Blood

Many Vital Functions

• Transports nutrients, oxygen, wastes, and hormones

• Helps maintain stability of interstitial fluids• Distributes heat• Defense against infections – all white blood

cells

Components of Blood

• 45% RBC’s – the Hematocrit or packed cell volume (PCV)

• 1% WBC’s and platelets5 kinds of WBC’s (Leukocytes)

neutrophils, eosinophils, basophilslymphocytes, monocytes

• 55% plasma – a mixture of water, AA’s, proteins, carb’s, lipids, vitamins, hormones, electrolytes, and cellular waste

Origin of Blood Cells• All blood cells originate in bone marrow from hematopoietic

stems cells (hemocytoblasts)• There is only about 1 in 10,000 of these stem cells in bone

marrow

Red Blood CellsAdults have 20-30 trillion (1/4 of human cells)

• Erythrocytes• Biconcave discs, thin near center, thicker at edges• Increases surface area for gases to diffuse through• Volume is about 1/3 hemoglobin (270 million/RBC)• Oxyhemoglobin – O2 and hemoglobin – bright red• Lose nuclei as cell matures – more space for hemoglobin

therefore THEY NEVER DIVIDE• Life span about 120 days – broken down in liver and spleen by

phagocytes• Produce ATP through glycolysis Why?• Red Blood Cell Count (RBCC) – increases with several days of

strenuous exercise or increase in altitude• This increases the blood’s oxygen-carrying capacityhttp://www.youtube.com/watch?v=fbk1Kmki5sg

Hemoglobin

• Consists of 4 polypeptides• Each polypeptide has a heme group• 1 molecule of oxygen can bind to each heme

Negative Feedback and Erythropoietin

Diet and RBC Production

• Vitamin B12 and Folic Acid – needed for growth and division of all cells

• Iron required for Hemoglobin synthesis, some is lost each day and needs to be replaced

• Anemia – a deficiency in RBC’s or reduction in amount of hemoglobin they contain

White Blood Cells

• Leukocytes• Protect against disease• 5 types circulate in the blood

- Neutrophils- Eosinophils- Basophils- Monocytes- Lymphocytes

White Blood Cells

Diapedesis

Blood Groups

• Karl Landsteiner1900 determined blood types (Nobel prize for Medicine in 1930)

1910 determined ABO blood antigen gene

Now known that >30 genes contribute to RBC surface features

Agglutination : the clumping of RBC’s when testing blood compatibility

• Reaction between blood cell surface molecules (antigens) and protein antibodies* Antibodies are “anti” because they are “against” specific antigens

Blood Types

• ABO Blood Groups

• Universal Donor:Blood Type O

antigen: neither A or Bantibodies: both anti-A

and anti-B

• Universal Recipient:Blood Type AB

antigen: A and B antibody: neither anti-A

nor anti-B

Rh Blood Group

• First studied in the rhesus monkey• In humans, several Rh antigens• Rh + surface antigens are present• Rh - surface antigens are NOT present• In the U.S.

15% of CaucasiansRh -

5% African Americans

Erythroblastosis Fetalistransfusion with Rh – blood are given to fetus before birth and baby after

birth to avoid possible brain damage or death

The Platelet Plug