Lab 5 Flashcards
cardiovascular
What is resting HR determined by?
rate at which the SA node produces APs (100 bpm) and then PSNS innervation by inhibiting this rate constantly during rest and changing it to 75bpm.
What is too low BP?
Bradychardia - below 60bpm
What is too high BP?
Tachycardia - above 100bpm
How does the HR increase during exercise?
SNS and endo (epi NE) innervates to increase it by opening Na channels wider which makes the pacemaker potential more pos and depol happens faster. thyroid hormone also affects and directly increases over days, also increases number of epi receptors. so rate of APs is increased.
How to calculate maxHR?
220 - age = max HR
How do you measure resting HR?
palpating radial artery pulse point. timer for 1 minute and count the number of beats = resting HR per min.
How does exercise affect the HR?
increases it.
What do the heart sounds relate to?
blood flow through the cardiac cycle. first sound is the closing of the tricuspid and mitral valve (atrioventricular valves) that causes turbulent flow at beginning of ventricular systole. second heart sound is when the semilunar valves close that causes turbulent flow at the beginning of ventricular diastole.
What info can listening to the heart sounds provide?
infof on the hearts condition and fxn, can be used to diagnose heart murmurs resulting from malfunctioning valves, holes in the interventricular or interatrial septa (septa defects) or other cardiac abnormalities.
What is used to listen to the heart sounds and where?
using a stethoscope on the chest by the apex of the heart for the LUB, and by the second intercostal space for the DUB.
How do the heart sounds change after exercise?
both louder/more intense. less of a pause inbtwn sounds bc heart beating faster.
What does an ECG look at?
electrocardiogram looks at all the electrical activity on the heart during the cardiac cycle. so looking at ion flow during APs throughout the conduction system.
What is the conduction system composed of?
non-contractile cardiac mm cells that have been modified to generate and spread electrical impulses/APs.
What is the pathway of electrical impulses in the conduction system?
start at SA node in R atrium, go interatrial to L atrium and go to AV node still in R atrium, then into Bundle of His and its branches down to the purkinje fibers.
What are the waves and intervals apart of the ECG?
P wave, QRS wave, T wave, P-Q interval, S-T interval, T-P interval, R-R interval.
Explain the waves.
P wave= atrial depolarization. QRS wave= ventricular depolarization and masked atrial repolarization. T wave= ventricular repolarization.
What happens during the P-Q interval/
interval btwn beginning of P wave and start of Q wave. atrial contraction bc of depol from P wave.
What happens during the S-T interval?
at end of S wave to start of T wave. ventricles depolarized and contracted. blood goes into arteries at this time.
What happens during the T-P interval?
btwn end of T wave and start of P wave. time when both atria and ventricles are at rest.
What is the R-R interval?
interval btwn two R waves in consecutive ECG readings. so the time it takes for one full cardiac cycle.
What do you need to know to calculate the HR form and ECG reading?
chart speed (how fast its going, speed is given). R-R interval so distance btwn each cardiac cycle (done by counting boxes).
What is the formula to calculate HR from an ECG?
chart speed/R-R interval. answer times 60 sec per min. units= beats/min.
Why is maintaining proper BP NB?
NB for the proper functioning of the heart and all the organs to which it supplies blood to.
What is blood pressure?
the force that blood exerts on the arterial walls during the contraction/systole and relaxation/diastole of the ventricles.
