lecture 21

Question 1

arteries

Answer 1

• are stretchy and elastic
• they stretch to accommodate a large volume of blood and they need to recoil to push blood farther away from heart and maintain pressure
• they branch into arterioles

Question 2

arterioles

Answer 2

• they are sympathetically innervated
• increase or decrease sympathetic input to regulate tone
• regulates blood pressure

Question 3

venous system

Answer 3

• serves as a volume reservoir
• has low pressure

Question 4

capillaries

Answer 4

• one cell layer thick
• exchange between blood and cells occur here

Question 5

give an example of blood distribution on organ needs when under sympathetic control

Answer 5

• when in a sympathetic scenario we need more blood for skeletal muscle and we don’t need a larger proportion going to the GI tract because sympathetic control halts digestion

Question 6

vasodilation

Answer 6

• increase diameter, so decrease in resistance
• decrease in blood pressure

Question 7

vasoconstriction

Answer 7

• decrease in diameter, so increase in resistance
• increase in blood pressure

Question 8

velocity of blood flow depends on

Answer 8

• diameter of blood vessel and how many there are

Question 9

as blood flows through circulation

Answer 9

• it looses pressure and establishes a pressure gradient

Question 10

why is pressure lost

Answer 10

• due to friction
• blood encounters friction by the nature of its viscosity
• friction between blood and vessel walls

Question 11

Fluid flow refers to

Answer 11

cardiac output

Question 12

the laws of fluid flow are

Answer 12

flow is proportional to the pressure gradient and inversely proportional to resistance

Question 13

greater resistance means faster or slower flow

Answer 13

• slower flow
• we will vasoconstrict

Question 14

smaller resistance means faster or slower flow

Answer 14

• fast flow
• meaning we will vasodilate

Question 15

venous return

Answer 15

the flow of blood into the right atrium from the peripheral vessels

Question 16

blood flow velocity is slowest through _________

Answer 16

capillaries

Question 17

capillaries have the smallest individual diameters, but have ….

Answer 17

largest cross sectional area because we consider collectively as a whole

Question 18

does the aorta have a large or small cross sectional area

Answer 18

small because there is only one aorta

Question 19

metarterioles

Answer 19

• provide an alternative route if precapillary sphincters are closed
• they also allow for larger materials (WBC) to bypass narrow capillaries and reach venous circulation

Question 20

precapillary sphincters

Answer 20

• open and close in respond to local metabolic conditions
• smooth muscle that can relax or contract and pinch off blood flow to a capillary

Question 21

capillaries are the site of _______

Answer 21

exchange

Question 22

capillaries are _____

Answer 22

• leaky
• approx 3L/day of fluid is filtered out of capillaries

Question 23

what happens when stuff leaks out of your capillaries into interstitial fluid

Answer 23

your lymphatic system will collect it, sweep it, scan it and makes sure there’s nothing that shouldn’t be there and then it will drop it back into your cardiovascular system