Cardiac Muscle - Quiz 1 Flashcards
other names for cardiac muscle cell
- cardiac myocyte
- cardiac muscle fiber
cardiac muscle cells contain
- actin
- myosin
- troponin
- tropomyosin
cardiac muscle cells are connected to one another by
- intercalated discs
intercalated discs contain
- desmosomes
- gap junctions
- fasciae adherentes (in transverse portion)
intercalated discs contain desmosomes for
- strength
intercalated discs contain gap junctions for
- low resistance pathways for action potential spread through atria and ventricles
Gap junctions connect
- atrial myocytes with other atrial myocytes
- ventricular myocytes with other ventricular myocytes
are atrial myocytes connected to ventricular myocytes
- why?
- no
- allows time for ventricles to fill
role of nodal and conducting cardiac cells
- set electrical rhythm
- make sure electrical spread happens in orderly and regulated fashion
which cardiac myocyte has the fastest spontaneous firing
- SA node
electrical coupling between cardiac cells occurs through
- intercalated discs
- gap junctions
electrical coupling between cardiac cells allows for
- synchronized spread of depolarization
what initiates the action potential
- SA node
what is the SA node also known as
- normal pacemaker
control of SA node
- autonomous
external stimulus of SA node
- no external stimulus needed
spread of action potential pathway
- SA node
- internodal tracts
- AV node
- common bundle of His
- left and right bundle branches
- purkinje fibers
internodal tracts help spread action potential to
- atria
atrial depolarization results in
- atrial contraction
contraction of atria occurs
- nearly simultaneously
atria connection to ventricles
- electrically insulated from ventricles
- except at AV node
what is the path for excitation from the atria to the ventricles
- AV node
speed of AV nodal cells conducting action potential
- slow
slow conduction of action potentials by AV node allows for
- a delay between atrial and ventricular contraction
- allows more time for ventricle to fill with blood
what occurs after ventricular depolarization
- ventricular contraction
where does contraction start in the ventricles
- starts in the apex then spreads to ventricle walls
coordination of contraction of two ventricles
- contract almost simultaneously
action potential between heartbeats
- no action potentials
- pacemaker cells are depolarizing
action potentials of myocytes from different regions of the heart
- have different action potentials