missed stuff

Question 1

what is the formula for cardiac index

Answer 1

CI= (SVxHR)/body mass

Question 2

what is the formula for systemic vascular resistance

Answer 2

SVR = (MAP - RAP)/(CO) x 80

Question 3

The “transient outward” currents are most prominent in what phase of the cardiac myocyte action potential

Answer 3

phase 1; these are the K+ and Cl- channels that cause early repolarization

Question 4

Hyperkalemic solutions, usually 24 mEq of K or more, are clinically used in cardiac surgical procedures to effect cardioplegia. Which of the following is the most likely reason that a cardioplegia solutions obtain cardiac standstill

Answer 4

Hyperkalemia depolarizes the cell membranes so that normal activation processes do not activate.

Question 5

On close examination of the electrocardiogram of a 65-year-old woman, the PR interval was measured to be 250 ms. All other parameters of the electrocardiogram were in the normal range. What was the most likely cause for this abnormal observation?

Answer 5

Slow conduction of impulses in the AV node

Question 6

During what phase of the “working” cardiac myocyte action potential do the L-type Ca channels start activating?

Answer 6

phase 0

Question 7

The rate at which the cell membrane depolarizes during phase 4 of the nodal cells can be influenced by which of the following factors interacting with the channels that carry the depolarizing current

Answer 7

cAMP

Question 8

Which of the following is the most likely reason that the wave of repolarization in the ventricles travels from epicardium to endocardium?

Answer 8

Myocytes of the epicardium have the shortest duration of the action potential and those of the endocardium have the longest.

Question 9

A 65-year-old patient with chronic kidney disease is admitted to the hospital with hyperkalemia. The patient is mistakenly administered a potassium bolus, resulting in life-threatening arrhythmias. Which of the following mechanisms best explains this complication

Answer 9

impaired repolarization of cardiac myocytes; excess potassium decreases the outflow of potassium ions during phase 3 (repolarization). this impairs repolarization, which screws up the ability of the heart’s depolariztion-repolarization cycle needed to work properly

Question 10

what is the function of phospholamban

Answer 10

it inhibits SERCA. if we phosphorylate it, we can activate SERCA nad uptake more calcium into the SR

Question 11

the sternal angle is at the level of which rib

Answer 11

2

Question 12

does inhibition of phospholamban cause increased or decreased contractility

Answer 12

increased; lets SERCA uptake calcium which gets the myocyte through the phases faster

Question 13

what does the internal thoracic artery branch off of

Answer 13

the subclavian artery

Question 14

the azygous veins are found in which division of the mediastinum

Answer 14

posterior mediastinum

Question 15

which vein originates from the left and crosses the midline to merge with the SVC

Answer 15

left brachiocephalic

Question 16

why can ACE inhibitors and ARBs be an issue in those with bilateral renal stenosis?

Answer 16

the ability of these drugs to lower ang II ability limits the ability of the already struggling kidney to properly filter blood. these kidneys rely on ang II to constrict the efferent arteriole to promote filtration, and these drugs prevent this process and can cause acute kidney failure

Question 17

what do superior costal facets articulate with

Answer 17

head of rib of the same number

Question 18

which nerve helps elevate the ribs during inspiration

Answer 18

the intercostal nerve

Question 19

what area of the heart is most prone to ischemia

Answer 19

subendocardium

Question 20

an abcess may lead to what other issue in a vessel

Answer 20

aneurysm

Question 21

what condition tends to cause valve fushion

Answer 21

acute rheumatic endocarditis

Question 22

local edema following a sprained ankle is likely due to…

Answer 22

increased capillary permeability; the vascular injury causes local edema

Question 23

what is the equation for resistance

Answer 23

deltaP/flow

Question 24

In a patient with aortic stenosis, which of the following would be the most likely reason that a high-velocity jet is observed across the aortic valve during ejection

Answer 24

blood is being ejected through a narrowed valve

Question 25

give ficks equation for arterial and venous blood

Answer 25

CO= (Vo2)/(ca - cv)

Question 26

In a patient with heart failure who is generally sedentary, the systemic arteriovenous oxygen difference is measured to be more than doubled when compared to normal values. What is the most likely reason for this observation

Answer 26

In a patient with heart failure, a common finding would be a reduction in cardiac output and lower flow of blood through capillary beds all through the body. This allows tissue to extract more oxygen from the blood, reducing the oxygen content in venous blood - and widening the arteriovenous oxygen difference.

Question 27

how to we calculate transcapillary pressure?

Answer 27

(plasma hydrostatic pressure + tissue oncotic pressure) - (tissue hydrostatic pressure + plasma oncotic pressure)

Question 28

which organs have high interstitial hydrostatic pressure

Answer 28

kidney and brain

Question 29

what are specialized pericytes in the brain called

Answer 29

astrocytes

Question 30

what keeps the ductus arteriosus open

Answer 30

PGE2 and hypoxia

Question 31

the ___ separates the left vagus and phrenic nerves

Answer 31

intercostal vein

Question 32

Which muscles are recruited to reduce thoracic volume during forced expiration?

Answer 32

internal instercostals, abdominal muscles