chapater 11 heart Flashcards
parasympathetic stimulation of hrt
- can be artificial-acetylcholine
- slows HR and decreases contractility
barroreceptors
- stretch receptors located in aortic arch and carotid sinus monitoring bp
- send signals to medullary cardiovascular center which regulates neural output to sympathetic and parasympathetic fibers
i. e. decrease in bp decreases signals to medullary cardiovascular center and thus increases sympathetic efferent activity and decreases parasympathetic efferent activity–resulting in increase HR and contractility
Erb’s point
-area at which pulmonic/aortic sounds are best heard
sympathetic stimulation of heart
- can be artificial-norepi
- produces increase HR and contractility
valves heard during S1
-AV valves, tricuspid, and mitral
valves heard during S2
-semilunar, aortic, pulmonic valves
opening snap
- usually opening of valve can’t be heard–only when damaged
- if AV valved is narrowed/stenotic can be heard-during diastole
ejection click
- not normal to hear
- stenotic semilunar valve during systole
cardiac cycle
sequence of valve openings/closure:
MVc TVc PVo AVo AVc TVo MVo
M1
- during S1
- from closure of mitral valve when left ventricle pressure rises to more than lt atrial pressure
T1
- tricuspid component of S1
- from closure of tricuspid valve when rt ventricle pressure> rt atrium pressure
isovolumetric contraction
- time btwn closure of AV valve and opening of semilunar valve
- pressure in rt ventricle>pulmonary artery–pulmonic valve opens
- pressure in lt ventricle>aortic artery–aortic valve opens
dicrotic notch
- point at which ejection is completed and aortic and left ventricular curves separate
- simultaneous to S2
A2
- part of S2
- aortic valve closes
- simultaneous with dicrotic notch
P2
- pulmonic component of S2
- point when rt ventricle pressure
isovolumetric relaxation
- time between closure of semilunar valves and opening of AV
- rt atrium pressure>rt ventricle –tricuspid valve opening
- lt atrium pressure>lt ventricle–mitral valve opening
S3
-after S2
-normal in children
-if occurs in pt>30 yoa-volume overload of ventricle
-could be from regurgitant valvular lesion and CHF
“kentucky”
atrial contraction (kick)
- end of diastole
- additional 20% of ventricle filling