uWorld 1

Question 1

what are club (aka clara) cells and what are their role

Answer 1

nonciliated, secretory constituents of the terminal respiratory epithelium
secrete club cell secretory protein and surfactant components
help detoxify inhaled substances via CYP450 mechanism

Question 2

what cells are responsible for the findings in centriacinar emphysema

Answer 2

neutrophils and macrophages
release PROTEASES (elastase, cathespins, MMPs) that degrade the eco and also generate free oxygen radicals that impair the function of protease inhibitors (A1AT)

Question 3

weight loss, mucosal pallor, hepatomegaly, and massive splenomegaly
gain-of-function mutation of non-receptor tyrosine kinase protein in hematopoietic cells, leading to persistent activation of signal transducers and activators of transcription (STAT) proteins

Answer 3

JAK 2 mutation
primary myelofibrosis
teardrop cells (dacrocytes) on peripheral smear

Question 4

what is ruxolitinib

Answer 4

JAK2 inhibitor

approved for treatment of primary myelofibrosis

Question 5

hydrocele results from what

Answer 5

incomplete obliteration of the PROCESSUS VAGINALIS (a projection of the peritoneal cavity that accompanies the descendant testis into the scrotum and ultimately toms the TUNICA VAGINALIS of the testis)

Question 6

what causes a bifid scrotum

Answer 6

malunion of labioscrotal folds (forms labia majora in females)

Question 7

what is the most common cause of CF

Answer 7

3-bp deletion that removes phenylalanine at deltaF508
impaired post translational modification in the endoplasmic reticulum (goes to proteasome and no CFTR on the cell surface at all)

Question 8

what kind of CF is seen in Ashkenazi jews

Answer 8

mutations causing premature termination of the transmembrane protein (nonsense, frameshift) also lead to a complete absence of membrane-bound CFTR

Question 9

mild CF disease is usually do to what

Answer 9

mutations impairing chloride iron conduction through CFTR or those causing decreased production of functionally normal CFTR (reduced mRNA or protein stability)

Question 10

what organism is gamma-hemolytic (no hemolysis) catalase-negative, can grow in presence of bile, but cannot grow in 6.5 NaCl

Answer 10

S. bovis

enterococci are the same except they can grow in 6.5NaCl

Question 11

what organisms are PYR (pyrrolidonyl arylamidase) positive

Answer 11

Strep progenies

enterococci

Question 12

what biochemical processes occur exclusively in the mitochondria

Answer 12

beta-oxidation of fatty acids
ketogenesis
citric acid cycle
parts of urea cycle (carbamoyl phosphate synthetase 1 and ornithine transcarbamoylase)
pyruvate carboxylation

Question 13

where does the pentose phosphate shunt occur

Answer 13

cytoplasm

transketolase is an enzyme of this pathway (B1 is a cofactor)

Question 14

what does pyruvate carboxylase do and where is it found in the cell

Answer 14

catalyzes the initial step in gluconeogeneissi by converting pyruvate to oxaloacetate (B7 is cofactor)
mitochondria

Question 15

what does ornithine transcarbomoylase do and where is it found in the cell

Answer 15

catalyzes the second step of the urea cycle where ornithine and carbamoyl phosphate are combined to form citrulline
mitochondria
deficiency leads to hyperammonemia and mental retardation

Question 16

what does succinate dehydrogenase do and where is it found in the cell

Answer 16

enzyme of TCA cycle that converts succinate fumarate
FAD+ to FAD2 happens here
inner mitochondrial membrane

Question 17

what does HMG CoA Lyase do and where is it found in the cell

Answer 17

mitochondrial enzyme that is responsible for ketogenesis from HMG CoA

Question 18

what is reaction formation

Answer 18

defense mechanism in which an individual TRANSFORMS UNACCEPTABLE FEELINGS or impulses into their EXTREME OPPOSITES
immature defense mechanism

Question 19

what is displacement

Answer 19

transfer of feelings or impulses toward a safer, more acceptable object
immature defense mechanism

Question 20

what is projection

Answer 20

involves attributing unacceptable impulses or behavior onto another person or situation
immature defense mechanism

Question 21

what is rationalization

Answer 21

individual makes excuses for unacceptable feelings or behavior
immature defense mechanism

Question 22

what segment of the nephron responds to vasopressin by increasing absorption of a specific solute that is important for generating high medullary concentration gradient

Answer 22

medullary segment of the collecting duct

Question 23

what is the greatest risk that occurs from a cavernous hemangioma in the brain and where are they found

Answer 23

intracerebral hemorrhage
most commonly found in the brain parenchyma above the cerebellar tentorium
pts often have seizures
lesions have tendency to bleed (irregular hyperdense/bright mass on head CT)

Question 24

what is the defect in xeroderma pigmentosa

Answer 24

endonuclease

Question 25

what does the presence of an S3 indicate in older individuals (its normal in the young) and what is causing the sound

Answer 25

left ventricular failure
sound is from:
- forceful, rapid filling of a ventricle that has normal or elevated compliance
- normal or even decreased filling rates when ventricular compliance is low
- blood flowing into an overfilled ventricle with high end-systolic volume

Question 26

what is the cause of pulsus paradoxus in cardiac tamponade

Answer 26

bulging of intraventricular septum when accumulation of large quantities of pericardial fluid prevents the expansion of the ventricular free walls
during inspiration, venous blood return increases and the intraventricular bulges into the left ventricle to allow the right ventricle to accommodate the increased blood volume-

resultant decrease in left ventricular filing produces pulsus paradoxus

Question 27

what type of obstruction is seen in hypertrophic cardiomyopathy and what kind of heart murmur is it associated with

Answer 27

dynamic left ventricular outflow obstruction

mitral regurgitation

Question 28

what is coopers ligament

Answer 28

aka pectineal ligament- thickened peace of pectineal facia

overlies the pectineal ridge of the pubic bone and is located posteriorly to the femoral canal

Question 29

what forms the posterior wall of the inguinal canal

Answer 29

transversals facia

Question 30

what is an opening in the transversals facia and is the site of protrusion of indirect inguinal hernias

Answer 30

deep inguinal ring

Question 31

what is the female equivalent of the spermatic cord

Answer 31

round ligament

leaves though the deep inguinal ring and passes through the inguinal canal

Question 32

what are the adverse effects of methotrexate

Answer 32

oral and GI ulceration
hair follicle tox (alopecia)
bone marrow tox (pancytopenia)
hepatotoxicity (hepatitis, fibrosis, cirrhosis)
pulmonary fibrosis

Question 33

what areas of the GI tract are exposed to the most gliadin and thus should be biopsied

Answer 33

duodenum
jejunum
see villus atrophy/flattening and lymphocyte infiltration of the intraepithelial cells

Question 34

what is used to diagnose lactose intolerance

Answer 34

hydrogen breath test (malabsorbed lactose is fermented by bacteria, thereby increasing the amount of hydrogen exhaled and confirming a diagnosis)

Question 35

gastric bands must pass through what structure in order to encircle the stomach

Answer 35

lesser omentum

Question 36

what is a gastric band

Answer 36

inflatable silicone device placed around the gastric cardia

it is intended to slow the passage of food, increasing satiety and limiting the amount of food consumed

Question 37

what is the lesser omentum and what ligaments make it up

Answer 37

double layer of peritoneum that extends from the liver to the lesser curvature of the stomach and the beginning of the duodenum
hepatogastric ligament
hepatoduodenal ligament

Question 38

what is found between the two layers of the lesser omentum, close to the right-sided free margin

Answer 38

hepatic artery
common bile duct
portal vein
lymphatics
hepatic plexus

Question 39

what is found b/w the two layers of the lesser omentum, near where the lesser omentum attaches to the stomach

Answer 39

right and left gastric arteries

gastric veins

Question 40

what is another name for the round ligament of the liver and what structure is it found in

Answer 40

aka ligamentum hepates teres (remnant of fetal umbilical vein)
contained in the falciform ligament

Question 41

what is the greater omentum

Answer 41

large fold of visceral peritoneum that extends from the greater curvature of the stomach, travels inferiorly over the small intestine, and then reflects on itself and ascends to encompass the transverse colon before reaching the posterior abdominal wall

Question 42

what is the gastrocolic ligament

Answer 42

section of the greater omentum that stretches form the greater curvature of the stomach to the transverse colon
forms part of the anterior wall of the lesser sac and is often divided during surgery to provide access to the anterior pancreas and posterior wall of stomach

Question 43

what is the splenorenal ligament derived from and what does it contain

Answer 43

derived form peritoneum and lies between left kidney and spleen
contains the splenic vessels and the rail of the pancreas

Question 44

what is the key metabolic difference of methotrexate and 5-FU

Answer 44

methotrexate prevents the reduction of folic acid to THF

5-FU binds THF and thymidylate synthetase in the stable-reaction intermediate form

Question 45

what are the functions of cytarabine and gemcitabine

Answer 45

pyrimidine analog antimetabolites that get incorporated into DNA leading to strand termination
gemcitabine is not S-phase specific (and inbitis ribonucleotide reductase) and cytarabine is

Question 46

what is fludarabine

Answer 46

a deamination-resistant purine nucleotide analog that exerts its cytotoxicity by many mechanisms, including inbhition of DNA polymerase,e DNA primate, DNA ligase, and ribonucelotide reductase
use to treat CLL