Deck XIII

Question 1

What are the two principle factors that regulate coronary blood flow?

Answer 1

Adenosine and Nitric oxide (NO)

Question 2

What is the difference in function of adenosine and NO in regulation of coronary blood flow?

Answer 2

NO mediates coronary vascular dilation in large arteries and pre-arteriolar vessels; adenosine acts as a vasodilator in small coronary arteries.

Question 3

A holosystolic murmur that increases in intensity on inspiration most likely represents what pathology?

Answer 3

Tricuspid regurgitation (the other holosystolic murmurs- mitral regurgitation or VSD do not typically increase in intensity on inspiration)

Question 4

How do you calculate total filtration rate of a substance?

Answer 4

(Inulin clearance)(Plasma concentration of substance X)

Question 5

How do you calculate the net excretion rate of a substance?

Answer 5

(Inulin clearance)(plasma concentration of substance X)- (tubular reabsorption of substance A)

Question 6

What is the difference between type I and type II muscle fibers?

Answer 6

Type I fibers- aeorbic metabolism with high myoglobin and mitochondrial concentrations; type II fibers- rapid, forceful movement (IIB- anerobic glycogenolysis and subsequent glycolysis, IIA- fast twitch generate ATP via aerobic metabolism)

Question 7

How do you calculate renal plasma flow (RPF)?

Answer 7

(1-hematocrit)(renal blood flow)

Question 8

What is an alternate equation for FF that uses RPF instead of RBF?

Answer 8

FF= GFR/ (1-Hct)(RBF)

Question 9

Lesions of the macula cause what condition?

Answer 9

Central scotomas

Question 10

Describe the changes in urea concentration along the proximal tubule of the nephron.

Answer 10

Urea is freely filtered from the glomerular capillaries and is poorly reabsorbed from the proximal tubule

Question 11

Describe the changes in bicarbonate concentration along the proximal tubule of the nephron.

Answer 11

Bicarb is actively reabsorbed in the proximal tubule due to the activity of carbonic anhydrase within proximal tubule cells. Bicarb concentration decreases in the proximal tubule as it continues through.

Question 12

What is the airway pressure at the FRC? What is the intrapleural pressure?

Answer 12

airway: 0 cm H2O; intraplural: -5 cm H2O due to the tendencies of the chest wall to expand and the lungs to collapse

Question 13

List the following in order of fastest to slowest cardiac conduction velocity: atrial muscle, AV node, purkinje system, ventricular muscle.

Answer 13

Purkinje system, atrial muscle, ventricular muscle, AV node

Question 14

How do transmembrane carrier proteins in the GLUT family transport glucose?

Answer 14

Facilitated diffusion

Question 15

Where is GLUT 4 found?

Answer 15

Skeletal muscle and adipocytes. It is insulin sensitive

Question 16

What is the function of GLUT2?

Answer 16

It facilitates the export of glucose from the liver, small intestine, and kidneys into circulation and helps to control insulin secretion in the pancreas.

Question 17

What are the manifestations of osteodystrophy?

Answer 17

Increased bone turnover, resorptive bone lesions

Question 18

What is osteitis fibrosa cystica?

Answer 18

The high bone turnover rate seen in hyperparathyroidism.

Question 19

What is the role of progesterone in ovulation?

Answer 19

Its secretion increases following ovulation (day 14) with formation of the corpus luteum. It then maintains the endometrium to allow for implantation.

Question 20

When do progesterone levels peak in the menstrual cycle?

Answer 20

In the mid-luteal phase

Question 21

A patient with one testicle is found to have elevated serum FSH levels and a normal serum LH level. What substance is likely to be impaired in this patient?

Answer 21

Inhibin B

Question 22

What is the role of LH in males?

Answer 22

To stimulate release of testosterone from leydig cells

Question 23

What is the role of FSH in males?

Answer 23

To stimulate release of inhibin B from the sertoli cells of the testes

Question 24

Describe the feedback loop between testosterone and LH and GnRH secretion in males.

Answer 24

Testosterone has negative feedback on LH and GnRH secretion

Question 25

What is the relationship of feedback between Inhibin B and FSH?

Answer 25

Inhibin B supresses FSH secretion.

Question 26

Where is inhibin B produced?

Answer 26

In the sertoli cells. It is the physiological inhibitor of FSH secretion (LH is primarily controlled by testosterone feedback)

Question 27

What is the equation for cardiac output in terms of oxygen consumption?

Answer 27

O2 consumption/ A-V O2 difference

Question 28

Describe the relationship between serum creatinine and GFR.

Answer 28

Nonlinear relationship where creatinine decreases as GFR increases. Approximately every time GFR halves, serum creatinine doubles.

Question 29

Describe the EKG findings in a patient with a-fib.

Answer 29

Tachycardia, irregular rhythm, narrow QRS complexes, no P waves “irregularly-irregular R-R intervals”.

Question 30

How is A-fib initiated?

Answer 30

By aberrant electrical impulses that arise within regions of heightened atrial excitability (most often the pulmonary veins)