1. Cardiovascular System: Blood
Chapter 14

2. Cardiovascular System
3 components
Blood, heart, and blood vessels
Transports substances to and from body cells
Hematology: branch of science concerned w/study of blood, blood-forming tissues

3. Blood The only liquid connective tissues with three functions
1. Transportation
Blood transports oxygen from lungs to cells throughout body
Carries nutrients from GI tract to body cells, waste products away from cells, hormones from endocrine glands to other body cells
2. Regulation
pH of body fluids
3. Protection
Blood clots in response to injury, which protects against excessive blood loss
Helps protect against disease
Ex. White blood cells

4. Blood Denser and more viscous (sticky) than water
pH ranges from
8% of total body weight
Hematocrit: the percentage of total blood volume occupied by red blood cells
2 parts
1. blood plasma
2. formed elements

5. Blood Plasma Liquid that contains dissolved substances
Contains plasma proteins
Albumins: help maintain proper blood osmotic pressure, important in exchange of fluids across capillary walls
Globulins: defensive proteins
Antibodies or immunoglobulins
Fibrinogen
Key protein in formation of blood clots

6. Formed Elements Cells and cell fragments Red blood cells
White blood cells
Platelets

7. Formation of Blood Cells
Hemopoiesis: the process by which the formed elements of blood develop
Before birth: occurs in the yolk sac of embryo and later in liver, spleen, thymus, and lymph nodes of fetus
3rd trimester: red bone marrow becomes site for hemopoiesis

8. Red Bone Marrow: highly vascularized connective tissue located in the microscopic spaces b/w trabeculae of spongy bone tissue
Red bone marrow cells come from pluripotent stem cells (have capacity to develop into many different types of cells)
Generate myeloid stem cells (develop. in red bone marrow and develop into diff. kinds of cells) and lymphoid stem cells (begin develop. in red bone marrow but complete in lymphatic tissue)

9. Red Blood Cells (RBCs) or erythrocytes
Protein called hemoglobin: carries oxygen and gives its red color
Mature RBCs are without a nucleus or organelles, cannot divide or do extensive metabolic activities

10. RBC life cycle Live for 120 days
1. Macrophages in spleen, liver, and red bone marrow phagocytize ruptured and worn-out red blood cells, break apart globin and heme of hemoglobin
2. globin  amino acids which can be used by body to create proteins
3. iron removed from heme and associates with transferrin (acts as transporter)
4. iron-transferrin complex  red bone marrow, RBC precursors use it in hemoglobin synthesis
Iron needed for heme
Amino acids for globin
Vitamin B12 needed for hemoglobin
(stomach produces intrinsic factor for absorption of B12

11. 5. Erythropoiesis in red bone marrow RBCs, enter circulation
6. When iron removed from heme:
Biliverdin: a green pigment Bilirubin: a yellow-orange pigment
Bilirubin enters blood liversecreted by liver cells into bilepasses into small intestine and large intestine
7. large intestine, bacteria convert bilirubin urobilinogensome absorbed into blood urobilinexcreted in urine
Most urobilinogen eliminated in feces
Brown pigment stercobilin

12. RBC Production Formation of just RBCs is called erythropoeisis
Near end of process: RBC precursor ejects nucleus reticulocyte (biconcave shape of red blood cell)
Negative feedback loop
Regulated by amount of oxygen in blood
Erythropoiesis and destruction of RBCs at same pace
If erythrop. can’t keep up with RBC destruction, erythro. increases

13. RBC Production
Hypoxia: deficiency of oxygenstimulates release of erythropoietin (EPO) which is hormone made by kidneys
EPOthru bloodred bone marrowstimulates erythropoeisis
Cyanosis: bluish-purple skin coloration due to prolonged hypoxia
Anemia: low # of RBCs or low hemoglobin

14. White Blood Cells WBCs or leukocytes Have nuclei, no hemoglobin
Granular or agranular
Granular: neutrophils, eosinophils, and basophils
Agranular: lymphocytes and monocytes

15. WBC functions Combat microbes by phagocytosis or produce antibodies
Neutrophils: respond first, phagocytosis, release enzymes such as lysozyme
Then monocytes arrive
wandering macrophages
Clean up cellular debris

17. Basophils involved in allergic reactions Lymphocytes-3 types
Eosinphils release enzymes that combat inflammation in allergic reactions
Basophils involved in allergic reactions
Lymphocytes-3 types
B cells-produce antibodies
T cells-attack viruses, fungi, transplanted cells, cancer, etc.
Natural killer cells -attack variety microbes and certain tumor cells

18. WBCs Have proteins called major histocompatibility antigens (MHC)
“cell identity markers”
Used to type tissues to identify compatibility of donors and recipients

19. WBC life spans A few days During infection, only a few hours
Leukocytosis: increase in the # of WBCs
Usually indicates inflammation/infection

20. Platelets Disc shaped No nucleus
When blood vessels damaged , platelets form blood clots
Release chemicals that promote blood clotting
Life span: 5-9 days

21. Hemorrhage: the loss of a large amount of blood from the vessels
Hemostasis: a sequence of responses that stops bleeding when blood vessels are injured
Hemorrhage: the loss of a large amount of blood from the vessels
Hemostatic response must be quick, localized, and carefully controlled
Three mechanisms:
1. vascular spasm
2. platelet plug formation
3. blood clotting (coagulation)

22. 1. Vascular Spasm smooth muscle contracts quickly causing a spasm
Reduces blood loss
vasoconstriction which further reduces blood loss

23. 2. Platelet Plug Formation
Platelets come together to form a platelet plug
1. platelet adhesion
2. b/c of adhesion, platelets change and enter the platelet release reaction
sustain vascular spasm
3. chemical release makes other platelets sticky  platelet aggregation forming a platelet plug

24. 3. Clotting (Coagulation)
Liquid part of blood: serum
Gel portion: clot
fibrin
Clotting (coagulation): is a series of chemical reactions that culminates in the formation of fibrin threads
If blood clots to easily thrombosis can occur (clotting in an unbroken blood vessel)

25. Clotting With the use of clotting factors 3 stages:
1. Prothrombinase is formed
2. Prothrombinase converts prothrombin (liver)  enzyme thrombin
3. Thrombin converts soluble fibrinogen (liver)  insoluble fibrin. Fibrin forms threads of clot.

26. Two pathways for clotting
1. Extrinsic Pathway
Occurs rapidly
Damaged tissue cells release tissue factor (TF) into blood from OUTSIDE blood vessels
Tissue eventually converted into prothrombinase
2. Intrinsic Pathway
Occurs more slowly
Activators in direct contact with blood or within blood

27. Clot Retraction
Clot retraction: consolidation or tightening of the fibrin clot
plasminogen
This can be activated to plasmin  clot is dissolved by digesting fibrin threads
Small clots dissolve in a process called fibrinolysis

28. Clotting Clots can form within blood vessels
Roughened vessel surface as a result of atherosclerosis, trauma, or infection
Thrombosis: clotting in an unbroken blood vessel
Thrombus  embolus

29. Emboli form in veins b/c slower blood rate
Pulmonary embolism: when embolus gets lodged in lungs
Ventricular failure or death
Blocking arteryblocks blood flow to brain, kidney, or heart stroke, kidney failure, or heart attack

30. Blood Groups and Blood Types
Isoantigens (agglutinogens): an assortment of glycolipids and glycoproteins on the surface of red blood cells
blood groups and within a blood group there may be different blood types
2 major blood groups
ABO and Rh

31. ABO blood group Based on 2 isoantigens Isoantibodies (agglutinins)
Antigens A and B
Type A (A antigen) and Type B (B antigen) blood, Type AB or O (no antigens)
Isoantibodies (agglutinins)
React with A and B antigens if mixed
Anti-A antibody (reacts with antigen A)
Anti-B antibody (reacts with antigen B)
So, If you have type A blood, you have A antigens on RBC surfaces, and anti-B antibodies in your plasma

32. Rh Blood Group Rh+ or Rh- Important in blood transfusions
Ex. Person with type A blood receives type B blood
1. The anti-B antibodies of recipient bind to B antigens of donor blood causing hemolysis
2. anti-A antibodies of donor plasma can bind to A antigens on recipients RBC, not serious though

33. People with type AB blood = “universal recipients’”
Type O blood= “universal donors”

34. Common Disorders
Anemia: oxygen carrying capacity of blood is reduced due to decreased RBCs or amount of hemoglobin
Sickle Cell Disease: has abnormal type of hemoglobin (Hbs). When this gives up oxygen, bend the erythrocyte into a sickle shape
Hemophilia: inability to produce blood clots
Leukemia