vascular system

Question 1

what are the 3 types of blood vessels?

Answer 1

arteries, arterioles and veins/venules.

Question 2

what is the structure of arteries/ arterioles?

Answer 2

large middle layer of smooth muscle so they can vasodilate/vasoconstrict - a ring of smooth muscle around entry to capillaries called pre capillary sphincters that can constrict/ dilate.

Question 3

what is the structure of veins/ venules?

Answer 3

large veins has pocket valves to stop back flow, have much thinner muscular layer allowing veinodilation + veinoconstriction - thicker outer layer helps support blood that sits in the pocket valve.

Question 4

what is venous return?

Answer 4

transport of blood from capillaries through venules, veins + either superior or inferior vena cava, to right atrium.

Question 5

what are the 5 mechanisms to help push blood against gravity?

Answer 5

pocket valves 
muscle pump 
respiratory pump 
smooth muscle
gravity

Question 6

what do pocket valves do?

Answer 6

prevent backflow.

Question 7

what does the muslce pump do?

Answer 7

veins between muscle that contract and squeeze blood back to heart.

Question 8

what does the respiratory pump do?

Answer 8

breathing is deeper during exercise due to abdomen squeezing large veins forcing blood back to the heart

Question 9

what does the smooth muscle do?

Answer 9

contract and relax

Question 10

what does gravity do?

Answer 10

blood from upper body aided by gravity as it descends from heart.

Question 11

what is blood pooling?

Answer 11

when insufficient pressure, blood will sit in the pocket valves.

Question 12

what happens if there is a decrease in SV or cardiac output?

Answer 12

it will decrease the amount of oxygenated blood to muscles meaning theres is decrease ability to contract + work aerobically.

Question 13

what is the distribution of cardiac output at rest?

Answer 13

15-20% supplied to muscles, rest to vital organs

Question 14

what is the distribution of cardiac output during exercise?

Answer 14

80-85% to working muscles, less supplied to organs, supply to brain is maintained, increase supply to skin during sub-maximal exercise ( all through vascular shunt)

Question 15

what is the vasomotor control centre?

Answer 15

it controls vascular shunt; it stimulates sympathetic nervous system to vasoconstrict + vosodilate the precapillary sphincters + artreioles supply of oxygenated blood.

Question 16

what is the atrerioles job in vascular shunting?

Answer 16

theyre primarily responsible for it, due to having thickest muscular layer, being vast in numbers.

Question 17

what else does the vascular control centre receive/do?

Answer 17

receives info from chemoreceptors, aorta + carotid arteries informing vvc lactic acid levels + CO2 have increase and oxygen and pH have decreased.

Question 18

how does the vcc + sympathetic nervous system work together?

Answer 18

VCC increases sympathetic stimulation cause capillary sphincters to constrict, which decreases blood flow to non-essential organs.