Free STEP1 Exam Braindumps (page: 41)

Page 41 of 213

A 71-year-old man was admitted to the hospital after getting very dizzy upon rising from the toilet seat. At that time his pulse was racing and he remembers that his stool looked very different than usual. Over the last 4 or 5 weeks before the incident, the patient self-medicated with high-dose ibuprofen three times a day to control some pain in his hips. What is the mechanism of action for nonsteroidal anti-inflammatory drugs (NSAIDs) to cause gastrointestinal (GI) bleeding?

  1. they inhibit arachidonic acid synthesis
  2. they inhibit bradykinin synthesis
  3. they inhibit cyclooxygenase
  4. they inhibit histamine synthesis
  5. they promote prostaglandin synthesis

Answer(s): C

Explanation:

NSAIDs inhibit cyclooxygenase and consequently inhibit (not promote, choice E) synthesis of prostaglandins. In the stomach, prostaglandins have a cytoprotective effect through inhibition of acid secretion, enhancement of mucosal blood flow, and stimulation of bicarbonate and mucus secretion.
Inhibiting these processes can cause stomach ulcers and bleeding such as described in the case.
Arachidonic acid (choice A) is not directly affected by NSAIDs--it is turned into prostaglandin by
the action of cyclooxygenases. NSAIDs do not regulate bradykinin and histamine synthesis (choices B and D).



A 52-year-old man has a history of anginal pain that until recently was responsive to nitrates. He is now evaluated for possible angioplasty. The graph in below figure shows the ECG of this patient. Blood flow across the mitral valve is largest around which indicated point in this ECG tracing?

  1. A
  2. B
  3. C
  4. D
  5. E

Answer(s): E

Explanation:

The most rapid filling of the ventricles occurs in early diastole, immediately after opening of the atrioventricular valves. This happens after the repolarization phase (T wave) and resulting relaxation of the cardiac ventricular muscle. Excitation of the atria (choice A) also results in increased blood flow into the ventricles, occurring around choice B. However, the flow at that time is less than during early diastole.
Ventricular contraction begins with the QRS complex (choice C) and lasts until the end of the T wave (choice D). During this time, the mitral and tricuspid valves are closed.



The graph in below figure shows the pressurevolume curve of the left ventricle of this patient (shaded area). The pressurevolume curve of a normal subject is shown for comparison (broken lines). Compared to normal, which term best describes this patient's heart?

  1. decreased afterload
  2. decreased preload
  3. decreased stroke volume
  4. increased force of contraction
  5. increased preload

Answer(s): D

Explanation:

Note that the end-diastolic volume of this patient is the same as that of a normal subject. Because the patient's stroke volume is larger than that of a normal subject, the force of contraction must also be larger.
This could be due to increased sympathetic tone or to the fact that the patient took inotropic medications.
The volume remaining after the ventricular contraction is correspondingly smaller compared to normal.
Preload (choices B and E) equals end-diastolic volume and is the same in the patient and normal subjects.
Afterload (choice A) is equal to arterial pressure. Both afterload and stroke volume (choice C) are larger in this patient compared to normal.



The graph in below figure shows the jugular vein pressure curve of this patient. If the first heart sound occurs between letters C and D, which part of the curve represents the atrial contraction?

  1. peak A
  2. peak C
  3. peak D
  4. trough B
  5. trough E

Answer(s): B

Explanation:

below figure shows the jugular vein pressure curve. Pressure in the jugular vein reflects atrial pressure and is highest during the atrial contraction (named the "a wave"). The "v wave" (choice A) represents the rise in atrial pressure before the tricuspid valve opens during diastole. The "y notch" (choice D) is due to the fall in atrial pressure during the ventricular filling phase. The "c wave" (choice C) is due to the rise in atrial pressure produced by the bulging of the tricuspid valve during isovolumetric contraction of the right ventricle. The "x notch" (choice E) coincides with the ventricular ejection phase.



Page 41 of 213



Post your Comments and Discuss USMLE STEP1 exam with other Community members:

nana commented on December 16, 2024
good information for practice
Anonymous
upvote

Nice commented on December 16, 2024
Nice nice nice
Anonymous
upvote

Jonas commented on December 16, 2024
Interesting
Anonymous
upvote

Gosia commented on December 16, 2024
Hi, did you have the same questions on exams?
POLAND
upvote

tom commented on December 16, 2024
it is very good
HONG KONG
upvote

sk commented on December 16, 2024
very usefull
Anonymous
upvote

harsha commented on December 16, 2024
a good way to practice
Anonymous
upvote

Rarebreed commented on December 16, 2024
These Dumps are super duper awesome. I passed my exams from these dumps on 14Th December 2024
NIGERIA
upvote

RJ commented on December 16, 2024
Preparing exam
UNITED STATES
upvote

CY commented on December 15, 2024
quite simple
HONG KONG
upvote

Kamala Swarnalatha commented on December 15, 2024
Good to use
Anonymous
upvote

kamala commented on December 15, 2024
Good to use this
Anonymous
upvote

BabeGirl commented on December 15, 2024
great stuff
Anonymous
upvote

Ousman commented on December 15, 2024
i am going to pass in this month
Anonymous
upvote

Roshan Thakur commented on December 15, 2024
Its very useful.
UNITED STATES
upvote

joe commented on December 15, 2024
dump still valid?
UNITED STATES
upvote

Priti commented on December 14, 2024
Answers seems to be correct
SINGAPORE
upvote

megha commented on December 14, 2024
pls give download file for dumps
Anonymous
upvote

Priti commented on December 14, 2024
Good questions
SINGAPORE
upvote

Priti commented on December 14, 2024
Good article
SINGAPORE
upvote

R Jeswanth commented on December 14, 2024
Hi This is Jai
AUSTRALIA
upvote

Anonymous commented on December 14, 2024
Good set or practice
Anonymous
upvote

??? commented on December 14, 2024
great collection of test questions. very effective to pass the exam
BANGLADESH
upvote

summer commented on December 13, 2024
nice questions
Anonymous
upvote

DIvesh commented on December 13, 2024
Good way to practice
JAPAN
upvote

redflame commented on December 12, 2024
great content
Anonymous
upvote

aini commented on December 12, 2024
best best best
Anonymous
upvote

Aung Naing Lin commented on December 12, 2024
good practice lesson
UNITED STATES
upvote

Mikronet commented on December 12, 2024
good pratice lessons
UNITED STATES
upvote

blaze commented on December 12, 2024
is the PDF worth it? Are these questions the same on the exam?
Anonymous
upvote

Mike Kutenda Chizinga commented on December 12, 2024
are these questions still valid
Anonymous
upvote

sas commented on December 12, 2024
good but not flexible
Anonymous
upvote

Anonymous commented on December 12, 2024
Very helpful and reference link also has been given.
Anonymous
upvote

Anonymous commented on December 12, 2024
Preparing or certification
Anonymous
upvote