Lecture 13: Composition and General Functions of Blood Mon 3 August

Question 1

What are the three general functions of blood?

Answer 1

Transport
Immune response
Coagulation

Question 2

What 10 things does the body have to transport?

Answer 2

1. O2
2. CO2
3. water
4. nutrients
5. Ions associated with pH and homeostasis
6. heat
7. hormones
8. waste products
9. immune cells
10. coagulation

Question 3

What is involved in the immune function of blood?

Answer 3

WBC (mostly) move in the blood to identify and destroy pathogens

Question 4

What is involved in the coagulation function of blood?

Answer 4

Platelets and coagulation factors in the plasma are responsible for blood clotting to prevent bleeding

Question 5

Describe the composition of blood

Answer 5

• 55% plasma

- 45% formed elements

Question 6

Describe the composition of plasma

Answer 6

• water
• plasma proteins
• other solutes

Question 7

What is the largest component of plasma?

Answer 7

water (92%)

Question 8

What three things make up the formed elements of blood?

Answer 8

1. Platelets
2. WBC
3. RBC

Question 9

What is the largest component of formed elements?

Answer 9

RBC (99.9%)

Question 10

What are platelets?

Answer 10

Cell fragments that participate in clotting to stop bleeding

Question 11

What is hematopoiesis?

Answer 11

The formation of blood cells

Question 12

Where is hematopoiesis initiated?

Answer 12

In the bone marrow

Question 13

Describe the process of hematopoiesis

Answer 13

hemocytoblasts is the progenitor that differentiates into all the different blood cells in the bone marrow

Question 14

What is the signal that makes hemocytoblasts differentiate into RBC?

Answer 14

the release of erythropoietin (EPO) which signals hemocytoblasts to go down the path to make RBC

Question 15

Describe the shape of RBC

Answer 15

biconcave disc shape with a large surface area:volume ratio

Question 16

What is the benefit of RBC having a large surface area:volume ratio?

Answer 16

Allows for efficient diffusion of gases and allows flexible movement through narrow capilaries

Question 17

Do RBC have nuclei? Why?

Answer 17

No because they differentiate from the hemocytoblasts and because it needs to fit as much haemoglobin as possible

Question 18

Describe the characteristics of RBC

Answer 18

• contains large amounts of haemoglobin
• haemoglobin takes up one third of the weight of RBC
• haemoglobin uses iron as part of the haem to bind O2
• four heam units per haemoglobin so each haemoglobin can bind to four O2 molecules

Question 19

What is hematocrit?

Answer 19

The fraction of blood occupied by the red blood cells

Question 20

What is low hematocrit called?

Answer 20

anemic

Question 21

What is high hematocrit called?

Answer 21

polycythemic

Question 22

What is the effect of testosterone on the production of RBC?

Answer 22

More testosterone = more EPO released = more RBC formed from hemocytoblasts so higher hematocrit

Question 23

Why do athletes train at high altitudes?

Answer 23

high altitudes = less O2 in the air = increased secretion of EPO from the kidneys = more RBC formation = more O2 can bind

Question 24

What is erythropoiesis?

Answer 24

the formation of red blood cells stimulated by erythropoietin