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* pls help me answer with explanations. thanks!!!!
 #519866  
  futuredoctor19 - 07/19/10 17:19
 
  1)T tubules enhance which of the following processes in striated muscle cells?
(a) delivery of the action potential to the interior of the myocytes
(b) reinforcement of the cell surface for the attachment of myofibrils
(c) scavenging of a nonhydrolysed neurotransmitter to terminate the contraction stimulus
(d) storage of higher concentrations of intracellular calcium to uniformly initiate contraction?
(e) structural stabilization of the postsynaptic membrane at the neuromuscular junction

2) A healthy 25M who has been training for a marathon during the past 6 months runs 15 miles daily. Endurance training of normal skeletal muscle leads to which of the following muscle adaptations?
(a) fiber-size reduction (b) fiber-type conversion from type I (slow) to type II (fast)?? (c) hyperplasia of myocytes (d) ↑ capillary to fiber ratio (e) ↑ G6P activity

NBME 6
A Healthy subject receives a 2 L OF ISOTONIC SALINE. Assuming no urine excretion, which of the following is the expected increase in volume (in L) of the extracellular fluid compartment?
a) 0.3
b) 1.0
c) 1.3
d) 1.7
e) 2.0.

A 60 year old woman is undergoing surgical excision of a renal cell carcinoma thrombus that extends into the right renal vein. During this procedure, the vena cava is temporarily occluded above the renal veins. Increased venous pressure is most likely to be noted in which of the following veins during the period of occlusion?

a)external iliac
b)hepatic
c)IMA
d) portal
e)splenic

2 days after sustaining an MI, A 65 yo man develops an acute AV block. Despite resuscitative efforts and the placement of a pacemaker, the patient dies. An autopsy is requested. Ischemic injury to the AV node is the suspected cause of the patient’s AV block. Evaluation of a section from which of the following locations is most appropriate to evaluate this patient’s AV node? (i know its either a or b, but cant decide...the other choices didnt make sense so i didnt list them)
a) Interatrial septum near the attachment of the septal cusp of the tricuspid valve
b) Wall of the RA along the orifice of the IVC.

NBME 5
3 graphs showing the relationship between cardiac output and HR, EDV, and SV for healthy elderly men and healthy younger men. It shows that EDV and SV is higher in the elderly compared to the younger population. Which of the following age related anatomic changes contribute to well-maintained cardiac output in the elderly men?
a) Dilated ascending aorta
b) Left ventricular dilation
c) LVH

A 49 YO woman with CAD undergoes coronary arteriography that shows a 50% decrease in the lumen of the LAD. For any arteriovenous pressure gradient, the flow thru this artery (compared with normal) wall decrease by a factor of which of the following?

a) 2
b) 4
c) 8
d) 16
e) 32

is it 16??

Fluid balance is studied in a blood-perfused muscle preparation with an intact lymphatic system from an experimental animal. After a control period during which all parameters are normal, increasing which of the following is most likely to increase the rate of lymph flow without affecting the protein content of the lymph?
a) Capillary colloid pressure
b) Capillary hydrostatic pressure
c) Constriction of precapillary sphincters
d) Endothelial transcytosis
e) Width of junctions between endothelial cells



NBME 7
45] 60M with a 10-year history of alcoholism is admitted to the hospital for treatment of acute esophageal bleeding. He is scheduled for an operation. In order to ↓ the portal venous pressure to the esophageal veins, it is most beneficial to join the portal vein to which of the following veins? (i think its b-IVC??)
(a) gastroduodenal (b) IVC (c) left gastroepiploic (d) splenic (e) superior mesenteric

33] 16M is brought to the ER because of intermittent testicular pain during the past 2 hours. Physical exam shows a swollen, red scrotum. Testicular torsion is suspected in this patient. The most appropriate diagnostic test is Doppler ultrasound to show the blood flow to the testicle from which of the following arteries?
(a) artery of the ductus deferens (b) cremasteric artery (c) direct branch from the aorta
(d) external pudendal artery (e) internal pudendal artery

[47] A healthy 24M is participating in a study of swallowing. The manometric pressure changes that occur while this man swallows are shown. This is from NBME 7..showing the different pressures from esophagus. i couldnt duplicate the graphs here but i hope u guys can recognize the question?

Which of the following traces best represents muscle activity in the upper esophageal sphincter?
A B C D E

[44] A healthy 40F inhales to total lung capacity and then exhales forcefully. The rate of expiratory airflow is highest at total lung capacity and ↓ linearly as exhalation continues. Which of the following is the most likely cause of the observed ↓ in expiratory airflow?
(a) airway compression (b) ↓ expiratory effort (c) ↓ intrapleural pressure (d) doming of the diaphragm
(e) ↑ elastic recoil
 
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* Re:pls help me answer with explanations. thanks!!!
#2150757
  esa - 07/19/10 20:19
 
 
1 a
2 -

nbme 6

1.-
2.a
3.a
nbme 5

1 -
2.d
3.b

nbme 7

45.b
33.c
44.a

 
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