heart Flashcards
2 divisions of the vascular system
pulmonary circuit (to lungs) systemic circuit (to body)
arteries
efferent vessels - go away from the heart
veins
afferent vessels - go towards the heart
capillaries
small vessels for gas exchange
how is left and right side divided
interventricular and interarterial septum
heart sounds?
valves closing
left atrium
receives blood from lungs
left ventricle
pumps blood to body
right atrium
receives blood from body
right ventricle
pumps blood to body
apex
bottom/tip - touches diaphragm
base
top - at level do rib number 2
pericardium
outer covering
coronary arteries
oxygenate the heart muscle
epicardium
innermost layer of pericardium
myocardium
muscle wall
endocardium
hearts inner surface and valves
right atrioventricular valve
tricuspid - right atrium to right ventricle
left atrioventricular valve
bicuspid or mitral - left atrium to left ventricle
pulmonary semilunar valve
right ventricle to pulmonary artery
aortic semilunar valve
left ventricle to aorta
valve function
chordae tendineae attach valves to papillary muscles
force of contraction pushes blood through the valves
CT/PM together prevent backflow into the atria
systole
ventricles are contracted
diastole
when the ventricles are relaxed
aorta
O2 - leaves left ventricle and goes to body (arches)
inferior/superior vena cava
no O2 - brings blood back to right atrium
pulmonary artery
no O2 - sends blood from right ventricle to lungs (trunk, left and right branches)
pulmonary veins
O2 - brings blood from lungs to the left atrium
electrical impulses and heart contraction
- SA mode fires causing right then left atrium to contract
- impulse hits AV node
- AV node sends impulse down bundle of His in interventricular sputum
- bundle of His branches into Perkinje fibers and goes to left and right ventricles
- right and then left ventricles contract
EKG or ECG
electrocardiogram - detects electricity of the heart with leads - see if heart is beating properly or if there are arrhythmias
P
impulse spreads across the atria and they contract
QRS complex
impulse spreads to ventricles triggering contraction (big spike because the ventricles are large)
T
ventricles return to resting state
cardiac cycle
from the start of one heart beat to the start of the next - both periods of contraction and one of relaxations
normal “sinus” rhythm
70-80 bpm
bradycardia
less than normal - <60 bpm
tachycardia
higher than normal - >100 bpm
heart block
damage to conduction paths disrupts normal rhythm
fibrillation
uncoordinated contraction that prevents normal function
angina pectoris
severe chest pain resulting from temporary loss of blood due to exertion or stress
cardiac output
CO - amount of blood ejected from the left ventricle each minute - ave: 5 liters/minute
calculating CO
stroke volume x heart rate
heart rate ave (beats/min): 75
stroke volume ave (ml/beat): 70
cardiac output (ml/min): 5250
how long for blood to pass through body once
1 min
Starlings Law
stroke volume determines force of heartbeat - during exercise more blood enters the ventricles causing them to stretch which in turn causes a harder contraction forcing more blood out - more in = more out
