic

Peptide (ANP)

•

Reduces blood pressure and blood volume by inhibiting:–

Events that promote vasoconstriction

–

Na+

and water retention

•

Is released in the heart atria as a response to stretch (elevated blood pressure)

•

Has potent diuretic and natriuretic

effects•

Promotes excretion of sodium and water

•

Inhibits angiotensin

II production

Mechanisms and Consequences of ANP Release

•

Estrogens:–

Enhance NaCl

reabsorption

by renal tubules

–

May cause water retention during menstrual cycles–

Are responsible for edema during pregnancy

•

Progesterone:–

Decreases sodium reabsorption

–

Acts as a diuretic, promoting sodium and water loss•

Glucocorticoids

–

enhance reabsorption

of sodium

and promote edema

Influence of Other Hormones on Sodium Balance

A More Complete View of Fluid Regulation (I)

A More Complete View of Fluid Regulation (II)

Adaptation to specialized Adaptation to specialized environmentsenvironments

Rats (sodium chloride)Rats (sodium chloride)

Hamsters (saccharin)Hamsters (saccharin)

Kangaroo rats (efficiency in Kangaroo rats (efficiency in retaining water)retaining water)

Camels (pouch and metabolized Camels (pouch and metabolized water)water)

Electrolyte

(Na+, K+, Ca++) Steady

State.•

Molecules or ions with an electrical charge

•

Electrolytes are salts, acids, and bases, but electrolyte balance usually refers only to salt balance

•

Amount

Ingested

= Amount

Excreted.•

Normal entry: Mainly

ingestion

in food.

•

Clinical

entry: Can include

parenteral

administration.•

Lost via perspiration, feces, and urine, Abnormal routes: e.g.. vomit and diarrhea

•

Concentration changes only when growing, gaining or losing weight

•

Salts are important for:–

Neuromuscular excitability

–

Secretory

activity–

Membrane permeability

–

Controlling fluid movements

Natrium

/ Sodium•

Na+

Ions -

136-142 mEq/liter–

Dominant ECF cations

–

Responsible for 90-95% of osmotic pressure–

Contribute 280 mOsm

of the total 300 mOsm

ECF solute concentration

•

Average daily intake exceeds normal requirements•

Regulation of Na+

ions–

Kidneys major route of excretion

–

65% of sodium in filtrate is reabsorbed in the proximal tubules,

25% is reclaimed in the loops of Henle

–

Small quantities lost in sweat•

Hormonal controls–

aldosterone

causes increased reabsorption

Na+

–

ADH release ceases if Na+ levels too low--dilute urine lost until Na+ levels rise

–

ANP increases Na+ and water excretion if Na+ levels too high•

Terms–

Hypernatremia

–

Hyponatremia

SODIUM PRINCIPLES•

1) Sodium ions do not cross cell membranes as quickly as water does

Na+

H2 O

H2 O H2 O

H2 O

H2 O

Na+


2) Cells pump sodium ions out of the cell by using sodium-potassium pumps

Na+

Na+

Na+

Na+


3) Increases in extracellular sodium ion levels do not change intracellular sodium ion concentration

Na+Na+

Na+Na+

Na+Na+

Na+

Na+

Na+

Na+

Na+

Na+Na+

Na+

Na+

Na+

Na+

Na+

Na+

Na+

HYPERNATREMIA•

Normal range for blood levels of sodium is app. 137 -

143 meq/liter

••

HypernatremiaHypernatremia

refers to an elevated serum sodium level (145 -150 meq/liter)

•

Increased levels of sodium ions are the result of diffusion and osmosis

Na+

RESULTS OF HYPERNATREMIA

•

1) Water is osmotically drawn out of the cells

–

Resulting in dehydration

•

2) Increase in extracellular fluid volume

Extracellular fluid

volume

Intracellular fluid

volume

GANGGUAN NATRIUMHIPONATREMIA

Hipo-osmolalitas OVERHIDRASI SEL

Sakit

kepalaGelisahKejang

HIPERNATREMIA

Hiper-osmolalitas DEHIDRASI SEL

HausGelisahcoma

Etiologi

: Hiperglikemia

Magnesium•

Found in bone matrix and as ions in body fluids–

intracellular cofactor for metabolic enzymes, heart, muscle & nerve function

•

1.3-2.1 mEq/liter in plasma•

Capacity of kidney to reabsorb is limited

•

Excess lost in urine•

Decreased extracellular

magnesium results in greater degree

of reabsorption•

Urinary excretion increased in hypercalcemia, hypermagnesemia, increased extracellular

fluid volume,

decreases in parathyroid hormone and acidosis

•

Potassium ionsintracellular 120-125 mEq/literplasma 3.5-5.0 mEq/liter–

Maintained in narrow range

–

Affect resting membrane potentials–

Excessive ECF potassium decreases membrane potential

–

Too little K+

causes hyperpolarization

and nonresponsiveness

–

Aldosterone distal nephron

P cells increases amount secreted

•

Terms–

Hyperkalemia

–

Hypokalemia

Regulation of Potassium (K+) Balance

•

Hipokalemia

gradien

konsentrasi

sel

dan

CES ↑

K+

> banyak

keluar

sel

potensial

membran

istirahat

> -

hiperpolarisasi eg. Muscle weakness•

Hiperkalemia

gradien

konsentrasi

↓

K+

> banyak

di dalam

sel

potensial

membran

istirahat

> + depolarisasi

eg. Cardiac arrhythmias

Gangguan

:-

Kehilangan

K+

pada

diare-

Koreksi

diare

yang tidak

tepat

defisiensi

relatif

Na+

& K+

-

Penyakit

ginjal-

Diuretik

yang tidak

hemat

kalium


•

Hyperkalemia

and hypokalemia

can:–

Disrupt electrical conduction in the heart

–

Lead to sudden death•

Less than 15% of filtered K+

is lost to urine regardless of need

•

K+

balance is controlled in the cortical collecting ducts by changing the amount of potassium secreted into filtrate

•

Excessive K+

is excreted over basal levels by cortical collecting ducts

•

When K+

levels are low, the amount of secretion and excretion is kept to a minimum

•

Type A intercalated cells can reabsorb some K+

left in the filtrate


Influence of Aldosterone

•

Aldosterone

stimulates potassium ion secretion by principal cells

•

In cortical collecting ducts, for each Na+

reabsorbed, a K+

is secreted •

Increased K+

in the ECF around the adrenal cortex causes:–

Release of aldosterone

–

Potassium secretion•

Potassium controls its own ECF concentration via feedback regulation of aldosterone

release

Regulation of Calcium•

Ionic calcium in ECF is important for:–

Blood clotting

–

Cell membrane permeability–

Secretory

behavior

•

Regulated within narrow range–

Elevated extracellular

levels prevent membrane

depolarization–

Decreased levels lead to spontaneous action potential generation

–

plasma 4.6-5.5 mEq/liter•

Hypocalcemia:–

Increases excitability

–

Causes muscle tetany

Regulation of Calcium

•

Hypercalcemia:–

Inhibits neurons and muscle cells

–

May cause heart arrhythmias

•

Calcium balance is controlled by parathyroid hormone (PTH) and calcitonin

•

PTH increases Ca2+

extracellular

levels and decreases extracellular

phosphate levels

•

Vitamin D stimulates Ca2+

uptake in intestines•

Calcitonin

decreases extracellular

Ca2+

levels

Regulation of Calcium and Phosphate

•

PTH promotes increase in calcium levels by targeting:–

Bones –

PTH activates osteoclasts

to break

down bone matrix–

Small intestine –

PTH enhances intestinal

absorption of calcium–

Kidneys –

PTH enhances calcium reabsorption

and decreases phosphate reabsorption•

Calcium reabsorption

and phosphate

excretion go hand in hand

Regulation of Calcium and Phosphate

•

Filtered phosphate is actively reabsorbed in the proximal tubules

•

In the absence of PTH, phosphate reabsorption

is regulated by its transport maximum and excesses are excreted in urine

•

High or normal ECF calcium levels inhibit PTH secretion–

Release of calcium from bone is inhibited

–

Larger amounts of calcium are lost in feces and urine–

More phosphate is retained

Influence of Calcitonin

•

Released in response to rising blood calcium levels

•

Calcitonin

is a PTH antagonist, but its contribution to calcium and phosphate homeostasis is minor to negligible

Phosphate•

Present as calcium phosphate in bones and teeth, and in phospholipids, ATP, DNA and RNA

•

plasma 1.7-2.6 mEq/liter•

HPO4

-2

is important intracellular anion and acts as buffer of H+ in body fluids and in urine–

mono and dihydrogen phosphate act as buffers in the blood

•

Plasma levels are regulated by parathyroid hormone & calcitriol–

resorption of bone releases phosphate

–

in the kidney, PTH increase phosphate excretion–

calcitriol increases GI absorption of phosphate

Regulation of Phosphate Ions

•

Under normal conditions, reabsorption of phosphate occurs at maximum rate in the nephron

•

An increase in plasma phosphate increases amount of phosphate in nephron beyond that which can be reabsorbed; excess is lost in urine

Regulation of Anions•

Chloride -

95-103 mEq/liter

•

Most prevalent extracellular anion•

Moves easily between compartments due to Cl-

leakage channels

•

Helps balance anions in different compartments•

Regulation–

passively follows Na+ so it is regulated indirectly by aldosterone levels–

ADH helps regulate Cl-

in body fluids because it controls water loss in urine•

99% of chloride is reabsorbed under normal pH conditions

•

Chloride shift & hydrochloric acid of gastric juice•

When acidosis occurs, fewer chloride ions are reabsorbed

•

Other anions have transport maximums and excesses are excreted in urine

Keseimbangan

Asam-BasaPengaturan

ketat

konsentrasi

ion hidrogen

[H+] bebas

Komponen

penting•

Kation, suatu

partikel

ion dengan

muatan

positif; dalam

medan

listrik

bergerak

ke

kutup

negatif

(katoda)•

Anion, suatu

partikel

ion dengan

muatan

negatif; dalam

medan

listrik

bergerak

ke

kutup

positif

(anoda)•

Asam

: Memberikan

H+

HCl

H+

+ Cl-

•

Basa

: Menerima

H+

OH-

+ H+

HOH

Tingkat disosiasi

suatu asam

selalu

konstan

konstanta

disosiasi

(K)

Chemical Buffer Systems

•

Strong acids –

all their H+

is dissociated

completely in water •

Weak acids –

dissociate partially in water

and are efficient at preventing pH changes•

Strong bases –

dissociate easily in water and

quickly tie up H+

•

Weak bases –

accept H+

more slowly (e.g.,

HCO3

¯

and NH3

)

[H+] di

CES 4 x 10-8

/ 0,00000004 ekuivalen

per liter35 –

45 nmol

/ L

pH pengukuran

kuantitatif

tingkat

keasaman

atau

suasana

alkali

suatu

larutan,

mengacu

pada

air murniSecara

matematika

pH = log 1 / [H+]pH = -log [H+]

- [H+] penyebut

berbanding

terbalik

dengan

pH-

Log perubahan

satu

satuan

pH = 10 x [H+]

•

Larutan

netral

mempunyai

pH 7; dalam

artian

konsentrasi

ion hydrogen adalah

10-7

molar atau

100 nanoequivalents/liter

pH <7 asam

pH >7 basa

pH darah

arteri

normal : 7,45pH darah

vena normal : 7,35

pH vena < arteri

o.k. adanya

H+

yang dihasilkan

oleh pembentukan

H2

CO3

dari

CO2

yang diserap

di

kapiler

jaringan

pH darah

< 7,35 asidosispH darah

> 7,45 alkalosis

pH darah

< 6,8 / > 8,0 †

Homeostasis pH pentingFluktuasi

[H+] mempunyai

dampak

pada

:

-

Eksitabilitas saraf dan ototasidosis

penekanan

eksitabilitas

↓

co., disorientasi,

komaalkalosis eksitabilitas

↑

co., kedutan

dan

spasme

otot,

sensasi

geli, gelisah, kejang-

Aktivitas enzimsebagian

rx

kimia

menjadi

lebih

cepat

sementara

yang lain

melambat-

Kadar K+

sel

tubulus

ginjal

reabsorpsi

Na+

& sekresi

H+

atau

K+

kecepatan

sekresi

K+

>< H+. Normal sekresi

K+

> H+

[H+] sebagian

besar

dihasilkan

aktivitas

metabolik, sebagian

kecil dari

makanan

1. Pembentukan

asam

karbonat

(H2

CO3

) sumber

utama

H+

oksidasi

nutrien

energi

+ H2

O + CO2

CO2

+ H2

O H2

CO3

H+

+ HCO3-

ca : enzim

carbohydrate anhidrase

di

kapiler

sistemik

hasil

metabolisme

CO2

↑

rx

ke

sisi asam

di

paru

CO2

kapiler

berdifusi

ke

alveolus dilepaskan

ke atmosfer

rx

ke

sisi

CO2

Normal sistem

pernafasan

mengimbangi

tingkat

metabolisme

ca

2. Asam

anorganik

co. sulfur dan

fosfor

dalam

protein makanan

diuraikan menjadi

asam

sulfat

dan

asam

fosfat

3. Asam

organik

yang dihasilkan

dari

metabolisme

perantara

co. otot

asam

laktatmetabolisme

lemak

asam

lemak

Pemasukan

H+

bersifat

terus

menerus, bervariasi

dan

pada dasarnya

tidak

diatur

Hydrogen Ion Regulation

• Concentration of hydrogen ions is regulated sequentially by:

1.

Chemical buffer systems –

act within seconds2.

The respiratory center in the brain stem –

acts

within 1-3 minutes3.

Renal mechanisms –

require hours to days to

effect pH changes

Sistem penyangga / buffer / dapar kimiawi Larutan buffer adalah larutan yang dapat memperkecil

penyimpangan pH pada penambahan suatu asam kuat atau basa kuat.

Buffer Campuran

dari:•

As. Lemah

& garamnya

dg basa

kuat, atau

• Basa

lemah

dan

garamnya

dg asam

kuat.

Sistem

Buffer•

Buffer BikarbonatCO2

(larut) + H2

O

H2

CO3

HCO3-

+ H+

• Buffer

non Bikarbonat

Hbuf

H+

+ Buf-

Penambahan

H / OH pada

Buffer

• Bila

mendapat

tambahan

H+

HCO3-

+ H+

H2

CO3

CO2

+ H2

O

H+

+ Buf-

Hbuf

•Bila

mendapat

tambahan

OH-

H2

CO3

+ OH-

H2

O + HCO3-

Hbuf + OH-

H2

O

+ Buf-

Buffers Change Strong Acids to Weak Acids

HCl

+ NaOHStrong Acid

BaseH2

CO3+ NaCl

Weak Acid Salt

Protein Buffer System

•

Plasma and intracellular proteins are the body’s most plentiful and powerful buffers

•

Some amino acids of proteins have:–

Free organic acid groups (weak acids)

–

Groups that act as weak bases (e.g., amino groups)•

Amphoteric

molecules are protein molecules that can

function as both a weak acid and a weak base

Phosphate Buffer System

•

Nearly identical to the bicarbonate system •

Its components are:–

Sodium salts of dihydrogen

phosphate (H2

PO4

¯), a weak acid

–

Monohydrogen

phosphate (HPO42¯), a weak base

•

This system is an effective buffer in urine and intracellular fluid

Na2

HPO4

+ H+

NaH2

PO4

+ Na+

Buffer utama

dalam

eritrosit

Grup

imidazol

terdpt

ion ferro

yg

mengikat

O2

peran

sebagai

buffer

Terdiri

dari

:

Sistem

oxyhemoglobin

(HbO2

)

Sistem

reduce hemoglobin (HHb)

Hemoglobin Buffer System

O2

paru

–

paru

vena HbO2

75% HbO2 95% arteri

Hb 25%

Hb

5%

jaringan

O2

H+

+ Hb

HHb

Sirkulasi vena

Sirkulasi arteriParu-Paru Jaringan

HCO3-HCO3

- HCO3-

H2 CO3H2 CO3

HHb HHbHHb

HbO2 HbO2HbO2

CO2CO2H2 O

H2 O

H+ H+

O2 O2

Cairan

interstitial

•Buffer Bikarbonat

Plasma

•

Sistem

Buffer Bikarbonat

•

Protein

•

Fosfat

anorganik

Eritrosit

•

Hemoglobin

•

Buffer Bikarbonat

• Fosfat organik

•

Fosfat

anorganik

Presentasi

Sistem

Buffer dalam

darah:

•Bikarbonat

plasma

35%

•Bikarbonat

Eritrosit

18%

•Hemoglobin

35%

•Protein plasma

7%

•Fosfat

organik

3%

•Fosfat

anorganik

2%

Secara

keseluruhan:

Sistem

Buffer Bikarbonat

Terbesar

(53%)

Dalam

plasma buffer terbesar

adalah

Sistem •

Buffer Bikarbonat

Dalam

Eritrosit

buffer terbesar

adalah •

Hemoglobin

Buffer secara

keseluruhan

”Buffer Base”

(BB)

Normal Buffer Base (NBB)

BB pada

keadaan

normal

( pH & HCO3-

) Normal

NBB dipengaruhi

kadar

Hb

!!!

Hb

20 g/dL

NBB = 50 mM/L

Hb

15 g/dL

= 48 mM/L

Hb

10 g/dL

= 46 mM/L

Hb

5 g/dL

= 44 mM/L

Base Excess (BE) BB yang dijumpai

–

NBB

Istilah

lain Delta base

BE dapat

memberi

nilai

0, + atau

–

nilai

normalnya

adalah

–3 sampai

+3

Secara

in vitro digunakan

untuk

menerangkan

gangguan

asam

basa

yang bersifat

metabolic, baik

berupa

metabolik

asidosis

atau metabolik

alkalosis.

BE <–3 mengindikasikan

defisiensi

basa

atau

kelebihan

asam; metabolik

asidosis

BE >+3 mengindikasikan

kelebihan

basa

atau

kekurangan

asam metabolik

alkalosis.

Kegunaan

BE di

klinik

untuk

pemberian

terapi, biasanya

terapi belum

diberikan

bila

kadar

belum

mencapai

–5 atau

+5

Henderson-Hasselbalch

equation

Konstanta

disosiasi

H2

CO3

:[H+] [HCO3

-] / [H2

CO3

] = K

pH = log 1 / [H+]

pH = pK

+ log [HCO3-] / [H2

CO3

]

H2

CO3

CO2

+ H2

O

pH = pK

+ log [HCO3-] / [CO2

]

pK

untuk

H2

CO3 = 6,1

Keadaan

normal rasio

[HCO3-] / [CO2

] dalam

CES 20:1

pH = 6,1 + log 20/1

= 6,1 + 1,3= 7,4

[HCO3-] yang dikontrol

fungsi

ginjal

[CO2

] yang dikontrol

fungsi

pernafasan

[CO2

] ≈

tekanan

parsial

CO2 (PCO2

)

pH =

Physiological Buffer Systems

•

The respiratory system regulation of acid- base balance is a physiological buffering

system•

There is a reversible equilibrium between:–

Dissolved carbon dioxide and water

–

Carbonic acid and the hydrogen and bicarbonate ions

CO2

+ H2

O H2

CO3

H+

+ HCO3

¯

Physiological Buffer Systems•

During carbon dioxide unloading, hydrogen ions are incorporated into water

•

When hypercapnia

or rising plasma H+

occurs:–

Deeper and more rapid breathing expels more carbon dioxide

–

Hydrogen ion concentration is reduced•

Alkalosis causes slower, more shallow breathing, causing H+

to increase

•

Respiratory system impairment causes acid-base imbalance (respiratory acidosis or respiratory alkalosis)

Renal Mechanisms of Acid-Base Balance•

Chemical buffers can tie up excess acids or bases, but they cannot eliminate them from the body

•

The lungs can eliminate carbonic acid by eliminating carbon dioxide

•

Only the kidneys can rid the body of metabolic acids (phosphoric, uric, and lactic acids and ketones) and prevent metabolic acidosis

•

The ultimate acid-base regulatory organs are the kidneys

Renal Mechanisms of Acid-Base Balance•

The most important renal mechanisms for regulating acid-base balance are:–

Conserving (reabsorbing) or generating new bicarbonate ions

–

Excreting bicarbonate ions

•

Losing a bicarbonate ion is the same as gaining a hydrogen ion; reabsorbing a bicarbonate ion is the same as losing a hydrogen ion

•

Hydrogen ion

secretion occurs in the PCT and in type A intercalated cells

•

Hydrogen ions come from the dissociation of carbonic acid

Reabsorption

of Bicarbonate•

Carbon dioxide combines with water in tubule cells, forming carbonic acid

•

Carbonic acid splits into hydrogen ions and bicarbonate ions

•

For each hydrogen ion secreted, a sodium ion and a bicarbonate ion are reabsorbed by the PCT cells

•

Secreted hydrogen ions form carbonic acid; thus, bicarbonate disappears from filtrate at the same rate that it enters the peritubular

capillary blood

Reabsorption

of Bicarbonate

•

Carbonic acid

formed in filtrate dissociates to release carbon dioxide and water

•

Carbon dioxide then diffuses into tubule cells, where it acts to trigger further hydrogen ion secretion

Generating New Bicarbonate Ions

•

Two mechanisms carried out by type A intercalated cells generate new bicarbonate ions

•

Both involve renal excretion of acid via secretion and excretion of hydrogen ions or ammonium ions (NH4

+)

Hydrogen Ion Excretion

•

Dietary hydrogen ions must be counteracted by generating new bicarbonate

•

The excreted hydrogen ions must bind to buffers in the urine (phosphate buffer system)

•

Intercalated cells actively secrete hydrogen ions into urine, which is buffered and excreted

•

Bicarbonate generated is:–

Moved into the interstitial space via a cotransport

system–

Passively moved into the peritubular

capillary blood

Hydrogen Ion Excretion

•

In response to acidosis:–

Kidneys generate bicarbonate ions and add them to the blood

–

An equal amount of hydrogen ions are added to the urine

Ammonium Ion Excretion

•

This method uses ammonium ions

produced by the metabolism of glutamine in PCT cells

•

Each glutamine metabolized produces two ammonium ions and two bicarbonate ions

•

Bicarbonate moves to the blood and ammonium ions are excreted in urine

Ammonium Ion Excretion

Bicarbonate Ion Secretion

•

When the body is in alkalosis, type B intercalated cells:–

Exhibit bicarbonate ion secretion

–

Reclaim hydrogen ions and acidify the blood•

The mechanism is the opposite of type A intercalated cells and the bicarbonate ion reabsorption

process

•

Even during alkalosis, the nephrons

and collecting ducts excrete fewer bicarbonate ions than they conserve

Gangguan keseimbangan asam-basa dibagi atas:

1. Asidosis Respiratorik

= Primary CO2 excess (kelebihan CO2 )

2. Asidosis Metabolik

= Primary HCO3- deficit (kekurangan CO3

-)

3. Alkalosis Respiratorik

= Primary CO2 deficit (kekurangan CO2 )

4. Alkalosis Metabolik

= Primary HCO3- excess (kelebihan CO3

-)

Respiratory Acidosis and Alkalosis

•

Result from failure of the respiratory system to balance pH

•

PCO2

is the single most important indicator of respiratory inadequacy

•

PCO2 levels–

Normal PCO2 fluctuates between 35 and 45 mm Hg

–

Values above 45 mm Hg signal respiratory acidosis

–

Values below 35 mm Hg indicate respiratory alkalosis

AcidosisAcidosisRespiratory acidosisRespiratory acidosis

due to alveolar hypoventilation due to alveolar hypoventilation

(accumulation of CO(accumulation of CO22

))

Possible causes: Respiratory depression, increased airway Possible causes: Respiratory depression, increased airway resistance (?), impaired gas exchange (emphysema, resistance (?), impaired gas exchange (emphysema, fibrosis, muscular dystrophy, pneumonia)fibrosis, muscular dystrophy, pneumonia)

Metabolic acidosisMetabolic acidosis

due to gain of fixed acid or loss of due to gain of fixed acid or loss of bicarbonate bicarbonate

Possible causes: lactic acidosis, Possible causes: lactic acidosis, ketoacidosisketoacidosis, diarrhea, diarrhea

Buffer capabilities exceeded once pH change appears in Buffer capabilities exceeded once pH change appears in plasma. plasma. Options for compensation?Options for compensation?

AlkalosisAlkalosisRespiratory alkalosisRespiratory alkalosis

due to alveolar hyperventilation due to alveolar hyperventilation

(excessive loss of CO(excessive loss of CO22

) ) Possible causes: Anxiety, excessive artificial ventilation, Possible causes: Anxiety, excessive artificial ventilation,

aspirin aspirin toxicosistoxicosis, fever, high altitude, fever, high altitude

Metabolic alkalosisMetabolic alkalosis

due to loss of Hdue to loss of H++

ions or shift of Hions or shift of H++

into into the intracellular space. Alkali administration. the intracellular space. Alkali administration.

Possible causes: Vomiting or Possible causes: Vomiting or nasogastricnasogastric

(NG) suction; (NG) suction; hypokalemiahypokalemia; antacid overdose; antacid overdose

Buffer capabilities exceeded once pH change appears in Buffer capabilities exceeded once pH change appears in plasma. plasma. Options for compensation?Options for compensation?

Respiratory and Renal Compensations

•

Acid-base imbalance due to inadequacy of a physiological buffer system is compensated for by the other system–

The respiratory system will attempt to correct metabolic acid-base imbalances

–

The kidneys will work to correct imbalances caused by respiratory disease

Respiratory Compensation

•

In metabolic acidosis:–

The rate and depth of breathing are elevated

–

Blood pH is below 7.35 and bicarbonate level is low

–

As carbon dioxide is eliminated by the respiratory system, PCO2

falls below normal•

In respiratory acidosis, the respiratory rate is often depressed and is the immediate cause of the acidosis

Respiratory Compensation

•

In metabolic alkalosis:–

Compensation exhibits slow, shallow breathing, allowing carbon dioxide to accumulate in the blood

•

Correction is revealed by:–

High pH (over 7.45) and elevated bicarbonate ion levels

–

Rising PCO2

Renal Compensation

•

To correct respiratory acid-base imbalance, renal mechanisms are stepped up

•

Acidosis has high PCO2

and high bicarbonate levels–

The high PCO2

is the cause of acidosis –

The high bicarbonate levels indicate the kidneys are retaining bicarbonate to offset the acidosis

•

Alkalosis has Low PCO2

and high pH–

The kidneys eliminate bicarbonate from the body by failing to reclaim it or by actively secreting it

Diagnosis of Acid-Base Imbalances

•

Evaluate –

systemic arterial blood pH

–

concentration of bicarbonate (too low or too high)–

PCO2 (too low or too high)

•

Solutions–

if problem is respiratory, the pCO2

will not be normal–

if problem is metabolic, the bicarbonate level will not be normal

Dehidrasi→ kehilangan

cairan

tubuhterjadi

pada

:

-

diare-

muntah

kronis-

evaporasi

melalui

kulit

pada

luka

bakar

luas-

pengeluaran

Na ginjal

↑ ↑

disertai

pengeluaran

air

-

Intake air kurang

→ volume ECF ↓

→ osmolalitas

ECF ↑ → ICF mengalir

ke

ECF sampai

tercapai

keseimbangan

osmotik

Volume ICF & ECF ↓ → dehidrasi

Dehidrasi

Isotonik-

Ada

kekurangan

keseimbangan

air dan

natrium

(dalam

proporsi

yang sama)-

Konsentrasi

natrium

serum normal (130 –

150 mmol/L)-

Osmolaritas

serum normal (275 –

295 mOsmol/L)-

Hypovolemia

terjadi

sebagai

hasil

kehilangan

banyak

cairan

ekstraselular

Dehidrasi

Hipertonik

(Hipernatremik)-

Terdapat

kekurangan

air dan

natrium, tetapi

proporsi

kekurangan

airnya

lebih

banyak-

Konsentrasi

natrium

serum meningkat

( >150 mmol/L)-

Osmolaritas

serum meningkat

( >295 mOsmol/L)-

Sangat

haus

yang lebih

berat

derajadnya

bila

dibandingkan

dengan

derajad

dehidrasinya-

Kejang

mungkin

bisa

terjadi

; terutama

bila

konsentrasi

natrium

lebih

dari

165 mmol/L-

Biasanya

akibat

dari

pemasukan

cairan

hipertonik

pada

saat

diare, atau

paparan

ke

lingkungan

panas

dengan

insensible water loss besar.

Dehidrasi

Hipotonik

(Hiponatremik)-

Adanya

kekurangan

air dan

natrium, tetapi

kekurangan

natriumnya

secara

relatif

lebih

banyak-

Konsentrasi

natrium

serum rendah

( < 130 mmol/L)

-

Osmolaritas

serum rendah

(275 mOsmol/L)-

Dapat

terjadi

pada

penderita

diare

yang minum

air dalam

jumlah

besar

atau

cairan

hipotonik

yang mengandung

konsentrasi

garam atau

bahan

terlarut

lain yang rendah

seperti

sari buah

, cola dan

the.

-

Terjadi

karena

air diabsorpsi

dari

usus

sementara

kehilangan

garam (NaCl) tetap

berlangsung

dan

menyebabkan

kekurangan

natrium

dan

kelebihan

air.

Prinsip

penanggulangan

dehidrasi

→ mengganti

volume cairan

yang hilang

(oral / parenteral)

< = 2,5 % → tidak

ada

dehidrasi

TBW ♀

< TBW ♂

(Total Body Water)→ sebab

lemak

♀

> ♂Ratio TBW → bervariasi

sesuai

jumlah

jaringan

lemakLean body Mass : berat

total jaringan

tanpa

lemak

TBW = ±

73,2 % LBM

Derajat

dehidrasi Jumlah

kehilangan

cairanRingan 2,5 –

5 % BBSedang 5 –

10 % BBBerat > 10 % BB

Ratio ECF (CES) / ICF (CIS) → lebih

besar

pada

bayi

dan

anak-anak

dibandingkan

dengan

dewasa

Absolut

ECF anak

< dewasa→ dehidrasi

lebih

cepat

terjadi

pada

bayi

dan

anak-anakDewasa

: 2/3 cairan

tubuh

adalah

CIS. Pada

bayi

hanya

setengahnya

Bayi

tidak

mampu

mengungkapkan

rasa haus

Susunan

garam

oralit

(yang dianjurkan

WHO)

NaCl

3,5 gramKCl

1,5 gramNaHCO3

2,5 gramGlukosa

20 gram→ larutkan

dalam

1000 cc air

Disorders of Water Balance: Dehydration

Excessive loss of H2 O from ECF

1 2 3ECF osmotic pressure rises

Cells lose H2 O to ECF by osmosis; cells shrink

(a) Mechanism of dehydration

Komposisi

Oralit

(dalam

mmol/L)Na

90

K 20HCO3

30Cl

80

Glukosa

111

Turgor

kulit

dapat

tampak

normal pada

bayi

obes

yang mengalami dehidrasi, karena

peningkatan

lemak

subkutan.

dan

dapat

tampak

abnormal pada

bayiyang

terhidrasi

adekuat namun

mengalami

malnutrisi.

Peka

rangsang

→ indikator

dini

hipovolemia.

Ubun-ubun

cekung

→ tanda

dehidrasi

tradisional

; timbul

pada dehidrasi

sedang

–

berat.

Orang

tua

→ penurunan

elastisitas

kulit

→ turgor

kulit

merupakan indikator

yang kurang

untuk

menentukan

dehidrasi.

•

Renal insufficiency or an extraordinary amount of water ingested quickly can lead to cellular overhydration, or water intoxication

•

ECF is diluted –

sodium content is normal but excess water is present

•

The resulting hyponatremia

promotes net osmosis into tissue cells, causing swelling

•

These events must be quickly reversed to prevent severe metabolic disturbances, particularly in neurons

Disorders of Water Balance: Hypotonic Hydration

Disorders of Water Balance: Hypotonic Hydration

Excessive H2 O enters the ECF

1 2 ECF osmotic pressure falls

3 H2 O moves into cells by osmosis; cells swell

(b) Mechanism of hypotonic hydration

SISTEM LIMFATIK-

jalur

tambahan

di

mana

cairan

dapat

mengalir

dari

ruang

interstisial

ke

dalam

darah

; cairan

: limfe

(bening)Cairan

yang berdifusi

dari

membran

kapiler

→

cairan

interstisiil

→

tidak

semua

kembali

ke

pembuluh

darah, sebagian

masuk

ke

pembuluh limfe

-

kapiler

darah

→ ruang

interstisial

ujung

vena kapiler

darahkapiler

limfe

-

dapat

mengangkut

protein (mencapai

25-50% total protein plasma) yang beredar

dan

zat-zat

berpartikel

besar

keluar

dari

jaringan

tubuh

,yang tidak

dapat

diabsorpsi

langsung

ke

kapiler

darah.-

terdapat

pada

hampir

seluruh

tubuh, kecuali

: permukaan

kulit, SSP,

saraf

perifer, endomisium

otot

dan

tulang

(pembuluh

interstisial

kecil, prelimfatik

→ pembuluh

limfatik

; otak

→ CSF → darah).

-

total cairan

limfe

: 2 –

3 L / hari-

susunan

isinya

hampir

sama dengan

susunan

cairan

jaringan

asalnya, tetapi

banyak

mengandung

limfosit

dan

fibrinogen (karena

itu

cairan

limfe

dapat

membeku), tidak

ada

CO2

, mengandung

sedikit

O2

, dan

cairan

limfe

yang berasal

dari

usus banyak

mengandung

lemak.

Komponen

:Kapiler limfatikSangat

halus, berpori-pori

; menuju

ke

pembuluh

limfatik

; mempunyai

katup

di

ujungnya.Pembuluh limfatikStruktur

mirip

vena ; lebih

kecil

dan

lebih

banyak

; mempunyai

banyak

katup

untuk

mencegah

aliran

balik

; berjalan

melewati

nodus

limfatik.Nodus limfatik / kelenjar limfatik / limfonodus = filter biologisUkuran

bervariasi

: dari

seujung

jarum

pentol

–

kacang

almond.Umumnya

berkelompok

di

berbagai

bagian

tubuh

; banyak

pada

palatin

(langit

mulut), tonsil faringeal, agregat

folikel

limfatik

di

usus

halus, kelenjar

timus, apendiks, limpa.

Fungsi

:

-

memfiltrasi

kuman. Infeksi

→ radang

: bengkak

dan

nyeri-

memproduksi

limfosit-

memproduksi

beberapa

antibodi

dan

antitoksin

Duktus limfatikus-

duktus

limfatikus

dekstra

(sisi

kanan

kepala, sebagian

toraks,

ekstremitas

kanan

atas), bermuara

di

vena subklavia

kanan.-

duktus

limfatikus

sinistra

/ duktus

torasikus

(ekstremitas

bawah,

organ abdomen & pelvis serta

sisi

kepala

kiri, sebagian

toraks sebelah

kiri, lengan

kiri), bermuara

di

vena subklavia

kiri.

Structure of lymphatic capillaries and a collecting lymphatic, showing also the lymphatic valves

Cairan

LimfeFungsi

:

-

Mempertahankan

kadar

protein yang rendah

dalam

cairan interstisiil

-

Mengembalikan

protein ke

dalam

peredaran

darah-

Mempertahankan

mekanisme

counter current di

ginjal

-

Mengangkut

enzim

dengan

molekul

besar

(lipase)-

Mengangkut

asam

lemak

rantai

panjang

& kolesterol

dari

saluran

pencernaan

(Sistem

Limfatik)-

Nodus

menyaring

cairan

limfe

dari

infeksi

kuman

dan

bahan-

bahan

berbahaya.-

Nodus

memproduksi

limfosit

untuk

sirkulasi.

•

Aliran

Limfe

:

-

tubuh

bagian

bawah- kepala kiri-

lengan

& thoraks

kiri

ductus

thoracicus

vena jugularis

interna

vena subclavia

kiri

•

Aliran

Limfe

:

-

Leher

& kepala

kanan-

Lengan

& thoraks

kanan

ductus

limfatikus

kanan

vena jugularis

interna

vena subclavia

kananLihat

gambar

Aliran

limfe

terjadi

karena

:-

gerakan

otot

rangka

(olah

raga, dsb)

-

Respirasi, pada

inspirasi

dan

ekspirasi

rongga

dada → mengakibatkan

adanya

perubahan

tekanan

-

efek

hisap

akibat

aliran

kecepatan

tinggi

dari

darah

di dalam

vena di

tempat

pembuluh

limfe

berakhir

(kontraksi

otot

jantung)-

kontraksi

ritmik

dinding

saluran

limfe

besar

Gangguan

sistem

limfatikObstruksi

→ saluran

limfe

tersumbat

oleh

filariaBagian

tubuh

yang terkena

terutama

ekstremitas

dan

skrotum→ Filariasis

→

Kaki gajah

Cerebro Spinal Fluid (CSF)Volume rongga

yang meliputi

otak

& sumsum

tulang

belakang±

1650 ml→

±

150 ml diisi

CSF

Cairan

otak

terdapat

di

:-

ventrikel

otak-

sisterna

sekitar

otak-

ruangan

sub arachnoid

yang meliputi

otak

dan

sumsum

tulang

belakangRuangan

tersebut

saling

berhubungan

→ CSF dapat

mengalir

bebas

Dibentuk

di

ventrikel

otak

oleh

pleksus

choroideus

pada

ke

4 ventrikel

otak

(terutama

ventrikel

lateralis)

, sebagian

kecil

oleh

pembuluh

darah

otak

dan

medulla spinalis

; dengan

cara

sekresi

aktifkecepatan

produksi

500 ml/hari

; pertukaran

3 x sehari.

-

Dari ventrikel

lateralis

(vent. I & II) melalui

foramen monroi

→

ventrikel

III , bersama

dengan

CSf

yang dibentuk

di

ventrikel

III →

melalui

akuaduktus

Sylvii

→

ventikel

IV, bersama

dengan

CSF yang dibentuk

di

ventrikel

IV →

melalui

foramen Magendi

& Luschka

→

sisterna

magna →

ruang

sub aranoid

yang mengelilingi

seluruh

otak

dan

MS (ruang

di

antara

piamater

& membran

arachnoidea).-

Diserap

melalui

vili

araknoidalis

ke

dalam

vena, terutama

sinus venosus

serebrum.-

Komposisi

: air, protein, glukosa, elektrolit, sedikit

limfositKonsentrasi

natrium

= plasma ; klorida

> 15% ; kalium

< 40% ; glukosa

< 30%.-

Fungsi

utama

: fungsi

protektif

otak

dan

MS

Susunan

CSF tidak

sama

dengan

ECF :- kadar Na 7 % >-

glukosa

30 % <-

K 49 % <

Pengukuran

tekanan

cairan

otak

dan

tes

Queckenstedt

Penderita

dalam

keadaan

berbaring

di

sisi

lateral tubuh. Dilakukan

punksi

lumbal

di

antara

vertebrae lumbal

III dan

IV, sehingga

jarum

punksi

mencapai

ruang

subarakhnoid. Jarum

dihubungkan

dengan

manometer air. Tinngi

cairan

dalam

pipa

manometer menunjukkan

tekanan

liquor cerebro spinalis

Tes

Queckenstedt

: menekan

kedua

sisi

leher

untuk

menekan

vena jugularis

interna

Pada

orang

sehat

→ tekanan

CSF ↑ → tes

Queckenstedt

positifbila

tekanan

pada

vena jugularis

ditiadakan

→ tekanan

CSF ↓

Keterangan

:tekanan

pada

vena jugularis

interna

→ aliran

balik

daarah

dari

sistem

vena otak

dihambat

→ sinus venosus

menggembung

→ menekan

CSF →

tekanan

CSF ↑(2-3 x normal)

Tes

Queckenstedt

positif

→ terjadi

kenaikan

tekanan

cairan

otak

→ normal

Tes

Queckenstedt

negatif

→ tidak

ada

peningkatan

CSF, berarti

:→ ada

bendungan

/ blok

di

canalis

vertebralis

Fungsi

CSF :melindungi

otak

terhadap

goncangan

/ benturan

(bantalan

/

cushion)

Pukulan

sangat

keras→ fenomena

countrecoup

kerusakan

pada

otak

petinju

tidak

di

daerah

frontal tetapi

di daerah

occipital

CSF tidak

dapat

melindungi

otak

terhadap

pukulan

rotasi

(pukulan rotasi

→ uppercut) → KO

Fungsi

CSF lain → pengatur

isi

tengkorak

(reservoir)volume darah

otak

↑ → volume CSF ↓

Ruang

PerivaskularRuangan

antara

pembuluh

daarah

yang masuk

ke

jaringan

otak

dan

piamaterFungsi

seperti

saluran

limfe

untuk

jaringan

otak

Fungsi

ruang

perivaskular→

-

mengangkut

protein dari

ruang

interstisial

otak

ke

CSF

-

mengangkut

bahan

lain dari

otak

ke

ruang

sub arachnoidcontoh

: pada

peradangan

otak, sedarah

putih

yang mati

diangkut

keluar

melalui

ruang

perivaskular

Gangguan

aliran

CSF :Ada

obstruksi

→ aliran

ke

ruang

sub arachnoid

terhambat

→

hidrocefalus

interna

/ non-komunikansCairan

tertimbun

di

sebelah

proksimal

sumbatan

dan

melebarkan

ventrikel

apabila

foramen Luschka

dan

Magendie

tersumbat

atau terdapat

hambatan

dalam

sistem

ventrikel

CSF menumpuk

dalam

ventrikel

atau

ruang

sub arachnoid (kapasitas

reabsorpsi

villi

arakhnoidalis

menurun) → hidrosefalus

eksterna

/ komunikans

Sawar

darah-otak(blood-brain barrier & blood-CSF barrier)-

Tempat

: pleksus

koroideus

dan

semua

endotel

kapiler

serebrum

(tight

junction).-

Kecuali

pada

: hipofisis

posterior, kelenjar

pineal, daerah

postrema

(permeabilitas

baik) → memiliki

reseptor

sensorik

terhadap

perubahanpada

cairan

tubuh.

-

Sangat

permeabel

: air CO2

, O2

, sebagian

besar

substansi

larutlemak

(co. alkohol)

-

Sedikit

permeabel

: elektrolit

(natrium, kalium, klorida)-

Tidak

permeabel

: protein plasma, molekul

organik

ukuran

besar

yang

tidak

larut

lemak.-

CSF-otak

sangat

permeabel

You have the weapons of knowledge go forth and conquer all

cairan tubuh

Documents