CH 17

BLOOD

The Functions of Blood• (1) Transport medium

that picks up food and oxygen

• (2) Picks up wastes for delivery to excretory organs

• (3) Transports hormones, enzymes, buffers, and other biochemical substances

Formed elements= 45%

• Red blood cells (RBC) aka erythrocytes

• White blood cells (WBC) aka leukocytes

• Platelets aka thrombocytes

Fluid Portion= 55%

Called plasma and composed of water, proteins, and solutes.

Red Blood Cells (Erythrocytes)

• No nucleus

• Primary component is hemoglobin which gives the red color and accounts for one third of cell volume

Function of RBCs

• Transport of oxygen and carbon dioxide depends on the hemoglobin

Formation of Red Blood Cells• Called Erythropoiesis.• Every minute you create 200 BILLION to replace

an equal number destroyed at that brief time!• Formation begins in bone marrow from

hematopoietic stem cells• Animation: http://health.howstuffworks.com/adam-200028.htm

Negative Feedback:-If oxygen levels decrease (like at high altitude),

kidneys release hormone erythropoietin, and this stimulates RBC production in red bone marrow.

Red Blood Cell Destruction

• Life span of RBCs is about 105 to 120 days. As they age, they break apart in the capillaries

• Macrophage cells phagocytose the cells, releasing amino acids, iron, and bilirubin

• ANIMATION: http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter21/

animation__hemoglobin_breakdown.html

White Blood Cells (Leukocytes)

• Classified by presence or absence of granules

• Granulocytes - have large granules

• Agranulocytes – do not have cytoplasmic granules

Granulocytes

• Neutrophils – small and numerous granules and 65% of total WBC count

• Eosinophils – large numberous granules, 2%-5% of WBCs

• Basophils – large but sparse granules that only .5% to 1% of WBCs

Agranulocytes

• Lymphocytes – smallest of leukocytes, 25% for WBCs

• Monocytes – largest of leukocytes

Formation of WBC

• Granulocytes originate in bone marrow.

• Agranulocytes originate in lymphatic tissue

Platelets

• Small, pale bodies that appear as irregular spindles or oval disks

• Physical properties include agglutination, adhesiveness, and aggregation

Function and Formation of Platelets

• Play important role in hemostasis (stoppage of blood flow) and blood clotting

• Form platelet plugs to stop flow of blood into tissues when damage occurs

• Platelets formed in bone marrow, lungs, and spleen by fragmentation of large cells called megakaryocytes.

• Life span of 7 days

ABO Blood Groups

U.S. Blood-type DistributionO+38 percent of population A+34 percent of population B+9 percent of population O-7 percent of population A-6 percent of population AB+3 percent of population B-2 percent of population AB-1 percent of population

Writing Blood Types

• Blood types are codominant genetic traitsBlood Type Homozygous Genotype Heterozygous

Genotype

Type A IAIA IAi

Type B IBIB IBi

Type AB - IAIB

Type O ii -

Example of a Blood Type Problem• Mother is type A (remember this could be

homozygous or heterozygous!)

• Father is type B (remember this could be homozygous or heterozygous!)

• What blood types could their children be?

Rh System• Rh-positive – Rh antigen is

present• Rh- negative – Rh anitgen not

present• Blood does not normally

contain anti-Rh antibodies, EXCEPT when an Rh-negative person is given a transfusion of Rh-positive blood or…a Rh-negative mother with a Rh-positive fetus (see next slide)

Erthryoblastosis fetalis

Erythroblastosis fetalis occurs when a mother’s Rh antibodies react with a fetus’s Rh positive cells.

Animation: http://www.marchofdimes.com/figure2_RhDisease.swf.swf

RhoGAM

• All Rh-negative mothers who could carry a Rh positive baby should be treated with RhoGAM

• RhoGAM stops the mother’s body from forming Rh antibodies so it prevents hurting the fetus of a Rh baby.

Blood Clotting• Four Components that help

clotting: are…Prothrombin, thrombin, fibrinogen, fibrin

• Extrinsic – chemicals released from damaged tissue

• Intrinsic – chemicals present in the blood

Disorder Animations • Sickle Cell Anemia:• Leukemia• Thrombosis• Embolism (a thrombus that has moved).

• Find the description of these diseases. Type them up in your own words (short definitions all on one page). Bring them in to receive 2pts for each correct definition on your test. You must be able to explain them to me at any moment that I ask you or you will lose credit. This must be your own work. No two should be exactly the same

Disorders Continued

• Anemia

Blood cannot carry sufficient oxygen to inadequete number of RBCs or hemoglobin

• Hemophilia (sex linked recessive- like colorblindness!) – blood clotting disorder