cardiovascular - lecture 2 Flashcards
What is the P wave?
beginning of arterial contraction (arterial depolarization)
what is the Q wave?
septum depolarizes (left to right)
what is the R wave?
ventricles depolarize from inside to outside
what is the S wave?
base of ventricles depolarize (purkinje fibres)
what is the T wave?
ventricle repolarization
what is the PQ intervel?
electrical excitation of atria to electrical excitation of ventricle
what is the ST segment?
ventricle contraction to expel blood
what is the Q-T intervel?
duration of ventricular contraction
what are cardiac arrhythmias caused by?
abnormal pacemaker rhythm
pacemaker shifting somewhere other than SN
blocks in impulse spread
abnormal impulse transmission
spontaneous generation of spurious impulses
what causes tachycardia?
increased body temp or blood loss
what is the pattern caused by premature ventricular contraction?
big swoop in ECG between T and P
what is the pattern caused by ventricular fibrillation?
multiple erratic impulses travelling in all directions
what is the pattern caused by heart blocks?
multiple Ps without QRS
what is the pattern caused by cardiac myopathies?
aboral QRS pattern
what is the process of excitation contraction coupling?
AP enters from adjacent cell
Ca2+ induced Ca2+ release through ryanodine receptor channels
local release causes Ca2+ spark, which creates a Ca2+ signal
Ca2+ ions bind to troponin to initiate contraction
Ca2+ ions unbind to troponin (relaxation)
Ca2+ is pumped back into sarcoplasmic reticulum for storage
Ca2+ is exchanged for Na+
Na+ gradient is maintained by Na+K+ATpase
what are the pressure changes in the heart?
ventricular pressure builds when mitral valve closes (R wave)
pressure builds slower when aortic valve opens (S)
pressure peaks between S and T
is mid drop when aortic valve closes
rejoins arterial pressure (low) when mitral valve opens
