Lec 15: Hormones & Brain Function Flashcards

1
Q

what are the 2 types of communication that occurs in neurons?

A

electrical

chemical

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2
Q

what is electrical communication of neurons?

A

WITHIN the neurons

transmission along the axon

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3
Q

what is chemical communication of neurons?

A

BETWEEN neurons

transmission at the synapse

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4
Q

list 6 components of the definition of a NT

A

1) exists in presynaptic axon terminals
2) presynaptic cells contains enzymes for synthesizing substance
3) substance is released when AP reach terminals
4) specific rec recognise the substance
5) application of the substance produces changes in postsynaptic potential
6) blocking release of the substance prevents nerve impulses

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5
Q

2 types of receptors for ACh and are they metabotropic/ionotrophic?

A

1) muscarinic = metabotropic

2) nicotinic (ionotrophic)
- muscle contraction

  • cholinergic transmission in cortex
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6
Q

what are the DA receptors?? are they metabotropic/ionotrophic?

A

D1-D5 = metabotropic

  • complex behaviours, motor function, reward, higher cognition
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7
Q

name the NE receptors

are they metabotropic/ionotrophic?

A

a1, a2, b1, b2= metabotropic

  • visceral organs
  • sympathetic NS, fight or flight
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8
Q

what are the 5-HT receptors?

are they metabotropic/ionotrophic?

A

5-HT1, 2, 3

  • all but one subtype of 5-HT3 = metabotropic
  • mood, sleep, higher cognition
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9
Q

are GABA receptors ionotropic or metabotropic??

A

GABA-A and GABA-C= ionotropic

GABA-B= metabotropic

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10
Q

what are the glutamate receptors?

are they metabotropic/ionotropic?

A

AMPA, kainate, NMDA= ionotropic

mGluR= metabotropic

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11
Q

ionotrophic VS metabotropic

A

IONotropic= allow different kinds of ions to travel in and out of the cell.

metabotropic= do not have a “channel” that opens or closes. Linked to another small chemical called a “G-protein.”

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12
Q

glutamatergic transmission uses which 3 receptors???

A

AMPA
Kainate
NMDA
(all ionotropic)

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13
Q

name 2 inhibitory transmitters in the brain

A

GABA

glycine

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14
Q

name the 3 classes and characteristics of GABA receptors

A

GABA-A= ionotropic, produce fast inhibitory effects via Cl channel

GABA-B= metabotropic, slow inhibiting effects through neurogliaform interneurons

GABA-C= ionotropic with Cl channel

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15
Q

how do GABA agonists work?

A
  • potent tranquillizers

- allow influx of Cl, hyper-polarization and inhibitory effects

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16
Q

how does alcohol work in relation to GABA rec

A

at GABA-A receptors

  • ionotropic
  • fast inhibitory effects
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17
Q

what is the cause of drug abuse?

how to reduce?

A

rebellion, money, boredom, experimentation, thrill-seeking, desperation, self-medication

  • education, coercion, punishment, environmental change, maturation, pressure to strop, life events
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18
Q

what is the cause of drug dependence?

how to reduce

A

genetics, brain chemistry sensitivity, input from the environment

  • treatment to positively affect abnormal brain function to reduce need for drug
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19
Q

name 4 effects of alcohol on the brain

A
  • effect is biphasic (initial stimulant phase followed by more prolonged depressant phase)
  • activated GABA-A rec (coupled to chloride channel, inc post synaptic inhibition, hyperpolarization)
  • chronic abuse damages nerve cells, and frontal lobes
  • binge= brain damage
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20
Q

FASD

A

fetal alcohol spectrum disorders

  • distinctive changes in facial features, stunted growth, intellectual disability, irritability, tremors, hyperactivity
  • neural crest cells affected by alcohol, failure of closing
  • fewer cerebral cortices, sometimes absence corpus callosum
  • thickening of cortical mass, small brain
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21
Q

explain what happens to migration of neurons due to alcohol

A
  • slow movement to the right place
  • migrating neurons are immature, lacking dendrites, with only a soma and immature axon at this point (in neocortex)
  • undifferentiated at the start of migration
  • differentiation begins as neurons migrate
  • they develop NT making ability (AP)
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22
Q

what are neuroepithelial cells?

A

neural stem cells

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23
Q

neuroepithelial cells of the ventricular zone do what??

A

give rise to radial glial cells that further differentiate into neurons or glial cells

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24
Q

what do radial glial cells do?

A

act as guide wires for migration of neurons

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25
what are 3 characteristics of migrating neurons?
immature only soma immature axon
26
what is aggregation?
cells that are done migrating align themselves with other cells and form structures
27
what is aggregation?
cells that are done migrating align themselves with other cells and form structures
28
how many layers of the cortex?
6
29
which type of cells are the largest in the cortex?
pyramidal cells
30
what are the 2 types of ACh receptors?
nicotinic muscarinic
31
what are nicotinic receptors?
- most ionotropic, excitatory | - muscles (antagonist= paralysis)
32
what are muscarinic receptors?
metabotropic excitatory/inhibitory
33
what is the function of ACh in the CNS and PNS?
- associated with motor functions (heart/muscles) - learning - memory
34
relation between ACh neurons and alzheimers
cholinergic neurons are depleted in AD
35
where is DA found in the brain???
in the mesostriatal pathway - originates in the midbrain - specifically the substantia nigra - innervates the striatum
36
mesolimbocortical DA pathway originates .... projects.... DA in this pathway is involved in... abnormalities associated with...
originates in midbrain (VTA) - project to limbic system and cortex - reward, reinforcement, learning - abnormalities= schizophrenia, addiction
37
NE released in which 3 brainstem regions?
Locus coeruleus (pons) lateral tegmental system (midbrain) dorsal medullary group
38
NE systems modulate....
processes including mood, arousal and sexual behaviour
39
where are serotonergic cell bodies found??
raphe nuclei - fibers project widely
40
5-HT implicated in....
sleep, mood, sexual behaviour and anxiety
41
what hormone does antidepressants act on???
inc 5HT activity depending on receptor subtype
42
what are endocrine glands?
release hormones within the body
43
what are the 9 general principles of hormone action
1) act in gradual fashion 2) act by changing probability/intensity of behaviour 3) reciprocal relationship between behaviour and hormones 4) multiple effects, one behaviour can be affected by several hormones 5) pulsatile secretion pattern (burst) 6) some controlled by circadian clocks 7) interact with other hormones and change their effects 8) across species, structure is similar, actions vary 9) only affect cells with a receptor protein for the hormone
44
list the 5 ways in which neural and hormonal communications differ
1) neural communication travels to precise destinations. Hormonal spread through body, picked up by cells with the proper rec (multiplicity of action) 2) neural= rapid, hormonal- slower - neuromodulators can influence activity of synaptic transmitters 3) distance traveled varies 4) neural messages= digital, sequences of all-or-none potentials - hormonal messages= analog/graded in strength 5) neural communications sometimes under voluntary control - hormones= involuntary
45
what is the chemical structure of : - protein hormone - amine hormone - steroid hormone
protein= string AA amine= modified AA steroid= 4 rings of C
46
hormones exert effects on cells and tissues by:
promoting proliferation, growth and differentiation of cells and modulating cell activity
47
how do protein and amine hormones function?
- act rapidly - when bind to extracellular part of a receptor, the receptor changes shape - intracellular part activates 2nd messenger
48
how do steroid hormones work?
act slowly when steroid-receptor complexes form, they alter protein production long-lasting effects - pass through membrane of the cell, bind to receptor in cytoplasm - rec chaparone these bound rec steroid into the nucelus AFTER dimerization - binding= conformational change - makes another protein binding domain available, and dimer of protein can go in to regulate gene expression
49
hormones are regulated by which feedback system??
negative - output feeds back and inhibits further secretion
50
what is an autocrine response?
involved endocrine gland releasing hormone and feeding back onto itself - accumulation of hormone prevents further release
51
what is target cell feedback?
hormone acts on its target cells, has biological effect - biological effect is detected by endocrine gland, inhibits further release
52
which region drives the endocrine gland via either neural or hormonal signals?
hypothalamic region
53
describe the 5 steps in brain regulation (feedback control)
``` hypothalamus --> (-) endocrine cells --> (+) target cells --> (+) biological response ``` --> [negative feedback]
54
name 2 other hormones involved in feedback control in anterior pituitary
1) tropic hormones (affect other endocrine glands) 2) releasing hormones (used by hypothalamus to control pituitary release of tropic hormones) - first releasing hormones act on cells to release tropic hormones
55
what is the pituitary gland?
small structure at base of brain release hormones that control the activity of bodys other hormone glands
56
2 parts of the pituitary gland
anterior pituitary (adenohypophysis) posterior pituitary (neurohypophysis)
57
what is the pituitary stalk??
infundibulum connects pituitary to hypothalamus - contains BV and axons
58
describe the hormone production by the posterior pituitary
- terminate in capillaries in posterior pituitary - direct effect from activating neurons within PVN of hypothalamus that will result in the release of hormones in capillary blood network
59
which 2 hormones does post pit secrete?
vasopressin (AVP) oxytocin
60
what is AVP/vasopressin
- aka ADH (antidiuretic) inc BP inhibit urine production
61
what is oxytocin?
involved in reproductive and parenting behaviour uterine contraction milk letdown reflex
62
describe the hormone release by the ant pit?
- hypothalamic neurons synthesize releasing hormones - axons converge on median eminence - releasing hormones secreted via hypophyseal portal system - releasing hormones carried to ant pit, release tropic hormones
63
hypothalamus is influenced by _____ ____, such as other hormones, and by ____ ____ from other brain areas
circulating messages synaptic inputs
64
characteristics of people wit tumours of the anterior pituitary reason???
tall, pronounced foreheads -- high GH secretion
65
name the 6 tropic hormones the ANT PIT releases
1) ACTH 2) TSH 3) FSH 4) LH 5) Prolactin 6) GH
66
what is ACTH
ANT PIT adrenocorticotropic hormone controls adrenal cortex and steroid hormone release CRH--> ACTH--> adrenal cortex (kidney)--> secrete corticosteroids
67
what is TSH?
ANT PIT thyroid-stimulating hormone increases thyroid hormone release TRH--> TSH --> thyroid--> thyroid hormones
68
gonadotropins influence the _____
gonads
69
what is FSH?
ANT PIT follice-stimulating hormone stimulate egg-containing follicles or sperm production GnRH/GNIH---> FSH--> testes/ovaries--> androgens/estrogens
70
what is LH
ANT PIT luteinizing hormone stimulate follicles to form the corpora lutea GnRH/GNIH---> LH--> testes/ovaries--> androgens/estrogens
71
what is prolactin
ANT PIT stimulates lactation in females involved in parental behaviour prolactin-releasing peptid/prolactin-inhibiting factor --> prolactin--> mammary glands --> milk production
72
what is GH?
ANT PIT growth hormone- aka somatotropin or somatotropic hormone influence growth (mostly during sleep) - stomach hormone ghrelin evokes GH release somatocrinin(+)/stomatostatin (-)--> GH --> bones--> bone growth
73
where are the adrenal glands located?
on top of each kidney
74
% of adrenal cortex/medulla
80% adrenal cortex 20% adrenal medulla
75
adrenal cortex secretes steroid hormone called....
adrenocorticoids (adrenal steroids)
76
what are glucocorticoids?
subgroup of adrenocorticoids involved with glucose metabolism
77
what is cortisol?
``` cortisol= humans corticosterone= mice/rats ``` glucocorticoids stress hormone - inc blood glucose, breaks down protein