Human Phys Quiz 3

25 July 2022
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question
Identify the ONE CORRECT statement regarding the skeletal neuromuscular junction. a) At the terminal bouton, voltage-gated Ca++ channels open to allow efflux of Ca++ that triggers acetylcholine release b)All neuromuscular junction synapses are excitatory
answer
b)
question
true or false: Parasympathetic activation produces a more diffuse effect compared to activation of the sympathetic nervous system
answer
false
question
A young boy darts into the path of a car after attending a Baltimore Orioles-Boston Red Sox baseball game with his father. In the accident the child suffered a broken thigh, broken shoulder blade and broken ribs. He also lost 30% of his blood during the accident. On arriving at the hospital, a number of tests were conducted on the lad. His hematocrit would have: a) decreased b) stayed the same as before the accident
answer
b)
question
How would you increase flow to the body without increasing aortic radius? i) increase cardiac muscle contractility ii) decrease pulmonary vein radius iii) decrease total peripheral resistance iv) increase total peripheral resistance v) increase venous return a) i.ii b) i.ii.iii c) i. iii. v d) ii. iii. v
answer
c)
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Why can extra-systoles occur after multiple stimulations? b) The cardiac muscle summates a) A stimulation occurs after the absolute refractory period has ended
answer
a)
question
You are conducting an experiment with a frogs heart. You administer three cholinergic drugs to the heart - waiting 5 min in between each treatment. WITHOUT washing the drugs off between administrations, explain what the effects on heart rate will be after: acetylcholine, atropine, pilocarpine.
answer
AcH - decreases HR atropine - increases HR pilocarpine - decreases HR
question
A decrease in afterload will lead to which of the following?
answer
increased stroke volume
question
true or false: a decrease in parasympathetic activity and an increase in sympathetic activity will decrease heart rate
answer
false
question
As mean arterial pressure increases, the ________, informing the medulla oblongata that blood pressure has indeed increased.
answer
frequency of action potentials from the baroreceptors increases
question
Conduction through which of the following is slow to allow atria to contract before the ventricles? a) SA node b) AV node
answer
b
question
Fenestrated capillaries are unique in their ability to ________. a) allow few molecules to pass between endothelial cells b) allow relatively large molecules to pass between endothelial cells
answer
b
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In response to a decrease in tissue metabolic activity, tissue oxygen concentrations ________, which causes a(n) ________. a) increase : constriction of the arterioles b) decrease: constriction of arterioles c) increase: dilation of arterioles d) decrease: dilation of venules
answer
increase : constriction of the arterioles
question
Mean arterial pressure can be increased by all of the following except ________. a) increasing EDV d) decreasing EDV
answer
d
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The preload is approximately the same as the ________. a) end-systolic pressure b) end-diastolic pressure c) MAP d) venous pressure
answer
b
question
The volume of blood ejected from the ventricle with each contraction can be described by the equation ________.
answer
EDV-ESV
question
What phase of the cardiac cycle is the heart in when all four valves of the heart are closed and ventricular pressure is less than atrial pressure?
answer
none
question
what is the formula for flow?
answer
flow = pressure gradient/resistance
question
Which of the following is responsible for the repolarization of pacemaker cells? a) increase in permeability to sodium b) increase in permeability to calcium c) increase in permeability to potassium d) decrease in permeability to potassium
answer
increase in permeability to potassium
question
Which of the following variables is NOT involved in the regulation of stroke volume? a) ventricular contractility b) EDV c) symatpethic nervous activity d) parasympathetic nervous activity
answer
d)
question
________ describes the movement of fluid out of the capillary, while ________ describes the movement of fluid into the capillary.
answer
filtration (hydrostatic): absorption (osmotic)