Cardiology 1 -
Basic Science
test questions
and answers
2025
What is the "lub" heart sound?
-systolic heart sound
-corresponds to mitral and tricuspid (atrioventricular) valve closure
What is the "dub" heart sound?
-diastolic heart sound
-corresponds to aortic and pulmonic (semilunar) valve closure
-may be physiologic splitting with inspiration from increased
ventricular filling secondary to decreased intrathoracic
pressure (aortic valve closes first)
What are the characteristics of cardiac muscle?
-only found in the heart
-highly coordinated contractions to pump blood to vessels
-striated; organized in sarcomeres; same banding as skeletal
but INVOLUNTARY contractions
-many mitochondria / myoglobin -> stream of ATP
, -held together by intercalated discs (allows contraction in wave-like
pattern to work as pump)
What is an action potential?
-rapid voltage change required by striated muscle cells to trigger
contraction
How is cardiac muscle different from skeletal muscle?
-cardiac can be self-generating (automaticity)
-conducted cell to cell directly
-have long duration, precluding fusion of individual twitch
What are characteristics of cardiac muscle cells?
-cells branch
- 1 to 2 nuclei, kept in middle
-have intercalated discs w gap junction (allow communication btwn
cells to promote depolarization wave)
-held tg during contraction by desmosomes
-"functional syncytium" - function as everything works in sync
-lots of mitochondria -> need lots ATP to keep contracting
What is the role of T tubules in cardiac muscle cell?
-found on transverse surface
-increase surface area
-allow extracellular Ca2+ to drop across cell where it binds on
outside
-calcium enters cell
-triggers sarcoplasmic reticulum
What is the role of the sarcoplasmic reticulum in cardiac muscle
cell?
-a "bag of calcium"
-draped over proteins of the cardiac cell
-calcium binds to receptors on the SR & opens channel for SR to
dump its own calcium
Basic Science
test questions
and answers
2025
What is the "lub" heart sound?
-systolic heart sound
-corresponds to mitral and tricuspid (atrioventricular) valve closure
What is the "dub" heart sound?
-diastolic heart sound
-corresponds to aortic and pulmonic (semilunar) valve closure
-may be physiologic splitting with inspiration from increased
ventricular filling secondary to decreased intrathoracic
pressure (aortic valve closes first)
What are the characteristics of cardiac muscle?
-only found in the heart
-highly coordinated contractions to pump blood to vessels
-striated; organized in sarcomeres; same banding as skeletal
but INVOLUNTARY contractions
-many mitochondria / myoglobin -> stream of ATP
, -held together by intercalated discs (allows contraction in wave-like
pattern to work as pump)
What is an action potential?
-rapid voltage change required by striated muscle cells to trigger
contraction
How is cardiac muscle different from skeletal muscle?
-cardiac can be self-generating (automaticity)
-conducted cell to cell directly
-have long duration, precluding fusion of individual twitch
What are characteristics of cardiac muscle cells?
-cells branch
- 1 to 2 nuclei, kept in middle
-have intercalated discs w gap junction (allow communication btwn
cells to promote depolarization wave)
-held tg during contraction by desmosomes
-"functional syncytium" - function as everything works in sync
-lots of mitochondria -> need lots ATP to keep contracting
What is the role of T tubules in cardiac muscle cell?
-found on transverse surface
-increase surface area
-allow extracellular Ca2+ to drop across cell where it binds on
outside
-calcium enters cell
-triggers sarcoplasmic reticulum
What is the role of the sarcoplasmic reticulum in cardiac muscle
cell?
-a "bag of calcium"
-draped over proteins of the cardiac cell
-calcium binds to receptors on the SR & opens channel for SR to
dump its own calcium
