Lecture 13: functions of blood

Question 1

What are the three key functions of blood?

Answer 1

Transport
Immune Response
Coagulation

Question 2

Describe the composition of plasma:

Answer 2

• Makes up approx. 55% of blood
• 7% is plasma proteins
• 1% is electrolytes and waste
• 92% is water

Question 3

What are the formed elements of blood?

Answer 3

• Platelets (<1%) - for blood clotting and prevents bleeding
• White blood cells (<1%) - for immune response within the body
• Red blood cells (99%) - specialized cells that transport oxygen

Question 4

What is Hematopoiesis?

Answer 4

Hematopoiesis is the formation of blood cells, Initiated in red bone marrow, which contains hemocytoblasts

Question 5

What cells create all blood cells?

Answer 5

Blood stem cells (Hemocytoblasts) are the progenitors for all blood cells

Question 6

Describe the Characteristics of
Red Blood Cells (Erythrocytes):

Answer 6

Biconcave Disc shape
- large surface area:volume ratio
- allows for efficient diffusion of gases
- flexibility for movement through narrow capillaries

Question 7

Describe the functional aspects and related structural components of RBCs:

Answer 7

• Contain large amounts of
  hemoglobin
• One-third weight of RBC
• Uses iron as part of the heme
  structures (left, red) to bind
  oxygen
• Four heme units, so each
  hemoglobin can bind four oxygen
  molecules

Question 8

What is hematocrit?

Answer 8

The fraction of blood occupied
by the red cells is called the
hematocrit

Question 9

Name for a person with low/high hematocrit:

Answer 9

• Low hematocrit = anemia (often iron deficient)
• High hematocrit = Polycythemia (maple syrup blood)

Question 10

What factor is required for Erythropoiesis (RBC generation)?

Answer 10

erythropoietin (EPO) which stimulates the generation of RBCs. The process is also augmented by testosterone

Question 11

What is the name of blood stem cells?

Answer 11

Hemocytoblasts