ppwt 5 Flashcards

1
Q

explain the core clock in animals

A

Bmal 1 and clock will bind to ebox (DNA)
they can form

  1. CRY1 and PER which will go to the nucleus and inhibit BMAL and clock -> negative feedback. Inhibit gene expression
  2. it will make ROR and REV. ror - stimulates the bmal 1 box and rev will inhibit
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2
Q

rev will
ror will
cry1+ per will

A

inhibit bmal 1
estimulate bmal
inhibit gene expression

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3
Q

explain endogenous mechanism

A

signal from the brain independent of external cues

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4
Q

circadian rhythm

A

24h cycle
hormone secretion, sleep-wake, body temperature

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5
Q

infradian rythm

A

longer than 24h cycle
reproductive cycle, hibernation, breeding

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6
Q

ultradian rhythm

A

shorter than 24h cycle
sleep stages, heart beat

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7
Q

what are some peripheral clocks and give some examples

A

external cues can change internal ones. For example temperature can change heart beat, pathogens - immune system etc

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8
Q

what are some examples of circadian rhythms

A

cortisol secretion, growth hormones, PRL

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9
Q

when is the max cortisol secretion? and GH?

A

cortisol is maximal between 6-8 am
and GH is maximal 1h after going to sleep

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10
Q

can circadian rhythms change during development? if yes give an example

A

yes, gonadotrophin is released mainly at nigh doing puberty but in adults it releases in pulsative fashion

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11
Q

why do we need to take rhytms into account when we measure hormone levels

A

because we need to see if the hormone in its “normal” rhytms has a hypo or hyper function

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12
Q

true or false
circadian thytms can be seen even if infradian rhythms

A

true

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13
Q

what is the pacemaker of the circadian rhythm

A

SCN - suprachiasmatic nucleus neurons

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14
Q

how much time is the circadian rhythms

A

more than 24h

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15
Q

what is the main stimulus that enters the SCN

A

Light

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16
Q

explain how light is connected to the SCN

A

scn receives light by the retinohypothalamic tract - which has a neural connection form retina to the SCN

17
Q

Where does SCN regulate melatonin

A

pineal gland

18
Q

when do melatonin levels peak

A

in the middle of the night

19
Q

how is pineal gland involved in the control of circadian rhythm

A

because it secretes melatonin

20
Q

explain the correlation between melatonin and other hormones

A

if someone is sleep less, the growth hormone will decrease because it is related to melatin at night

21
Q

what are other functions of melatonin

A
  • adjust jet lag
  • aid elderly sleep
  • antioxidant, anti agent ( but in a high concentration)
  • enhance immunity, tumor therapy - not clear evidence
22
Q

side effects of melatonin

A
  • day time sleepiness
  • desensitization of melatonin if doses too high
  • adverse events with those that has seizures
23
Q

explain - and + control

A

-: endocrine tissue produce hormone impact target cell which produce metabolite or hormone to inhibit endocrine tissue production of hormone

+: endocrine tissue produce hormone, acts on target tissue, which produces hormone that will reinforce hormone production by endocrine

24
Q

explain the central control and what does it impact

A

hypothalamus -> pituaitary -> target gland

25
Q

what are the causes of some endocrine disorders

A
  • overproduction
    -underproduction
  • altered tissue response
  • tumors of endocrine organ
  • excessive hormone metabolism