cairan tubuh
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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)
Sherwood, Human Physiology, 6th
edition
Sherwood, Human Physiology, 6th
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
Sherwood, Fisiologi Manusia, edisi
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)
Sherwood, Human Physiology, 6th
edition
Sherwood, Human Physiology, 6th
edition
Sherwood, Human Physiology, 6th
edition
Sherwood, Human Physiology, 6th
edition
Sherwood, Human Physiology, 6th
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++
ELECTROLYTE BALANCE•
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
ELECTROLYTE BALANCE•
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
Sherwood, Fisiologi Manusia, edisi
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)
Sherwood, Fisiologi Manusia, edisi
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
Sherwood, Fisiologi Manusia, edisi
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.
Sherwood, Fisiologi Manusia, edisi
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
HOMEOSTASIS AIR DAN ELEKTROLITHOMEOSTASIS AIR DAN ELEKTROLIT
ADH ADH HH22 OO
AA RBFRBF
HipotalamusHipotalamus ReninRenin
BB AngiotensinAngiotensin
OsmolalitasOsmolalitas ALDOSTERONALDOSTERON
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+
SODIUM PRINCIPLES•
2) Cells pump sodium ions out of the cell by using sodium-potassium pumps
Na+
Na+
Na+
Na+
SODIUM PRINCIPLES•
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
Regulation of Potassium (K+) Balance
•
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
Regulation of Potassium (K+) Balance
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
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