Heart Basics Flashcards
what is the heart physiology
a muscular pump
where is the heart located
in the thoracic cavity (mediastinum)
what is the heart between
the 2nd and 5th ribs
is the heart on the midline
about 2/3 left of the midline
size of heart
size of fist
anatomical angle of heart
45 degrees
what are the layers of the heart (3)
epicardium, myocardium, and endocardium
epicardium is also called what
visceral pericardium
what is myocardium and what does it function
cardiac muscle tissue
it contracts to produce force to push blood throughout vasculature
what “skeleton” is in myocardium
fibrous skeleton
what makes up the fibrous skeleton
elastic and collagen fibers
collogen functions in the fibrous skeleton
provide physical support to cardiac m. cells
distributes force fo contraction
reinforces valves and openings to b.v
prevent over expansion of heart
elastic functions in the fibrous skeleton
returens heart to original shape after contraction
is the myocardium layer striated
yes, this is a regular arrangement of actin and myosin where ends of each overlap. the molecules themselves are parallel
what are intercalated discs in the myocardium
are between adjacent cells. are interlocking membranes
desmosomes def
cell junctions reinforced by intermediated filaments
gap junctions def
pores that allow for ions movement, the heart chambers to contract as syncytium.
what type of connective tissue is endocardium
loose/areolar CT
what cells are in endocardium
simple squamous epithelium
what is endocardium continuous with
epimysium
what does the simple squamous epithelium in endocardium allow for in related to blood flow
decreases friction to blood flow
What are the 3 main parts of the pericardial sac
parietal pericardium
visceral pericardium
pericardial cavity
what is the pericardial sac
a protective covering that surrounds the heart
what are the 2 layers of parietal pericardium
fibrous layer and serous layer
information on the fibrous layer of the parietal pericardium
Location, type of tissue, fucntion
superficial, and anchors heart to diaphragm and ribs
dense irregular ct
protects heart from over expanding
information on the serous layer of the parietal pericardium
cell type
function
simple squamous epithelial cells
secretes srous fluid into pericardial space. a lubricant .
what is between the fibrous and serous layer
vascular aereolar CT
what layer is within visceral pericardium
serous layer
information on the serous layer of the visceral pericardium
cell type, function, facing what
simple squamous ephithelium,
sercretes fluid
facing pericardium cavity
function of the pericardial cavity
is wehre the fluid secreted by the 2 serous layers collects.
decreases friction
does the right side of the heart deal with oxygenated or deoxygenated blood
deoxygenated
does the left side of the heart deal with oxygenated or deoxygenated blood
oxygenated
what is the pulonary circulation
right side of heart
low oxygen
high co2
heart and lungs
what is systemic circulation
left side of heart
high oxygen
low co2
heart and rest of body
pulonary ciruclation order starting in RA
right atrium, right ventricle, pulmonary trunk/arteries (R/L), branching to pulmonary capillaries , converging to pulmonary veins (R/L), then left atrium.
what happens at pulonary capillaries
at lungs do gas exchange
order of systemic circulation starting in LA
left atrium, left ventricle, aorta, systemic capillaires, superior/inferior vena cava, and right atrium
what happens at systemic capillaries
picking up CO2 and delivering O2
what does the “hole in the heart” refer to
and what are the 2 examples
hole in tissue between R/L atrium
foramen ovale to fossa ovale
and
ductus arteiosus to ligumentum arteriosum
single drop of blood pathway starting at Right atrium
RA, RV, pulatory trunk, R/L pulmatory arteries, pulatory capillaries, pulatory veins, LA, LV, aorta, systemic capillaries, superior or inferior vena cava,, back to RA
What do heart valves do
prevent back flow of blood
what are the 2 types of heart valves
atrioventricular valves and semilunar valves
what are the two types of AV valves
Right/left AV valves
where are AV valves located
betweeen atria and ventricle
right AV valve, tricuspid or bicuspid
tricuspid
left AV valve, tricuspid or bicuspid
bicuspid
what do chordae tendonae and papillary muscle do
prevent the prolapse of a valve (AV valve)
how many cusps do semilunar valves have
3
what are the 2 semilunar valves
pulmonary SL valve
aortic SL valve
when do SL valves open
when ventricular pressure exceeds artery pressure
what do SL valves push blood into
artery
when do SL valves close
when ventricular pressure drops below artery pressure
when do AV valves close
when ventriccular pressure exceeds atrial pressure
what is the mitral valve
AV valve between LA and LV
what is mitral regurgitation called and means what
leaky valve/heart murmur
when the valve isnt sufficient to prevent the backflow fo blood and decreases the efficiency of the heart
what is mitral stenosis occur when and can lead to what
the narrowing of valve
could be because of scar tissue or plaque build up
can lead to hypertension
how does valve replacement happen
open heart surgery
can replace with mechanical, biological, or rubbery made valve. no option is perfect
what is the NS role in the electrical system of heart
to speed up or slow down
what is autorhythmicity
cardiac muscle self excites (contrcts without any external stimulation
does the electrcal event precede or come after a mechanical event
precedes
what is conducting system
cells responsible for initiating and distributing stimulus for heart to contract
modified cardiac m. cells cause the cell membrane to not maintain a stable RMP/threshold.
leads to more leaky to NA and fewer myofibirls and cells are smaller
what is the normal resting heart rate
70 bpm
what is affected in tonic inhibition
parasympathetic NS.
at rest, the PSNS is firing and communicates with SA node by secreteing ACh
what is the stress response
sympathetic NS
SNS communicates with SA node via norepinephrine
what do artificial pacemakes do
stimulate a regular heartbeat when the natural (SA NODE) electrical pacing system is irregular or not transmitting properly
5 steps of the electircla system of the heart
atria fill, sa node self excites, depolarization.
impuulse spreads via internodal fibers, and depolarize, then the impulse arrives at AV node and atria complete depolarization, they contract as a unit, the atria then repolarize and relax, the AP spread to L?R buncle branch, then the ventricles depolairze and contract
pressure when AV valves close
ven pressure > atrial Pressure
pressure when semilunar valves close
ven pressure< aorta pressure
pressure when Av valves open
ven pressure < atrial pressure
what happens during atrial fibuilation
no p wave, atrial muscel cells are depolarizing/contracting independent of one another
