Week 5- the cardiovascular system

Question 1

What is the purpose of the cardiovascular system?

Answer 1

-transport of oxygen and nutrients to the tissues
-removal of CO2 wastes from tissues
-regulation of body temperature

Question 2

What are the two major adjustments of blood flow during exercise?

Answer 2

-increased cardiac output
-redistribution of blood flow from inactive to active muscles

Question 3

What is the role of arteries and arterioles?

Answer 3

To carry blood away from the heart

Question 4

What is the role of capillaries?

Answer 4

exchange of O2, CO2 and nutrients with tissues

Question 5

What is the role of veins and venules?

Answer 5

carry blood towards the heart

Question 6

What is the pulmonary circuit?

Answer 6

-right side of the heart
-pumps deoxygenated blood to the lungs via pulmonary arteries
-return oxygenated blood to the left of the heart via pulmonary veins

Question 7

What is the systemic circuit?

Answer 7

-left side of the heart
-pumps oxygenated blood to the right side of the heart via veins
-left ventricle–> aortic arch- receives blood at a high pressure from the left ventricle
-aorta is elastic so can stretch and expand to cope with the high pressure of blood

Question 8

What are the wall components of blood vessels?

Answer 8

-smooth muscle
-collagen
-elastin
-endothelium

Question 9

What vessel contains valves to prevent backflow of blood?

Answer 9

Veins

Question 10

What produces the main resistance to flow?

Answer 10

arteries and arterioles

Question 11

What happens at the precapillary sphincters?

Answer 11

resistance is created by vasoconstriction to redirect blood flow

Question 12

What is resistance?

Answer 12

measure of hinderance or opposition to blood flow through a vessel, caused by friction between the blood and the vessel wall

Question 13

What is total peripheral resistance?

Answer 13

sum of resistances to flow in all individual organs

Question 14

What is blood flow directly proportional to?

Answer 14

the pressure difference between the two ends of the system

Question 15

what is pressure proportional to?

Answer 15

the difference between MAP and right arterial pressure

Question 16

What is resistance dependent upon?

Answer 16

-length of the vessel
-viscosity of the blood
-radius of the vessel (greatest influence on resistance)

Question 17

What is local vascular resistance?

Answer 17

the resistance to blood flow in an organ or tissue calculated from pressure and local organ/tissue flow

Question 18

What are the sources of vascular resistance?

Answer 18

-MAP decreases throughout the systematic circulation
-larges BP decrease occurs across the arterioles- they are called ‘resistance vessels’

Question 19

What is arteriovenous difference?

Answer 19

The amount of oxygen taken up from 100ml of blood at each heart beat

Question 20

What is the Fick equation a relationship between?

Answer 20

cardiac output and a-vO2 difference and VO2

Question 21

What send afferent feedback to higher brain centres for the initial drive of the cardiovascular system?

Answer 21

-heart mechanoreceptors
-muscle chemoreceptors (muscle spindles and GTO)
-pressure sensitive receptors (baroreceptors)

Question 22

What are baroreceptors sensitive to?

Answer 22

changes in arterial blood pressure

Question 23

What are muscle mechanoreceptors sensitive to?

Answer 23

force and speed of muscular movement

Question 24

What are muscle chemoreceptors sensitive to?

Answer 24

changes in the chemical environment
(H ions, CO2, pH changes)

Question 25

Where is a hypotensive stimulus detected?

Answer 25

in the aorta by baroreceptors

Question 26

What does a hypotensive stimulus cause?

Answer 26

-increase in the total peripheral resistance
-increased HR
-increased cardiac output which increase blood flow

Question 27

What plays an important role in resetting the arterial baroreflex during exercise?

Answer 27

-Central command
-exercise pressor reflex