Quiz Flashcards
1
Q
The distal bony attachment (insertion) of the flexor carpi ulnaris tendon includes the
A.base of the index (2nd) metacarpal. B.base of the thumb (1st) metacarpal. C.capitate. D.radius. E.pisiform.
A
E
2
Q
Musculoskeletal ultrasound is useful for which of the following applications? (check all that apply)
A. differentiation of abscess versus cellulitis
B. identification of long-bone fractures
C. identification of (and guidance for removal of) soft tissue foreign bodies
D. identification of tendon injury
E. procedural guidance for nerve blocks
A
All of the above
3
Q
In which of the following study types does the investigator assign the exposure or treatment? A.Ecologic study B.Randomized clinical trial C.Case report study D.Cohort study E.Case-control study F.Cross sectional study
A
Answer Key: B
Feedback: In clinical studies, both random and non-random, the investigators determine who gets the exposure or treatment.
4
Q
The spiral groove of the humerus is a landmark to both surgeons and radiologists. The artery that accompanies the radial nerve in this groove is the
A.posterior humeral circumflex. B.radial. C.middle collateral. D.profunda brachii. E.superior ulnar collateral.
A
Answer Key: D
5
Q
The muscle that is the prime flexor of the proximal inter-phalangeal (PIPJ) joint of the middle finger is the
A.interosseus. B.lumbrical. C.flexor digitorum superficialis. D.flexor digitorum profundus. E.flexor carpi ulnaris.
A
Answer Key: C
6
Q
As you sit at your desk, your hand and forearm lie flat on the desk, palm up. You move so that your thumb points perpendicular to the plane of the palm. The movement that occurred is called A.flexion. B.adduction. C.pronation. D.supination E.abduction.
A
Answer Key: E
7
Q
Entry of acetyl-CoA into the citric acid cycle decreases as
A.the ratio of [ATP]/[ADP] increases.
B.[AMP] increases.
C.the ratio of [NAD+]/[NADH] increases.
D.the rate of electron transport increases.
A
A
8
Q
The axillary nerve, which can be visualized on an MRI scan,
A.passes through the triangular space.
B.innervates the teres major muscle.
C.has a cutaneous branch, the superior (upper) lateral brachial cutaneous nerve.
D.passes through the foramen formed by the superior transverse scapular ligament and the suprascapular notch.
E.is derived from the lateral cord of the brachial plexus.
A
Answer Key: C
9
Q
What is the advantage of having glucose-6-phosphatase present in the hepatocyte?
A.It produces glucose from glucose-6-P which permits it to be exported for the cell.
B.It exchanges the phosphate from the 6 to the 1 position on glucose and allows it to enter the glycogen synthetic pathway
C.It exchanges the phosphate from the 1 to the 6 position on glucose and allows it to enter the glycogen synthetic pathway
D.it adds the glucose-6-P to the terminus of the growing glycogen polymer.
A
Answer Key: A
Feedback: Glucose - 6 -P cannot be transport out of the hepatocyte and must be phosphorylated first.
10
Q
The annular ligament stabilizes the A.ulnar styloid process. B.neck of the radius. C.humerus. D.hook of the hamate to the pisiform. E.dorsal tubercle (Lister’s) of the radius.
A
B
11
Q
Researchers conducting an investigation ito the efficacy of an anti-osteoporosis drug decided to limit participants to women over the age of 65. this is an example of reducing confounding factors by A.matching. B.stratification. C.adjustment D.inappropriate investigation bias
A
B
12
Q
Malonyl-CoA inhibits ß-oxidation at which step?
A.Fatty acid -» Fatty acyl CoA (cytosol)
B.Fatty acyl CoA (cyt)->Fatty acyl Carnitine (mito)
C.Fatty acyl carnitine (mito)-> Fatty acyl CoA (mito)
D.Fatty acyl CoA (mito) ->Fatty enoyl CoA (mito)
A
B
13
Q
Your ER patient has a laceration over the distal forearm (over the dorsoradial aspect). Your exam shows that there is no sensation on the dorsum of the hand overlying the 1st dorsal interosseous muscle. You suspect interruption of the
A.superficial branch of the radial nerve. B.dorsal branch of the ulnar nerve. C.median nerve. D.deep branch of the ulnar nerve. E.deep branch of median nerve.
A
A
14
Q
Ketone bodies can be used as a fuel by all the following tissues EXCEPT A.brain. B.skeletal muscle. C.heart. D.adipose cells. E.red blood cells.
A
E
15
Q
As you sit at your desk, your hand and forearm lie on the desk, palm up. You turn your hand and forearm so that the palm faces down. This movement is referred to as A.flexion. B.hyperextension. C.circumduction. D.circumduction. E.pronation.
A
E
16
Q
During fasting, an individual lacking carnitine palmitoyltransferase II would present with all of the following EXCEPT
A.increased levels of fatty acids in the plasma.
B.increased levels of dicarboxylic acids excreted into the urine.
C.increased levels of ketone bodies in the plasma.
D.increased levels of oxidized acylcarnitines excreted into the urine.
E.decreased rate of beta-oxidation in the mitochondria.
A
C
17
Q
- A 20- year old male complains that he cannot do strenuous exercise without suffering from muscle cramps and fatigue. He says his urine is often burgundy colored. Otherwise, he appears to be in good health. A defect in carbohydrate metabolism is suspected, but the patient shows no signs of abnormal blood glucose levels, either after a meal or during a fast. Biopsies of liver and muscle showed the glycogen in both tissues to be of normal structure and amount. His exercising forearm was studied by P31 nmr, which is able to measure the levels of ATP, ADP, AMP, and Pi. The intracellular pH can be calculated from the ratio of various ionic forms of phosphate. All the following results are expected EXCEPT which one after intense exercise?
A.Abnormally high ADP B.Abnormally high AMP C.Abnormally high ATP D.Abnormally high Pi E.Abnormally high pH
A
C
18
Q
Diabetics and children with inborn errors of fructose and galactose metabolism all suffer from cataracts. The common cause is that the lenses of their eyes have an over-accumulation of
A.the sugar that is not metabolized properly (glucose, fructose, or galactose)
B.the reduced forms of these sugars
C.the oxidized forms of these sugars
D.the phosphorylated forms of these sugars.
A
B
19
Q
The first intermediate in glycolysis that has an anhydride bond capable of driving ATP synthesis is A.Glyceraldehyde 3-phosphate B.1,3 bisphosphoglycerate C.Glycerate 3-phosphate D.Glycerate 2-phosphate E.Phosphoenolpyruvate
A
Answer Key: B
Feedback: All the phosphorylated intermediates up to 1,3 bisphosphoglycerate are phosphoesters, not phosphoanhydrides or mixed anhydrides. A mixed anhydride is one formed from phosphate and a carboxylic acid.
20
Q
A 37-year-old women died of necrotizing fasciitis, a severe, insidiously advancing, soft-tissue infection, after routine outpatient surgery at a hospital (patient A) A man who was at the same hospital on the same day also developed necrotizing fasciitis but survived (patient B) . On examination of the hospital records, 12 other people over the preceding 16 months who had been treated in the surgical unit were also diagnosed with the infection. The source of the infection was never found.
The organisms isolated from the blood cultures of patient A and Patient B above were Gram positive, beta hemolytic cocci that were catalase negative and bacitracin sensitive. Which ONE of the following best describes the key property of the major virulence determinant of this organism? It
A.binds the Fc region of antibodies directed against it.
B.causes endotoxic shock.
C.causes lysis of red blood cells in vivo.
D.inhibits uptake of the organism by neutrophils
E.promotes coagulation of plasma in vitro.
A
Answer Key: D
Feedback:
Explanation-case is group A streptococci (by microbiological description and clinical problem of necrotizing fasciitis)
A. is wrong because that describes protein A of Staphylococcus aureus
B. is wrong because endotoxin= LPS; group A streptococci are Gram positive
C. is wrong because hemolysin is not a major virulence determinant of the organism; M protein is the major determinant and is anti-phagocytic (see D)
D. is right because it describes the primary mechanism of virulence of group A streptococci-evasion of uptake by PMNs evoked by M proteins
E. is wrong because coagulase is made by Staphyloccocus aureus, not group A streptococci
21
Q
Sebaceous glands secrete in what manner?
A.merocrine. B.halocrine. C.paracrine. D.apocrine. E.endocrine.
A
Answer Key: B
Feedback: Sebaceous glands secrete by halocrine secretion.
22
Q
A high incidence of skin infections occurred among members of a high school wrestling team. Several of the teenagers were treated with methicillin, but the infections did not resolve. Gram-positive bacteria were isolated from the inflamed skin lesions and bacteria of similar morphology were isolated from the wrestling mats and a tube of taping gel. All of the isolates had the same pattern on pulsed field gel electrophoresis (PFGE) and all were resistant to methicillin. Which of the following events is most likely responsible for methicillin resistance in this organism?
A.Acquistion of a plasmid that encodes ß-lactamase
B.An rRNA gene that underwent spontaneous mutation
C.Integration of a gene that encodes penicillin-binding protein PBP2’ into the chromosome
D.Mutation in a gene that increases the expression of an efflux pump system
E.Spontaneous mutation in the DNA gyrase gene
A
Answer Key: C
Feedback: Explanation: Based on the description of the organism and its resistance to methicillin the most likely agent is Staphylococcus aureus.
A. is incorrect because methicillin is a semi-synthetic penicillin that is resistant to most bacterial ß-lactamases.
B. is incorrect because the methicillin inhibits cell wall synthesis and does not target ribosomes to inhibit protein synthesis.
C. is the correct response because it is well documented that MRSA have arisen via integration of a sophisticated cassette into the bacterial chromosome that encodes an altered PBP.
D. is incorrect because resistance to methicillin in S. aureus does not occur via increased efflux from the cell via derepression of an active efflux pump system.
E. is in correct because methicillin does not target topoisomerases such as DNA gyrase A to affect transcription and, or replication.
23
Q
A 4-year-old child presents with multiple vesicular lesions on the mucous membranes of the mouth. These lesions resolve spontaneously with 3 weeks. During the subsequent 12 months, the child suffers several recurrences of blisters around the peri-oral region. In all cases, there is complete recovery followed by symptom-free intervals. The virus responsible for these symptoms A.causes hand-foot-and-mouth disease. B. causes keratitis and encephalitis. C.has a negative-sense RNA genome. D.is transmitted by fecal-oral route. E.replicates in the cytoplasm.
A
B
24
Q
Mesissner’s corpuscle is responsive to what type of stimulation?
A
light touch
Feedback: Encapsulated nerve endings increase the sensitivity and specificity of the nerves for different stimuli. Meissner’s corpuscles are responsive ;low frequency stimuli and are found in the fingertips and toes.
25
Glucose that is radiolabelled with C14 at the C-1 position was incubated with red blood cells, and the lactic acid excreted by them was collected for analysis. In which carbon atom (s)of lactic acid was the label be found?
```
A.C-1 only
B.C-2 only
C.C-3 only
D.C-1 and C-3
E.C-1, C-2, and C-3
```
Answer Key: C
Feedback: correct answer C-3 only
Look at a chart of the pathway that shows the open chain forms of the sugars. The tricky part of this follow-the-label question is to determine which carbon is labeled after the aldolase step. Although it may appear to be the C-1 of dihydroxyacetone phosphate, it is C-3. From there it is easy to follow the label through to lactate.
26
In muscle, creatine kinase catalyzes the synthesis of creatine phosphate according to the reaction shown below. Given the standard free energy change for hydrolysis of ATP is –7.3 kcal/mol, and for hydrolysis of creatine phosphate is – 10.3 kcal/mol, what is the free energy change of the above reaction starting with 1M reactants and 1M products?
ATP + creatine creatine phosphate + ADP
A.
17.6 kcal/mol
B.
– 10.3 kcal/mol
C.
– 7.3 kcal/mol
```
D.– 3.0 kcal/mol
E.0 kcal/mol
F.+ 3.0 kcal/mol
G.+ 7.3 kcal/mol
H.+ 10.3 kcal/mol
I.+ 17.6 kcal/mol
```
Answer Key: F
27
```
The mechanism for the contact dermatitis initiated by contact with nickel is
A.type I acute.
B.type II cytotoxic antibody mediated.
C.type III immune complex mediated.
D.type IV delayed cell mediated.
```
Answer Key: D
| Feedback: Antigens activate lymphocytes which activate macrophage to secrete inflammatory molecules.
28
```
A single skin lesion that is raised, red, and 1.2cm long by 2.0cm wide is most properly referred to as a
A.papule
B.bulla
C.plaque
D.herpetiform eruption
```
Answer Key: C
Feedback: Correct Answer: C - A plaque is a raised skin lesion larger than 1.0 cm, the color of the lesion does not change the lesion type.
A) is incorrect because a papule is a raised lesion less than 1.0 cm. B) is incorrect because a bulla is filled with clear fluid. D) is incorrect because eruption does not describe a solitary lesion and herpetiform describes the distribution of multiple lesions, not a single lesion.
29
A 2 year old boy presents with erythema over most of his body. Fluid-filled cutaneous blisters are also present and the skin on his face, shoulders, and arms has undergone desquamation. His mother reports that the boy was fine until a few days earlier, when redness began to develop around his mouth. A diagnosis of scalded skin syndrome is made. The toxin responsible for the observed manifestations of this disease
A.forms immune complexes, which deposit in the skin.
B.induces nonspecific proliferation of helper T cells.
C.promotes unregulated actin polymerization in dermal cells.
D.selectively kills endothelial cells via inhibiting protein synthesis.
E.splits desmosomes in the stratum granulosum epidermis
Answer Key: E
Feedback: Explanation: The toxin that is responsible for scalded skin syndrome is exfoliatin. Answer E is correct because it describes the mechanism of action of exfoliatin. Answers B, C, and D describe the mechanism of action of other bacterial toxins including superantigens in the case of B. Answer A is incorrect because the skin manifestations of scalded skin syndrome are not due to specific antibody forming particulate complexes with exfoliatin or any other bacterial molecule.
30
```
A strain of bacteria, E. Gads, ferments glucose to lactate, showing that the enzymes of glycolysis are produced by the organism. It can also ferment glycerol to lactate, but the pathway is not known for sure. Experiments showed that the first step is phosphorylation of glycerol to 3-glycerol phosphate. Researchers then proposed a few possibilities for the second step. Their working assumption was that the organism converts glycerol 3-phosphate to an intermediate in glycolysis, and does so in the fewest possible steps. On this basis, all agreed that the enzyme involved in step 2 is most likely a(n):
A.dehydrogenase
B.isomerase
C.mutase
D.aldolase
E.enolase
```
Answer Key: A
Feedback: Glycerol 3-phosphate can be converted to either glyceraldehyde 3-phosphate or dihydroxyacetone phosphate via a dehydrogenase, using NAD+ as the cofactor. The reaction converts hydroxyl groups to carbonyl groups.
31
Which cell type of the integument is most likely to contain mature pigment granules?
A.Macrophages
B.Fibroblasts of the dermis.
C.Melanocytes
D.Langerhans cells
E.Keratinocytes of the basal and lower spinosus layers.
Answer Key: E
Feedback: The melanocyte produces the melanosomes, the pigment granules. However, as it matures, it is pushed into or phagocytosed by the surrounding keratinocytes of the stratum basale. As these cells move into the stratum spinosus, the melanosomes are retained for a period of time. The melanosomes are lost in the later stages on keratinocyte differentiation.
32
A patient wants to be treated for their onychomycosis.
Which of the following should be recommended.
A.Topical clotrimazole cream
B.Oral terbinafine
C.Oral penicillin
D.Intravenous amphotericin
E.Surgical excision and amphotericin
Answer Key: B
Feedback: Explanation: Onychomycosis is a fungal infection of the nail which is most often caused by one of the dermatophytes. B is the correct answer because fungal infection of the nail typically requires systemic administration of an antifungal (terbinafine, griseofulvin, or an azole). A is wrong because topical antifungal therapy of onychomycosis is frequently ineffective. C is wrong because penicillin is not an antifungal. While D and E would likely be effective, these choices are not correct because the risk of amphotericin therapy is not typically warranted nor necessary for the treatment of onychomycosis.
33
Spaghetti and meatballs and the below scenario is associated with what Dx:
A 33 year old woman is seen in clinic with a chief complaint of pink patches on her chest and back. These skin lesions do not itch or hurt. A KOH prep of skin scrapings reveals the following:
The description of pink patches on the skin that do not itch or hurt is consistent with pityriasis versicolor, which is most often caused by Malassezia furfur. The KOH prep reveals the classic “spaghetti and meatballs” appearance of M. furfur, which is due to the circular yeasts and the elongated pseudohyphae.
34
A 67 year old man visits your clinic complaining of numbness in his toes. Upon examination you discover that the numbness is actually confined to the big toe on his left foot. Based on your knowledge of anatomy, you predict that he may have a compression lesion
A.on the left side of the spine at the level of L5
B.on the right side of the spine at the level of L5
C.on the right side of the spine at the level of C8
D.that is impinging on the coccygeal nerve which causes the numbness
E.on the left side of the spine at the level of C8
Answer Key: A
Feedback:
A compression lesion at L5 could damage the posterior nerve rootlets and impair sensation. Although L5 is also involved in sensation of the lower leg, S1 contributes to that area of the leg as well, so all sensation would not be lost.
C8 is involved in sensation of the forearm and hand.
Coccygeal nerve gives sensation to the skin over the coccyx.
35
Your preceptor at the simulation center told you about the triangle of auscultation as a good spot to try hear respiratory sounds. In your anatomy dissection of the back, you see that this area is formed by the borders of the
A.The angle created with the neck when the left arm is raised above the head with the elbow flexed at approximately 30 degrees.
B. The transverse processes and the spinous process of the T3 vertebra.
C. Longissimus, illiocostalis, and spinalis muscles.
D. Latissimus dorsi, trapezius and the rhomboid major (medial edge of the scapula).
E.Trapezius, erector spinae, and the splenius capitus
Answer Key: D
36
Your 12 year old son is studying biology in school and was told that dark-skinned people have “natural sunscreen” that helps prevent sunburn when they are outside in the summer sun. He asks you to explain this and you tell him that it is because people who live in the southern regions of the world have developed
A.Larger and more stable melanosomes.
B.More melanocytes, the cells that produce the dark pigment seen in the skin.
C.A thicker stratum corneum than found in Caucasian skin
D.A different variation of melanin called pheomelanin which is more effective at absorbing ultraviolet rays.
E.Increased turnover in sun-damaged melanin pigment.
Answer Key: A
Feedback: The melanosomes of dark skinned people are larger and more stable than those found light skinned people. Consequently the concentration of melanosomes builds up in cells and melansomes persist through several cell divisions in the stratum spinosum.
The other answers are incorrect statements. Pheomelanin is the yellow-red pigment and is not believed to be particularly effective in protecting against UV rays
37
Entry of acetyl-CoA into the citric acid cycle decreases as
A.the ratio of [ATP]/[ADP] increases.
B.[AMP] increases.
C.the ratio of [NAD+]/[NADH] increases.
D.the rate of electron transport increases.
Answer Key: A
38
You ask the clinical lab to determine the minimal inhibitory concentration (MIC) of penicillin for an isolate of Escherichia coli. The lab performs a broth dilution assay starting with an optical density (turbidity) reading of 0.05, followed by incubation for 24 hours. The next day, the lab reports the data. Based on these data and within the tested range of antibiotic concentrations, what is the MIC of your strain?
Antibiotic Concentration Tube # Ending micrograms/ml Turbidity
```
1 0 2.0
2 0.1 1.5
3 0.5 0.85
4 1.0 0.2
5 2.0 0.05
6 5.0 0.05
7 10 0.05
8 100 0.05
```
```
A.0.1micrograms/ml
B.0.5 micrograms/ml
C.1.0 micrograms/ml
D.2.0 micrograms/ml
E.100 micrograms/ml
```
Answer Key: D
Feedback: The answer is D. The minimum inhibitory concentration is the concentration of drug that inhibits 99% of the population. Thus, we are looking for virtually complete inhibition of growth. This would be evidenced by a lack of change in the Turbidity. 2.0 micrograms/ml is the lowest concentration of drug tested that inhibits all growth.
39
The erector spinae muscles
A.are enclosed by the anterior and posterior layers of the thoracolumbar fascia in the lumbar region.
B.include the semispinalis capitis muscle.
C.include the splenius capitis muscle.
D.are deep to the transversospinal muscles.
E.are innervated by ventral primary rami of spinal nerves.
Answer Key: A
40
Which ONE of the following mechanisms of action CORRECTLY describes the toxin that is the most potent of all biological agents?
This toxin
A.binds to MHC class II molecules on antigen presenting cells and to Vβ region the T cell receptor.
B.cleaves a specific protein in the neuroexocytosis apparatus
C.directly converts ATP to cAMP in the presence of calmodulin.
D.removes a specific adenine residue from rRNA by an RNA N-glycosidase activity that inactivates ribosomes.
E.selectively disrupts lipid rafts on neuronal cell membranes
Answer Key: B
Feedback: Botulinum toxins (7 different serotypes) are the most potent of all bacterial toxins. They act at the neuromuscular junction to prevent release of acetylcholine (causes flaccid paralysis). The way in which botulinum toxin prevent release of acetylcholine is to cleave synaptobrevin, syntaxin or SNAP-25 (the main components of the SNARE complex). The particular substrate depends on the botulinum serotype.
41
The extreme toxicity of cyanide results from its high affinity in binding to
A.FADH2 in the reduced form of succinate dehydrogenase.
B.heme c in cytochrome c.
C.heme a3 at the active site of cytochrome oxidase.
D.heme b in the cytochrome bc1 complex.
E.Fe/S clusters in both complex I and complex III.
C
42
```
tion 6 of 23
1.0 Points
The spinal cord in the adult usually terminates at the level of the
A.second segment of the sacrum
B.first or second lumbar vertebra.
C.posterior superior iliac spines.
D.sacral hiatus
E.third or fourth lumbar vertebra.
```
B
43
```
Which type of cells produce myelin sheaths around axons in the central
nervous system?
A.Schwann Cells
B. Astrocytes
C.Microglia
D.Oligodendrocytes
E.Ependymal Cells
```
D
44
A 37-year-old women died of necrotizing fasciitis, a severe, insidiously advancing, soft-tissue infection, after routine outpatient surgery at a hospital (patient A) A man who was at the same hospital on the same day also developed necrotizing fasciitis but survived (patient B) . On examination of the hospital records, 12 other people over the preceding 16 months who had been treated in the surgical unit the surgical unit were also diagnosed with the infection. The source of the infection was never found.
The organisms isolated from the blood cultures of patient A and Patient B above were Gram positive, beta hemolytic cocci that were catalase negative and bacitracin sensitive. Which ONE of the following best describes the key property of the major virulence determinant of this organism? It
A.binds the Fc region of antibodies directed against it.
B.causes endotoxic shock.
C.causes lysis of red blood cells in vivo.
D.inhibits uptake of the organism by neutrophils.
E.promotes coagulation of plasma in vitro.
Answer Key: D
Feedback: Explanation-case is group A streptococci (by microbiological description and clinical problem of necrotizing fasciitis):
A. is wrong because that describes protein A of Staphylococcus aureus
B. is wrong because endotoxin= LPS; group A streptococci are Gram positive
C. is wrong because hemolysin is not a major virulence determinant of the organism; M protein is the major determinant and is anti-phagocytic (see D)
D. is right because it describes the primary mechanism of virulence of group A streptococci-evasion of uptake by PMNs evoked by M proteins
E. is wrong because coagulase is made by Staphyloccocus aureus, not group A streptococci
45
Based on the tenants of selective toxicity and what you know about the mechanism of action of most major antibiotics, which of the following targets would be the LEAST LIKELY candidate for a new antibiotic that freely diffuses across all cell membranes?
A.Components of the folic acid biosynthetic pathway
B.Components of the peptidoglycan biosynthetic pathway
C.Components of the bacterial DNA gyrase
D.Lipid A
E.Ribosomal subunits
Answer Key: E
Feedback: E is correct. The mitochondria contain ribosomes that look very similar to prokaryotic ribosomes. Due to this similarity, a drug that can diffuse across all of the membranes in the cell and targets ribosomal subunits may end up affecting the host cell; it would therefore not be selectively toxic.
46
In the typical cell described in class, a postsynaptic potential is produced by a transmitter binding to a receptor channel that opens and increases its permeability to potassium. This will result in
A.no change in the postsynaptic cell’s membrane potential.
B.an ionotropic excitatory postsynaptic potential.
C.a metabotropic excitatory postsynaptic potential.
D.an ionotropic inhibitory postsynaptic potential.
E.a metabotropic inhibitory postsynaptic potential.
Answer Key: D
Feedback: Answer D.
Opening a potassium channel in the postsynaptic membrane increases the membrane permeability to potassium. Increasing the permeability to an ion moves the membrane potential toward the equilibrium potential for that ion. In the cell in class, the resting membrane potential was -90 mV and the equilibrium potential for potassium was -97 mV. Moving the membrane potential toward the potassium equilibrium potential will hyperpolarize the cell away from threshold making it more difficult for any excitatory inputs to drive the cell to threshold. The PSP is ionotropic because the postsynaptic receptor is the actual channel. If it were metabotropic, the receptor would release a second messenger that would, in turn, open a separate ion channel in the membrane.
47
```
A mother brings her 6-year-old son to the emergency room. The child has a fever, headache and is complaining of general aches and pains. After determining that the child has a bacterial infection, the physician administers both drug A and drug B. Over the course of the next 24 hours, the child’s symptoms do not noticeably improve, however another child with the same infection improves dramatically when given drug A alone. Which of the following combinations of drugs would be the MOST LIKELY to result in the above scenario if they were administered as drug A and drug B, respectively?
A.Amphotericin B and Penicillin
B.Bacitracin and Polymyxin
C.Penicillin and Chloramphenicol
D.Tetracycline and Chloramphenicol
E.Trimethoprim and Sulfonamide
```
Answer Key: C
Feedback: The answer is C. The described scenario indicates antagonistic antibiotic interactions. The most likely drugs to interact with one another in the described way would be a bacteriostatic and bactericidal combination. Penicillin is bactericidal, but requires active cell growth to be effective. Thus, adding chloramphenicol, which is bacteriostatic, inhibits the action of penicillin.
48
```
Ketone bodies can be used as a fuel by all the following tissues EXCEPT
A.brain.
B.skeletal muscle.
C.heart.
D.adipose cells.
E.red blood cells.
```
E
49
The latissimus dorsi muscle
A.inserts on the posterior aspect of the humerus.
B.is a lateral rotator of the arm.
C.is innervated by dorsal primary rami of thoracic spinal nerves.
D.forms a border for both the triangle of auscultation and the lumbar triangle.
E.usually receives its blood supply from branches of the first part of the axillary artery.
D
50
During a summer research project, you decide to characterize the biochemical effects of a novel mutation that has recently been discovered in the skeletal troponin C (TnC) molecule. You know that the patients that express this mutant isoform of TnC experience episodes of weakness and paralysis. Based on your knowledge of E-C coupling, which of the following biochemical properties do you expect the mutant TnC to exhibit?
A.Increased binding affinity for Ca2+ leading to decreased actin and myosin interaction.
B.Decreased affinity for Ca2+ leading to decreased actin and myosin interaction.
C.Increased binding affinity for Ca2+ leading to reduced Ca2+ release from the sarcoplasmic reticulum
D.Decreased binding affinity for Ca2+ leading to reduced Ca2+ release from the sarcoplasmic reticulum
E.Decreased binding affinity for Ca2+ leading to decreased phosphorylation of myosin light chain.
Answer Key: B
Feedback: Answer B is correct. Calcium released from the SR binds to TnC, causing a conformational rearrangement of the thin filaments exposing the myosin binding site on actin. Reduced actin and myosin interaction would be expected to lead to weakness or paralysis.
51
Your patient describes severe posterior neck pain, radiating along the distribution of of a single spinal nerve. You obtain an MRI and discuss the findings with Dr. Smirniotopolous. In addition to other findings, he indicates that there is “absence of the normal fat pad” in the intervertebral foramen. Which of the following best describes this finding?
A.It may indicate compression of the spinal nerve
B.The pad is normally associated with the ventral roots.
C.Its absence is often a normal variant.
D.It correlates with a fracture of the vertebral body.
E.It indicates an occult fracture of the pedicle.
Answer Key: A
| Feedback: Clinical pearl
52
What mechanism is responsible for the rapid repolarization of the membrane during an action potential in an unmyelinated axon?
A.The closing of a voltage-gated sodium channel
B.The closing of a voltage-gated potassium channel
C.The opening of a voltage-gated sodium channel
D.The opening of a voltage-gated potassium channel
E.An increase in activity of the sodium potassium ATPase pump.
Answer Key: D
Feedback: The cell is depolarized by the voltage-gated sodium channel that brings the membrane to positive values at the peak of the action potential. Closing the voltage-gated sodium channel will stop the depolarization but will not repolarize the cell to its resting potential since the cell has accumulated some extra positive charge. To repolarize the cell, it must lose the excess positive charge. This is accomplished by opening a voltage-gated potassium channel. At the peak of the action potential, both the electrical forces (since here the inside of the cell is now positive) and the concentration forces (since the concentration of potassium is higher on the inside of the cell) will combine to eject potassium from the cell and repolarize it back to the resting potential.
53
Mitochondria in brown fat of human infants and hibernating animals regulate heat generation by controlling the rate of electron transport. Increased heat output results from an increased rate of electron transport due to
A.inhibition of the ADP-ATP antiporter.
B.inhibition of F1F0 ATP synthase.
C.blockage of NADH reoxidation.
D.increased permeability of the inner mitochondrial membrane.
E.decreased rate of O2 consumption.
D
54
```
An isolate of Escherichia coli susceptible to both tetracycline and ampicillin was grown in liquid culture (50 ml) in the absence of both drugs. The doubling time of growth (viable cells) is 30 min. Tetracycline was added when the culture contained 5 x 108 cells/ml, and the optical density of the culture immediately ceased to increase. After 30 min incubation, ampicillin was then added to the culture, and the culture was incubated for an additional 60 min. The cells were then washed extensively and suspended in 50 ml of sterile saline. Dilutions were then plated on appropriate agar plates to determine the number of viable cells/ml. Which of the following numbers MOST CLOSELY approximates the viable count you would expect?
A.0
B.1 x 10E9 cells/ml
C.2 x 10E9 cells/ml
D.4 x 10E9 cells/ml
E.5 x 10E8 cells/ml
```
Answer Key: E
Feedback: The answer is E. The described scenario indicates antagonistic antibiotic interactions. Addition of tetracycline which is bacteriostatic, inhibits the action of ampicillin.
55
During fasting, an individual lacking carnitine palmitoyltransferase II would present with all of the following EXCEPT
A.increased levels of fatty acids in the plasma.
B.increased levels of dicarboxylic acids excreted into the urine.
C.increased levels of ketone bodies in the plasma.
D.increased levels of oxidized acylcarnitines excrete d into the urine.
E.decreased rate of beta-oxidation in the mitochondria.
Answer Key: C
56
The ligamenta flava
A.are pierced by dorsal primary rami of spinal nerves.
B.connect laminae of adjacent vertebrae.
C.form part of the capsule surrounding synovial intervertebral joints.
D.are thickened in the neck to form the ligamentum nuchae.
E.connect the spinal cord to the dura mater.
B
57
```
Which enzyme is activated by direct binding of cAMP to a regulatory subunit?
A.Adenylate cyclase
B.Protein kinase A
C.Phosphorylase kinase
D.Protein phosphatase
E.Phosphorylase
```
B
58
```
Which ONE of the following compounds is uniquely found in peptidoglycan and is absent from mammalian cells?
A.Glycine
B.L-alanine
C.L-lysine
D.meso-diaminopimelic acid
E.N-acetyl-D-glucosamine
```
Answer Key: D
Feedback: Of the listed choices, only meso-diaminopimelic acid is found in peptidoglycan and is not present in mammalian cells. The other choices are found in both bacteria and mammalian cells.
59
You observe an acute rise in the temperature of the patient undergoing surgery. Concerned, you examine the limbs and find that the muscles are rigid and stiff, suggesting malignant hyperthermia. What is the most likely cause of this condition?
A.Increased activity of the SR Ca2+ pump leading to accumulation of Ca2+ in the cytoplasm and increased skeletal muscle contraction.
B.Increased myosin light chain kinase activity relative to myosin light chain phosphatase leading to increased skeletal muscle tone.
C.Spontaneous increase in cellular ATP resulting in an increase in actin ATPase activity and increased contraction.
D.Spontaneous increase in cytoplasmic Ca2+, due to unregulated and persistent activation of the SR Ca2+ release channel (ryanodine receptor).
E.Blockade of neurotransmission preventing depolarization of skeletal muscle stimulating the muscle to rapidly contract.
Answer Key: D
Feedback: Answer D is correct. Muscle rigidity occurs when muscles fail to relax. This can occur when ATP is completely absent from the cell (rigor state), however this is not one of the choices. Alternatively, the maintained presence of Ca2+ in the cytoplasm will lead to continuous contraction, such as would occur if there is unregulated and persistent activation of the Ca2+ release channel in the SR.
60
In the typical cell described in class, a postsynaptic potential is produced by a transmitter binding to a receptor channel that opens and increases its permeability to potassium. This will result in
A.no change in the postsynaptic cell’s membrane potential.
B.an ionotropic excitatory postsynaptic potential.
C.a metabotropic excitatory postsynaptic potential.
D.an ionotropic inhibitory postsynaptic potential.
E.a metabotropic inhibitory postsynaptic potential.
Answer Key: D
Feedback: Answer D.
Opening a potassium channel in the postsynaptic membrane increases the membrane permeability to potassium. Increasing the permeability to an ion moves the membrane potential toward the equilibrium potential for that ion. In the cell in class, the resting membrane potential was -90 mV and the equilibrium potential for potassium was -97 mV. Moving the membrane potential toward the potassium equilibrium potential will hyperpolarize the cell away from threshold making it more difficult for any excitatory inputs to drive the cell to threshold. The PSP is ionotropic because the postsynaptic receptor is the actual channel. If it were metabotropic, the receptor would release a second messenger that would, in turn, open a separate ion channel in the membrane.
61
What phenomenon causes the anatomical sing known as "dimpling" of the breast?
A.Blockade of the lymph ducts in the axillary region
B.Thickening of the dermis due to radiation treatment following breast cancer.
C.Traction of Cooper's suspensory ligaments by growing cancer cells
D.Hyperplasia of the pectoralis major following the metaplastic spread of cancer cells.
Answer Key: C
Feedback: Answer C. As the cancer spreads, the cell mass impinges of the suspensory ligaments of Cooper. As the cells invade the ligament the normally elastic ligaments stiffen. When the woman raises her arm, the characteristic dimpling can be observed.
62
```
As the intensity level of aerobic exercise increases, which one of the following metabolites increases in concentration and most directly stimulates oxidative phosphorylation?
A.NAD+
B.ADP
C.ATP
D.Creatinine
E.Lactate
```
Answer Key: B
63
A young man fell asleep with a book wedged under his arm and awoke in the morning unable to extend his wrist and fingers. Movement at the shoulder appeared normal. Which of the following structures most likely involved is the
```
A.lateral cord of the brachial plexus.
B.medial cord of the brachial plexus.
C.ulnar nerve.
D.radial nerve.
E.median nerve nerve.
```
D
64
A 17 yo male complains of R shoulder pain after playing Thanksgiving day football with his cousins. They started by playing two-hand touch and ended the game when your patient was tackled and pile-driven into the grass by a 250 pound cousin. He felt immediate pain in his right shoulder. Since that time he has had pain with any shoulder motion. He can move the shoulder in full range of motion, but it really hurts to do so. Which of the following exam findings do you NOT expect him to have?
A.Teenderness to palpation over the AC joint
B.Echymosis and swelling over the mid-clavicle
C.Pain with a resisted adduction test
D.A "square shoulder" deformity
Answer Key: D
65
What is the primary method for increasing the force of contraction of a skeletal muscle?
A.Increasing the firing frequency of the muscle fibers.
B.Recruiting small muscle fibers and then larger muscle fibers as the force needed increases.
C.Recruiting motor units from small to large as the force of contraction is increased.
D.Adjusting the initial muscle length to match the amount of force needed for the contraction.
Answer Key: C
Feedback: Skeletal muscle force is increased by recruiting motor units from small to large and the required force increases.
A. Increasing the firing frequency of either motor units or muscle fibers will increase muscle force but it is not the primary method of force control. Motor unit recruitment is the major regulator of muscle force.
B. Muscle fibers do not vary significantly in size in most skeletal muscles. The muscle has many motor units of different sizes but the number of fibers in the individual motor unit are fixed and do not change with increasing force.
D. Skeletal muscle is pretty much restrained by the skeleton so it cannot change length enough to make large changes in its force of contraction. It tends to work on the peak of the length-tension curve where its force of contraction is maximum.
66
```
The internal vertebral venous plexus is found in the
A.epidural space.
B.subdural space.
C.subarachnoid space.
D.central canal of the spinal cord.
E.transverse foramina.
```
Answer Key: A
| Feedback: Blood flow is critica to tissue and organ functionl. Check atlas.
67
In the emergency room (ER), your patient has a laceration in the anterior midline of his forearm, midway between the elbow and the wrist, that measures two-inches across. He also states that he has lost some feeling in his middle finger. Based on these items, and even before you examine him, you already suspect injury to the
A.pronator quadratus muscle.
B.supinator muscle.
C.superficial branch of the radial nerve.
D.deep (motor) branch of the ulnar nerve.
E.median nerve.
Answer Key: E
68
A 47 yo male complains of R shoulder pain after playing Thanksgiving day football with his nephews. He played all-time quarterback and threw the ball more than he had since high school. He doesn't remember hurting the shoulder during the game, but remembers the shoulder was a little sore after the game. The pain has steadily increased every day since then. It hurts to brush his hair, hurts to get his wallet out of his back pocket and is starting to wake him up at night. Which of the following exam findings do you NOT expect him to have
A.4/5 strength on R empty can test.
B.painful arc of motion on shoulder abduction
C.tenderness to palpation over the AC joint
D.painful Neer test
Answer Key: C
Feedback: Correct Answer: C. The patient has a subacromial impingement/rotator cuff degeneration. A, B, and D are all consistent with that diagnosis. Tenderness to the AC joint is not typical of rotator cuff/impingement.
69
```
During contraction of a skeletal muscle, which of the bands or structures do not change length?
A.Sarcomere
B.A-band
C.I-band
D.the myofibril
```
Answer Key: B
Feedback: The length of the A-band remains fixed during contraction. The A-band represents the thick filament that does not change length.
70
```
As an anatomical and imaging guide, the following articulates with the sternum at the
sternal angle (of Louis). The
A.clavicle.
B.costal cartilage of the 1st rib.
C.costal cartilage of 2nd rib
D.xiphoid process.
E.pulmonary ligament.
```
Answer Key: C
| Feedback: Correct answer is costal cartilage of 2nd rib.
71
You are evaluating a 43 year old female who complains that her hand is becoming "extremely clumsy" and you note that the ring and small fingers are "clawed" in hyperextension. The most likely to be impaired is the
A.median nerve at the elbow.
B.radial nerve at the mid-humeral level.
C.ulnar nerve at the wrist.
D.musculocutaneous nerve in the distal arm.
E.posterior cord of the brachial plexus.
Answer Key: C
72
Which of the following is true?
A.The artery of Adamkiewicz is the major blood supply to the posterior regions of the cervical spinal cord.
B.The conus medullaris contains no neural elements.
C.The denticulate ligament separates the ventral rootlets from the dorsal rootlets.
D.The spinal ganglion contains the majority of motor efferent fibers exiting the spinal cord.
E.The pia mater is the most superficial of the meninges.
Answer Key: C
73
In a working muscle, which step in fatty acid metabolism is activated by AMP binding to the AMP-sensitive protein kinase?
A.
Transport from the blood into the cytosol
B.
Conversion of fatty acid to fatty acyl CoA
C.Conversion of fatty acyl CoA to fatty acyl carnitine
D.Transport of fatty acyl carnitine into the mitochondrial matrix
E.
The first step of the beta oxidation spiral (Acyl CoA dehydrogenase reaction)
Answer Key: C
Feedback: AMP actives AMP-PK which inhibits Acetyl CoA carboxylase. Inhibition lowers malonyl CoA. Malonyl Coa is a negative regulator of Fatty Acyl CoA conversion to Fatty acyl carnitine. Slide 34 in Roseman fatty acid metabolism lecture.
74
Acetaminophen
A.
Should never be given to young children because of the risk of developing Reye’s syndrome
B.metabolism can be reduced by chronic ethanol use
C.
Is a powerful anti-inflammatory agent
D.
Is excreted unchanged by the kidney
E.overdose can lead to hepatic necrosis and liver failure
Answer Key: E
Feedback: Acetaminophen is metabolized and one of the by-products is NAPQI (N-acetyl-p-benzoquinone imine). chronic alcoholism will induce higher levels of CYP2E leading to more MAPQI which is damaging to the liver.
Acetaminophen is not a strong anti-inflammatory medicine.
75
```
Infiximab and etanercept are efficacious in treating rheumatoid arthritis because they directly interfere with signaling by
A.prostaglandins
B.leukotrienes
C.prostacyclins
D.TNF-alpha
E.TGF-beta
```
Answer Key: D
Feedback: Infiximab is an antibody that binds to TNFa. Etanercept is a fusion protein containing Antibody portion fused to the TNF receptor that binds to TNF.
76
The buttocks are sometimes used as the site for intramuscular injection. To locate the site for injection, the recommendation is to form four quadrants with a horizontal line level with the point of the sacrum (supertrochanteric plane) and a vertical line that bisects the buttock. The site of injection will be in the
A.upper lateral quadrant below the iliac crest
B.lower lateral quadrant of the buttock
C.upper medial quadrant of the buttocks, while avoiding the sacrum.
D.lower medial quadrant of the buttocks, in the fleshy portion of gluteus maximus.
Answer Key: A
Feedback:
Using the upper lateral quadrant avoids the possibility of hitting the sciatic nerve or its branches or the inferior gluteal nerve.
77
On x-ray examination of the leg of a 8 y.o. boy, you view what appears to be severe infection of the tibia. What is the most common way for bacteria to infect long bones?
A.During surgical implantation of hardware and pins
B.Traumatic insertion of foreign objects
C.Hematogenous transport of bacteria into the bone
D.Spread of infection from a contiguous focus
Answer Key: C
78
A patient with glucose 6-phosphate dehydrogenase deficiency was inadvertently given a sulfa drug to treat a bacterial infection. Which of the following will be likely to occur as a consequence of taking the drug?
A. Low NADPH/NADP+ ratio in cells
B. Low NADH/NAD+ ratio in cells
C.Negligible amount of malondialdehyde in blood
D.Low concentration of ribose 5-phosphate
E.High concentration of reduced glutathione
Answer Key: A
Feedback: Answer: “a”. Glucose 6-phosphate dehydrogenase deficiency results in a slower rate of the oxidative reactions of the pentose phosphate pathway. Oxidative stress from taking sulfa drugs and bacterial infections can quickly deplete the NADPH, especially in red blood cells. The NADH/NAD+ ratio is low all the time, and is unlikely to get much lower from taking the drug. Therefore “b” is not a good answer. Depletion of NADPH will cause accumulation of reactive oxygen species in the cell, which damage membranes, proteins, and DNA. Degradation of membrane lipids by peroxidation from radical chain reactions will produce malondialdehyde, which is an indicator of radical damages when detected in blood and urine samples. Therefore, the concentration of malondialdehyde will increase due to the deficiency of the glucose 6-phosphate dehydrogenase and taking the sulfa drug. Ribose 5-phosphate can be produced from the oxidative reactions or from fructose 6-P and glyceraldehyde 3-P through transketolase and transaldolase catalyzed reactions. Therefore its concentration is unlikely to be affected. The level of reduced glutathione will decrease, rather than increase, because the major role of NADPH is to maintain a high ratio of reduced to oxidized glutathione.
79
The pentose phosphate pathway and glycolytic pathways are linked by which of the following?
A.Both pathways produce NADH.
B.Phosphopentose epimerase catalyzes conversion between ribulose 5-P and xylulose 5-P.
C.6-Phosphogluconate dehydrogenase generates ribulose 5-P from the pentose phosphate pathway intermediate 6-phosphogluconate.
D.Transketolase and transaldolase convert pentose 5-P to fructose 6-P and glyceraldehyde 3-P.
E. Triose phosphate isomerase and aldolase convert fructose 1,6-bisphosphate to glyceraldehyde 3-P.
Answer Key: D
Feedback: The answer is “d”. Transketolase and transaldolase work together to convert ribose 5-P and xylulose 5-P to fructose 6-P and glyceraldehyde 3-P. Both ribose 5-P and xylulose 5-P are generated by isomerization or epimerization of ribulose 5-P, which is the product of the oxidative reactions of the pentose phosphate pathway. Fructose 6-P and glyceraldehyde 3-P are intermediates in the glycolytic pathway. The two pathways also share the same starting material, glucose 6-phosphate. Answer “a” is incorrect because the pentose phosphate pathway produces NADPH, not NADH. Both ribulose 5-P and xylulose 5-P are intermediates in the pentose phosphate pathway, thus “b” is not the correct answer. Reactions in “c” are also in the pentose phosphate pathway only. Reactions in “e” are in the glycolytic pathway.
80
A 35 year old elementary school teacher presents to your outpatient clinic with complaints of 4 weeks of hand stiffness and pain in all of her metacarpal phalageal joints (MCP’s) and proximal interphalangeal joints (PIP’s). The stiffness lasts most of the day and she has noticed swelling at these joints and has difficulty making a fist. Her symptoms began rather suddenly over the course of a few days. She has no other associated symptoms. In the course of your interview she relates that a number of children at her school have been sick with an illness that manifests as a rash that gives them a “slapped cheek” appearance.
```
You suspect that this may represent a viral arthritis, likely parvovirus B-19. How would you classify this arthritis?
A.Chronic oligoarticular
B.Chronic polyarticular
C.Acute polyarticular
D.Acute oligoarticular
```
Answer Key: C
Feedback: Answer (1): C. The classification of an arthritis helps define your differential diagnosis. In this case the symptoms have been present for less than 6 weeks suggesting a broader differential which includes viral arthritis. Any arthritis affecting > 4 joints is considered polyarticular.
81
A 65 year old white female presents for evaluation of hand pain of many years duration. She reports the gradual onset of pain in her distal interphalangeal joints (DIP) and 1st carpal metacarpal (CMC) joints. The pain is made worse with activity, specifically knitting. She reports morning stiffness which lasts 15-20 minutes as well as stiffness after periods of inactivity. She does not recall any swelling. She has been evaluated in the past and has radiographs which reveal asymmetric joint space loss in the DIP’s and 1st CMC with osteophyte formation, subchondral sclerosis, and some central erosions leaving a “gull wing” pattern at the DIP’s. She reports modest symptom relief with Tylenol 1gm three times daily, but has returned to clinic to see if there are any new treatment modalities. Examination reveals loss of active and passive range of motion at the DIP joints. She has firm nodular masses at her DIP joints which you feel are consistent with Heberden’s nodes. There is no palpable synovitis. Examination of her nails reveals no pits. Her skin examination reveals no rashes. Heart and lung examination is unremarkable.
How would you classify this disease process?
A.
Chronic non-inflammatory polyarthritis
B.
Chronic inflammatory oligoarthritis
C.
Acute non-inflammatory oligoarthritis
D.
Acute inflammatory oligoarthritis
Answer Key: A
Feedback: Answer : A. The classification of an arthritis helps define your differential diagnosis. In this case the symptoms have been present for more than 6 weeks. Any arthritis affecting > 4 joints is considered polyarticular.
82
The inferior gluteal nerve innervates the _________ muscle.
```
A. gluteus medius
B. tensor fascia latae
C. gluteus minimus
D.adductor magnus
E.gluteus maximus
```
E
83
How do sympathetic, parasympathetic, and somatic innervation (and tone) interact to control rectal/anal continence?
A.Somatic (voluntary) innervation controls the external sphincter and the internal sphincter. Sympathetic and parasympathetic innervation do not play a role in defecation.
B.Defecation is controlled by the autonomic nervous system (sympathetic and parasympathetic innervation) and the somatic system does not play a role.
C.Somatic (voluntary) innervation controls the external sphincter. Sympathetic innervation contracts the internal sphincter and parasympathetic innervation inhibits the contraction of the internal sphincter.
D.Somatic (voluntary) innervation controls the external sphincter. Sympathetic innervation inhibits contraction of the internal sphincter and parasympathetic innervation activates the contraction of the internal sphincter.
C
84
The anal and urogenital triangles are separated by an imaginary line (anatomical/surgical landmark) connecting the
```
A. pubic tubercles.
B.coccyx and pubic symphysis.
C. ischial tuberosities.
D. ischial spines.
E.posterior inferior iliac spines.
```
C
85
A 67 year old Caucasian male presents to the emergency department with a chief complaint of sudden onset right knee swelling and pain which began 24 hours ago. He does not recall any falls or injuries. He has a known history of chronic kidney disease, mild congestive heart failure, hypertension, and hyperlipidemia. The pain is described as intense, ten out of ten, and woke him from sleep yesterday morning. He reports feeling feverish in the past 24 hours, but has not noted any rigors. He has been unable to walk and is in a wheelchair. The knee is red, visibly swollen, and warm to the touch. Range of motion testing and further examination is limited by pain.What is the next best course of action?
A.Weight bearing radiographs of the knees
B.IV administration of vancomycin 30mg/kg every 12 hours
C.Arthrocentesis with synovial fluid analysis for crystals, cell count, and culture
D.Laboratory evaluation with complete blood count, erythrocyte sedimentation rate, uric acid, and complete metabolic panel.
Answer Key: C
Feedback: Answer (4): C. Any monoarthritis is considered a septic arthritis until proven otherwise. The appropriate course of action is arthrocentesis with evaluation for cell count, culture, and crystal analysis. Laboratory evaluation, while helpful in this case, cannot be interpreted in the absence of synovial fluid analysis. Weight bearing radiographs of the knees, may provide useful information, but does not help with determining the etiology of an acute inflammatory arthritis. Likewise, antibiotic administration would be inappropriate until a diagnosis of a septic arthritis is made.
86
Endochondrial bone formation is uniquely characterized by
A.the presence of a cartilage template.
B.cells that secrete collagen.
C.the absence of blood vessels.
D.an increase in collagen phosphorylation.
E.fetal development from the neurotube.
A
| Feedback: Only A is correct and unique to endochondrial formation.
87
```
As the intensity level of aerobic exercise increases, which one of the following metabolites increases in concentration and most directly stimulates oxidative phosphorylation?
A.NAD+
B.ADP
C.ATP
D.Creatine
E.Lactate
```
B
88
The fascial compartments of the leg play a role in bacterial sepsis because they
A.form a barrier that bacteria cannot penetrate.
B.limit the volume the muscle can swell during infection.
C.create an aerobic environment in which staph organisms cannot survive.
D.create an anaerobic environment that fosters the survival of staph organisms.
E.direct extracellular fluid drainage into the lymphatic system.
Answer Key: B
Feedback: Limit the volume the muscle can swell during infection. This is important because suppuration (pus formation) can increase pressure in the compartment. This is relieved by fasciotomy.
89
```
Intermittent claudication is
A.limping.
B.wrist soreness
C.shortness of breath.
D.stiff back.
```
Answer Key: A
| Feedback: Limping. Usually caused by ischemia in the leg muscles due to narrowing of the arteries.
90
The antimalarial drug pamaquine is converted to a derivative in the liver that causes “oxidative stress” to all cells. Red blood cells are most susceptible to this metabolite because they cannot replace damaged proteins and lipids, and individuals with glucose 6-phosphate dehydrogenase deficiency are particularly vulnerable. What is the primary, direct reaction of this metabolite that starts the chain of events leading to cell destruction?
A.Suicide inactivation of residual glucose 6-phosphate dehydrogenase
B.Oxidation of the active site sulfhydryl of glyceraldehyde 3-phosphate dehydrogenase
C.Peroxidation of membrane lipids
D.Oxidation of glutathione
E.Oxidation of NADPH
E
91
```
Which of the following are risk factors for lower back pain?
A.Repetitive vibration
B.Depression
C.Smoking
D.A soft bed
E.Minimal activity
F.back muscle weakness
G.all of the above
```
G
