UWorld Practice Test #1

Question 1

What is the relative speeds of the electrical signal within the heart. Where is it fastest and where is it slowest?

Answer 1

Park AT VENtricular AVenue

Purkinje…Atria…Ventricles…AV Node

Question 2

Bone tumor associated with Paget Disease

Answer 2

Osteosarcoma

-remember that this is destruction of normal trabellular bone pattern, mixed radiodensities, periosteal new bone formation, lifting of the cortex, and Codman’s triangle

Bimodal distribution

Seen on metaphasis of long bones (unlike ewing which is in diaphysis)

Question 3

Globus sensation in throat

Answer 3

• common abnormal sensation of a foreign body, tightness, or fullness in the throat. It often worsens when swallowing saliva and may be aleviated when swallowing food
• It is a functional disorder, there is no structural defect
• Frequently associated with anxiety or other underlying psych issues

“Lump in your throat”

Question 4

DNA laddering

Answer 4

DNA fragments in multiples of 180bp is a sensitive indicator of apoptosis

-A hallmark of cancer is the ability to evade apoptosis, particularily the intrinsic (mitochondrial) pathway of apoptosis (seen in BCL2 overexpression in t(14;18) follicular lymphoma)

Question 5

What is drug X and drug Y

Answer 5

Drug X must be ACh since when it is combined with Phyostigmine (an AChE-I, the effect is increased).

Thus, drug Y must be a muscarinic antagonist, and the most likely drug would be Atropine (results in decreased muscle contraction)

-Ipatroprium and Tiotroprium work via similar mechanisms and could be Y as well.

Question 7

What does this pt have and what are some common features?

Answer 7

Acute Promyelicytic Leukemia (APL) which is a translocation of t(15:17). See auer rods

tx: all-trans retinoic acid

Question 8

What cytokine is produced exclusively by lymphocytes

Answer 8

IL-2 produced exclusively by antigen stimulated T-cells

NOT:

IL-1 –> produced by mononuclear phagocytes

TNF-alpha –> produced by macrophages

INF-alpha –> produced by macrophages, NK, monocytes, B-cells

Question 9

What is this lesion and what would you see histologically?

Answer 9

Molluscum Contageiosum. The papulles are pruritic and have umbilicated centers

Caused by the poxvirus. Transmitted through direct contact or fomites

Under microscope will see epidermal hyperplasia along with molluscum bodies. These will be filled with large eosinophilic cytoplasmic inclusions of viral particles

Question 10

Key defense mechanisms. LEARN THEM!!!

Acting out

Denial

Displacement

Intellectualization

Passive Agressive

Projection

Rationalization

Reaction formation

Regression

Splitting

Sublimation

Suppression

Answer 10

Question 11

Label the parts of this image and where does Sildalfinil work?

Answer 11

A: tunica albuginea (Buck fascia)

B: corpus cavernosum

C: deep fascia

D: Corpus spongiosum

E: urethral lumen

Question 12

What organ secretes like this?

Answer 12

This is the exocrine pancreas

Contains fixed concentrations of Na and K that are virtually identical to those of the plasma

Levels of bicarb and Cl vary with pancreatic flow rate (which increases in response to secretin)

The inverse relationship of bicarb and Cl is due to a chloride bicarb exchanger on the apical surface of ductal cells

Question 13

PTSD vs Acute stres disorder

Answer 13

PTSD >1 month

ASD > 3 days < 1 month

Question 14

Relative Risk calculation

Answer 14

The risk in exposed subjects vs the risk of unexposed subjects

RR= (a/(a+b))/(c/(c+d))

Question 15

Number needed to treat

Answer 15

1/ARR

Question 16

60-70% of pts with myathinia gravis also have what?

10-15% of MG patients have what?

Answer 16

60-70 –> hyperplastic thymic tissue

10-15 –> thymoma

Question 17

Pt in DKA, what are Na, K and Glucose levels in serum (early on before treatment)

Answer 17

Na –> LOW due to the osmotic activity of glucose (serum Na drops 1.6 for every 100 mg/dl rise in glucose)

K –> HIGH due to acid driving K/H exchange and because insulin driving K into cells is absent (total K body stores are actually depleted and will need to be replaced but appear high at first)

Glucose –> HIGH

Question 18

Bilateral thombi in the lateral ventricles of a premature newborn seen on autopsy is caused by what?

Answer 18

This is due to interventricular hemorrhage, also known as germinal matrix hemorrhage (dense cellular and vascular layer of subependymal zone of the brain from which neurons develop) This should involute at 28 weeks gestation. This is a weak area of the brain and lacks structural support, which makes it vulnerable to spontaneous hemorrhage.

Can cause altered mental status and eventual death

Question 19

Misoprostol vs Metoclopramide

Answer 19

Misoprostol –> PGE 1 analog that prevents NSAID induced peptic ulcers (and also maintenance of PDA)

Metoclopramide –> D2 receptor antagonist used as an antiemetic, and to treat gastroperesis

Question 20

Nitrates effect on end diastolic LV volume and HR

Answer 20

Decrease EDLVV by direct vascular smooth muscle relaxation, which causes systemic venodilation

This causes a drop in BP that results in a REFLEX TACHYCARDIA

Question 21

Allelic Heterogeneity

Answer 21

different mutations in the same gene locus cause similar phenotypes (more than one type of mutation is possible in a given gene)

3 children can all have Beta-Thalassemia with 3 different mutations caused the disease

Question 22

Hemochromatosis

Answer 22

AR disease caused by excessive GI Iron absorption. Affected individuals store iron in the form of hemosiderin in the dermis and various parenchymal organs

Usually only presents after age 40 when significant amounts of iron have accumulated

Skin pigmentation is often and called “bronze diabetes”

DM from pancreatic island destruction is also common

Question 23

Steps of ELISA test

Answer 23

1. known antigen is fixed to the surface of a well
2. pt serum is added. If present, antigen specific antibodies bind the antigen and remain fixed to the well. Plate is then washed
3. anti-human immunoglobulin antibody is added coupled to a substrate modifying enzyme. This binds the bound antibodies
4. Finally, a substrate which is modified by the enzyme to elicit a color change is added

Question 24

How do efflux pumps work in bacterial antibiotic resistance?

Answer 24

Most antibiotic efflux pumps are powered by moving protons against their concentration gradient out of the cell coupled with moving the antibiotic against its concentration gradient.

Can also occur via sodium gradients or ATP mediated pumps

Question 25

The process of insulin synthesis and secretion

Answer 25

1. N-terminal signal peptide direct preproinsulin to the Rough Endoplasmic Reticulum (cytoplasm)
2. Signal peptide is cleaved and preproinsulin becomes proinsulin (in rough ER). Also packaged into vesicles to be sent to golgi
3. Proinsulin is cleaved into insulin and C-peptide in rough ER and packed into secretory granules (golgi)

Question 26

How can you surgically treat cases of axillary hyperhydrosis

Answer 26

Ablate the thoracic sympathetic trunk

Question 27

What is this red safranin O stain of? (healthy individual)

Answer 27

Collagen Type 2

This is hyaline cartilage (articular) (glass-like)

Can see chondrocytes embedded in a matrix of proteoglycans and collagen. The predominant type of collagen in hyaline cartilage is type II

The blue at the bottom is subchondral bone

The articular surface is the blue line at the top

Question 28

Remnants of the gubernaculum in males and females

Answer 28

Males –> anchors testes within scrotum (scrotal ligament)

Females –> ovarian ligament + round ligament of the uterus (ligamentum teres), passes through inguinal canal and attaches to the labia majora. The superior portion persists as the proper ovarian ligament, which connects uterus to ovary

Question 29

What is the breakdown pathway of NE and Epi and what would be elevated specifically in a catecholamine secreting tumor?

Answer 29

Metanephrines, Normetanephrine and Vanillymandelic Acid will all be elevated in a catecholamine secreting tumor

Question 30

What happens to the blood pH, O2, CO2 when get a DVT that becomes a PE

Answer 30

This is a V/Q mismatch that will lead to decreased O2 because of hypoxemia. This will increase ventilation and thus decrease CO2 but will be unable to fully compensate.

Since you are blowing off that CO2, the pH will rise

**Respiratory Alkalosis without significant improvement in hypoxemia**

Question 31

Treatment of carcinoid syndrome

Answer 31

Surgical resection

Octreotide (somatostatin analog)

Question 32

Oral diabetic med that induces differentiation of preadipocytes into adipocytes and incresing glut-4 transporter expression on the adipocyte

Answer 32

Pioglitazone (also rosiglitazone)

This is a member of the glitazone family that increases insulin sensitivity in peripheral tissue. Binds to PPAR-y nuclear transcription receptor

Question 33

Lactulose use and mechanism

Answer 33

Acidify the GI tract and trap NH4+ for excretion

This is used for hepatic encephalopathy or hyperammonia when the patient presents with asterixis

Question 34

Hoarsness caused by aortic aneuysm is affecting what nerve and then what muscle?

Answer 34

The recurrent laryngeal nerve wraps under the aortic arch and would be effected by the dilated aorta

The recurrent laryngeal nerves innervate all intrinsic muscles of the larynx (Crycoarytnoids, arytnoids) responsible for sound production EXCEPT FOR THE CRICOTHYROID

Question 35

Acute onset anemia, with evidence of hemolysis in a 40 year old man who just started sulfa antibiotics has what??

Answer 35

G6PD deficiency!!

Seen more frequently in African, Asian, Mediterranian

Causes extravascular and intravascular hemolysis

Remember it is a defect in G6PD leading to reduced glutathione and increased RBC susceptibility to oxidant stress

Brought on by SULFA drugs, fava beans, antimalarials, infections

Question 36

abdominal viscera drain to what lymph node?

Answer 36

L Supraclavicular lymph node. This is Virchow’s Node

–> thorax, abdomen via thoracic duct