Erythrocytes, or red blood cells (RBCs)

Leukocytes, or white blood cells (WBCs)

Platelets

majority of the ‘formed elements’

hemoglobin, which is a red pigment, is part of each cell

hematocrit – how many red blood cells

and since most are RBCs – a measurement of health

RBCs production is stimulated by erythropoietin

how many red blood cells

and since most are RBCs – a measurement of health

Biconcave discs, anucleate, essentially no organelles

Filled with hemoglobin (Hb), a protein that functions in gas transport

Contain the plasma membrane protein spectrin and other proteins that:

Give erythrocytes their flexibility

Allow them to change shape as necessary

can form stacks for smoother flow

Biconcave shape has a huge surface area relative to volume

Erythrocytes are more than 97% hemoglobin

ATP is generated anaerobically, so the erythrocytes do not consume the oxygen they transport

Structural characteristics contribute to RBCs gas transport function

RBCs are dedicated to respiratory gas transport

Hb reversibly binds with oxygen and most oxygen in the blood is bound to Hb

Hb is composed of the protein globin, each bound to a heme group

Each heme group bears an atom of iron, which can bind to one oxygen molecule

Each Hb molecule can transport four molecules of oxygen

holding carbon dioxide

this molecule changes shape as it binds

this is the largest collection of lymphoid tissue in the body

but it functions in both the circulatory and the lymphatic system

removes worn blood cells and platelets

stores iron from recycled RBCs

stores platelets

immune responses from B and T cells occur here as blood and lymph passes through

Unique to the individual 

Recognized as foreign if transfused into another individual

Promoters of agglutination and are referred to as agglutinogens 

Presence or absence of these antigens is used to classify blood groups

Two antigens (A and B) on the surface of the RBCs 

Two antibodies in the plasma (anti-A and anti-B)

– Rh+ antibodies of a sensitized Rh– mother cross the placenta and attack and destroy the RBCs of an Rh+ baby

Rh– mother becomes sensitized when exposure to Rh+ blood causes her body to synthesize Rh+ antibodies

an invader

Ex. bacteria or virus

body meets a cell with the Rh marker on it

this would be when you are Rh - negative

blood has abnormally low oxygen-carrying capacity

It is a symptom rather than a disease itself

Blood oxygen levels cannot support normal metabolism

Signs/symptoms include fatigue, paleness, shortness of breath, and chills 

A secondary result of hemorrhagic anemia

Inadequate intake of iron-con

Impaired iron absorption

results from:

Deficiency of vitamin B12

Lack of intrinsic factor needed for absorption of B12

Treatment is intramuscular injection of B12; 

– results from a defective gene coding for an abnormal Hb called hemoglobin S (HbS)

HbS has a single amino acid substitution in the beta chain

This defect causes RBCs to become sickle-shaped in low oxygen situations

polycythemia

or blood dopping

the only blood components that are complete cells:

Are less numerous than RBCs

Make up 1% of the total blood volume

Can leave capillaries via diapedesis

Move through tissue spaces

do NOT carry oxygen

neutrophils, eosinophils, and basophils

Contain cytoplasmic granules that stain specifically (acidic, basic, or both) with Wright’s stain

Are larger and usually shorter-lived than RBCs

Have lobed nuclei

Are all phagocytic cells

 account for 1–4% of WBCs 

Have red-staining, bilobed nuclei connected via a broad band of nuclear material

Have red to crimson (acidophilic) large, coarse, lysosome-like granules

Lead the body’s counterattack against parasitic worms

Lessen the severity of allergies by phagocytizing immune complexes 

Account for 0.5% of WBCs and:

Have U- or S-shaped nuclei with two or three conspicuous constrictions

Are functionally similar to mast cells

Have large, purplish-black (basophilic) granules that contain histamine

Histamine – inflammatory chemical that acts as a vasodilator and attracts other WBCs (antihistamines counter this effect)

lymphocytes and monocytes:

Lack visible cytoplasmic granules

Are similar structurally, but have different jobs

Have spherical (lymphocytes) or kidney-shaped (monocytes) nuclei

Account for 25% or more of WBCs and:

Have large, dark-purple, circular nuclei with a thin rim of blue cytoplasm

Are found mostly enmeshed in lymphoid tissue (some circulate in the blood)

account for 4–8% of leukocytes 

They are the largest leukocytes

They have abundant pale-blue cytoplasm

They have purple-staining, U- or kidney-shaped nuclei

They leave the circulation, enter tissue, and differentiate into macrophages

Are highly mobile and actively phagocytic

Activate lymphocytes to mount an immune response

Monocytes use the bloodstream for about a day to circulate

Then they enter tissues and are called 

Immature WBCs are found in the bloodstream in all leukemias

Bone marrow becomes totally occupied with cancerous leukocytes

The WBCs produced, though numerous, are not functional

Death is caused by internal hemorrhage and overwhelming infections

Treatments include irradiation, antileukemic drugs, and bone marrow transplants

are fragments of megakaryocytes which remain in the bone marrow

Platelets function in the clotting mechanism by forming a temporary plug that helps seal breaks in blood vessels

Their granules contain serotonin, Ca2+, enzymes, ADP, and platelet-derived growth factor (PDGF)

circulate 9-12 days then removed by phagocytes

350,000 /u l , formation stimulated by thrombopoietin, IL – 6, others

about 1/3 in spleen / liver at any time

1. transport chemicals to site needed, to initiate and control clotting

2. clump together forming a plug until clotting occurs

3. contract their actin and myosin filaments to reduce the size of the clot and the break in the vessel

large cell that remains in the bone marrow

breaks off pieces of itself and releases them to the blood

can release about 4000 pieces before it is degraded

widespread clotting in intact blood vessels

Residual blood cannot clot

Blockage of blood flow and severe bleeding follows

Most common as:

A complication of pregnancy

A result of septicemia or incompatible blood transfusions

most common of the inherited bleeding disorders

person is missing this stabilizer for one of the factors