1. Primary function: uses hemoglobin to transport oxygen.

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1 1. Primary function: uses hemoglobin to transport oxygen. Secondary functions: 2. Carbon dioxide transport. 3. Takes part in clotting 4. Maintains body temperature 5. Supplies osmotic pressure to draw interstitial fluid back into the capillaries

2 Description: Are small flattened discs; thinner in the middle than on the sides Why is this shape important? 1. Gives RBC s a larger surface area than if they were round. 2. Gives them flexibility to fold as they move through capillaries.

3 RBC s contain hemoglobin (Hb) which binds reversibly with oxygen. This means the bond is weak and can easily be broken. Why is this important? Oxygen must be available to diffuse into the tissues. ph becomes slightly more acidic as blood goes through tissues and takes on carbon dioxide. This causes oxygen to leave the hemoglobin since the bond is weak.

4 Hb structure: is a protein (globin) which is bound to a pigment (heme). Heme contains iron.

5 Hb function: takes on oxygen in the lungs and becomes oxyhemoglobin. Travels to the tissues where it releases oxygen. It can carry some carbon dioxide back to the lungs to be removed from the body. REVIEW: Carbon monoxide (CO) combines 200 times better to hemoglobin than oxygen does. Why is this of practical importance to us? CO latches onto the hemoglobin and will not let go. It takes up space normally used to carry oxygen. Tissues die from lack of oxygen. Sources of CO-auto exhaust, faulty furnace vents, crack in furnace, cigarette smoke.

6 RBC s make up about 45% of our blood volume. Plasma makes up the rest. The measure of the # of RBC s in a person s blood is called an: hematocrit We measure this clinically to see if a person is: anemic

7 Production of RBC s occurs in the red bone marrow(stem cells differentiate into RBC s). Red blood cells are also called erythrocytes and the process of their formation is called erythropoiesis. Hematopoiesisis a general term for the production of cells found in the blood. Erythropoiesis is specific to production of red blood cells.

8 Regulation of the RBC production: The blood circulates a small amount of hormones to keep up regular rbc production (about 2 million per second). The kidneys continually regulate oxygen levels. If the levels fall outside of homeostatic range then your tissues would not receive enough oxygen-a condition called hypoxia. The kidneys are first to detect this decrease in oxygen.

9 Regulation of the RBC production: Reasons for hypoxia: reduced rbc s because of hemorrhage (bleeding), iron deficiency (leading to insufficient hemoglobin), reduced availability of oxygen (ex-respiratory illness or high altitudes) Kidneys release the hormone eythropoietin (EPO) which circulates in the blood and stimulates the stem cells of the red marrow to produce more RBC s. (A negative feedback mechanism)

11 Types of Anemia-The body is deficient in Hb. Is due to 1. Too few RBC s. Hemorrhagic anemia: loss of blood Hemolytic anemia: RBC s are lysed (ruptured) due to infection or mis-matched blood Aplastic anemia: destruction of red marrow due to toxins, X-ray or chemotherepy.

12 Whenever a tissue is injured, the body uses a positive feedback mechanism to repair it. This prevents unnecessary blood loss from occurring in even the smallest cuts. Blood clotting is performed by clotting factors. These are normally found in blood, but when a tissue is injured, more are produced and released in the liver. There are 13 different clotting factors involved. Synthesis of 4 of the clotting factors requires vitamin K

13 When a tissue is injured- Three main steps in hemostasis. 1. Occurrence of Vascular spasms: Injured endothelial cells and platelets (along with other factors) produce chemicals that cause vascular spasmswhich lead to vasoconstriction or closing down of a blood vessel. Smooth muscle within the artery walls contracts when injured, helping the artery constrict.

14 2. Platelet Plug Formation: Platelets do not normally stick together, or to the lining of blood vessels. However, when tissue is injured this causes platelets to do 2 important things: a. They swelland form spikesand they then become stickyso they form clumps.

15 2. Platelet Plug Formation: continued b. They release chemicals that cause further vasoconstriction(constricting of closing of vessels) and also attract more plateletsto the area to form further clumps. Within 1 minute a platelet plugis built up which reduces blood loss.

16 3. Coagulation: During this process, blood is transformed from a liquid to a gel. First the blood protein, fibrinogenis stimulated to attach to itself to form a stringy net called a fibrinmesh. This traps RBC s. This temporarily seals the hole until the blood vessel can be permanently repaired. This complicated process involves over 30 different substances and many steps.

17 Anticoagulants are factors that inhibit clotting. These are important to prevent a clot from getting too large and preventing it from entering the flowing blood stream. Animation of hemostasis

Cardiovascular System. Blood Components

Cardiovascular System. Blood Components Cardiovascular System Blood Components 1 Components of Blood Formed elements: erythrocytes, leukocytes, platelets Plasma: water, proteins, other solutes The components of blood can be divided into two