Integration of cardiovascular mechanisms

Question 1

Factors which influence MAP?

Answer 1

Heart Rate
Stroke Volume
Systemic vascular resistance

Question 2

Main site of systemic vascular resistance?

Answer 2

Arterioles

Question 3

Components of cardiovascular system?

Answer 3

Heart - pump
Arteries - passageway of blood from heart to tissues
Arterioles - major resistance vessels
Capillaries - Site of gas exchange, nutrients and water between blood and tissues
Veins - Contains most of blood volume during rest - passageways of blood from tissues to heart

Question 4

What must venous return provide?

Answer 4

The heart with sufficient blood to pump

Question 5

Name for veins?

Answer 5

Capacitance vessels

Question 6

How is HR mainly regulated?

Answer 6

Autonomic nervous system

Question 7

How is SV mainly regulated?

Answer 7

Preload
Myocardial contactility
Afterload

Question 8

CO equation=

Answer 8

CO= HR x SV

Question 9

How can MAP be estimated?

Answer 9

DBP + 1/3 pulse pressure

Question 10

How is systemic vascular resistance regulated?

Answer 10

By vascular smooth muscles

Question 11

What does contraction of vascular smooth muscles cause?

Answer 11

Vasoconstriction and decreases SVR and MAP

Question 12

What are vascular smooth muscles controlled by?

Answer 12

Intrinsic and extrinsic mechanisms

Question 13

What is resistance to blood flow directly proportional tp?

Answer 13

Blood viscosity and length of blood vessel

Question 14

What is resistance to blood flow inversely proportional to?

Answer 14

Radius of blood vessel to the power of 4

Question 15

Resistance to flow equation?

Answer 15

R proportional to n.l/r^4
n=blood viscosity 
L= length of blood vessel
r= radius of blood vessel 
R= resistance to flow

Question 16

What does extrinsic control of vascular smooth muscle involve?

Answer 16

Nerves and hormones

Question 17

If we constrict muscle in arterioles what happens?

Answer 17

Increases resistance and decreases flow

Question 18

What are vascular smooth muscles supplies by?

Answer 18

Sympathetic nerve fibers

Question 19

Vascular smooth muscle neurotransmitter and receptor it works on?

Answer 19

Noradrenaline

acts on alpha receptors

Question 20

Vasomotor tone?

Answer 20

Vascular smooth muscle partially constructed at rest

Question 21

Control of vascular smooth muscles via hormones?

Answer 21

Adrenaline
Organ specific
Depends on predominant type of receptor

Question 22

What does adrenaline acting on alpha receptors cause?

Answer 22

Vasoconstriction

Question 23

What causes vasodilation?

Answer 23

Adrenaline acting on beta 2 receptors

Question 24

Where are alpha receptors predominantly found?

Answer 24

Skin
Gut
Kidney arterioles

Question 25

What receptor is found on cardiac and skeletal muscle arterioles?

Answer 25

Beta2 receptors

Question 26

Other hormones which extrinsically affect vascular smooth muscle control?

Answer 26

Angiotensin 2- causes vasoconstriction | Antidiuretic hormone- causes vasoconstriction

Question 27

What do local metabolic changes within an organ influence?

Answer 27

Contraction of arteriolar smooth muscles

Question 28

What factors causes relaxation of arteriolar smooth muscles?

Answer 28

Vasodilation | Metabolic hyperaemia

Question 29

What do other local chemicals released within an organ influence? and when are they released

Answer 29

Contraction of arterial and arteriolar smooth muscles | Following a tissue injury or inflammation

Question 30

Examples of humoral agents which cause contraction of arteriolar smooth muscles resulting in vasoconstriction?

Answer 30

Serotonin Thromboxane A2 Leukotrienes Endothelin

Question 31

Endothelin?

Answer 31

Potent vasoconstrictor released from endothelial cells- production stimulated by various agents which cause vasoconstriction

Question 32

What s endothelium important for?

Answer 32

Maintenance of vascular health

Question 33

What can endothelial damage/dysfunction be caused by?

Answer 33

High BP High cholesterol Diabetes Smoking

Question 34

What are endothelial produced vasodilators?

Answer 34

Anti-thrombotic Anti-inflammatory Anti-oxidants

Question 35

Endothelial produced vasoconstrictors are?

Answer 35

Pro-thrombatic Pro-inflammatory Pro-oxidants

Question 36

What does a cold temperature cause?

Answer 36

Vasoconstriction

Question 37

What does warmth cause?

Answer 37

Vasodilation

Question 38

What is vasomotor tone caused by?

Answer 38

Tonic discharge of sympathetic nerves resulting in continuous release of noradrenaline

Question 39

What will increased sympathetic discharge cause in vascular smooth muscles?

Answer 39

Increase the vasomotor tone = Vasoconstriction

Question 40

What causes decreased vasomotor tone (vasodilation)?

Answer 40

Decreased sympathetic discharge to vascular smooth muscle

Question 41

There is no significant parasympathetic innervation of arterial smooth muscles. True or False?

Answer 41

There is no significant parasympathetic innervation in arterial smooth muscle EXCEPT in penis and clitoris.

Question 42

What hormone controls vascular smooth muscle?

Answer 42

Adrenaline from the adrenal medulla

Question 43

Explain the affect of adrenaline?

Answer 43

Largely organ specific - depends on predominant type of receptor

Question 44

What does adrenaline acting on alpha receptors cause?

Answer 44

Vasoconstriction

Question 45

What are important in immediate control of BP?

Answer 45

Angiotensin 2 | ADH

Question 46

Intrinsic control of vascular smooth muscles can override extrinsic controls? True or False?

Answer 46

True

Question 47

What do intrinsic control of vascular smooth muscle include?

Answer 47

Chemical and physical factors

Question 48

Intrinsic control of vascular smooth muscles?

Answer 48

These match the blood flow of different tissues to their metabolic needs