BLOOD AND THE CARDIOVASCULA

R SYSTEM

Chapter 17-19

Blood:Main function of blood – primary

transportation fluid of the body provides: 1.) pickup & delivery services2.) protection necessary to withstand

“foreign invaders”

Composition of Blood:

Fun facts:fluid tissue w/ chemicals dissolved in it &

cells floating in itabout 8% of our body wt & its vol in healthy

adults is 5-6 liters (6 quarts)color depends on the amt of O2

pH is btw 7.35 & 7.45

Bloody Parts:liq part is plasma

– makes up 55% of total blood volume– is 90% H2O

– contains plasma proteins, nutrients, respiratory gases, hormones,

wastes, & cell metabolism products – functions to transport various solutes &

distributes body heat throughout the body

suspended in the plasma are formed elements there are 3 main types with subtypes1.) Red Blood Cells - (RBCs) – Erythrocytes – in 1 drop there are normally 4-6 million RBCs – account for 45% of the total volume of a blood sample (hematocrit)2.) White Blood Cells –(WBCs)- Leukocytes – normally 4000-11,000 WBCs in 1 drop – subtypes:

a.) Granular Leukocytes – have granules in their cytoplasm – 3 types:

1.) Neutrophils, 2.) Eosinophils, & 3.) Basophilsb.) Nongranular Leukocytes – 2 types:1.) Lymphocytes – “B’” & “T”, 2.) Monocytes

3.) Platelets – Thrombocytes – normally 250,000 – 500,000 in 1 drop

***RBCs, WBCs, & Platelets are constantly being destroyed, so new ones must continuously be made

- 2 kinds of connective tissue make blood cells

a.) Myeloid Tissue – Red Bone Marrow –forms all types except lymphocytes & monocytes

b.) Lymphatic Tissue – found in lymph nodes, thymus & spleen – forms lymphocytes & monocytes

Life span of Blood Cells:- Erythrocytes – 4 months- Granular leukocytes – few days- Nongranular leukocytes – 6 months

Red Blood Cells – Erythrocytes- disk shaped w/ no nucleus & very few organelles - provides a larger area for O2 & CO2 exchange

- functions:1.) transports O2 to other cells using hemoglobin

– this pigment carries the bulk of the O2 carried by the blood – very efficient syst

2.) transports CO2 away from the cells

- RBCs affect the viscosity of blood – too many, blood is thick; too few, blood is thin- Hemoglobin content affects the amount of O2 being carried by the blood - normal hemoglobin content for males is 13-18g per 100mL of blood & for females is 12-16g per 100mL

White Blood Cells – Leukocytes

- function – DEFENSE!- can slip in & out of the blood vessels – diapedesis- respond to areas of infection by (+) chemotaxis – moving towards chemicals diffused by the damaged cells- use amoeboid motion to move through tissue spaces

- types & specific functions:

A.) Neutrophils – comprise 40-70% of total WBCs – become phagocytic in infected tissue – live a few days as they destroy themselves when destroying the pathogenB.) Monocytes – 4-8% of total WBCs – they mature, circulate for a few hours & then migrate to infected tissue where they enlarge & become macrophages that will engulf microbesC.) Lymphocytes - 20-45% of total WBCs – produce antibodies (B -lymphocytes) & cells that attach microbes directly (T-lymphocytes)

D.) Eosinophils – 1-4% of total WBCs – protect from irritants & phagocytize parasites that cause allergiesE.) Basophils – 0-1% of total WBCs – function in allergic reactions by discharging histamine, also secretes heparin which prevents blood clotting

Platelets – Thrombocytes

- function – blood clotting – plugs a torn or cut vessel & stops bleeding- not true cells – fragments of large multinucleate cells called megakaryocytes that rupture releasing the platelets

steps to blood clotting:

1.) injury to vessel makes rough spot in lining – the platelets become “sticky” & cling to the damaged site – they then release chemicals to attract more platelets2.) once anchored, platelets release serotonin which cause blood vessels to spasm – which narrows the vessel to prevent blood loss until clotting can occur3.) at the same time, injured tissue is releasing thromboplastin4.) platelet factors combine with thromboplastin, Ca2+ ions, & other blood protein clotting factors to form a prothrombin activator5.) the prothrombin activator converts prothrombin to thrombin6.) thrombin then reacts with fibrinogen proteins to form fibrin which makes a mesh-work that traps RBCs & forms the clot

- within the hour the clot retracts & squeezes serum from the mass to pull the ruptured edges together

Blood Serum

– plasma minus its clotting factors still contains antibodies

- plasma test are used to determine concentration of food molecules in the blood – for conditions like diabetes- presence of certain enzymes indicate certain diseases such as:1.) transaminase – heart attack has occurred2.) alkaline phosphatase – liver & bone diseases3.) acid phosphatase – prostate cancer4.) lactic dehydrogenase – Duchenne Muscular Dystrophy

Blood Types

– identified by antigen in the RBCs- antigen – substance that can stimulate the body to make antibodies – any substance foreign to the body- antibody – a substance made by the body in response to stimulation by an antigen – very specific – reacts to particular antigen that stimulated its production

- there are 4 blood types:1.) Type A – contains anti-B antibodies2.) Type B – contains anti-A antibodies3.) Type AB – contains neither anti-A & anti-B antibodies

- “universal recipient”4.) Type O – contains both anti-A nor anti-B antibodies

- “universal donor”- Rh system – based on the Rhesus monkey

- Rh Positive – contains the Rhesus factor- Rh Negative – does not contain the Rhesus factor- If (+) is introduced to a (-), anti-Rh antibodies

appear