Blood Today’s Lesson Components of the blood. Mechanism of Clotting. Blood Clot Dangers.

A) The 6 Jobs of Blood 1) Maintains our water balance 2) Regulates & distributes body core temperature 3) Regulates pH balance 4) Protects our bodies against invaders 5) Self seals any leaks 6) Carry Gases, Wastes & Nutrients

B) Components of Blood 1) Plasma –55% of total blood content –90% water, 10% proteins, vitamins, glucose etc. –There are 3 Important Plasma Proteins. 1. Albumins – control osmotic balance 2. Globulins - make antibodies for protection 3. Fibrinogen –blood clotting agent

B) Components of Blood… (no need to copy down) Blood Cells –Your body has three major types of blood cells A. Erythrocyte - red blood cells B. Leukocytes - white blood cells C. Platelets – also known as platelets

B) Components of Blood… 2) Red Blood Cells transport oxygen (O 2 ) contain hemoglobin –heme (iron pigment), globin (protein structure) –without hemoglobin 1L of blood can hold 3ml of O 2 –with hemoglobin 1L of blood can hold 200ml of O 2 –~ 280million hemoglobin / RBC RBC are biconcave – to increase the surface area for gas exchange

RBC Pictures & Shapes

Erythrocytes – RBC’s RBC have no nucleus  WHY? RBC’s produced in bone marrow (ribs, sternum & femur) life span of 120 days

Erythrocytes – RBC’s Anemia - deficiency in hemoglobin or RBC –  in O 2 delivery –can be caused by excess bleeding –a dietary deficiency in iron –Gold ring test

B) Components of Blood… 3) White Blood Cells RBC 700 : WBC 1 (greatly outnumbered  Why?) all have nuclei main job is to protect body from infection two main groupings of leucocytes 1. Granulocytes - made in bone marrow 2. Agranulocytes - made in bone marrow, modified lymph nodes (tonsils, arm pits)

WBC Pictures

B) Components of Blood… 4) Platelets no nucleus disc-shaped, very small, made in the bone marrow less numerous than RBC important for blood clotting (filled with thromboplastin)

C) Blood Clotting 6 Steps: 1) Blood vessels damaged (ie cut or bruise) 2) Platelets go to site of injury 3) Platelets release a chemical  THROMBOPLASTIN (1 st switch) 4) Thromboplastin activates the blood protein Prothrombin

5) Prothrombin changes into Thrombin (2 nd switch), in presence of Vitamin K & Calcium. 6) Thrombin changes the plasma protein Fibrinogen into Fibrin * Fibrin forms a sticky thread-like net to form a clot. Why 2 switches instead of spontaneous clotting?

C) Blood Clotting…

D) Blood Clot Dangers 1) Thrombus: a blood clot that seals off a blood vessel If in brain  cerebral thrombus = stroke If in heart  coronary thrombus = MI

D) Blood Clot Dangers 2) Embolism: a blood clot that dislodges from one area, travels to another & forms a blockage Frequency increases as we age

Review Questions 1. Blood is composed of a group of similarity shaped cells that carry out a similar function 2. Plasma and cellular components are the two major components of blood 3. Albumins – maintain osmotic pressure Globulins – produce antibodies to provide protection against invading microbes and parasites Fibrinogens – are important for blood clotting 4. The function of hemoglobin is to carry oxygen 5. The controlled production of red blood cells is called erythropoiesis

6. Any factor which will lower oxygen levels in the blood will stimulate red blood cell production. –E.g. exercise, moving to high altitude, hemorrhaging 7.Aneima is a condition that results in the reduction of blood oxygen levels. It is usually associated with a reduced red blood cell production or lower than normal levels of hemoglobin 8. White blood cell contain a nucleus, are capable of some independent movement, and functions as a fence against disease 9. Production of antibodies and phagocytosis 10. Platelets initiate the blood clotting reaction