An adult male becomes hypotensive during surgery because of blood loss. Intravenous administration of 500 ml of which of the following solutions will have the greatest effect in restoring blood volume, and thus blood pressure to normal?
Answer(s): A
Intravenous solutions are distributed in the various body fluid compartments based on osmolality and their ability to penetrate the vascular wall and the cell membrane. The proteins in blood plasma will remain within the vascular compartment because of their low permeability across the vessel wall. Thus, 500 mL of blood plasma will remain in the vascular compartment. Water (choice B) passes across the cell membrane and the vascular wall easily. Hence distilled water will distribute itself between cellular and extracellular spaces, meaning only a small portion will actually contribute to blood volume, the other choices (C, D, and E) cross the vascular barrier and distribute partially to the extravascular space and thus are less effective intravascular volume expanders.
Using laboratory micropuncture technique, blood plasma is collected from both the afferent arteriole and efferent arteriole of a renal cortical glomerulus. Which of the following has the lowest afferent/efferent arteriole concentration ratio?
The process of glomerular ultrafiltration creates a tubular fluid that is essentially protein free. Hence, as plasma passes from the afferent arteriole, through the glomerular capillaries to the efferent arteriole, the protein albumin concentration rises as approximately 20% of the fluid is filtered out, leaving the albumin behind, giving an afferent/efferent arteriole concentration ratio of approximately 0.8. By contrast, the glomerular capillary membrane is freely permeable to water and other small particles such as glucose (choice A), chloride (choice B), potassium (choice D), and sodium (choice E), so their concentrations do not change as approximately 20% of water and solute are filtered into Bowman's capsule, giving afferent/ efferent arteriole concentration ratios of 1.0.
It is known that stretch receptors contained in the walls of the atria convey nerve impulses to the brainstem via the vagus nerve. Under normal conditions, these nerve impulses are most likely to occur during ventricular systole. What information is communicated to the brain by these nerve impulses?
Answer(s): C
The atrial stretch receptors are depolarized by stretch of the atria proportional to the magnitude of venous- filling pressure. The frequency of action potentials rises to a maximum at the peak of the atrial "v" wave, which signals maximum atrial filling during ventricular contraction. Although the remaining choices (A, B, D, and E) may be influenced by the filling of the heart by venous pressure, the information conveyed to the brain via the atrial stretch receptors relates directly to the filling pressure of the atria themselves.
High-dose glucocorticoid therapy for treatment of rheumatoid arthritis remains highly controversial. It is widely agreed that it is highly effective in controlling acute rheumatoid inflammation, but it may also result in significant adverse effects. Complications of high-dose glucocorticoid therapy include which of the following?
Answer(s): D
High-dose exogenous glucocorticoids suppress the adrenal neuroendocrine axis. Patients treated for longer than 2 weeks need to be tapered off glucocorticoids slowly to avoid adrenal insufficiency. Other complications of high-dose glucocorticoids include growth suppression, not excessive growth (choice A) in children and volume overload, not volume depletion (choice E). Hyperkalemia (choice B) and hyponatremia (choice C) are observed in adrenal insufficiency due to loss of mineralocorticoid effects and are not relevant to glucocorticoid therapy.
A 53-year-old healthy male undergoes an exercise stress test, running on a treadmill until a maximum exertion is obtained. Which of the following statements correctly describes effects of autonomic nerve activity on the cardiovascular system in such a healthy subject?
Answer(s): B
Since cardiac SA nodal cells receive tonic input from both sympathetic and parasympathetic nerves, heart rate increases whenever sympathetic firing rate increases or parasympathetic firing rate decreases. In humans, the parasympathetic innervation of ventricular muscle is negligible (choice D), and the strength of contraction increases with increasing preload and with increasing sympathetic firing rate (choice E). With few exceptions, blood vessels are not innervated by parasympathetic nerves, and there is little effect of changes in parasympathetic tone on total peripheral resistance (choices A and C).
Share your comments for USMLE STEP1 exam with other users:
very usefull
need certification.
great exam prep
i require dump
good morning, could you please upload this exam again,
hi can you please upload the dumps for sap contingent module. thanks
good questions
looking forward to the real exam
good ones for exam preparation
this is a good experience
hi everyone
waiting for the dump. please upload.
upload cks exam questions
awesome training material
where is dump
q. 289 - the correct answer should be b not d, since the question asks for the most secure way to provide access to a s3 bucket (a single one), and by principle of the least privilege you should not be giving access to all buckets.
please i need if possible h12-831,
good collection of questions and solution for pl500 certification
i would like to appear the exam.
i am very happy as i cleared my comptia a+ 220-1101 exam. i studied from as it has all exam dumps and mock tests available. i got 91% on the test.
need this dump
its really good to eventuate knowledge before appearing for the actual exam.
this is great
please i want the questions to pass the exam
i need to pass exam
great, i appreciate it.
please could you upload (isc)2 certified in cybersecurity (cc) exam questions
good questions, wrong answers
im preparing for exams
question no: 42 isnt azure vm an iaas solution? so, shouldnt the answer be "no"?
im study azure
i need this now
i took the aws saa-c03 test and scored 935/1000. it has all the exam dumps and important info.
Keeping this site free takes real effort. We constantly battle automated scraping and unauthorized content copying. A quick account helps us protect the community and keep the site free.
To continue studying for your STEP1, please sign in or create a free account.