What are the 2 major divisions of the heart?
pulmonary
systemic
pulmonary circuit (3)
right side of the heart
carries blood to lungs
lower pressure
systemic circuit (3)
left side of the heart
carries blood to the rest of the body
higher pressure
pericardium
double layered sack surrounding the heart that allows the heart to beat without friction
what are the 3 layers of the pericardium?
parietal pericardium
visceral pericardium (epicardium)
pericardial cavity
parietal pericardium
outer, tough layer
visceral pericardium (epicardium)
inner, thin, smooth
covers the heart surface
myocardium
electrical nonconductor; muscles and valves attach to this
endocardium
smooth inner lining of the heart; what blood is touching
structure of cardiac muscle (3)
short, branched cells
fewer SR
intercalated discs that have electrical junctions
What are 3 things needed for the cardiac muscle to be almost exclusively aerobic?
rich in myoglobin
large # of mitochondria
large glycogen storage
left and right atria
receive blood returning to the heart
left and right ventricle
pump blood into arteries
atrioventricular valves right? left?
right=tricuspid
left=bicuspid
cords connect AV valves to papillary muscles
chordae tendineae “heart strings”
semilunar valves
control flow into great arteries
characteristics of the heartbeat? (3)
myogenic:electrical activity
autorhythmic
spread of electrical activity follows a particular pathway
myogenic
electrical activity of heartbeat originates with heart
autorhythmic
each cell in heart can spontaneously depolarize and contract
SA node (2)
pacemaker, initiates heartbeat
contains cells that are fastest to spontaneously depolarize
_____ and _____ are electrically isolated
atria and ventricles
steps for conduction of heartbeat?
SA node-> AV node->AV bundles(via septum)->purkinje fibers (via moderator band)
cardiodynamics
movements and forces generated during the cardiac cycle
Cardiac Output=
Heart Rate * Stroke Volume
What is the cardiac output at rest? what does it increase to once there is an increase in CO2?
5L/min; 21L/min
cardiac reserve
difference between a persons max and resting CO
when does the cardiac reserve increase?decrease?
with fitness; disease
what changes cardiac output?
changes in heart rate and stroke volume
stroke volume=
EDV- ESV
What are factors that affect the ESV of stroke volume? (3)
preload
contractibility
afterload
What are factors that affect the EDV of stroke volume?
ventricular filling time->faster HB->reduces filling time
venous return
Anything that increases blood volume, then ___ ___ increase
venous return
preload (ESV)
degree of muscle stretch before contraction
the more blood in the ventricle before contraction, the greater the _____ on the ventricle. The more ____ the longer the ____ can _____
stretch; stretch, filament;slide
what is responsible for stretching the heart?
blood
contractibility (ESV)
amount of force produced during a contraction at a given preload
During contractibility, the increasing amount of ____ ___ in the cardiocytes allows for more sliding filaments
free calcium
What factors control contractibility? (4)
ANS
hormones
drugs
ion concentration
afterload
the force the contraction ventricle must exceed before blood can be ejected
A ____ afterload increases ____ and decreases ___
higher; ESV;SV
When is afterload increased? (4)
constriction of peripheral blood vessels
circulatory blockage
high blood pressure
valve stenosis
tachycardia
resting adult HR above 100
bradycardia
resting adult HR below 60