Lab 6 Flashcards
what occurs in the plateau phase
Ca + + moves in slowly and sustained
how many chambers does a frog heart have
3
how many chambers does a human heart have
4
Frank Stearling Law of The Heart
Stroke volume of the heart increases in response to an
increase in the volume of blood filing the heart
increased blood volume =
increased stretch of the myocardium
Role of Norepinephrine
NE binds beta-adrenergic receptors on cells of SA node
Role of Acetylcholine (Ach):
ACh binds to muscarinic receptors on cells of SA node
causing a membrane hyperpolarization
what ion current, regulate spontaneous depolarization
(generating pacemaker potentials at threshold)
Potassium
cardiac output =
Heart rate * Stroke Volume
what causes the P wave
atrial depolarization caused by SA node
after atrial depolarization where is the impulse delayed
AV node
where does ventricular depolarizatoin begin? what does this cause?
Apex
QRS complex and atrial repolarization
what causes the T wave
ventricular repolarization at apex
where are pacemaker cells located in
sinoatrial node (SA)
function of SA node
produce pacemaker potentials which depolarize membrane and produce AP
where all the gap junctions located
intercalated disks between adjacent myocardial cells
function of AV nodes
provide an electrical pathways between the atria and ventricles
after depolarization passes through AV node where does it go to
bundle of HIs to Purkinje Fibers
function of purkinje fibers
make gap junctional contacats with most myocardial cells in ventricles
electrocardiogram function
recording of cardiac electrical activity
components of the ECG are
P wave
QRS complex
T wave
sphygmomanometer apparatus function
use ECG recordings and blood pressure to investigate heart rate
T/F heart rate is profoundly influenced by the ANS
T
define cardiac output
produce of Heart Rate X Stroke Volume
name the piezo-electric device that works as an accelerometer
pulse transducer
function of pulse transducer
converts movements of active surface of transduce into an electrical signal
blood flow is directly dependent on
blood pressure
what is a sphygmomanometer
inflatable blood pressure cuff conneceted to a manometer
purpose of sphygmomanometer
occlude blood flow in the brachial artery
define systolic pressure
pressure at which pulse is again detectable
max bp
define diastolic pressure
pressure at which normal height is regained
what must you swab the skin with
cotton wool with 70% alcohol solution at the area where you will place each electrode
where is the “earth” connected to
patients akle
how is bp usually recorded?
systolic/diastolic
define respiratory cardiac arrhythmia
a variation in heart rate that occur with each cycling of breathing
the condition respiratory cardiac arrhythmia is more pronounce in
children
at inspiration what pressure decereases
intrathoracic
Describe Bainbridge Reflex
increased venous filling activates stretch receptors in vena cava and right atrium
info sent to medulla
alters heart rate
Describe Baroreceptor Reflex
changes in arterial pressure which stimulate baroreceptors in aorta and carotid bodies
info sent to medulla
alters heart rate
at expiration what pressure increases
intrathoracic
