Wk8-9 AUTONOMIC NERVOUS SYSTEM Flashcards

(55 cards)

1
Q

Functions of hypothalamus

A

metabolism

Mediation of stress

reproductive behaviour and growth

body temperature

ANS + endocrine function

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2
Q

2 important regions of hypothalamus

A

Paraventricular nucleus

Median eminence

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3
Q

Paraventricular nucleus

A

2 parts

lateral = magnocellular neurons

medial = parvocellular neurons

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4
Q

Median eminence

A

contains blood vessels that are striated

This is part of the BBB still allowing movement of hormones

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5
Q

2 main parts of pituitary gland

A

Anterior pituitary

Posterior pituitary

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6
Q

Anterior pituitary

A

master gland controlling other glands including, thyroid, adrenal and mammory glands.

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7
Q

Anterior pituitary pathway

A

Parvocellular neurosecretory cells produce neuro-hormones (releasing factors)

released into the vicinity of portal vessels in the median eminence cells,

transported to anterior pituitary

cause the release of hormones from specialised secretory cells

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8
Q

Paraventricular nucleus neuro-hormones

A

Gonadotropin releasing hormone (GnRH), pre optic area

Thyrotropin releasing hormone (TRH), magnocellular (for body), parvocellular (for brain)

Corticotropin releasing hormone (CRH), parvocellular

Growth Hormone, Releasing Hormone (GHRH), parvocellular

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9
Q

Posterior pituitary pathway

A

vasopressin (also called anti diuretic hormone)

oxytocin release (magnocellular).

These are not released in portal system, they are neurotransmitters in brain.

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10
Q

Stress hormones is …. pituitary gland function

A

anterior

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11
Q

Stress hormone pathway

A

stress detected by brain

Corticotropin releasing hormone (CRH) released from nerves in PVN.

Transported to anterior pituitary by portal system

Acts on corticotrophs (type of cell) causing release adrenocorticotropic hormone

Acts on cortex of adrenal gland causing cortisol release into blood

Mobilises energy stores and suppresses immune system

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12
Q

Sex hormones are controlled by

A

hypothalamus and pituitary

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13
Q

Sex hormone pathway

A

Psychological and sensory influences detected by brain

Gonadotropin releasing hormone (GnRH) released from preoptic area of hypothalamus (not PVN).

Transported to anterior pituitary by portal system

Acts on gonadotrophs causing them to release folic stimulating hormone (FSH) + lutenising hormone (LH)

Acts on ovaries and testes

In females, causes estrogen release (cyclic release of hormones for menstrual cycle)

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14
Q

Vasopressin

A

Magnocellular neurons direct straight to the posterior pituitary gland, no portal systems in median eminence needed.

End in conjunction with fenestrated vessels, dumping their contents into them and therefore causing vasopressin release.

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15
Q

How is vasopressin release stimulated

A

by dehydration, changes in tonicity, detected by osmoreceptors in the forebrain and info sent to magnocellular neurons.

Hemorrhage (blood loss), detected by blood/ cardiac volume receptors in forebrain or recepotrs in kidney which release angiotensin.

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16
Q

Oxytocin

A

Stimulated by suckling of newborn babies, crying from mothers own or even unrelated babies.

oxytocin magnocellular neurons activated.

posterior pituitary release oxytocin

affects breasts releasing milk

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17
Q

leptin

A

Ob gene (obesity gene) product

circulates in the bloodstream in proportion to fat mass.

inhibits promoting neurons and excites inhibiting neurons.

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18
Q

2 types of neurons contained in arcuate nucleus

A

orexigenic

anorexigenic

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19
Q

orexigenic neurons

A

PROMOTE FEEDING

NeuropeptideY (NPY)

Agouti Related Peptide (AgRP)

axonal projections in paraventricular nucleus through dedicated NPY receptors

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20
Q

anorexigenic neurons

A

INHIBIT FEEDING

Proopiomelanocortin (POMC)

Cocaine Amphetamine Regulated Transcript (CART)

Active ingredient acts to inhibit effects of feeding in the paraventricular nucleus

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21
Q

Starvation response

A

Orexigenic neurons activated

Inhibited secretion of hypophysiotropic hormones in the paraventricular nucleus

promote energy expenditure (metabolism to lose weight gained by now eating)

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22
Q

Full response

A

Anorexigenic neurons activated

Promoted secretion of hypophysiotropic hormones in the paraventricular nucleus

inhibition energy expenditure (metabolism to halt losing energy as have stopped eating)

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23
Q

Short term food regulation

A

Ghrelin hunger hormone builds up in the brain before and reduced after a meal.

After a meal, satiety hormones increase to say you are not hungry anymore.

Gastric distension of stomach activates stretch receptors = Helps to say we are full.

24
Q

Liking pathways

A

objective affective reaction that is mediated for taste in the brain by mu opoids at nucleus accumbens

25
Wanting pathways
an objective motivational process that is often termed “incentive salience” mediated by dopamine
26
What is the function the the ANS
looks after the body as a whole, allowing the individual to survive and reproduce.
27
ANS in the spinal cord
coming out of the side and middle of the spinal cord (lateral, middle). Sensory information comes in the dorsal root.
28
The ANS nerves function
uses nerves to enhance or suppress activity. para and sympa are functionally opposing and will not work at the same time
29
Neurotransmitter pathway
Transmitter precursor taken up into nerve terminal metabolising enzymes form neurotransmitter. stored in vesicles so it doesn’t break down (Nitric oxide not stored as it is labile). Exocytotic Vesicle release contents occurs due to AP. Visceral efferent in the ANS spray neurotransmitter around in the effector tissue These receptors are all metabotropic, which are sensitive to low doses all over the place. set up large numbers of second messengers within their cell.
30
Describe an ANS junction
Not a synapse, a junction varicosities contain vesicles along axons
31
Every nerve that has it’s cell body in the CNS and comes out to become part of the ANS...
uses acetylcholine as its main neurotransmitter Includes pre-ganglionic nerves includes para postganglionic nerves
32
What is a NANC system
main transmitter neither ACh or NA. non adrenergic non cholinergic
33
Sympathetic ANS
flight/fight response brain (pre, myelinated) and spinal nerve (post, unmyelinated) communicate in ganglion.
34
NORADRENILINE
SYMPATHETIC Synthesised in vesicles acts on alpha and beta adrenoceptors
35
ADRENOCEPTORS
Alpha: noradrenaline potent excitatory/contraction sit under nerve, most likely affected Beta: isoprenaline potent inhibitory (except heart excitation) away from nerves
36
ATP acts as a
co transmitter. It is released along with NA
37
Parasympathetic ANS
rest/digest response preganglionic straight from brain, long neurons. ganglion on edge of organ pelvic organs at bottom of back nerves from end of spinal cord
38
ACETYLCHOLINE
PARASYMPATHETIC synthesised in cytoplasm of a varicosity, transported to vesicles. acts on muscarinic receptors ACh removed by acetylcholinesterase, choline taken back up
39
Nicotinic receptors
acted on by ACh terminals of preganglionic nerves coming from CNS of parasympathetic
40
NITRIC OXIDE
PARASYMPATHETIC synthesised on demand, not stored in vesicles increase in cytoplasmic calcium required inhibits smooth muscle contraction
41
Outline the adrenal medulla
inner part of an adrenal gland, hormones initiate the flight or fight response, adrenaline and noradrenaline.
42
Energy homeostasis
- ANS controls glucose conversion to glycogen in the liver and muscle. isn’t working = diabetes Leptin and Insulin from food intake = brain not hungry anymore
43
Brown and white fat
ANS controls interchange between white and brown fat by glitazones
44
Human sexual response: males
Penile artery: Nitric oxide = vasodilator Noradernaline = vasoconstrictor Vas Deferens/Ejaculation : ATP = 1st fast contraction Noradrenaline = 2nd slow contraction Erection: parasympathetic nervous system supplies arteries, it does not usually supply arteries. enzyme digests = stop erection
45
How does viagra work
Viagra inhibits enzyme breakdown so that cGMP lasts a bit longer and the erection remains. Viagra cannot work if the nerves are totally severed no neurotransmitter is even produced for Viagra to inhibit.
46
Sexual response: Females
Vaginal secretion: CGRP – vasodilator (sensory)
47
Where do drugs NOT affect neurotransmission
Ion exchange pumps
48
ACh inhibition
Botox inhibits ACh, injected into specific muscles Antichonilesterases can be targeted to help with myasthenia graves and alzheimers
49
NA inhibition
Blocked NA release by noradrenergic neuron blocking drugs, stop sympathetic responses Activated NA release by drugs taken up into terminal causing NA release, + affect uptake 1 process leaving more NA enhance transmission + inhibit break down
50
what are activating NA drugs called
indirect sympathomimetics = mimic response indirectly
51
Targeting receptors
has more precise affects than targeting transmitters
52
Agonists
stimulate | suffix is mimetics
53
Antagonists
inhibit | suffix is lytics
54
Nictonic receptor drugs
too hard to target as they have complex systems and responses.
55
Muscarinic receptor drugs
muscarinic agonist = para response muscarinic antagonist = oppose response