1. Chapter 14 Blood

2. Structure & Function Blood is a type of connective tissue (consists of cells in a matrix) Function – pH – Volume – 5L (in avg. adult male) Temp. – 100.4 º F. Accounts for 8% of body weight Color varies from scarlet (O 2 rich) to dark red (O 2 poor)

3. Structure Composition – composed of 3 types of cells (called solid portion): 1. RBCs – 2. WBCs – 3. platelets -

4. Structure The solid portion makes up 45% of a blood sample Called the hematocrit (HCT) or packed cell volume (PCV) Matrix (liquid portion) – Makes up remaining 55% of sample; mostly H 2 O, nutrients, etc.

5. Hematopoiesis – Production of blood cells (RBCs, WBCs & platelets)

6. Erythrocytes (RBCs) Structure: 1. biconcave disks three advantages: A. B. no point within the cytoplasm is far from the surface; ideal for gas exchange C.

7. Erythrocytes Structure: 2. 3. Mature RBCs lack nuclei; allows more room for Hb (each RBC is 1/3 Hb by volume) Normal RBC count: 4-6 million/mm³ of blood (in avg. adult) (slight incr. after meals or exercise; decr. from anemia, leukemia, or hemorrhage)

8. Hemoglobin Hb consists of the protein globin→ Each has 4 polypeptide chains & 4 heme groups (pigment) where O 2 binds Hb combines easily w/O 2 – When O 2 is released from the RBC, deoxyhemoglobin is produced; makes blood dark bluish-red

9. Hemoglobin Normal Hb levels – 14-18 gm/100 ml of blood (in avg. adult male) Cyanosis – Symptoms – bluish lips & nail beds, dizziness, fainting, fatigue, muscle weakness

10. Dietary Factors for RBC Production Two B-complex vitamins (B 12 & Folic acid) are imp. for normal RBC production Both are needed for DNA synthesis Lack of B 12 – Iron (Fe) – needed for production of Hb (Vit C increases absorption of Fe in the digestive tract) Anemia –

11. Control of RBC Production

12. Life Cycle of an RBC

13. Destruction RBC RBC break down from wear and become ruptured when travelling through the kidney and spleen. Hemoglobin breaks down into 4 globin groups and heme groups

14. Destruction of RBC cont. The iron gets reused to make more hemoglobin or is stored in the liver as ferritin.