cardiovascular system Flashcards
what vessels are the site of nutrient, gas and waste exchange?
capillaries
what does the pulmonary circuit do?
sends oxygen-poor blood to the lungs
what does the systemic circuit do?
sends oxygen-rich blood and nutrients to the body
What is the deepest layer in the wall of the heart?
Endocardium
which structures are part of the wall of the heart?
epicardium
myocardium
endocardium
which structures are part of the coverings of the heart?
pericardium
fibrous pericardium
parietal pericardium
what is endocardium
blood comes in contact with the layer
what is pericardium
double layer membrane
what is epicardium
contains adipose tissue
what is fibrous pericardium
outer layer of the pericardium
composed of dense connective tissue
what is myocardium
made of cardiac muscle
what is parietal pericardium
serous layer - secretes serous fluid
lines the fibrous pericardium
what is the pericardial cavity?
contains the secreted serous fluid
what is the visceral pericardium?
outermost layer of the wall of heart
called epicardium
what is the aorta?
largest artery in the body and the main artery of the systemic circuit
what is the pulmonary trunk?
large main artery of the pulmonary circuit
what is the left pulmonary vein?
returns blood from the lungs
what is the inferior vena cava?
main vein draining lower body
what is the right pulmonary artery?
brings oxygen poor blood to the lungs
what is the superior vena cava?
large vein that drains the upper body
what is the right atrium?
upper right thin walled chamber of the heart
what is the pulmonary valve?
- valve at the beginning of the pulmonary trunk
- also known as right semilunar valve
- reduces backflow of blood from the pulmonary circuit
what is the tricuspid valve
- valve between the right atrium and right ventricle
- also known as right atrioventricular valve
- prevents backflow of blood to the right atrium
what is the right ventricle
lower right thick walled chamber of the heart
what is the papillary muscle
nipple like muscle inside the ventricles
what is the mitral valve
- valve located between the left atrium and left ventricle
- also known as bicuspid valve or left atrioventricular valve
- prevents backflow of blood to the left atrium
what is the chordae tendineae
connective tissue strips that attach AV valves to papillary muscle
what is the left ventricle
lower left thick walled chamber of the heart
what is the aortic valve
- valve between left ventricle and aorta
- also known as left semilunar valve
- reduces backflow of blood from the systemic circuit
what is the fibrous skeleton?
connective tissue that surrounds the heart valves
where is the heart located?
in the thoracic cavity
where is the heart positioned?
between the lungs
in front of the vertebral column
behind the sternum
what is the base of the heart?
point of attachment for major vessels
more superior
what is the apex of the heart?
points inferiorly and to the left and sits at the level of the fifth intercostal space
what is the order of (oxygen poo) blood flow through valves
tricuspid
pulmonary
bicuspid
aortic
what happens to the chordae tendineae when papillary muscles contract with ventricles?
they become taut
prevent valves from opening into the atrium
what are the systemic capillaries?
smallest blood vessel in the body tissue
what vessel does the left ventricle pushes blood into?
aorta
When do the semilunar valves open?
When pressure in the ventricles is greater than that of the arteries
At the beginning of ventricular diastole, what position are the AV valves in?
AV valves are closed.
What state are the ventricles in when the AV valves are open?
Ventricular diastole
do AV valves and semilunar valves are open at the same time?
no
What occurs after ventricular systole begins?
The semilunar valves open.
What is the position of the valves during ventricular filling?
AV valves are open; semilunar valves are closed.
When the first heart sound is heard, what is occuring with the heart valves?
the AV valves are closing.
What causes the semilunar valves to open during the cardiac cycle?
when the ventricular muscle contracts and generates blood pressure within the ventricle higher than within the arterial tree.
how does contraction of the heart begin?
with an autorhythmic impulse of the SAN located in the superior portion of the atrial wall
what happens after the impulse of the SAN?
acts as a pacemaker
impulses disperse through the myocardium of the atria
what happens after the impulses reach the myocardium of the atria
The impulse then arrives at the AVN located in the inferior interatrial septum
what happens one the AV nodes fire?
signal travels into the AV bundle and AV bundle branches, both of which are located in the interventricular septum.
what happens when the signal reaches the interventricular septum?
makes a U-turn at the apex of the heart, the signals are then carried by the Purkinje fibers through the exterior walls of the ventricles.
what do parasympathetic fibers of the vagus nerve secrete? and why?
acetylcholine to decrease heart rate
