Download Heart Anatomy The Heart Heart Membranes Layers of the Heart

Heart Anatomy
The Heart
Heart Anatomy
Heart Membranes
· pericardium - double-walled sac around the heart
fibrous pericardium - tough and dense
protects the heart
anchors it to surrounding structures
prevents overfilling of the heart with blood
serous pericardium - thin and slippery
reduces friction
· cone-shaped muscular organ about the size of
your fist
· weighs less than a pound
· 2/3 lies to the left of the body's midline
· apex (tip) tilted to the left
Layers of the Heart Wall
· epicardium - external heart
surface
often infiltrated with fat
· myocardium - heart muscle
responsible for muscle
contraction
arranged in spiral and
circular bundles
· endocardium - a simple
squamous epithelium lining
the inner surfaces of the heart
and blood vessels
Chambers of the Heart
· 4 chambers
R and L atria on top of R
and L ventricles
· atria - small, thin-walled
chambers that receive blood
pumps blood "downstairs" to
ventricles
· ventricles - large, muscular
pumping chambers
pumps blood outside of heart
· R and L side of heart divided
by a septum
Atria
· right atrium - receives
deoxygenated blood
through superior vena
cava and inferior vena
cava
passes blood to right
ventricles through the
tricuspid valve
· left atrium - receives
oxygenated blood
through four pulmonary veins
pulmonary = lungs
2 veins from each lung
passes blood to left ventricles through bicuspid
(mitral) valve
Heart Anatomy
Ventricles
· papillary muscles and chordea
tendinaea play a role in valve
function
· discharging chambers (pumps)
of the heart
walls thicker than atria
· right ventricle - pumps
deoxygenated blood through
pulmonary semilunar valve
and pulmonary trunk toward
the lungs
· left ventricle - pumps oxygenated blood through aortic
semilunar valve and aorta to all body parts
Double Pump
· R side of heart handles oxygen
poor blood ONLY
pulmonary circuit
R heart
lungs
systemic circulation
L heart
body
R heart
harder work = bigger, stronger
structures
· blood travels in 2 distinct loops
double pump
picks up O2 from lungs
drops off O2 to body cells
thicker wall than R ventricle
Pulmonary Circulation
· circulates blood to lungs
· R atrium
R ventricle
pulmonary arteries
pulmonary arterioles
pulmonary capillaries
CO2 and O2 exchanged
pulmonary venules
pulmonary veins
L atrium
Path of Blood
body
superior/inferior vena cava
R atrium
thru tricuspid valve
R ventricle
thru
pulmonary semilunar valve
pulmonary trunk
pulmonary arteries
lungs
pulmonary
veins
L atrium
thru bicuspid valve
L
ventricle
thru aortic semilunar valve
aorta
body
L heart
· L side of heart handles oxygen
rich blood ONLY
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Systemic Circulation
systemic = body systems
circulates blood to body
aorta - largest artery
superior/inferior vena cava largest veins
superior - collects blood from
head, chest, arms
inferior - collects blood from
lower body
· L ventricles
aorta
major
body regions
veins
superior/inferior vena cava
Coronary Circulation
· myocardial cells require a continual supply of
oxygenated blood
· supplied by the coronary arteries
branch off of aorta
· angina - chest pain
· blockage of coronary
blood vessels can cause
a myocardial infarction
(heart attack)