notes on blood vessels

Question 1

arteries

Answer 1

1) carry oxygenated blood from heart to rest of body
2) walls are thick and muscular with elastic tissue to stretch and recoil as heart beats to maintain high pressure
3) folded endothelium allows artery to expand to maintain high pressure
4) pulmonary arteries take deoxygenated blood to the lungs

Question 2

arterioles

Answer 2

1) smaller than arteries
2) a layer of smooth muscle(allows expansion/contraction to control amount of blood flow to tissues) but less elastic tissue

Question 3

capillaries

Answer 3

1) smallest blood vessels
2) substances like glucose/oxygen are exchanged between cells and capillaries, so they’re adapted for efficient diffusion(thin one cell thick walls)

Question 4

venules

Answer 4

1) thin walls than contain some muscle cells

Question 5

veins

Answer 5

1) take deoxygenated blood back to the heart under low pressure
2) wider limen than equivalent arteries
3) little elastic/muscle tissue
4) contain valves tp prevent backflow
5) blood flow is aided by muscle contraction
6) pulomary veins take oxygenated blood to the heart from the lungs

BLOOD:
rbc
wbc
platelets
proteins
water
dissolved solutes

Question 6

tissue fluid

Answer 6

1) at the start of the capillary bed, nearest to the arteries the hydrostatic pressure inside the capillaries is greater than the hydrostatic pressure in the tissue fluid - this difference in hydostatic pressure forces fluid out of the capillaries into spaces around the cells, forming tissue fluid
2) as fluid leaves, hydrostatic pressure reduces in the capillaries, so the hydrostatic pressure is much lower at the end of the capillary bed nearest to venules
3) oncotic pressure is generated by plasma protein present in the capillaries which lower water potential, at venule end of capillary bed, the water potential in capillaries is lower than water potential in tissue fluid due to fluid loss and high oncotic pressure, so some water re-enters the capillaries from tissue fluid at venule end by osmosis.

TISSUE FLUID:
no RBC(size)
few WBC(only if theres an infection)
no platelets(only if capillaries are damaged)
few/no proteins(size)
water(higher water potential than blood)
dissolved solutes

Question 7

lymphatic system

Answer 7

1) excess tissue fluid passes into lymph capillaries = lymph
2) valves prevent backflow
3) lymph gradually moves towards main lymph vessels in thorax, returned to blood neart heart

LYMPH:
no RBC(size)
WBC
no platelets
no proteins(size)
antibodies 
water(higher water potential than blood)
dissolved solutes