UWorld Exam 1 Section 3

Question 1

Describe the pathogenic course of pulmonary HTN

Answer 1

1) Injury to pulmonary endothelium
2) Narrowing of pulmonary vascular bed with resultant RV hypertrophy
3) Accelerated vascular injury secondary to increased pulmonary arterial pressure
4) Further rise in RV afterload
5) Dilation of RV

Question 2

What is the enzyme responsible for the first step of beta- oxidation of fatty acids

Answer 2

Acyl-CoA dehydrogenase

Question 3

What is the enzyme responsible for the first step in fatty acid synthesis

Answer 3

Acetyl-CoA carboxylase

Question 4

What are the substrates of CYP450

Answer 4

Always Think When Outdoors:

A - Anti-epileptics

T - Theophylline

W - Warfarin

O - OCPs

Question 5

What are the inducers of CYP-450

Answer 5

Corona, Guiness, ‘N’ PBRS induce Chronic alcoholism

C - Carbamazepine

G - Griseofulvin

N - Nevirapine

P - Phenytoin

B - Barbiturates

R - Rifampin

S - St. John’s Wort

Chronic alcoholism

Question 6

What are the inhibitors of CYP-450

Answer 6

SICKFACES.COM:

S - Sodium valproate

I - Isoniazid

C - Cimetidine

K - Ketoconazole

F - Fluconazole

A - Acute alcohol abuse

C - Chloramphenicol

E - Erythromycin (macrolides)

S - Sulfonamides

C - Ciprofloxacin

O - Omeprazole

M - Metronidazole

Question 7

Describe the Internal Ribosome Entry and it’s function in eukaryotic translation

Answer 7

Eukaryotic translation is initiated when the small ribosomal subunit bind the 5’ cap of mRNA (facilitated by initiation factors, IF) and scans for the AUG start codon within the Kozak consensus sequence

Internal ribosome entry is an alteranative method used by apoptotic cells whereby a distinct nucleotide sequence (usually in the 5’ untranslated region) allows translation to begin in the middle of mRNA

Question 8

Most frequent site of involvment in Crohn disease

Answer 8

Terminal ileum

Question 9

What disease is characterized by decreased mineralization of osteoid

Answer 9

Osteomalacia

Question 10

What disease is characterized by excessive bone resportion out of proportion to new bone formation

Answer 10

Osteoporosis

Question 11

Differentiate between compact and trabecullar bone

Answer 11

Compact - dense, hard, outer bone shell

Trabecullar - inner cancellous/spongy bone separated by interconnecting marrow spaces

Question 12

What are the 2 main microscopic forms of bone

Answer 12

Woven - immature, first bone to be laid down during fetal osteogenesis and following a fracture. Will be later remodelled to lamellar bone

Lamellar - stronger bone containing regular, parallel collagen fibers and sheets

Question 13

What disease is characterized by the abnormal fomation of lamellar bone

Answer 13

Paget disease of the bone

Question 14

What nerve may be complicated in dilation of the aortic arch, and which muscles may be affected?

Answer 14

L recurrent laryngeal nerve

May lead to paralysis of most of the intrinsic laryngeal muscles (posterior cricoarytenoid, lateral cricoarytenoid, oblique arytenoid, transverse arytenoid, thyroarytenoid) - responsible for sound production

Does no innervate the cricothyroid

Question 15

What is the only DNA virus that replicates in the cytoplasm

Answer 15

Poxvirus

Question 16

What is the abnormal heart sound associated with an atrial septal defect?

Answer 16

Widely split S2

Question 17

What is achalasia and what is the cause?

Answer 17

Esophageal motility disorder characterized by the absence of esophageal peristalsis in the distal esophagus and lower esophageal sphincter (LES) that is unable to relax

Due to damaged ganglion cells of the myenteric plexus

Question 19

Describe the location and deficits of Broca’s and Wernicke’s area

Answer 19

Broca:

• located in inferior frontal gyrus of the dominant (usually left) hemisphere
• lesion = expressive aphasia (slow speech consisting primarily of nouns and verbs - agrammatism); speech is punctated by pauses; preserved speech comprehension; patients are aware of their expressive language dysfunction

Wernicke:

• located in the caudal superior temporal gyrus
• lesion: receptive (sensory) aphasia; fluent aphasia (speech flows but is meaningless); patients are unaware of their problem

Question 20

What are some examples of unmyelinated neuron fibers (aka group C nerve fibers)

Answer 20

Those responsible for slow pain (dull, burning, or visceral pain), heat sensation, olfaction, and postganglionic autonomic NS axons

Question 21

Are preganglionic autonomic nerve fibers myelinated or unmyelinated?

Answer 21

Myelinated

Question 22

Describe the components of MHC class II and what parts are expressed vs. not expressued during antigen processing

Answer 22

During antigen processing within the cell, the invariant chain brings the alpha and beta chains of MHC II together

The invariant chain is then removed from the MHC-invariant complex and replaced by an external protein

The MHC-peptide comples (containing a-chain, b-chain, and external protein) is then expressed at the cell surface

Question 23

What are clinical symptoms of iron deficiency anemia other than weakness and fatigue?

Answer 23

Glossal pain, dry mouth, atrophy of the tongue papilla, alopecia

Question 24

What is pagophagia and what disease is it specific for?

Answer 24

Craving for ice

Specific for iron deficiency