L18 - Cardiovascular System 1

Question 1

What are the functions of the circulatory system?

Answer 1

distribution of dissolved gases and other molecules
circulating hormones
mediate inflammatory and host defense responses against invading organisms
conserve or release heat near skin surface

Question 2

What type of circuit is the circulatory system?

Answer 2

parallel

Question 3

What causes blood flow to decrease?

Answer 3

increased resistance which is caused by width, viscosity and length

Question 4

What causes blood flow to increased?

Answer 4

increased difference in pressure, cannot flow if no pressure difference

Question 5

What is tone?

Answer 5

basal state of muscle contraction in smooth muscle

Question 6

What are adjustments from normal tone known as?

Answer 6

vasoconstriction and vasodilation

Question 7

What is vasoconstriction caused by?

Answer 7

myogenic activity, O2, CO2, endothelin, sympathetic stimulation, vasopressin; angiotensin II, cold

Question 8

What is vasodilation caused by?

Answer 8

myogenic activity, O2, CO2, nitric oxide, sympathetic stimulation, histamine release, heat

Question 9

What is a myogenic response?

Answer 9

reflex constriction upon stretching of blood vessel walls and reflex dilation upon detection of lower blood flow

Question 10

What is blood flow proportional to?

Answer 10

the pressure difference in a tube

Question 11

How does blood flow in the capillaries compare to the blood flow in arteries and veins?

Answer 11

much slower due to huge cross-sectional area which facilitates exchange / diffusion

Question 12

What is the structure of arteries?

Answer 12

very elastic

energy storage

Question 13

What is the structure of veins?

Answer 13

less elastic
wider
expand easily - reserve

Question 14

What is the structure of capillaries?

Answer 14

single cell thin

diffusion / exchange occurs here

Question 15

What is bulk flow?

Answer 15

overall / mass movement of fluid between blood and interstitial fluid

Question 16

What is absorption?

Answer 16

fluid movement form interstitium into capillaries

Question 17

What is filtration?

Answer 17

fluid movement out of capillaries into interstitium

Question 18

What is oedema?

Answer 18

interstitial fluid accumulation

Question 19

The osmotic pressure attracting fluid absorption from the interstitium into capillaries is the result of what?

Answer 19

protein such as albumin

Question 20

What is the composition of plasma and interstitial fluid?

Answer 20

almost equal solute concentrations
plasma = significant protein presence (albumin)
interstitial fluid = low protein presence

Question 21

What pressures influence distribution between the capillary and the interstitial fluid?

Answer 21

osmotic pressure = due to solute concentration

hydrostatic pressure = pressure exerted by containment of fluid

Question 22

Which end of a capillary does filtration occur? Why?

Answer 22

towards the arterial end

increased hydrostatic pressure

Question 23

Which end of a capillary does absorption occur? Why?

Answer 23

towards the venous end

decreased hydrostatic pressure