BIOL 320: Exam 2 2026 Questions and
Answers
What causes a heart murmur? - Correct answer-reflex back through valves by not
sealing correctly due to inflammation, calcium crystals, scarring
What does the heart skeleton do? - Correct answer-provides site for muscles
attachment, electrical insulation between atria and ventricles, plate of fibrous
connective tissue between atria
What are desmosomes? - Correct answer-velcro that holds cells together
What are gap junctions? - Correct answer-allows ions to pass
What are intercalated disks? - Correct answer-specialized cell to cell contact
What is the functional syncytium? - Correct answer-all cardiac muscle acts as a
single unit electrically
What causes the plateau phase in a heart's action potential? - Correct answer-
calcium
What is the rate of the SA node? - Correct answer-70-75 bpm
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, What is the delay of the AV node and why? - Correct answer-1/10 a second allows
for both atria to contract
What is the neurotransmitter for the sympathetic ANS? - Correct answer-
norepinephrine
What is the neurotransmitter for the parasympathetic ANS? - Correct answer-
acetylcholine
What is the Bainbridge reflex? (atrial reflex) - Correct answer-Heart rate increases
when blood volume increases
How does thyroxin affect heart rate? - Correct answer-longer, slower HR
What can cause an arrhythmia? - Correct answer-nicotine, caffeine
What is fibrillation? - Correct answer-rapid irregular uncoordinated contraction (no
blood movement)
What is arrhythmia? - Correct answer-irregular, uncoordinated heartbeat
What is ectopic focus? - Correct answer-abnormal pacemaker forms, non-nodal
variable effects
What causes bradycardia? - Correct answer-drugs, overactive PS-ANS, athlete,
high stroke volume, warning sign of brain edema
©COPYRIGHT 2025, ALL RIGHTS RESERVED 2
Answers
What causes a heart murmur? - Correct answer-reflex back through valves by not
sealing correctly due to inflammation, calcium crystals, scarring
What does the heart skeleton do? - Correct answer-provides site for muscles
attachment, electrical insulation between atria and ventricles, plate of fibrous
connective tissue between atria
What are desmosomes? - Correct answer-velcro that holds cells together
What are gap junctions? - Correct answer-allows ions to pass
What are intercalated disks? - Correct answer-specialized cell to cell contact
What is the functional syncytium? - Correct answer-all cardiac muscle acts as a
single unit electrically
What causes the plateau phase in a heart's action potential? - Correct answer-
calcium
What is the rate of the SA node? - Correct answer-70-75 bpm
©COPYRIGHT 2025, ALL RIGHTS RESERVED 1
, What is the delay of the AV node and why? - Correct answer-1/10 a second allows
for both atria to contract
What is the neurotransmitter for the sympathetic ANS? - Correct answer-
norepinephrine
What is the neurotransmitter for the parasympathetic ANS? - Correct answer-
acetylcholine
What is the Bainbridge reflex? (atrial reflex) - Correct answer-Heart rate increases
when blood volume increases
How does thyroxin affect heart rate? - Correct answer-longer, slower HR
What can cause an arrhythmia? - Correct answer-nicotine, caffeine
What is fibrillation? - Correct answer-rapid irregular uncoordinated contraction (no
blood movement)
What is arrhythmia? - Correct answer-irregular, uncoordinated heartbeat
What is ectopic focus? - Correct answer-abnormal pacemaker forms, non-nodal
variable effects
What causes bradycardia? - Correct answer-drugs, overactive PS-ANS, athlete,
high stroke volume, warning sign of brain edema
©COPYRIGHT 2025, ALL RIGHTS RESERVED 2
