CARDIO- overview of cardiovascular system Flashcards
what is passive diffusion
movement of molecules down a concentration gradient
what is convective transport
movement of solutes / fluids down a pressure gradient
what are the features of passive diffusion
random
undirected
thermal movement of molecules
occurs via equation - time is proportional to distance squared
passive diffusion is good over short distances but not good for long distances
why is a cardiovascular system required to maintain body function
establishment of convective transport for perfusion to organs / peripherals
what are the roles of the heart and blood vessels in the cardiovascular system
transport oxygen and substrates to cells
transport carbon dioxide and metabolites for excretion
distribution of hormones
transport of defence mechanisms
thermoregulation
outline the electrical conduction of the heart
SA node atrium AV node bundle branches purkinje fibres ventricles
what is the function of elastic vessels
large arteries
accommodate stroke volume
convert intermittent ejection onto continuous flow
what is the function of resistance vessels
resistance vessels - arterioles - control arterial BP - control local blood flow
what is the function of capacitance vessels
venules, veins
control filling pressure - reservoir of blood
what is the function of exchange vessels
capillaries
nutrient delivery to the cells
tissue, water and lymph formation
removal of metabolic waste
define HR
number of heart beats per min
define stroke volume
volume of blood ejected from the heart per beat
define total peripheral resistance
resistance of blood vessels to blood flow
what is cardiac output
hr x sv
what is blood flow
arterial BP / TPR
what controls cardiac output
filling pressure - hypovolemia
sympathetic / parasympathetic autonomic nerves - excercise
chemical factors - adrenaline
afterload - hypertension
describe the vessel circulation of blood
arteries arterioles capillaries diffusion venules veins vena cava
explain pressure differences that maintain blood flow
oscillating pressure in aorta
arterioles pressure drops
pressure drops in capillaries
pressure maintains low through venules and veins
outline the velocity of blood flow through the circulation
remains high in the aorta
drops in capillaries - aids exchange
out of capillaries and into venules - increases velocity
where is most of the blood circulation at any one time
capillaries
what is the equation for calculating blood velocity
blood flow / cross sectional area
outline the blood flow and pressure relationship
development of appropriate blood pressure is essential for maintaining blood flow and oxygen transport to tissues /organs
what is the blood pressure of systemic circulation
120 / 80
what is the blood pressure in pulmonary circulation
25 / 15
hat affects blood pressure
CO and TPR
what effect will a decrease in CO have
decrease in blood volume - reduce BP and produce poor blood flow to tissues
what effect will an increase in TPR have
excessive arteriole constriction will switch off blood flow to tissues
associated with an increase in BP upstream on constriction - potential cause and consequence of hypertension
what is meant by the saying the cardiovascular system in a dual circulation
in parallel - cardiac output is split up - safeguards oxygen supply - most of the organs are supplied this way
therefore if there is an occlusion in say the lower part of the body the upper part is unaffected
in series - some organs use ‘used’ blood - liver and kidney - can be an issue for these organs if the CVS is compromised
true / false - the cardiovascular system is a closed system
true
