Pressure and flow in arteries and veins

Question 1

systolic pressure

Answer 1

start of tapping sounds

Question 2

diastolic pressure

Answer 2

silence after thumping sounds

Question 3

pulse pressure

Answer 3

normal is 120/80 systolic over diastolic

Question 4

changes in aortic pressure wave as it passes through vascular tree

Answer 4

affected by stroke volume, velocity of ejection, elasticity of arteries, total peripheral resistance

Question 5

changes in blood velocity and total cross sectional area of the arteries

Answer 5

pressure falls throughout. velocity is related to total cross section- fastest in aorta and vena cava, slowest in capillaries. small drop through arteries, large drop through arterioles, low when gets to capillaries, leaves a small pressure difference pushing blood back through the veins, pulmonary circulation pressure.

Question 6

things that affect venous pressure and return

Answer 6

gravity, rhythmic skeletal muscle contraction, respiratory pump increases venous return, venomotor tone, systemic filling pressure. this is important because venous return affects end diastolic volume which affects preload which affects the pumping ability of the heart

Question 7

veins are thin walled so

Answer 7

pressure is low, external influences affect flow

Question 8

mechanisms that prevent clotting

Answer 8

physical barrier that stops blood contacting collagen, produces prostacyclin and NO which inhibit platelet aggregation, produce tissue factor pathway inhibitor which stops thrombin production, expresses thrombomodulin and heparin which inactivate thrombin, secretes tissue plasminogen activator (t-PA) which breakdown clot

Question 9

clotting involves

Answer 9

platelet plug, fibrin clot