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 platelets 5 kinds of WBC’s (Leukocytes) neutrophils, eosinophils, basophils lymphocytes, 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 Cells Adults have 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 – O 2 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 capacity

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 B 12 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 Landsteiner 1900 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 B antibodies: 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 Caucasians Rh - 5% African Americans

Erythroblastosis Fetalis transfusion with Rh – blood are given to fetus before birth and baby after birth to avoid possible brain damage or death

The Platelet Plug