Overview of cardiovascular system Flashcards
describe varying vessel function
vessels can redirect or store blood
what do arterioles act as?
‘the taps’ controlling resistance (and therefore flow) to each vascular bed
what is the flow equation
flow = difference in pressure/resistance
classification of aorta
elastic arteries
wide lumen, elastic wall, damp pressure variations
classification of arteries
wide lumen, strong non-elastic wall
low resistance conduit (channel)
describe arterioles
resistance vessels
narrow lumen, thick contractile, muscular wall
can control resistance and therefore flow
allow regional redirection of blood
classification of capillaries
exchange vessels
narrow lumen, thin wall
classification of venules
capacitance vessels
wide lumen, distensible wall (capable of being dilated)
low resistance conduit (channel), & reservoir
allows fractional distribution of blood between veins & rest of circulation (esp. heart)
classification of veins
capacitance vessels
wide lumen, distensible wall
low resistance conduit, & reservoir
allows fractional distribution of blood between veins & rest of circulation (esp. heart)
what is carried in the blood (6)
O2 and CO2 nutrients metabolites hormones heat
describe blood storage in vessels
at any one time about 2/3 of the blood in our bodies is stored in vessels called capacitance vessels
these allow fractional distribution of blood-blood being stored can be ejected back to the heart if needed
what does it mean to have equal output
all the blood that goes through the right side of the heart must go through the left
what does the blood leave the heart through and where does it go?
Blood leaves the heart then through the aorta from which it is distributed to major organs by large arteries
describe what is meant when you say the major organs are in parallel
they all receive oxygenated blood from the heart at the same time
why is being ‘in parallel’ a good thing
all tissues get oxygenated blood at the same time
allows for regional redirection of blood ie send it to another vascular bed- there are some exceptions to this though
give examples of parallel circulation
lungs hypothalmus head legs arms
what happens with the gut and the liver to make them only partly in series?
blood moves from the gut directly to the liver and then the liver processes the blood and breaks down, balances, and creates the nutrients.
what does the hypothalmus do
produces releasing factors that affect the anterior pituitary gland
what is the resting cardiac output
5000 ml/min
why does the kidney receive a large cardiac output but not use up a lot of O2?
it takes a lot of blood because its function is to filter it
what is weird about the heart’s own cardiac output?
it has a very small cardiac output
why does the skin receive quite a lot of blood from the heart
for thermoregulation - body sends hot blood to the skin
what is the central venous pressure
blood pressure in the venae cavae
amount of blood returning to the heart and the ability of the heart to pump the blood back into the arterial system
how can you change direction of flow?
by reducing flow and increasing the resistance to flow
what does in series mean
happens successively
2 sides of the heart are ‘in series’
what is the septum
muscular layer that divides the heart in 2
what is the myocardium
muscular wall around heart. It is thicker on L ventricle as it has to push blood through the whole systemic circulation so needs high pressure
R only to pulmonary so needs less muscle
what is the mitral valve
on the left side
allows blood to move from L atrium to L ventricle
what is the tricuspids valve
3 cusps to it
on the right
prevents back flow of blood from the right ventricle into the right atrium.
what is chordae tendinae
tendinous chords
stop valves inverting turning inside out – they stop the valves at the right time when shutting
what are the papillary muscles?
muscles located in the ventricles of the heart. They attach to the cusps of the atrioventricular valves (also known as the mitral and tricuspid valves) via the chordae tendineae
when they contract they keep tension on the chordae tendinae and prevent inversion or prolapse of these valves on systole
