Chapter 12: Blood

Roughly 5 liters per person Blood is heavier than water (components

are made primarily of water with other biochemicals added in!)

Varies with:◦ Body size ◦ Changes in fluid and electrolytes/salt◦ Amount of adipose fat tissue◦ Gender (males have more than females!)

Blood Volume

Blood Composition

Def: % of formed elements in blood◦ Mostly red blood cells (RBCs) ◦ WBCs and platelets– less than 1%

Normal values ◦ In males- mid to high 40’s◦ In females- low 40’s

When centrifuged/spun:◦ White blood cells (WBCs) and platelets form a thin

very thin layer on top – called “buffy coat” – between plasma and RBCs

Hematocrit

Hematopoiesis◦Def: process by which immature stem cells

become specialized◦Become either RBC, WBC or platelets◦Location: Occurs in red bone marrow

Formation of Blood cells

Red Blood Cells Also called

erythrocytes Biconcave shape

◦ Increases surface area/volume ratio

Mature cells lack nuclei 1/3 filled with

hemoglobin ◦ Oxygen carrying

polypeptide molecule

Hemoglobin Composed of four

chains (polypeptides) Also has iron or “heme”

group attached Called oxyhemoglobin

when oxygen is bound to it (bright red color)

Called deoxyhemoglobin when oxygen is released (darker color)

Red Blood Cell Counts The higher the # of

RBCs = higher oxygen carrying capacity◦Change in # affects

health – greatly!◦Used, in part, to help

diagnose and evaluate diseases

Typical range◦Males: 4,600,000 –

6,200,000 cells per mm3

◦Females: 4,200,000 – 5,400,000 cells per mm3

Hematopoiesis (red blood cell formation)◦ Before Birth: yolk sac, liver, and spleen◦ After Birth: red marrow ◦ Controlled very precisely by homeostatic

mechanisms Production influenced by:

◦ Vitamin B12 ◦ Folic acid◦ iron

Red Blood Cell Life Cycle

Circulate for 120 days Old or damaged RBC’s are destroyed

(removed from blood circulation daily)◦ Phagocytized by macrophages in liver or spleen◦ Hemoglobin is broken into heme and globin◦ Heme is broken into iron and biliverdin

(greenish pigment)◦ Biliverdin is converted to bilirubin ◦ Iron is stored in liver or brought to marrow◦ Biliverdin and bilirubin are secreted in bile

Red Blood Cell Life Cycle (cont)

Control of Red Blood Cell Production

Also called leukocytes Production stimulated by interleukins and colony-stimulating factors

Two groups:◦1) Granulocytes - have granular cytoplasm

Neutrophils Eosinophils Basophils

◦2) Agranulocytes - no cytoplasmic granules Monocytes Lymphocytes

White Blood CellsWBC animation

Granulocyte Average 54-62% of leukocytes Fine cytoplasmic granules that are

light purple in neutral stain

Nucleus: 2-5 lobes Lifespan: about 12 hours Function: phagocytize bacteria and other

particles

Neutrophils

Granulocyte Average 1-3% of leukocytes Coarse cytoplasmic granules that are deep

red in acid stain Nucleus: 2 lobes Lifespan: about 12 hours Function: destroy certain parasites and

control inflammation or allergic reactions

Eosinophils

Granulocyte Average ‹1% of leukocytes Relatively few, irregularly shaped

cytoplasmic granules that are deep blue in basic stain

Nucleus: 2 lobes Lifespan: about 12 hours Function: release heparin and histamine

Basophils

Monocytes Agranulocyte Average 3-9% of

leukocytes Nucleus: Varied

shape Lifespan: several

weeks or months Function:

phagocytize materials

Agranulocyte Average 25-33% of leukocytes Nucleus: Large and round Lifespan: may live for years Function: function in immune response

Lymphocytes

Normal range: 5,000-10,000 mm3

Differential White Blood Cell Count◦ Distinguish how many of each type◦ Can be important for diagnosing some

disorders/problems◦Excessive:

If your WBC count exceeds 10,000, this is leukocytosis (infection)

Ex: Appendicitis◦Deficiency:

If you WBC count is below 5,000, this is leukopenia (low count)

Ex: typhoid fever, influenza, measles, mumps, chickenpox, AIDS, polio

White Blood Cell CountWBC animation

White blood cells are also called leukocytes◦UP!!!

When discussing hematocrit, WBCs make up the majority of your blood.◦DOWN!!!

The more WBCs you have, the better you’re probably feeling.◦DOWN!

Lymphocytes function to assist your immune system◦UP!!!

Thumbs Up, Thumbs Down

Neutrophils are granulocytes.◦YES!!!

Basophils phagocytize materials.◦NO!!!

Monocytes make up the majority of your WBCs.◦NO!!!

Have an excessive WBC count can mean an infection like appendicitis.◦YES!!!

WBC REVIEW!

Also celled thrombocytes Made from megokaryocyte

◦ Large cells in red bone marrow Production stimulated by thrombopoietin

(hormone) Lack nucleus ½ the size of RBC Lifespan: about 10 days Function: form blood clots, help close breaks

in damaged blood vessels Normal range: 130,000-360,000

Blood Platelets

91-2% water Remainder is

mixture of biochemicals◦ Proteins, nutrients,

hormones, electrolytes

Function: ◦ Transporting

nutrients, gases and vitamins

◦ Regulate fluid and electrolyte balance

◦ Maintain proper pH

Blood Plasma

Main component of dissolved substances Remain in plasma (not metabolized/broken

down) Types:

◦1) Albumin (60%) Help establish colloid osmotic pressure Transports lipids and steroid hormones

◦2) Globulins (36%) Transport of ions, lipids and fat-soluble vitamins

and some antibodies◦3) Fibrinogen (4%)

Function in blood coagulation and clotting

Plasma Proteins

Most important blood gases:◦ Oxygen◦ Carbon dioxide

Plasma nutrients:◦ Materials absorbed from digestive tract

Ex: Amino acids, simple sugars, nucleotides, lipids◦ Fats (triglycerides)◦ Phospholipids◦ Cholesterol◦ Lipoproteins

When Fats, phospholipids, cholesterol combine with proteins Large size

Blood Gases and Nutrients

Nonprotein Nitrogenous Substances◦ Amino acids◦ Urea and uric acid

Electrolytes◦ Various ions (K+, Ca+, Cl-)

Other Blood Substances

Def: the stoppage of bleeding Important when blood vessels are damaged

(following injury) Vasospasm

◦ Contraction of blood vessel walls in response to small break

Platelet plug◦ Platelets adhere to damage and to each other to

create a plug; may release serotonin to cause vasoconstriction

If previous two are unsuccessful, blood clot may form (through coagulation)

Hemostasis

Def: formation of blood clot

Damaged tissue releases tissue thromboplastin (hormone)

After series of rxns, prothrombin activator is created

Prothrombin activator (with Calcium) converts prothrombin to thrombin

Thrombin cuts fibrinogen into fibrin fibers that form a meshwork over the damage

Blood Coagulation

Blood Coagulation (cont)

Blood Disorders Hemophilia

◦Uncontrolled bleeding (hemorrhaging) following injury, frequent nosebleeds, blood in urine

◦Inherited clotting disorder◦Carried on X chromosome (recessive)

Von Willebrand Disease◦Tendency to bleed and bruise easily◦Inherited clotting disorder◦Far less severe than hemophilia

Blood DisordersLeukemia

◦Symptoms: Fatigue, frequent colds/fevers, chills,

sweats, bruising, bone pain◦Diagnosing: Few RBCs and platelets, TOO many WBCs

(notice the prefix “leuk” from leukocytes)◦Cause: Red bone marrow producing too many

granulocytes cancer cells are not controlled – spread

◦Treatment: Stem cell transplants, chemotherapy

drugs

Normal smear

Leukemia smear

Types: A, B, AB, O Typing is based on antigens found on

RBC’s Two most important groups:

◦ 1) ABO group◦ 2) Rh group

+ and – of each type Ex: A-, B-, AB-, O-; A+, B+, AB+, O+

Blood Types

ABO System Blood type is codominant (A and B are BOTH equally dominant)

Possible blood type genotypes (genetic code) ◦A (IAIA or IAi)◦B (IBIB or IBi)◦AB (IAIB)◦O (ii)

ABO Incompatibility

ABO Incompatibility Mixing blood types

can cause agglutination

Rh Blood Group

Possible Rh Blood Types:◦ + (++ or +-)◦ - (--)

Erythroblastosis fetalis Condition cause by Rh incompatibility

between mother and fetus

Blood Typing Review Questions I have O- blood. What type can I receive?◦O- ONLY

I have AB+ blood. What type can I receive?◦ANY!!!

I have B- blood. Who can take my blood?◦B+ or B-; AB+ or AB-