The Heart Flashcards
what keeps the blood in motion
the heart
4 chambers of heart
2 atria
2 ventricles
2 circuits of heart
pulmonary
systemic
which ventricle pumps blood to lungs
right
what transports blood away from the heart
arteries
vessels that interconnect arteries and veins
capillaries
what surrounds the heart
pericardium
2 layers of the pericardium
outer = fibrous pericardium inner = serous pericardium
inner serous pericardium layers
epicardium (visceral layer)
outer parietal layer
space between 2 serious layers
pericardial cavity filled with pericardial fluid
purpose of pericardial fluid
lubrication = reduces friction
3 layers of the wall of the heart
epicardium = external
myocardium
endocardium = internal, endothelial
what does the myocardium consist of, what does it do
cardiac tissue
pumps the heart through rhythmic contraction + relaxation of this layer
ventricle muscles are thicker than atrial and on the left side because
left ventricle pumps blood to the entire body
cardiac muscle has a ____ appearance
striated
cardiac muscle is dependent on
aerobic respiration- lots of mitochondrian and myoglobin
do cardiac muscle cells require CNS information
no
what connects CMC
intercalated discs
cells are bound together by
desmosomes
what locks CMC together during contraction
desmosomes
what binds the myofibrils of adjacent cells together
intercalated discs
CNC are connected into a functional syncytium by
gap junctions
ability to generate own rhythm
autorhythmicity
- the heart’s contractile activity is myogenic
2 types of autorhythmic cells
pacemaker cells
conduction fibers
what cells in the heart generate AP
pacemaker cells
the pacemaker cells of the myocardium are located
sinoatrial node = pacemaker of the heart
atrioventricular node
where are conduction fibers of the heart found
internodal pathways
bundle of HIS
purkinje fibers
how to determine which cells set the heart rhythm
fastest cells = pacemaker
coordination of heart by
gap junctions
gap junctions and desmosomes are part of the
intercalated disc
signal from SA to AV by
internodal pathway
signal spread in atrial muscles by
interatrial pathways
what transmit impulses to the rest of the myocardial cells
purkinje fibers
5 phases of electrical activity in the heart (ion permeability)
0: increased perm to Na+
1: decreased perm to Na+
2: increased perm to Ca2+, decrease to K+
3: increased perm to K+, decrease Ca2+
4: resting membrane potential
5 phases of heart electrical activity
depolarization brief repolarization plateau repolarization rest
impulses from the ___ can modify SA pacemaker activity
ANS
ANS innervates the
SA node
AV node
cardiac cells
smooth muscles of cardiac blood vessels
NE from the SNS causes
increase in HR and force of contractions by acting on beta adrenoceptors on nodal and contractile cells
ACh from the PNS causes
decrease in HR and force of contractions
activate muscarinic receptors on nodal and contractile cells
what centers in the MO can modify heart rate
cardioacceleratory center- sympathetic = increase HR
cardioinhibitory center- parasympathetic = lower HR
what conducts from the AV node to the apex of the heart
bundle of his or the AV bundle
the bundle of his does what going down to the apex
branches into L and R bundle branches
