Blood Todays Lesson Components of the blood Mechanism

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 p. H 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) n 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) n contain hemoglobin n – – n heme (iron pigment), globin (protein structure) without hemoglobin 1 L of blood can hold 3 ml of O 2 with hemoglobin 1 L of blood can hold 200 ml of O 2 ~ 280 million hemoglobin / RBC are biconcave – to increase the surface area for gas exchange

RBC Pictures & Shapes

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

Erythrocytes – RBC’s n 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 n RBC 700 : WBC 1 (greatly outnumbered Why? ) n all have nuclei n main job is to protect body from infection n 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 n disc-shaped, very small, made in the bone marrow n less numerous than RBC n important for blood clotting (filled with thromboplastin) n

C) Blood Clotting n 1) 2) 3) 4) 6 Steps: Blood vessels damaged (ie cut or bruise) Platelets go to site of injury Platelets release a chemical THROMBOPLASTIN (1 st switch) 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 threadlike 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 n If in brain cerebral thrombus = stroke n 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 n Frequency increases as we age

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

n 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 n 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 n 8. White blood cell contain a nucleus, are capable of some independent movement, and functions as a fence against disease n 9. Production of antibodies and phagocytosis n 10. Platelets initiate the blood clotting reaction