physiology week 9

Question 1

What is the primary role of red blood cells

Answer 1

• Transports hemoglobin, which carries oxygen from lungs to tissues

Question 2

Why must the hemoglobin remain inside the red blood cells

Answer 2

• To avoid loss through the capillary and kidney membranes

Question 3

What else does red blood cells contain

Answer 3

• Carbonic anhydrase, which is an enzyme that catalyses the conversion of C02 and water into carbonic acid

Question 4

What are the roles of carbonic anhydrase

Answer 4

• An enzyme that catalyses the conversion of c02 and water into carbonic acid
• It enables efficent C02 transport as bicarbonate ions
• Contributes to acid-base buffering in the blood due to hemoglobin properties

Question 5

What is the shaoe and size of RBC

Answer 5

• Has a biconcave disc
• Volume of 90-95 cubic meters
• Has a flexible bony like structure which allows the deformation for passage through capillaries without rupture

Question 5

What are the sites of red blood cell production in the embroyonic stage:
-Early weeks
-Middle trimester
-Last trimester+ after birth

Answer 5

• Early weeks:
  -Primitive nucleated red blood cells are produced in the yolk sac
  Middle trimester
  -The liver is the primary ogran for RBC and some is also produced in the spleen and lymph
  LAST TRIMESTER & AFTER BIRTH
  -RBC production shifts to the bone marrow

Question 5

During childhood where are red blood cells produced

Answer 5

• In the marrow of nearly all bones up to 5 years of age

Question 6

During Adulthood where is red blood cells produced

Answer 6

• In the membranous bones:
  -Vertberae
  -Sternum
  -Ribs
  -ilia

Question 7

What is the aging effect in relation to bone marrow

Answer 7

• Bone marrow productivity decreases as age increases even in membranous bones

Question 8

Where do circulating red blood cells orginate from

Answer 8

• Multipotential hematopoietic stem cells (HSCs) in the bone marrow
• The stem cells self renew to maintain their supply, but their numbers decrease with age

Question 9

What happens as HSCs( hematopoietic stem cells) reproduce

Answer 9

-Most cells differentiate into specific cell types while a small portions remains a HSCs

Question 10

• Where do commited cells arise from

Answer 10

• They arise from multipotent stem cells and are specific to a cell line

Question 11

Whay do commited stem cells produce

Answer 11

• They produce colonies of specific blood cells such as
• CFU-E , which forms erythrocytes)RBC)
  -CFU-GM, which formes granulocytes and monocytes

Question 12

What are growth inducers
And how many exist

Answer 12

• They are proteins that control growth and reproduction of stem cells
• At least 4 major growth inducers exist

Question 13

Name an example of a growth inducer and its role

Answer 13

• Interleukin -3 and it promotes the growth of nearly all types of committed cells

Question 14

What are differentiation inducers

Answer 14

-Proteins that control differentiation of stem cells into specific blood cell types.
Each differentiation inducer acts on a specific committed stem cell.

Question 15

Name factors outside the bone marrow that regulate growth and differentiation

Answer 15

–Low oxygen levels which increases RBC production
-Infections which stimulates production of specific white blood cells to combat the infection