CVS; Hemodynamics

Question 1

Circulating blood volume in 70kg man

Answer 1

5.6 L 8T% of the body weight

Question 2

In bone marrow, percentage of cells that make up a) WBC producing cells b)RBC producing cells

Answer 2

WBC –> 75%

RBC –> 25%

Question 3

The most abundant WBCs

Answer 3

neutrophils

Question 4

Least abundant WBCs

Answer 4

Basophils

Question 5

Half-life of platelets

Answer 5

4 days

Question 6

Which cells form platelets?

Answer 6

Megakaryocytes in bone marrow, via creation of demarcation tunnels

Question 7

Thrombocytosis refers to

Answer 7

increase in number of platelet count

Question 8

half life of RBCs

Answer 8

120 days

Question 9

Define hematocrit

Answer 9

the ratio of the amount of RBCs to the volume of blood (the percentage of RBCs in blood)

Question 10

Amount of Hb in circulating blood in an adult

Answer 10

900g

Question 11

Structure of hemoglobin A1c and its clinical significance.

Answer 11

Similar to Hemoglobin A2 which has 2 beta chains and 2 sigma chains, except Hemoglobin A1c’s beta chain is glycosylated.
Because it increases in patients with diabetes mellitus, it is a useful indicator of this condition and the effectiveness of treatment

Question 12

Percent of hemoglobin in adults that is in the form A2?

Answer 12

2.5%

Question 13

Structure of Hb

Answer 13

4 subunits; each subunit is made of a heme and a 2 chain polypeptide called globin

Question 14

Factors affecting Hb’s affinity to oxygen?

Answer 14

Temperature
pH
concentration of 2,3-biphosphoglycerate

Question 15

Change in charge of iron when Hb is converted to methemoglobin.

Answer 15

From ferrous (Fe2+) to ferric (Fe3+)

Question 16

Congenital absence of methemoglobin reductase leads to

Answer 16

hereditary methemoglobinemia

Question 17

Why fetal blood has high levels of oxygen?

Answer 17

Because it binds less strongly to 2,3-BPG, it’s able to hold oxygen for longer

Question 18

2 molecules used to synthesize the heme portion of Hb?

Answer 18

glycine + succinyl-CoA

Question 19

Explain the use of phototherapy in treating infants with jaundice.

Answer 19

Jaundice is caused by excess hemolysis resulting in build up of bilirubin. When exposed to light, bilirubin is converted to lumirubin which has a shorter half-life and so degrades more easily.

Question 20

Functions of proteins.

Answer 20

1. Maintain oncotic pressure
2. Carriers of hormones, lipid soluble substances
3. Involved in defense as antibodies
4. 3rd mechanism of buffering capacity
5. Involved in blood clotting coagulation cascade
6. Albumin acts as source of nutrients because it’s rich in essential AAs

Question 21

Between albumin and globulin which one is more abundant?

Answer 21

Albumin

Question 22

Which globulin transports ferrous ions (Cu2+) ?

Answer 22

alpha-2 globulin

Question 23

2 methods for measuring blood-flow

Answer 23

N20/Kety method (measures cerebral blood flow)
Plethysmography (water-tight chamber that uses the amount of water displaced to measure changes in arterial and venous volume)
Para-aminohippuric acid clearance rate (measures renal blood flow)
Dopplerflow meters (rely on ultrasonography; frequency of waves = rate of flow)

Question 24

What is the critical velocity?

Answer 24

The velocity at or above which blood flow changes from laminar to turbulent