lecture 5 - cardiovascular system: introduction to CVS Flashcards
why do we need a cardiovascular system?
exchange and transport of nutrients to maintain life
single cell organisms don’t need a specialised exchange system
functions of the CVS
controlled and continuous flow of blood
homeostasis
transport of hormones
organisation of the CVS
2 circulations in series served by 2 pumps in series
what are the 2 circulations in the CVS?
systemic
• high pressure, left, oxygenated
• supplies whole body
pulmonary
• low pressure, right, deoxygenated
• only supplies the lungs
each circulation receives the same volume of blood
what are the 2 chambers of the heart
atrium and ventricle
what are the 2 types of valves in the heart?
atrioventricular valves
semilunar valves
what are the 2 atrioventricular valves?
right = tricuspid left = mitral/bicuspid
what are the 2 semilunar valves?
right = pulmonary left = aortic
what causes the valves to open and close
pressure differences
what is stroke volume (SV)?
volume of blood pumped by 1 ventricle
what is cardiac output (CO)?
total volume of blood pumped per ventricle per minute
CO = HR x SV
what is venous return (VR)?
amount of blood returning to the heart
under steady state conditions VR = CO
what is the vascular system made of?
arteries
arterioles
capillaries
veins
arteries
- high pressure
- elastic
- distribution
arterioles
- high resistance
- site for control of blood flow to tissues
- surround by lots of vascular smooth muscle
