Exam 3 lecture 22 Flashcards
(15 cards)
Murmur
Abnormal heart sounds of blood flowing the wrong way
Systole
Chamber contracts
Diastole
Chamber relaxes
Stroke volume
Volume pumped in 1 cardiac contraction
Cardiac output
Volume pumped in 1 minute
SV * HR
Heart rate, tachycardia, bradycardia
60-100bpm
> 100 bpm
< 60 bpm
Contraction steps
- A and V diastole
- A systole, V diastole
- V systole, A diastole
Cardiac muscle contraction
-Similar to skeletal muscle contraction
-Electrically excitable
Neurogenic: nervous system tells to contract
Myogenic: Stimulus comes from heart itself
Intrinsic conduction system
-Autohythmic cells (pacemaker cells) generate electrical signal (A.P)
-Depolarization: more +
-Repolarization: back to -
Threshold: amount of change in M.P before signal can be sent
-Slow depolarization: pacemaker potential, allows for heart to control HR on its own
Slow depolarization action potential graph
-not flat, slow and gradual increase
-Small # of Na going into cells
-More Na, faster heart rate
SA node (sinoatrial)
AV node (atrioventricular)
-Pacemaker
-Backup pacemaker
Bundle of his
Bundle branches
-Carries signal down septum
-Takes signal to left and right
Purkinje fibers
-Sends signal to muscle to contract
EKG
-Records only electrical activity
Extrinsic regulation of cardiac output
-ANS modifies cardiac output
-Parasympathetic NS (rest): HR down, SV down
-Sympathetic NS (fight): HR up, SV up