Autonomic Nervous System and Basic Endocrinology Flashcards

1
Q

The afferent nervous system is composed of______________

A

Sensory Neurons

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2
Q

The efferent nervous system is composed of the ______________ and ______________

A

Autonomic NS and Somatic NS

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3
Q

What is the function of the Autonomic Nervous System?

A

Maintenance of homeostasis

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4
Q

Most autonomic signals are ____________ consciously and not under ________ control

A

Not perceived

Voluntary control

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5
Q

Autonomic nerves consist of 2 neurons, the ____________ and ___________ neurons synapse in ganglia

A

Pre-ganglionic and Post-ganglionic

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6
Q

What are the advantages of a 2 neuron chains in the ANS?

A
  • 1 Pre-ganglionic neuron can synapse onto many postganglionic neurons
  • 1 Pre-ganglionic neuron can synapse onto both excitatory and inhibitory neurons
  • Information from sensory axons can act before reaching the CNS
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7
Q

Sympathetic nerves have a _____ preganglionic neuron and a _____ postganglionic neuron.

A

Short

Long

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8
Q

Sympathetic nerves exit the CNS in the _______ and _______ regions of the spine

A

Thoracic and Lumbar regions

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9
Q

Due to the short length of the ___________ neuron, the ganglia of the sympathetic nerves form a body close to the spinal cord called the _______________

A

Pre-ganglionic

Sympathetic trunk

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10
Q

What does the sympathetic trunk allow sympathetic neurons to do?

A

“Talk” to each other

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11
Q

Parasympathetic nerves have ______ preganglionic neurons and _____ postganglionic neurons

A

Long

Short

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12
Q

Parasympathetic nerves exit the ______ and _______ region of the spine

A

Brain

Sacral

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13
Q

Parasympathetic and Sympathetic nerves generally exert _________ effect on an organ

A

An opposite

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14
Q

Sympathetic stimulation causes heart rate and cardiac output to ________.

A

Increase

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15
Q

In the presence of noradrenaline the contractility of the ventricle ______ which causes cardiac output to ______.

A

Increase, Increase

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16
Q

What are the effects of increased Sympathetic NS activation?

A

Increased Heart Rate and CO
Constriction of arteriole and venous smooth muscle
Dilation of pupils
Relaxation of smooth muscle in the airways
Breakdown of Glycogen and Fat stores
Increased sweating

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17
Q

Discuss the redistribution of blood flow when the Sympathetic NS is activated.

A
  • At rest 15-20% of blood flow goes to the skeletal muscles
  • When sympathetics are stimulated blood vessels in the skeletal muscles dilate
  • The blood vessels in the kidney, stomach, intestines and liver constrict
  • This causes 80-85% of blood flow to go to the skeletal muscles during activity
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18
Q

Sympathetic NS activity stimulates the __________ to release ________ into the blood which reinforces sympathetic actions.

A

Adrenal Medulla

Adrenaline

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19
Q

Do the Parasympathetic and Sympathetic nervous systems always have opposite effects?

A

No, for example in the salivary glands they both stimulate secretion of saliva

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20
Q

What is the Dive reflex?

A

When the face is submerged in water, mechanoreceptors and thermoreceptors activate the parasympathetics resulting in pronounced Bradycardia (Abnormally slow HR)

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21
Q

What is the Cold Shock response?

A

Submersion in cold water will stimulate cutaneous cold receptors to activate the sympathetic NS resulting in pronounced Tachycardia (Abnormally fast HR)

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22
Q

With respect to the ANS, what is the function of the hypothalamus?

A

To integrate information it receives into a coherent pattern of autonomic responses

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23
Q

What is the major neurotransmitter for all pre-ganglionic-post-ganglionic synapses?

A

Acetylcholine

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24
Q

What does Cholinergic mean?

A

The neuron releases Acetylcholine at its synapse

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25
Q

What does Adrenergic mean?

A

The neuron releases Noradrenaline at its synapse

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26
Q

In sympathetic pathways, the pre-ganglionic neuron is ____________ and the post-ganglionic is ____________

A

Cholinergic

Adrenergic

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27
Q

In sympathetic pathways sweat glands both the pre-ganglionic and post-ganglionic neurons are __________

A

Cholinergic

28
Q

In parasympathetic pathways the pre-ganglionic neuron is _________ and the post ganglionic neuron is __________

A

Cholinergic

Cholinergic

29
Q

Why is the effect of Acetylcholine short lived?

A

Acetylcholine is rapidly broken down by exctracellular Aceytlcholinesterases

30
Q

Why is the effect of Noradrenaline short lived?

A

Noradrenaline is rapidly reabsorbed by the sympathetic nerves

31
Q

What are catecholamines?

A

Substances derived from the amino acid tyrosine

i.e. Adrenaline, Noradrenaline

32
Q

Why are the effects of adreanline and noradrenline in the blood short lived?

A

They are inactivated in the liver by catechol-O-methyltranferase

33
Q

What are adrenergic receptors?

A

Receptors specific to Noradrenaline and Adrenaline

34
Q

What effect do α1 - adrenergic receptors have?

A

They stimulate contraction of the smooth muscle in arterioles and veins

35
Q

What effect do α2 - adrenergic receptors have?

A

They inhibit the release of insulin from the endocrine pancreas

36
Q

What effect do β1 - adrenergic receptors have?

A

They stimulate an increase in heart rate and force of contraction

37
Q

What effect do β2 - adrenergic receptors have?

A

They stimulate the smooth muscle in the airways to relax. These receptors have a greater affinity for adrenaline than noradrenaline

38
Q

What are cholinergic receptors?

A

Receptors specific to Acetylcholine

39
Q

What is a Muscarinic Acetylcholine receptor?

A
  • A receptor named after the agonist muscarine
  • Found on effector (target) cells innervated by the parasympathetic nerves
  • It can be blocked by atropine
40
Q

Whats is a Nicotinic Acetylcholine receptor?

A
  • A receptor named after the agonist nicotine

- These receptors are found on post-ganglionic cell bodies and post-synaptic membranes of skeletal muscle cells

41
Q

Peptide hormones are stored in _________. They are _________ and so bind to receptors on the cell membrane.

A

Vesicles

Lipophobic

42
Q

Give some examples of Tyrosine derivative hormones

A

Adrenaline/Noradrenaline
Dopamine
Thyroxine

43
Q

The pituitary gland is also known as the ________

A

Hypophysis

44
Q

Nerves that can secrete hormones are called __________

A

Neuroendocrine cells

45
Q

The Posterior Pituitary is also called the

A

Neurohypophysis

46
Q

Explain how hormones are release from the Neurohypophysis

A
  • Hormones are made in the hypothalamus’ neuroendocrine cell bodies
  • The hormones are then stored in their axons in the neurohypohysis
  • Hormones are released into the blood in response to neural stimulation
47
Q

The Anterior Pituitary is also called the

A

Adenohypophysis

48
Q

How is the hypothalamus able to communicated with the Adenohypophysis?

A

It can send chemical signals via the Hypothalamo-pituiatry portal vessels

49
Q

What does GHRH stand for?

A

Growth Hormone Releasing Hormone

50
Q

What does CRH stand for?

A

Corticotropin Releasing Hormone, stimulates the release of ACTH

51
Q

What does TRH stand for?

A

Thyrotropin Releasing Hormone, stimulates secretion of Prolactin and TSH

52
Q

What does GnRH stand for?

A

Gondaltropin Releasing Hormone, stimulates the release of FSH and LH

53
Q

What does SS stand for?

A

Somatostatin, Inhibits the release of FSH and GH

54
Q

What does DA stand for?

A

Dopaminne, it inhibits the release of Prolactin

55
Q

Cortisol is released by the ___________ of the adrenal gland at a rate of about ___mg a day

A

Zona Reticularis

10mg/day

56
Q

Under basal conditions, what is cortisols function?

A

Maintaining homeostasis of metabolic processes and fluid balance

57
Q

Explain how Cortisol is secreted under stressful conditions

A
  1. The hypothalamus increases secretion of CRH
  2. CRH goes to the Ant. Pit. causing it to release ACTH
  3. ACTH goes to the Zona Reticularis portion of the Adrenal Gland’s cortex and stimulates the secretion of Cortisol
58
Q

During stress what does Cortisol do?

A

Increase glucose and oxygen supply to the skeletal muscles, heart and brain
Increases Muscle performance

59
Q

At the liver, cortisol causes an increase in _____________

A

Gluconeogenesis

60
Q

Cortisol prevents cells that aren’t necessary from taking up _________ and __________

A

Amino Acid and Glucose

61
Q

By activating _________ cortisol increases the amount of free fatty acids that can be used and an alternative fuel

A

Lipolysis

62
Q

In order to conserve energy, cortisol suppresses __________, __________ and __________ functions

A

Immune, Digestive and Reproductive

63
Q

What is Cushing’s Disease?

A

Overproduction of Cortisol

64
Q

Cushings Disease can be caused by:

A
  1. Over-secretion of CRH by a hypothalamic tumour
  2. Over-secretion of ACTH by a anterior pituitary tumour
  3. Negative feedback issue, insensitivity to raised cortisol levels
65
Q

What are some of the effects Cushings disease?

A

Diabetes Mellitus
Central Obesity
Thinning of Skin and bruising
Muscles

66
Q

How do you treat Cushings disease?

A

Removal of the tumour