94 terms

ch. 14 the heart

where does the heart lie?
2/3 to the left of the midline within the mediastinum
cardiovascular system
consists of pump (heart), blood, closed sytem in which blood is carried
has four chambers
enclosed laterally by the_______
______ by the vertebral column
_______ by the sternum
sac that covers the heart
visceral pericardium or epicardium
inner layer of the pericardium
parietal pericardium
outer layer of the pericardium
pericardial cavity
potential space between the visceral and parietal pericardium, contains serous fluid
wall of the heart
3 distinct layers supplied with blood vessels
external layer of the wall
middle layer of the wall
contains cardiac muscle fibers, thickness varies in dif. sections according to function
innermost layer of the wall
lines the cavities of the heart, covers the valves and smooth muscle that opens and closes the valves
chambers of the heart
right and left halves with each half having 2 chambers
atria or atrium
upper chambers of the heart
lower chambers of the heart
receive blood from veins
interatrial septum
separates the 2 atria
recieve blood from the atria
interventricular septum
separates the 2 ventricles
pumping chambers
upper and lower chambers
separated by valves
sulcus or sulci
2 grooves on the surface of the heart
R. atrium
recieves blood from all tissues except the lungs
coronary sinus
drains blood from the heart itself into the R. atrium
inferior vena cava
drains blood from the lower part of the body into the right atrium
superior vena cava
drains blood from the upper part of the body into the right atrium
tricuspid valve
valve between the RA and RV
chordae tendinae
cords of the tricuspid valve that extend into the ventricle and are attached to it
tricuspid valve
3 leaflets or cusps. allows blood to enter RV when RV relaxes and closes when RV contracts
R. ventricle
right inferior portion of the heart, pumps blood to the lungs
R. ventricle
walls are thinner that the LV
contracts and closes the tricuspid valve, opens the pulmonary valve
pulmonary valve
lies at the entrance of the pulmonary trunk or artery
pulmonary valve
closes when the RV relaxes to allow it to fill with blood
always leave from the heart
always come back to the heart
receives oxygenated blood from the lungs
pulmonary veins
four veins that send blood to the LA from the lungs
mitral valve
between the LA and LV
mitral valve
stronger and thicker than the tricuspid valve
bicuspid valve
mitral valve
mitral valve
closes when LV contracts and opens when it relaxes
left inferior portion of the heart, pumping chamber
aortic valve
between the LV and the aorta
semilunar valves
pulmonary and aortic valve
atrioventicular valve
tricuspid and mitral valves
coronary arteries
branch from the aorta as it leaves the heart and curl back across the chambers of the heart
coronary arteries
hearts blood supply rich in O2
cardiac cycle
when the atria contract as the ventricles relax, make up 1 heart beat
systole, part at the highest pressure
heart sounds
caused by valves closing
cardiac output
stroke volume X number of beats per minute
stroke volume
volume of blood ejected per beat
normal cardiac output
5L per minute
cardiac muscle fibers
arranged end to end and side to side, intercalated disks
contracts as a whole unit
heart muscles
need a constant supply of O2 and ATP
cardiac muscle tissue
has a higher number of mitochondria (power house)
1st sound of the heart beat
mitral and tricuspid valves closing
2nd sound of the heart beat
pulmonary and aortic valves closing
abnormal heart sound (valves)
the narrowing of any body part
SA node
pacemaker of the heart
located in the floor of the RA, below the opening of the superior vena cava
SA node
SA node
sinoatrial node
SA node
responsible for rhythmic contractions of the heart
AV node
receives impulses from the SA node, it's delayed to allow the atria to empty and the ventricle to fill with blood
bundle of HIS
receives impulses from the AV node
bundle branches
receive impulses from the bundle of HIS
purkinje fibers
receive impulses from the bundle branches
purkinje fibers
spread out from the septum into the ventricles, causing the ventricles to contract
K and Ca
generate an electrical current as an impulse travels along the cardiac muscle fibers
place electrodes on skin, electrodes are connected to wires on EKG machine, which picks up the current and records it on special paper
action of the atrium
action of ventricles
action of ventricles regaining the electrical charge
the loss of electrical charge
medulla oblongota
sends impulses to SA and AV node by way of the vegas nerve
located in the aorta and carotid arteries and are sensitive to changes in BP
what happens when your body temp increases
heart rate goes up
heart rate goes up when
increase in epinephrine, thyroxine, sodium or potassium increases
foramen ovale
hole in the heart of a fetus that connects the 2 atrium
ductus arteriosus
lies between the pulmonary artery and aorta in a fetus
ductus arteriosus
blood is bypassing the lungs, resp. system is not occuring at this point
when does the heart start pumping in a fetus
by the 4th week
ductus venosus
blood bypasses the liver in a fetus