Chapter 18- Circulatory System: Blood

Roles of Blood Respiration Nutrition Waste elimination Thermoregulation Immune system Water and Acid/base balance Internal communication

Functions Carries- oxygen, carbon dioxide, nutrients, wastes, hormones, and heat. Protection – inflammation, destroys microorganisms and cancer cells, antibodies neutralize toxins, initiates clotting. Regulation – transfers water to and from tissues. Helps stabilize water balance, buffers acids and bases, and helps stabilize pH.

Blood Made of two components – Plasma – clear extracellular fluid. Proteins, enzymes, nutrients, wastes, hormones, and gases. (55% of blood) Plasma proteins Albumins – smallest. Affects viscosity and osmolarity. Globulins – alpha, beta, & gamma Fibrinogen – precursor of fibrin

Formed elements – blood cells and platelets (bone marrow). Erythrocytes (red blood cells) (RBC) carry gases Leukocytes (white blood cells) (WBC) antibodies Granulocytes Neutrophils, eosinophils, basophils Agranulocytes Lmphocytes monocytes

Hematocrit – Ratio of plasma to formed elements Viscosity – resistance of a fluid to flow Whole blood – 4.5-5.5 Plasma – 2.0 Osmolarity – total amount of dissolved particles High osmolarity – blood stream absorbs too much fluid, BP goes up. Low osmolarity – blood stream does not absorb enough fluid, edema, swollen tissues.

Blood cell production Leukocyte production – leukopoiesis – 3 pathways 1. B progenitors become B lymphocytes 2. T progenitors become T lymphocytes 3. granulocyte – macrophage colony-forming units become granulocytes and monocytes. Red bone marrow – stores granulocytes and monocytes until needed. Lymphocytes – develop in the bone marrow, migrate to the thymus, and mature there. Move on to spleen, lymph nodes, and other places. Responsible for long term immunity. Survive for decades.

Granulocytes – circulate in the blood for 4-8 hours, then migrate to tissues for 4-5 days. What are the types of granulocytes? Monocytes – circulate in the blood for 10-20 hours, migrate to the tissues and change into macrophages, live for years.

Hemopoiesis – cellular comments of blood production Hemopoietic tissues – yolk sac – a membrane all vertebrates produce that are blood islands that produce stem cells that colonize fetal bone marrow, liver, spleen, and thymus. Liver stops erythropoiesis around birth. Spleen stops producing RBCs soon after birth, but produces lymphocytes for life. 1. after birth – all 7 formed cells are produced in red bone marrow. 2. also, lymphocytes are produced in thymus, tonsils, lymph nodes, spleen, and intestines.

Formation of RBCs Erythrocyte – negative feedback system. Drop in RBC count – hemorrhaging, blood will have less O2 – hypoxemia. Sensed by kidneys and produces a hormone that stimulates RBC production. Emphysema – changes in lung tissue cannot be compensated for, but the body tries resulting in polycythemia – Too many RBCs. Iron is necessary. Not enough leads to problems. Other coenzymes needed – vitamin B12, folic acid, vitamin C, and copper.

Anemia Any deficiency in the number of erythrocytes. Types of Anemia: Loss of blood 1. bleeding – hemorrhage 2. hookworm Destruction of RBCs Parasitic infections Lead poisoning

Improper formation of RBCs Sickle cell anemia Cooley’s anemia Familial hemolytic jaundice – spleen activity makes the RBCs fragile, they break. Pernicious anemia – vitamin B12 deficiency Iron deficiency – anemic. Leukemia – over production of leucocytes.

Abnormalities in Leukocyte count Normal count: 5,000 – 10,000 cells/mL Leukopenia – below normal. Poisoning, radiation sickness, AIDS, measles, mumps, chicken pox, poliomyelitis. Leukocytosis – above normal. Infection, allergies, other diseases, dehydration, and emotional disturbances.

Leukemia – cancer of the hemopoietic tissues Leukemia – cancer of the hemopoietic tissues. Produces too much or high numbers of leukocytes and their precursors. Acute leukemia – appears suddenly, rapid decline, death within a few months. Chronic leukemia – slow development, typical survival 3 years Treatment – chemotherapy and bone marrow transplant Side effects – anemia, hemorrhaging, and infections

Blood Types

Discovered by Karl Landsteiner, won Nobel Prize Antigens (agglutinogens)- proteins on the surface of RBCs. Antibodies (agglutinins) – plasma proteins Blood types: A, B, AB, and O (ABO blood typing). Antigens of ABO blood group are membrane proteins with short carbohydrate chains attached. Antibodies of the ABO blood group appear at 2-8 months of age in response to bacteria in the gut. Antibody A called anti-A, reacts against antigen A. Antibody B, called anti-B, reacts against antigen B.

Universal recipient – AB Universal donor - O ABO typing is done by placing a drop of blood in a drop of anti-A serum and another in anti-B serum. Which ever one clumps, the blood is that type. If both clump then type AB If neither clumps then type O Universal recipient – AB Universal donor - O

Rh group Determined by three genes C,D, and E. Each has 2 alleles. (C,c/D,d/E,e) No matter what the C & E genotype is, if a person is DD or Dd, they have antigen Rh and are Rh positive. If dd, person lacks Rh antigen, Rh- Blood type is written (A- or A+)