Cardiac Cycle Flashcards
What is Venus return
The flow of blood back to the heart from the veins
Mechanics of Venus return are?
Smooth muscle
Pocket valves
Skeletal-muscle pump
Respiratory pump
Heart as a suction pump
Smooth muscle VR?
Contracts squeezing the blood in the veins back to the heart
Pocket valves
Prevent back flow of blood
Skeletal-muscle pump
Muscle contracts reducing space within the muscle which forced blood thru veins to the heart.
Respiratory pump
During exercise changes in pressure occur causing inhalation and exhalation.
Heart as a suction pump-
Stretching of the cardiac fibres causes pressure to drop causing a suction pump and increasing Venus return
Anticipatory rise?
An increase in Heart rate before the event. Adrenaline and nora-adrenaline r released increase activation of SA NODE increase HR.
Ejection fraction
% of blood ejected by the LV during each cycle
Starlings law
Heart can only pump out what it receives from Venus return. Increase heart rate, stroke volume and cardiac output means more Venus return
SAAB PV
Sino-atrial node
Atrial systole
Av node
Bundle of HIS
Purkinje fibres
Ventricular systole
What makes up the Autonomic nervous system
Sympathetic and para-sympathetic
What happens in the sympathetic nervous system
Heart rate increases.
Fight or flight.
Accelerator nerve.
Adrenaline and Nora-adrenaline released.
What happens in the para-sympathetic nervous system?
Heart rate decreases.
Rest+digest.
Vegas nerve
Acetyl-choline is released.
Transportation of oxygen
When % of oxygen in blood is low haemoglobin release what?
Oxygen
