blood and circulatory system Flashcards
what is systemic circulation
oxygenated blood to the body away firm the heart via aorta
after giving o2 deoxygenated blood returns to the heart via veins
what is pulmonary circulation
deoxygenated blood from right atrium to lungs to re oxygenate it
oxygenated blood return to heart via pulmonary vein
structure of artery
narrow lumen
elasticated walls
function of artery
cope with blood under high pressure
allows vasoconstriction
maintain pressure of blood
structure of vein
wide lumen
valves
function of vein
prevent back flow of blood
low resistance to blood flow
structure of capillary
narrow
one cell thick
thin
function of capillary
gaseous exchange
structure of arterioles
elasticated walls
thinner walls
function of arterioles
regulate blood pressure
lead to capillaries
structure of venules
valves
wide lumen
function of venules
connect capillaries to vein
prevent back flow of blood
what is the venous return mechanism
process by which blood returns to right side of the heart
things that help venous return
gravity
skeletal muscle pump
respiratory pump
pocket valves
venomotor control
pressure gradient
how does gravity help venous return
assists with flow of blood above the heart
how’s does skeletal muscle pump help venous return
contracting veins force blood forwards towards the heart
how does respiratory pump help venous return
changes in pressure during inspiration and expiration
how do pocket valves help venous returns
direction back to the heart
how does venomotor control help venous return
limited capacity of veins to change shape
how does pressure gradient help venous return
exists between venous pressure and right atrial pressure aids the process of blood returning to the heart
how is blood flow controlled
change in blood vessel’s diameter
what is the vasometer centre
in the medulla oblongata
controls blood pressure/flow
what happens if cardiac output increases
baroceptosr and chemoreceptors are stimulated
what is vasomotor control
ability of arteries and arterioles to change their shape
how does the heart fill with blood
blood fills the atria while the atrioventricular valves are shut
atrial blood pressure exceeds ventricular pressure resulting the av VALVES TO OPEN
blood flows to ventricles
the atria contract and then so do the ventricles
ventricular pressure rises, opening the semilunar valves
blood flows to the aorta and pulmonary veins
