heart chapter 20 Flashcards
how many layers are there in the heart wall and what are they
3
epicardium- outer layer/visceral layer
myocardium- thick, middle, muscular layer
endocardium- lines the heart chambers
how many layers does that serous percardium have and what are they
2
parietal layer - outer layer
visceral later- inner wall aka epicardium
what are the vessels of the coronary circulation?
LCA + RCA ( and the 2 major branches they divide)
great cardiac vein and middle cardiac vein
LCA (Left coronary artery) divides 2 major branches ___
a. anterior interventricular artery
b. circumflex artery
RCA (right coronary artery) divides 2 major branches ___
a. right marginal artery
b. posterior interventricular artery
where do cardiac veins join at?
coronary sinus
where does the coronary sinus empty blood into?
right atrium
what are the 2 cardiac veins of the coronary circulation?
great cardiac vein (anterior)
middle cardiac vein (Posterior interventricular)
what does the coronary circulation help the heart meet?
metabolic demands and 5 % of circulating blood flows through this
how many valves does the heart have and name them
4 valves
1. tricuspid
2. bicuspid/mitral
3. pulmonary valve
4. aortic valve
what is the valve between atrium and ventricle?
AV
(atrioventricular valve)
what are the valved between the exit of each ventricle
semilunar valves
what are the 2 semilunar valves and where are they
- pulmonary valve right ventricle to pulmonary trunk
- aortic valve
left ventricle to aorta
what are the 2 AV valves
- right AV which was 3 cusps (tricuspid)
- Left AV which has 2 cusps (bicuspid/mitral)
what are cardiocytes and how are they connected to eachother
cardiac muscle cells which are connected by intercalated discs
- autorhythmic
- has 1 central nucleus
what are intercalated discs composed of
interdigitating folds, mechanical junctions, electrical junctions
describe skeletal muscle contraction + its refractory period
action potential in muscle is brief and ends as a contraction (twitch)
twitch contraction is short
refractory period ends before peak tension develops
twitches summate and tetanus occurs
describe cardiac muscle contraction + its refractory period
action potential is prolonged and period of active muscle cells contraction is extended.
refractory period continues until relaxation is well under way so summation does not occur nor do tetanic contractions
what happens if heart is in tetany?
it could not pump blood
what is the cardiac cycle?
period between the start of 1 heartbeat and beginning of the next
systole (systolic)
chamber contraction
- higher #
diastole (diastolic)
chamber relaxation
- lower #
what are the 2 phases the cardiac cycle can be divided into in each chamber of the heart?
systole and diastole
describe the cardiac cycle SIMPLIFIED
heart beat (contraction) followed by relaxtion
basically atria contracts then ventricles contract then relaxation occurs again