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Flashcards in deck_568909 Deck (64):
1

Give two factors which are under the control of the autonomic nervous system

Heart rateBlood pressure

2

What three physiological features does the autonomic nervous system control to have an effect?

Smooth muscleExocrine secretionRate and force of contraction in the heart

3

What are the two sections of the autonomic nervous system?

The sympathetic and the autonomic

4

What are the two series of neurones in the ANS called?

Pre-ganglionic and post-ganglionic

5

What is a ganglion?

A collection of nerve cell bodies in the PNS

6

What is a nuclei?

Collection of nerve cell bodies in the CNS

7

Describe the structure of the autonomic nervous system

Pre-ganglion with nerve cell body in CNSPost-ganglion with nerve cell body in PNS

8

What is the outflow of the sympathetic nervous system?

Thorcolumbar outflow

9

What are the spinal roots of the sympathetic nervous system?

T1 - L2

10

What is the structure of a sympathetic pathway?

* Short pre-ganglionic, long post-ganglionic neurone

11

What are the three places a sympathetic outflow may synapse?

- At the same level as origin- At different level to origin- May not synapse in paraverterbral chain

12

What neurotransmitter is used by pre-ganglionic neurones in sympathetic outflow?

Acetycholine for cholinergic receptors

13

What receptors do post ganglionic neurones express?

Nicotinic receptors

14

What type of neurotransmission do most sympathetic post-ganglionic neurones use?

Noradrenergic (secret noradrenalin

15

What classes of adrenoreceptors exist?

a 1 & a 2b 1 & b2

16

What are the exceptions to the noradrenergic rule of sympathetic outflow?

Some sympathetic synapses, such as those in perspiration and ejaculation pathways are cholinergic

17

What type of outflow is used by the parasympathetic nervous system?

Cranio-sacral outflow

18

What is the structure of a parasympathetic pathway?

Long pre-ganglionic nerve fiber - short post-ganglionic nerve fibre

19

What type of neurones are parasympathetic pre-ganglionic?

Cholinergic

20

What receptors do post-ganglionic neurones express?

Nicotinic receptors

21

What type of neurones are post-ganglionic parasympathetic?

Cholinergic

22

What type of receptors do parasympathetic work on on cells?

Muscarinic, G-protein coupled

23

For each organ, name the sympathetic receptor HeartAirwaysPupilSweat Glands

Heart - B1Airways - B2Pupil - A1Sweat Glands - A1 (M3)

24

For each organ, name the sympathetic effectHeartAirwaysPupilSweat Glands

Heart - Increase rate/force of contractionAirways - RelaxPupil - DilationSweat Glands - Localised secretion (a1), general secretion (m3)

25

For each organ, name the parasympathetic receptorHeartAirwaysPupilSweat Glands

Heart - M2Airways - M3Pupil - M3Sweat glands - None

26

How does adrenaline/noradrenaline interact with b - adrenoreceptors?

Activates G protein SStimulates Adenylyl CyclaseActivates glycogenolysis, lipolysis

27

How does Acetylcholine interact with M3 receptors?

GqStimulates Phospholipase CCauses smooth Muscle Contraction

28

How does acetylcholine interact with M2 receptors?

GiInhibits Adenylyl CyclaseStimulates K+ Channel, slowing of Cardiac Pacemaker

29

How does light interact with rhodopsin?

GtStimulates Cyclic GMP, PhosphodiesteraseVisual Excitation

30

What happens when a1 receptors are stimulated by adrenaline?

Activates GqStimulates Phospholipase CSmooth Muscle Contraction

31

What happens when a2 receptors are stimulated?

G protein I activated(- Adenylyl Cyclase)

32

What happens when M1 and M3 receptors are activated?

G protein Q activatedActivates phospholipase C

33

What happens when M2 receptors are activated?

G protein I activatedInhibits adenylyl cyclase, stimulating K+ channel and causing slowing of Cardiac Pacemaker

34

What role does the sympathetic branch of the autonomic nervous system play control of blood vessels?

Innversates the smooth muscle in the walls of arteries, aterioles and veins. Causes vasoconstriction of arterioles via a1 receptors

35

What is the term for the constant control the sympathetic nervous system has over the vasculature?

Vasomotor tone

36

What is meant by saying vasomotor tone in skin is high?

arterioles, pre-capillary sphincters and arterio-venous anastomoses are generally shut down. Variation in sympathetic outflow produces large changes in skin blood for, for thermoregulation.

37

What is vasomotor tone in skeletal muscles?

high at rest, but in exercise is antagonised by vasodilator metabolites.

38

What is vasomotor tone in gut?

vasomotor activity is high until a meal is consumed, when various vasodilators produced in the gut tissue antagonise it.

39

What is the principal way in which distribution of flow around the body is controlled?

The interplay between sympathetic vasoconstrictor tone and the action of vasodilator substances

40

What can vascular tone in the skin and skeletal muscle also be used for?

Controlling peripheral resistance

41

Where is sympathetic outflow to blood vessels controlled from?

The brain, via vasomotorcentres in the medulla oblongata

42

What structures does the autonomic nervous system effect in the heart? (parasympathetic and sympathetic)

SA and AV nodes both affect heart rate

43

What does parasympathetic and sympathetic activity respectively?

Para - Slows heartSymp - Speeds it up

44

What is the mechanism of control to decide whether heart should be slowed down or sped up?

Baroreceptors in arch of aorta and carotid sinuses detect pressure and feedback to the medulla oblongata, the control centre of autonomic activity

45

What is the hr if all autonomic inputs are pharmacologically blocked?

100 bpm

46

How is a normal resting heart rate of 60 bpm produced?

parasympathetic dominates the sympathetic at rest.

47

How are initial increases in heart rate determined?

Initial increases in heart rate are brought about by reduction in parasympathetic outflow. Increasing Sympathetic outflow makes further increases.

48

As well as speeding up heart rate, what is the other role of sympathetic nerve fibres?

Innervate ventricular cardiac myocytes, increasing force of contraction and cardiac output

49

What is the sympathetic pathway for control of the heart?

NA - B1 Receptors

50

What is the parasympathetic pathway for control of the heart

Ach - M2 receptors

51

If you gave someone an injection of adrenaline, what would happen?

There would be an increase in heart rate, stroke volume and therefore cardiac outputThe arterioles to the skin would vasoconstrict (action of adrenaline on α1 receptors)The airways would dilate (action of adrenaline on β2 receptors)

52

List the probable physiological effects of giving an individual a drug which antagonises the action of noradrenaline at a-adrenoreceptors.

Arteriolar vasodilation, reduces blood pressure and may cause posturalhypotensionInitial increase in heart rate mediated by baroreceptor reflexRelaxes GI and urinary sphincters

53

List the physiological effects of a poisonwhich inactivates acetylcholinesterase (such as a nerve gas or insecticide).

Ef fects on autonomic transmission: increased sal ivary, lacrimal , bronchial and G.I .secret ions, bronchoconstrict ion, reduced hear t rate and blood pressure, constr ictedpupilsEf fects on neuromuscular junct ion: init ial ly muscular twitching then paralysis due toNMJ blockadeEf fects on the brain: init ial ly excitat ion causing convulsions, later depression ofcerebral funct ion, unconsciousness and respiratory failure

54

Why would someone with inactivated acetylcholinesterase be paralysed?

The continued presence of ACh (theneurotransmi tter at the neuromuscular junct ion) wil l prevent subsequent contract ion ofskeletal muscle due to depolar ising block via nicotinic ACh receptors

55

Parasympathetic control of the heart is via the ... nerve Sympathetic control of the heart is via the ... nerves

VagusCardiac

56

What is vasoconstrictor tone due to?

The action of noradrenaline on a - adreno receptors

57

What is total peripheral resistance?

Blood pressure/ cardiac output

58

What are the sympathetic receptors of the heart?

B1

59

What are the parasympathetic receptors of the heart?

M2

60

What are the sympathetic receptors of the blood vessels to noradrenaline?

a1

61

What are the receptors to adrenaline to the blood vessels within skeletal muscle? Whatdo they cause to happen?

B2Dilation

62

What are the sympathetic receptors of the liver and what do they stimulate?

a, b2Glycogenolysis and gluconeogenesis

63

What are the sympathetic receptors of the sweat glands? What do they cause to happen?

Ach, MSecretion

64

What are the other proper sympathetic receptors of the sweat glands?

a, respond to circulating adrenaline