November 8, 2023

Question 1

Given the following:

➢{Hb} is 14g/100mls blood
➢Arterial blood Hb is 90% saturated based on the arterial PO2
➢Venous blood Hb is 60% saturated at the resting venous PO2

Calculate the (a-v) O2 difference

Answer 1

Aterial:
1.34(0.9) = 1.206mls O2/g Hb
14g Hb/100mls x 1.206mls O2/g Hb
= 16.884 vols%

Venous:
1.34(0.6) = 0.804mls O2/g Hb
14g Hb/100mls x 0.804mls O2/g Hb
= 11.256 vols%

(a-v)O2 difference:
16.884 - 11.256
= 5.63 vols%

Question 2

Use words to describe why a superbly trained athlete can experience hypoxemia during intense exercise

ANSWER QUESTIONS AT BEGINNING OF EACH LECTURE

Question 3

what is the response of the kidney and bone marrow to reduced O2 delivery?

Answer 3

increase EPO secretion and RBC production

Question 4

how does the kidney and bone marrow negative feedback loop work when there is reduced tissue O2 delivery

Answer 4

1. reduced O2 carrying capacity
2. kidney secretes Erythropoietin (EPO)
3. EPO stimulates bone marrow to produce RBCs
4. Increased O2 carrying capacity

Question 5

How does EPO affect stem cells

Answer 5

1. EPO stimulates the differentiation of stem cells into erythroblasts and further into erythrocytes
2. Precursors that lead to RBCs

3.Proliferation of erythroblasts

4.Maturation (enucleation) of reticulocytes into the RBC (removal of nucleus)

page 116

Question 6

what is Aplastic Anemia and how does it occur

Answer 6

Occurs when the bone marrow is destroyed by radiation or chemicals (insecticides, herbicides, organic solvents, paint removers, and other toxic chemicals); since RBCs are made in bone marrow you will become anemic

Question 7

how is Aplastic Anemia treated

Answer 7

requires a bone marrow transplant

Question 8

in what scenario is Aplastic Anemia done on purpose

Answer 8

Sometimes done on purpose, as with chemotherapy to treat blood cancers(i.e. lymphomas); destroy stem cells, then replace it

Question 9

how are anemias characterized?

Answer 9

low Hct and Hb

Impaired endurance performance (fatigue)

Question 10

how is Aplastic anemia induced:

Answer 10

chemically induced

Question 11

how is Sickle cell anemia induced:

Answer 11

genetically induced

Question 12

how is Pernicious anemia induced:

Answer 12

surgically or diet induced

Question 13

how is Iron-deficiency anemia induced:

Answer 13

diet induced

(meat and fish are important sources of Fe; the redder the meat or fish, the more iron)

Question 14

what are the results of 2 weeks of iron deficiency:

➢VO2 Max
➢Hematocrit
➢Mitochondrial enzymes
➢Endurance

Answer 14

➢VO2 max decreases about 50%
➢ Hematocrit decreases 60% (100 to 40)
➢ Mitochondrial enzymes decrease about 80% (100 to 20)
➢ Endurance totally diminishes

graph on page 118

Question 15

what are the results of Dietary iron repletion over 7 days after having 2 weeks of iron deficiency:

➢VO2 Max
➢Hematocrit
➢Mitochondrial enzymes
➢Endurance

Answer 15

➢VO2 max is closely related to O2 transport capacity (related to Hct)

➢ Mitochondrial enzymes and endurance take a few days to increase

➢ All increase to about normal within a week

Question 16

how does Vitamin B12 affect RBC

Answer 16

Stimulates RBC synthesis

Question 17

what does a lack of Vitamin B12 do

Answer 17

Lack of Vitamin B12 causes anemia

Question 18

where can Vitamin B12 in the regular diet

Answer 18

found in fish, meat, yogurt, milk, etc.

Question 19

what diet is deficient in Vitamin B12

Answer 19

It is deficient in the vegan diet

Question 20

what is Pernicious Anemia

Answer 20

deficiency in Vitamin B12

Question 21

How does Vitamin B12 lead to RBC synthesis once ingested

Answer 21

1. Parietal cells in the stomach secrete IF (intrinsic factor)
2. IF binds ingested vitamin B12 (B12 can’t be absorbed without IF)
3. IF-B12 complex is absorbed by the gut by endocytosis and travels to the bone
   marrow
4. Vit B12 stimulates RBC synthesis in bone marrow cells

Question 22

what is the primary cause of Pernicious Anemia

Answer 22

Lack of parietal cells result in a lack of B12 being taken up (can be sufficient in diet just not being absorbed because no IF meaning not being taken up into bone
marrow)

The primary cause of pernicious anemia is a deficiency of intrinsic factor, a protein produced by the stomach lining. Intrinsic factor is necessary for the absorption of vitamin B12 in the small intestine. Without sufficient intrinsic factor, vitamin B12 cannot be effectively absorbed, leading to a B12 deficiency.

Question 23

what is Sickle Cell Anemia

Answer 23

Sickle cell anemia: a genetic disease due to a ‘point mutation’ in the beta globin gene; it affects 0.14% of the African American population in the US

Question 24

how many globin subunits are in adults Hb?

How many polypeptide chains?

Answer 24

In adults Hb, there are 2 alpha and 2 beta globin subunits

(4 polypeptide chains)

Question 25

how many amino acid chains does the alpha globin subunit have? How many does the beta-globin subunit have?

Answer 25

The alpha globin subunit has 141 amino acid chains beta globin subunit has 146 amino acids

Question 26

what is each globin subunit bound to

Answer 26

Each subunit is bound to heme, which contains a central iron atom which binds O2

Question 27

3 nucleotides = ______ amino acids

Answer 27

3 nucleotides = 1 amino acids

Question 28

what is a ‘point mutation’

Answer 28

a change in a single nucleotide base (ex: ATCG) within the DNA sequence of a gene.

Question 29

How does Sickle Cell Anemia happen

Answer 29

a change in a single nucleotide base in the codon for glutamate results in amino acid switch in the primary structure (valine instead of glutamate) this causes Beta globin proteins that are mutated, to polymerize(combine together) the cell at a low PO2 → this leads to distorted RBC shape and stiff cells which plug capillaries, then break (hemolysis), and this leads to anemia

Question 30

how many nucleotides in the B-globin gene are required to code for the functional protein

Answer 30

3x146

Question 31

what subunits are expressed in fetal Hb

Answer 31

alpha2, gamma2 Gamma are expressed in children

Question 32

what subunits are expressed in adult Hb

Answer 32

alpha2, beta2 Beta and alpha are expressed in adults

Question 33

when Gamma gene shut off

Answer 33

Gamma gene is shut off postnatally

Question 34

what is Hydroxyurea

Answer 34

1. a drug that increases the production of fetal Hb by inducing gamma (y) subunit expression 2. this competes with the beta subunit during Hb synthesis and ‘replaces’ it, leading to more Hb F (fetal) in the blood

Question 35

Fetal Hb does not have the mutated beta globin subunit which causes sickling

Answer 35

Fetal Hb does not have the mutated beta globin subunit which causes sickling

Question 36

does Hb F or Hb adult have stronger affinity for O2

Answer 36

Hb F has a stronger affinity for O2

Question 37

The Function of Myoglobin (Mb) and How does it work

Answer 37

An iron containing protein which binds O2 and is found in muscle Mb stores O2 and facilitates its diffusion within the muscle cell to the mitochondria

Question 38

which has a higher O2 affinity Mb or Hb

Answer 38

Mb has a higher affinity for O2 than Hb does

Question 39

why is Mb Important in aquatic animals

Answer 39

Important in aquatic animals so they can store sufficient O2 to remain underwater for long periods of time not so much in other mammals for endurance purposes

Question 40

explain the Mb “knockout” animal (mouse) experiment

Answer 40

removed Mb from mouse results showed: Heart and skeletal muscle become pale However, endurance performance was not impaired

Question 41

how is Mb useful as a diagnostic tool

Answer 41

It is supposed to be in muscle, and if you find it in the blood, this means it has leaked out (rhabdomyolysis) - muscle injury has taken place Breakdown product of released myoglobin (ferrihemate) is toxic to kidney epithelial cells, and can cause acute renal failure Because myoglobin is also found in high concentration in the heart, it is a sensitive marker for cardiac muscle injury, making it a potential marker for heart attack in patients with chest pain

Question 42

Describe some characteristics of Restrictive Lung disease (stiff lung): compliance: elasticity: examples of Restrictive disease: air inspiration/expiration:

Answer 42

Decreased compliance increased elasticity Pulmonary fibrosis, pulmonary edema Hard to get air in, decreased volume of air per breath

Question 43

Describe some characteristics of Obstructive Lung Disease (COPD): compliance: elasticity: examples of obstructive disease: air inspiration: Tidal volume:

Answer 43

Increased compliance decreased elasticity (floppy lung) Emphysema, bronchitis (small airway, obstructive diseases, causes often related to smoking) Asthma (large airway, obstructive disease) Easy to get air in, difficult to get air out Smaller tidal volume