Save
Biology - module 2
Mass transport in animals
The cardiac cycle
Save
Share
Learn
Content
Leaderboard
Learn
Created by
Izzy B23
Visit profile
Subdecks (1)
Pressure changes and valves
Biology - module 2 > Mass transport in animals > The cardiac cycle
3 cards
Cards (17)
Heart beats by
contraction
and relaxation of cardiac muscle
It’s co ordinated by
electrical
activity and accompanied by heart sounds - from the
valves
in heart closing
One complete
relaxation
and
contraction
is one heartbeat
Valves open when pressure in front of them is
greater
- forces valve
open
When pressure after valve
exceeds
pressure before it - pushing or blood towards
valve
closes it
Valves on open in one direction - blood flow
unidirectional
Contraction of atria using
atrial
muscle called atrial
systole
contraction of ventricles using ventricular muscles called
ventricular
systole
relaxation of the heart muscle called
diastole
Diastole
heart
relaxed
AV valves
open
- atria and then ventricles fill up with blood
SL valves
closed
to prevent
back
flow of blood from previous beat
Atrial systole
begins at right
atrium
- quickly spreads to
left
to co ordinate heartbeat
atria
contract
- squeeze blood into ventricles
muscles close at top of
veins
preventing back flow
Ventricular systole
ventricles
contract
and squeeze blood through
arteries
- SL valves
open
and AV valves
closed
Cardiac output =
stroke
volume x
heart rate
During exercise
body needs more oxygen and
glucose
for increased
respiration
to increase release of energy for muscle
contraction
heart rate will
increase
With time cardiac muscle become stronger and
contract
harder which increases the stroke
volume
- same cardiac output but
lower
heart rate
See all 17 cards