Cardiovascular system Flashcards
major function of the cardiovascular system
transportation
force to move the blood around the body is provided by the
beating heart and by blood pressure
heart is enclosed within the
mediastinum
mediastinum
medial cavity of throax
great vessels of body emerge from
posterosuperior aspect or base
heart is enclosed by double walled sac called
pericardium
Loosely fitting superficial part of pericardium is called
fibrous pericardium
function of fibrous pericardium
protect heart and anchors it to surrounding structures, such as disparage and sternum
deep to fibrous pericardium is the slippery
serous pericardium
slippery lubricating fluid is produced by
serous pericardial membranes
function of the fluid secreted by serous pericardial membranes
allows heart to beat easily
inflammation of pericardium
pericarditis
pericarditis often results
in the decrease in the serous fluid
heart walls are composed of
epicardium
myocardium
endocardium
myocardiums consist of
thick bundles of cardiac muscle twisted and whorled into ringlike arrangements
layer that contacts
myocardiums
the myocardium is reinforced internally by a dense fibrous connective tissue network called the
“skeleton of the heart”
Glistening sheet of endothelium that lines the heart chambers
endocardium
heart has how many chambers or cavities?
4
2 atria and 2 ventricles
each of the chambers in heart is lined with
endocardium
function of endocardium
helps blood flow smoothly through the heart
superior atria are primary
receiving chambers
not important in pumping activity
atria
inferior thick walled ventricles are the
discharging chambers
actual pumps of the heart
ventricles
right ventricle forms most of the
heart’s anterior surface
septum that divides the heart longitudinally is referred to as either
interventricular septum or interatrial septum
heart functions as a
double pump
right side of the heart works as
the pulmonary circuit pump
the pulmonary circuit pump receives;through
oxygen poor blood from veins
large superior and inferior venae cavae
from which all systemic arteries branch to supply essentially all body tissues
aorta
pumps the blood out through
pulmonary trunk
pulmonary trunk splits into
pulmonary arteries
function of pulmonary arteries
carries blood to lungs, where oxygen is picked up and co2 is unloaded
oxygen rich blood drains from the what and is returned to what side of the heart through?
Lungs
Left side
through pulmonary veins
circulation from the right side of the heart to the lungs and back to the left side of the heart is called the
pulmonary circulation
function of pulmonary culation
carry blood from to the lungs for gas exchange and then return it to the heart
blood returned to the left side of the heart is pumped out of the heart into the
aorta
oxygen poor blood circulates from the tissues back to the right atrium via
the systemic veins
characteristics of left ventricle
pumps blood over a much longer pathway
walls are thicker than right ventricle
much more powerful pump
difference between systemic circulation and pulmonary circulation
systemic- carry oxygen rich blood to all body organs
pulmonary- carry blood from lungs for gas exchange and then return it to the heart
located between atrial and ventricular chambers
atrioventricular (AV)
Left AV valve
bicuspid or mitral
consists of 2 flaps
Right AV valve
tricuspid valve
consists of 3 flaps
Tiny white cords
chordae tendenae
function of chordae tendenae
anchors the flaps to the walls of the ventricles
When ventricles contract,
they pres on the blood in their chambers and the intraventricular pressure begins to rise
guards the bases of the 2 large arteries leaving the ventricular chambers
semilunar valves
semilunar valves are known as the
polmonary and aortic semilunar valves
AV valves are open during and closed during
heart relaxation
ventricles are contracting
semilunar valves are closed and open during
heart relaxation
ventricles are contracting
The cuntional blood supply and that oxygenates and nourishes the heart is provided by
right and left coronary arteries
coronary arteries branch from the
base of the aorta
coronary arteries encircles the heart in
coronary sulcus
another name for coronary sulcus
atriventricular groove
myocardium is drained by; which is drained into an enlarged vessel on the posterior of the heart called the
several cardiac veins
coronary sinus
empties into the right atrium
coronary sinus
when the heart beats at a very rapid rate, the myocardium may receive
an inadequate blood supply because the relaxation periods are shortened
Situations in which the myocardium is deprived of oxygen often result in
crushing chest pain called angina pectoris
myocardial infarction is commonly called
heart attack or coronary
heart valves are important because
it moves the blood forward through the heart
2 systems act to regulate heart activity
nerves of the autonomic nervous system
intrinsic conduction system
autonomic nervous system act like
brakes and accelerators to decrease or increase the heart rate depending on which division is activated
Another name for intrinsic conduction system
nodal system
intrinsic conduction system is built into
the heart tissue and sets its basic rhythm
Important part of the intrinsic conduction system
sinoatrial
sinoatrial is located in the
right atrium
has the highest rate of depolarization in the whole system
sinoatrial (SA)
SA is often called the
pacemaker
Clinical procedure for mapping the electrical activity of the heart
electrocardiography
atria and ventricles are separated from one another by
“insulating” connective tissue
heart begins to beat at their own rate, which is slower, some or all the time
heart block
Lack of an adequate blood supply to the heart muscle leads to
fibrillation
define fibrillation
a rapid, uncoordinated shuddering of the heart muscle
fibrillation makes the heart
totally useless as a pump
major cause of death from heart attacks in adults
fibrillation
rapid heart rate
tachycardia
a heart rate that is substantially slower than normal
bradycardia
prolonged tachycardia progress to fibrillation
fibrillation
Synstole and diastole
heart contraction and relaxation
refers to the events of one complete heart beat, during which both atria and ventricles contract and then relax
cardiac cycle
abnormal and unusual heart sounds are called
heart murmurs
function of the intrinsic conduction system
coordinate the action of the heart chambers and increases heart beat
to which chambers do the terms systole and diastole apply?
left ventricle
what causes the lub dup sounds heard with a stethoscope?
operation of the heart valves
Describe cardiac output
the amount of blood pumped out by each side of the heart
cardiac output is the product of the
heart rate and the stroke volume
stroke volume is the
volume of blood pumped out by a ventricle with each heart beat
stroke volume increases as the force of
ventricular contraction increases
critical factor controlling stroke volume is
how much the cardiac muscle cells are stretched before they contract
important factor stretching the heart muscle is
venous return
anything that increases the volume or speed of venous return also increases
stroke volume and force of contraction
when the pumping efficiency of the heart is depressed so that circulation is inadequate to meet tissue needs
congestive heart failure
if the left heart fails
pulmonary congestion occurs
if the right heart fails,
peripheral congestion occurs
feeds the capillary beds in the tissues
arterioles
walls of blood vessels have
3 coats or tunics
thin layer of edothelium resting on a basement membrane
tunica intima
describe tunica media
bulky middle coat
smooth muscle and elastic fibers
sheets of elastic tissue
elastic laminae
smooth muscle is controlled by
sympathetic nervous system
changes the diameter of vessels
smooth muscle
outer most tunic
composed of?
function?
tunica externa
fibrous connective tissue
support and protect vessels
amount of blood returning to the heart
venous return
larger veins have;
that prevents
valves
prevent backflow of blood
also helps return blood to the heart
respiratory pump
transparent walls of the capillaries are only
one cell layer thick
just the tunica intima
exchanges between the blood and the tissues can be made because of
the capillaries are only only cell layer thick
tiny capillaries tend to form interweaving networks called
capillary beds
flow of blood from an arteriole to a venule through a capillary bed is called
microcirculation
capillary bed consists of 2 layers
vascular shunt
true capillaries
describe vascular shunt
a vessel that directly connects the arteriole and venule at opposite sides of the bed
describe true capillaries
actual exchange vessels
root of each true capillary and acts as a valve to regulate the flow of blood into capillary
precapillary sphincter
when precapillary sphincter are relaxed
blood flows through the true capillaries and takes part in exchanges with tissue cells
when precapillary sphincter are contracted
blood flows through the shunts and bypasses the tissue cells
common in people who stand for long periods of time
varicose veins
a serious complication of varicose veins is called
thrombophlebitis
describe thrombophlebitis
inflammation of a vein that results when a clot forms in a vessel with poop circulation
common consequence of thrombophlebitis is
clot detachment and pulmonary embolism
all venous blood must pass through the
pulmonary circulation
pericarditis cause pericadial layers to
bind and stick to each other, forming painful adhesions that interfere with heart movements
superior atria are primarily
receiving chambers
when ventricles contract
blood is propelled out of the heart and into the circulation
supplies oxygen and nutrient rich blood to all body organs
systemic circulation
AV precent
backflow into the atria when the ventricles contract
semilunar valves are called pulmonary or aortic semilunar valves because
it guards the bases of the 2 large arteries leaving the ventricular chambers
when the ventricles are contracting and forcing blood out of the heart
leaflets are forced open
when the ventricles relax
blood begins to flow backward toward the heart, closing valves
AV valves are open during
heart relaxation
forces the heart to pump and repump the same blood
incompetent valve
valve flaps become stiff often because of repeated bacterial infection of endocardium
valvular stenosis
valvular stenosis forces heart to
contract more vigorously than usual
functional blood supply that oxygenates and nourishes the heart is provided by the
right and left coronary arteries
if angina pectoris is prolonged the oxygen deprived heart cells may die forming
infarct
causes heart muscle depolarization in only one direction, from atria to the ventricles
intrinsic conduction system
crescent shaped node of the intrinsic conduction systeem
sinoatrial
damage of the SA node results in a
slower heart rate
heart in complete relaxation
mid to late diastole
during early diastole
the intraventricular pressure drops
shortly after ventricular contraction begins and the pressure within the ventricles increases rapidly, closing the AV valves
ventricular systole
at the end of systole, the ventricules relax, the semilunar valves snap shut preventing backflow and for a moment the ventricles are completely closed
early disatole
first heart sound;
caused by;
lup
closing of AV valves
second heart sound;
caused by;
dup
semilunar valves close at the end of systole
anything that increases the volume or speed of venous return also increases
stroke volume and force of contraction
plays a major role in increasing the venous return
muscular pump
the most important external influence on heart rate is the
activity of the autonomic nervous system
during physical or emotional stress, the nerves of the; more strongly stimulate;
sympathetic division of the autonomic nervous system
SA and AV nodes and the cardiac muscle
slow and steady the heart, giving it more time to rest during noncrisis time
parasympathetic nerves
What is the effect of epinephrine on heart rate?
It mimics sympathetic nerve stimulation and speeds up the heart rate.
resting heart is the fastest in a
fetus
Congestive heart failure is usually a progressive condition that reflects weakening of the heart by
coronary atherosclerosis
describe coronary atherosclerosis
clogging of the coronary vessels with fatty buildups
describe pulmonary edema
blood vessels within the lungs become swollen with blood, the pressure with them increases, and fluid leaks from the circulation into the lung tissue causing pulmonary edema
most noticable in the distal parts of the body
edema
