cardiovascular system Flashcards
what is in the heart
left atrium
right atrium
left ventricle
right ventricle
aorta
pulmonary artery
pulmonary vein
vena cava
tricuspid valve
bicuspid valve
semi lunar valve
what are the 2 circuits
pulmonary circuit- where blood goes from the heart —- lungs—-heart (right side)
systemic circuit- where the blood goes from the heart—-body—-heart (left side bigger pump)
explain what this means- the heart is 2 pumps working as 1
there is 2 sides of the heart which both vitalize in specific circuits and functions.
there’s 2 pumps one on the left and one on the right and which there seperated by a septum.
the right side pumps blood to the lungs (pulmonary circuit? and the left side pumps blood to the body (systemic circuit).
however they both contract in unison.
why is cardiac muscle classed as involuntary
because it’s myogenic meaning it can stimulate it’s own impulses and it doesn’t require stimulation from the brain.
what are the stages of contraction in the heart
- conduction of the heart begins with an electrical impulse in the sinoatrial node.
- this spreads over the walls of both atria causing them to contract together
- the impulse then reaches the atrioventricular node which will hold it temporarily this delay allows both atria’s to contract fully.
- the impulse then continues passing via the bundle of his, down the septum wall and then spreads throughout the purkinje fibres
what 2 words are involved with the idea of contraction
systole- contraction
diastole- relaxation
what is one complete beat of the heart called
the cardiac cycle (0.8seconds)
what is the cardiac cycle stages
atrial systrole
ventricle systole 0.3 sec
atrial diastole
ventricle diastole 0.5sec
define stroke volume
the amount of blood leaving the heart during one contraction
define heart rate
the number of beats per minute
define cardiac output
the amount of blood pumped out of the heart per minute
stroke volume x heart rate
define bradycardia
when resting heart rate is less than 60
how to calcuate moment
force x arm (distance m)
identify the process by which cardiac muscles stimulated to contract ?
- a electrical impulse travels down from the sino atrial node to the av node.
- this causes the atrial walls to contract (systole).
- the av node conducts the impulse through the bundle of his to the branched network of purkinje fibres.
where is the cardiac control centre
in the medulla oblongata in the brain
what is in the cardiac control centre
- chemoreceptors- chemicals
- baroreceptors- blood pressure
- proprioceptors- movement
there is also temperature which is intrinsic and adrenaline which is hormonal.
there is also 2 nerves the cardiac accelerator nerve and the vagus nerve.
what are the 2 aspects to the cardiac control centre
- sympathetic nervous system
- parasympathetic nervous system
what is the sympathetic nervous system
it is responsible for increasing heart rate via the cardiac accelerator nerve