1 / 14

Chapter 14

Chapter 14. Blood. Structure & Function. Blood is a type of connective tissue (consists of cells in a matrix) Function – transports O 2 & nutrients, maintains homeostasis, protection from blood loss & infection pH – 7.35-7.45 Volume – 5L (in avg. adult male) Temp. – 100.4 º F.

caryn-acosta
Télécharger la présentation

Chapter 14

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter 14 Blood

  2. Structure & Function • Blood is a type of connective tissue (consists of cells in a matrix) • Function – transports O2 & nutrients, maintains homeostasis, protection from blood loss & infection • pH – 7.35-7.45 • Volume – 5L (in avg. adult male) • Temp. – 100.4 º F. • Accounts for 8% of body weight • Color varies from scarlet (O2 rich) to dark red (O2 poor)

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

  4. Structure • The solid portion makes up 45% of a blood sample • Called the hematocrit (HCT) or packed cell volume (PCV) • Matrix (liquid portion) – plasma; clear,straw-colored • Makes up remaining 55% of sample; mostly H2O, nutrients, etc.

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

  6. Erythrocytes (RBCs) • Structure: • 1. biconcave disks • three advantages: A. increase SA B. no point within the cytoplasm is far from the surface; ideal for gas exchange C. flexible; can squeeze thru tiny b.v.

  7. Erythrocytes • Structure: • 2. Contain hemoglobin (Hb); allows them to carry resp. gases more efficiently • 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 O2 binds • Hb combines easily w/O2 – called affinity ( or attraction) for O2 • Produces oxyhemoglobin; makes blood bright red • When O2 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 – occurs when O2 is deficient (hypoxia) & levels of deoxyhemoglobin incr. • Symptoms – bluish lips & nail beds, dizziness, fainting, fatigue, muscle weakness

  10. Dietary Factors for RBC Production • Two B-complex vitamins (B12 & Folic acid) are imp. for normal RBC production • Both are needed for DNA synthesis • Lack of B12 – usually caused by a disorder of the stomach lining not producing sufficient intrinsic factor (substance needed for B12 absorption) • Iron (Fe) – needed for production of Hb (Vit C increases absorption of Fe in the digestive tract) • Anemia – deficiency or destruction of RBCs (see Table 14.4 – Types of Anemia in text)

  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. • Macrophages break down RBC and their contents. • Hemoglobin breaks down into 4 globin groups and heme groups • Heme breaks down into biliverdin (green pigment)

  14. Destruction of RBC cont. • Biliverdin breaks down into bilirubin (orange) • The iron gets reused to make more hemoglobin or is stored in the liver as ferritin.

More Related