CIRCULATORY SYSTEM: Module 3 Flashcards
Electric coordination of cardiac cycle
SAN generates electrical impulse (wave of excitation)
Impulse spreads over atria causing walls to contract
Wave passes to AVN and AV valves where impulse delayed
Impulse passes into purkine tissue in septum to causing ventricles to contract
What is a feature of the cardiac muscle
Conductive
SAN
Sino-atrial node
Generates electrical impulse
AVN
Delays electrical impulse between going from aria walls to ventricle walls to allow atria to finish contracting before ventricle
Bradycardia
Slow heart rhythm
Ectopic heartbeat
Extra beat or early beat of the ventricles
Electrocardiogram
A trace that records hearts electrical activity
Fibrillation
Uncoordinated atrial and ventricular contraction
Myogenic muscle
Muscles that can initiate its own contraction
Purkyne tissue (His)
muscle fibres in ventricles that conduct wave of excitation
open circulatory system
not enclosed in blood vessels
(e.g insects)
closed circulatory system
enclosed in blood vessels
(e.g all mammals)
single circulation
blood travels body in one loop
(e.g fish)
double circulation
blood travels in two loops: pulmonary and systemic
(e.g humans)
arteries explained
carry blood away from heart to body (e.g aorta)
they have thick muscular walls and alot of elastic tissue
as they deal with high pressure
the small lumen ensures high pressure is maintained
veins explained
the carry blood from body to the heart (e.g pulmonary vein)
they have thin walls as low pressure and lots og blood going to heart
has valves to prevent backflow of blood
capillaries explained
conneting vessels between veins and arteries (e.g venules)
have small pores to allow exchange of substance of products to tissues
walls are one cell thick to reduce diffusion distance
arial systole
atria contract
increasing pressure in atria
pushing blood into ventricles through the av valves
ventricular systole
ventricles contract
increasing pressure in ventricle
pushing blood out through arteries
passing through sl valve
diastole
semi lunar valves close
pressure in ventricles and atria drops
blood flows from veins into atria
