Test 4 Heart Flashcards
heart
a muscular double pump
with two functions:
Right Side of Heart
receives oxygen poor blood and then pumps this blood to the lungs to pick up oxygen and dispel carbon dioxide (Pulmonary circuit)
Left side of heart
receives the
oxygenated blood from the lungs
and pumps this blood throughout
the body. (Systemic circuit)
atria
(x 2): superior chambers (separated by the interatrial septum)
that receive blood returning from the pulmonary and systemic circuits
ventricles
x2
inferior chambers (separated by the interventricular
septum) that pump blood around the two circuits.
The heart lies in
the thorax posterior to the sternum, left of the
midline and rests on the superior surface of the diaphragm
pericardium
(“Around the heart”): a triple layered sac
fibrous pericardium
outer strong layer of dense
connective tissue
serous pericardium
formed from two layers
- parietal layer
- viceral layer
parietal layer
fused to fibrous pericardium
viceral layer
aka epicardium
pericardial cavity
Fluid-filled space between the parietal and
visceral layers of serous pericardium
pericardial cavity function
contains a lubricating fluid that reduces friction between
the beating heart and the outer wall of the pericardial sac
epicardium
visceral layer of the serous pericardium
myocardium
consists of cardiac muscle
-Muscle arranged in circular and spiral patterns
endocardium
endothelium resting on a layer of connective tissue
-Lines the internal walls of the heart
vessels returning blood to the heart
Superior and inferior venae cavae and Right & Left Pulmonary veins
vessels conveying blood away from the heart include
-Pulmonary trunk (which splits into right and left pulmonary arteries) Ascending aorta (three branches) – brachiocephalic, left common carotid, and left subclavian artery
right atrium receives
oxygen-poor blood from the superior and
inferior vena cava and the coronary sinus, and pumps it into the right
ventricle through the tricuspid valve.
internally, the right atrium has two parts
a smooth walled posterior
part and an anterior part lined by horizontal ridges called the pectinate
muscles.
Heart valve ensures? (function)
unidirectional blood flow through the heart
each heart valve consist of?
two or three cusps, which are flaps of
endocardium reinforced by cores of dense C.T
heart valves open and close in response to?
differences in blood
pressure on each side of the valves.
what are the two atrioventricular valves
tricuspid and bicuspid valves
function of atrioventricular valves
prevent the backflow of the blood into the atria during contraction of
the ventricles
what happens when the ventricles are relaxed
the valves are forced open by the
blood pressure exerted on their atrial side.
when the ventricles start to contract
the pressure within them
rises and forces the blood superiorly against the valve cusps…pushing
the edges of the cusps together and closing the AV valves
The right ventricle
e receives deoxygenated blood from the right
atrium via the tricuspid valve, and pumps it into the pulmonary
arteries via the pulmonary semilunar valve and pulmonary trunk.
the internal walls of the right ventricle are marked with
irregular ridges of muscle called
trabeculae carneae
cone shaped papillary muscles project from
the walls into the
ventricular cavity and attach to strong bands called chordae tendineae
- The chordae tendineae attach to
the flaps (cusps) of the tricuspid valve
the papillary muscles of the heart serve to?
limit the movements of
the bucuspid and tricuspid valves. These muscles contract to tighten the
chordae tendineae, which in turn prevent inversion
the papillary muscles brace the valves against
the high pressure, preventing regurgitation of ventricular
blood back into the atrial cavities
chordae tendineae
or heart strings, are cord-like tendons that
connect the papillary muscles to the tricuspid valve and the bicuspid
valve in the heart
the chordae tendineae prevents
the flaps from being everted into the
right atrium
the two semilunar valves
pulmonry and aortic valves
function of semilunar valves
prevent
backflow from the great arteries into the ventricles.
as ventricles contract and intraventricular pressure rises
blood is pushed up against semilunar valves, forcing them open
as ventricles relax and intraventricular pressure fails
blood flows back from arteries, filling the cusps of semilunar valves and forcing them to close
the left atrium
receives oxygenated blood returning from the lungs
via the pulmonary veins, and pumps it into the left ventricle
the left ventricle receives
oxygenated blood from the left atrium via
the bicuspid valve, and pumps it into the aorta via the aortic semilunar
valve
left ventricle, like the right ventricle, contains
s trabeculae carneae, papillary
muscles, chordae tendineae, and the cusps of the bicuspid valve (mitral
valve).
coronary circulation
the functional blood supply to the heart
muscle itself.
collateral routes ensure
blood delivery to heart even if major vessels
are occluded
