NBME 21

Question 1

What is SvO2 (mixed venous oxygen tension)?

Answer 1

Amount of oxygen bound to hemoglobin as it returns to the right side of the heart after traveling to the tissues. Will be decreased in situations where the tissues are extracting more o2 from the blood

Question 2

Where do metolazone, chlorthalidone act?

Answer 2

Inhibit NaCl in early DCT

Question 3

What innervates the M3 receptor on detrusor muscle?

Answer 3

Pelvic nerve (PNS)

Question 4

What does the pudendal nerve do to the urinary system?

Answer 4

Releases ach onto the nicotinic receptor, causes external sphincter to contract

Question 5

How does the hypogastric nerve work?

Answer 5

Releases noradrenaline
Binds B3 on detrusor causing relaxation, binds alpha 1 receptor and causes contraction of internal sphincter. Overall it causes urinary retention

Question 6

Chancre: small painless ulcer w/ clean base caused by?

Answer 6

Tryponema aka syphillis

Question 7

Aortic dissections are tears in?

Answer 7

Intima

Question 8

What is an AD mutation of Uroporphyrinogen decarboxylase going to cause? What is it associated w/ how do you treat?

Answer 8

Porphyria Cutanea Tarda, accumulated Uroporphyrin in the urine. Most common porphyrea. Is associated w/ alcohol consumption and HepC

Question 9

Porphobilinogen deaminase mutation that leads to accumulation of Porphobilinogen and ALA along with painful abdomen, port wine urine, polyneuropathy, psychological disturbances

Answer 9

Acute intermittent porphyria. Treat with hemin and glucose

Question 10

Unregulated activation of kallikrein, bouts of diffuse edema.

Answer 10

C1 esterase inhibitor deficiency

Question 11

JG cells are modified smooth muscle cells located where?

Where are macula densa cells located?

Answer 11

JG: afferent arteriole

Macula Densa: distal tubule

Question 12

How does the induction of Hepcidin by IL-6 cause Anemia of Chronic Dz?

Answer 12

Hepcidin is an acute phase reactant that decreases iron absorption by degrading ferroportin and decreases iron release from macrophages—> anemia of chronic disease (decrease in iron, decrease in TIBC, but increase in ferritin)

Question 13

Donor anti-leukocyte antibodies against recipient neutrophils and pulmonary endothelial cells

Answer 13

Transfusion related acute lung injury

Question 14

Ferguson reflex

Answer 14

Stretch or dilation of the cervix and vagina are strong stimuli for oxytocin secretion

Question 15

Which NRTI causes pancreatitis?

Answer 15

DIDANOSINE

Question 16

What type of HSR is a Hyperacute transplant rejection?

Answer 16

Occurs within minutes due to pre-existing RECIPIENT ABs that react to DONOR ANTIGEN (type II HSR). IgG or IgM plus complement

Question 17

Berkson bias

Answer 17

When studies are done on populations that are treated at one hospital or by one doctor rather than the community

Question 18

Contralateral thalamic lesions can cause what syndrome?

Answer 18

Central Post Stroke Pain Syndrome: neuropathic pain post stroke

Question 19

Where does osteosarcoma metz to?

Answer 19

Lungs

Question 20

Where does the thyroid get its blood supply from?

Branch of carotid, branch of thyrocervical trunk

Answer 20

Superior thyroid artery (external carotid)

Inferior thyroid artery (thyrocervical trunk)