the vascular system

Question 1

functions of blood

Answer 1

• transport nutrients like O2 and glucose
• protect and fight disease
• maintain homeostasis and regulate temperature

Question 2

arteries

Answer 2

• carries oxgenated blood to heart and muscles
• high pressure and speed
• large layer of smooth muscles allows vasoconstriction and dilation

Question 3

arterioles

Answer 3

• divided from arteries slows blood flow
• ring of smooth muscle surrounding the entry of capillaries called pre- capillary sphincters that dilate and constrict

Question 4

capillaries

Answer 4

• brings blood close for muscles for gaseous exchange
• one cell thick

Question 5

veins and venules

Answer 5

• transports deoxygenated back to heart
• venules leaving capillary beds reconnect to form veins
• small layer of smooth muscle to allow venodilation/constriction
• one way pocket valves

Question 6

venous return

Answer 6

the return of blood back to the heart largely against gravity

Question 7

mechanisms of venous return

Answer 7

assist blood back to the heart to maximise venous return during exercise

Question 8

pocket valves

Answer 8

prevent the back flow of blood

Question 9

smooth muscles

Answer 9

venoconstricts to create venomotor tone which aids the movement of blood

Question 10

gravity

Answer 10

blood from the upper body, above the heart is helped to return by gravity therefore its passive

Question 11

muscle pump

Answer 11

skeletal muscles contract compressing veins located between them squeezing the blood back to the heart

Question 12

respiratory pump

Answer 12

• during breathing a pressure difference between the thoracic and abdominal cavity is created squeezing blood back to the heart
• as exercise increases f the respiratory pump is maximised

Question 13

redistribution of blood

Answer 13

from 20% at rest to 88%

Question 14

vasomotor control centre (VCC)

Answer 14

found in the medulla oblongata in the brain and controls the vascular shunt mechanism

Question 15

vasomotor tone

Answer 15

the partial state of smooth muscle constriction in the arterial walls//;

Question 16

vascular shunt mechanism

Answer 16

the redistribution of cardiac output around the body from rest to exercise which increases the percentage of blood flow to the skeletal muscles

Question 17

sympathetic stimulation

Answer 17

controls the diameter of arteriole and pre-capillary sphincters

Question 18

vasodilation

Answer 18

a decrease in sympathetic stimulation causes a widening of the diameter of the arteriole and pre-capillary sphincters

Question 19

vasoconstriction

Answer 19

an increase in sympathetic stimulation causes a narrowing of pre-capillary sphincters and arteriole diameters

Question 20

how does the vascular shunt mechanism work

Answer 20

• receptors send info to the VCC which uses the sympathetic nervous system to increase or decrease sympathetic stimulation to the arterioles AND pre-capillary sphincters

Question 21

VSM at the muscles during exercise

Answer 21

VCC decreases sympathetic stimulation of arterioles and pre-capillary sphincters causing vasodilation increasing blood flow

Question 22

VSM at the organs during exercise

Answer 22

VCC increases sympathetic stimulation of arterioles and pre-capillary sphincters causing vasoconstriction decreasing blood flow