18.2 Flashcards
how are cells connected to each other in cardiac muscle
intercalated discs that contain desmosomes and gap junctions
what are the functions of desmosomes
structural strength
what is the function of gap junctions
allow electrical current to travel from cell to cell
why is the heart muscle a functional syncytium?
gap junctions allow for the heart to beat as a single coordinated unit
why does the heart have a large amount of mitochondia
because the heart is constantly beating therefore it needs a lot of energy duh
what are pacemaker cells
self-excitable cells that initiate their own depolarization as well as depolarizing of the heart`
what triggers the release of CA2+ from the sarcoplasmic reticulum
influx of CA2+ in the extracellular fluid
what does the intrinsic conduction system of the heart do and what does it consist of
sets the basic rhythym of the heart
pacemaker cells that have unstable resting potentials to produce pacemaker potentials that continuously depolarize initiating the action potentials that are conducted through the heart
what does the extrinsic innervation of the heart do
modifies the basic heart rhythm - faster or slower
what is the flow of electicity though the heart?
sinoatrial node atrioventricular node bundle of His right and left bundle branches purkinje fibers
what is special about the atrioventricular node
it pauses briefly to allow the atria to finish contracting before the ventricles contract
what are arrhythmias
irregular heart rhythms
what is fibrillation
rapid, irregular contractions of the heart
what is the treatment of fibrillation
defibrillation which gives an electrical impulse all throughout the heart to reset the impulses
the autonomic nervous system modifies the heartbeat through cardiac centres in the???
medulla oblongata
