ppwt 8 development and puberty Flashcards

1
Q

How growth hormone was discovered

A

Injection of crude extract of the pituitary gland in animal caused increased gorwth

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2
Q

what are the 2 parts of the pituitary gland

A
  • anterior (adenohypophysis)
  • posterior (neurohypophysis)
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3
Q

what hormones are excreted from the pituitary gland and where they have a function?

A
  • prolactin (PRL) has a role in lactation
  • thyrotropin or thyroid stimulating hormone (TSH) has an action on the thyroid
  • adrenocorticotropin (ACTH) has a role in the adenal
  • LH (luteinizing hormone) and FSH (follicle stimulating hormone) has an action on gonads
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4
Q

Where does theses hormones act
- PRL
- TSH
- ACTH (adrenocorticotropin)
- LH/FSH

A
  • PRL - lactation
  • TSH - thyroid
  • ACTH - adrenal
  • LH/FSH - gonads
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5
Q

the pituitary is controlled by

A

the hypothalamus

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6
Q

where does the pituitary gland sits on

A

hypophyseal fossa - sphenoid bone

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7
Q

explain what happens to the development of the hypothalamus and pituitary when a baby is developing

A

22 days: there os a pharyngeal opening and the ectodermal starts to thicken. The cells moves inward towards the central and they will form the Ratheke’s pouch

42 days : the rathke’s pouch is formed

60 days: the rathke’s pouch closes down and will become closer to the nuerohypophysis primordium which will form the posterior lobe and the rathke’s pouch will form the anterior pituitary

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8
Q

what will form the posterior and the anterior love

A

rathke’s pouch will form the anterior pituitary
neurohypophysis primordium will form the posterior pituitary

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9
Q

what are the nuclei that the hypothalamus forms

A
  • paraventricular nuclei
  • supraoptic nuclei
  • arcuate nucleus
  • anterior and posterior pituitary
  • ventromedial nucleus
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10
Q

what hormones do supraoptic and paraventricular nuclei produces

A

oxytocin or vasopressin

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11
Q

how is the supraoptic and paraventricular nuclei and where does they terminate

A
  • large neurons, terminate in the posterior pituitary
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12
Q

where does the hormones of the hypophysiotropic nuclei (PVN, Arc, PeVN) terminate

A

in the median eminence (ME)

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13
Q

how is the hypophysiotropic nuclei

A

smaller neurons

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14
Q

explain the location, what hormones are produce, where they will act on and what it happens to hypothalamic control over the endocrine system
- magnicellular neurons

A

magnicellular neurons are located in the supraoptic and periventricular.
They produce oxytocin and vasopressin hormones
and their axons go to the posterior pituitary land and secrete oxytocin and vasopressin that will go to the bloodstream and regulate kidney, uterus and mamary gland

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15
Q

explain the location, what hormones are produce, where they will act on and what it happens to hypothalamic control over the endocrine system
- parvicelluar hypophyseotropic neuron

A

parvicellular hypophyseotropic neuron are located on the Periventricular paraventricular and arcuate nucleus.
They produce TRH, CRH, somatostatin, GHRH, gnRH and dopamine.
The axon will terminate in the median eminence (ME) an it will secrete their hormone in the capillary blood and will come back by the portal vein that will produce a second wave of hormone having an effect on the cells that will secrete other hormones
- for example GHRH will have an effect on the call seomatotroph and it will secrete GH .

The pituitary hormone ester the blood stream via venous capillaries

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16
Q

where is the location of the magnicelluar neuron

A

supraoptic and paraventricular

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17
Q

where is the location of the parvicellular hypophyseotropic neuron

A

Arcuate, perivenetricular and paraventricular

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18
Q

which hormones is produced by arcuate

A

GHRH, GnRH and dopamine

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19
Q

which hormones are produced by the Periventricular and paraventricular

A

TRH, CRH and somastatin

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20
Q

true or false
hypothalamus integrates external and internal cues to secrete diverses hromones but because of the brain blood barrier is impermeable to various hormones

A

true

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21
Q

What parts of the brain have permeability which can interact with the hypothalamus also called (circumventricular organs)

A
  • organum vasculosum of the lamina terminalis (OVLT)
  • Subfornical organ (SFO)
  • median eminence (ME)
  • subcommissural organ (sco)
  • area postrema (ap)
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22
Q

explain what is the circumventricular organs

A

they are permeable to the BBB and they have a connection to the hypothalamus meaning that the substances that come in can trigger reactions. The circumventricular organs are exposed to hormones, metabolites and toxins

23
Q

where does hypothalamus receives sensory imputs from

A
  • external environment (light, temperature…)
  • internal (blood pressure, hormone levels)
24
Q

where does the hypothalamus send signals to

A
  • anterior and posteiror pituitary gland
  • cerebral cortex
  • parasymphatetic and symphathic neurons
25
Q

what is the most predominant cell type in the anterior pituitary gland

A

somatotroph

26
Q

what products (hormones) do these cell types produce
- corticotroph
- thyrotroph
- gonadotroph
- somatotroph
- lactotroph

A
  • corticotroph : ACTH
  • thyrotroph : TSH
  • gonadotroph : LH/FSH
  • somatotroph: GH
  • lactotroph : prolactin PRL
27
Q

True or false
cells co express multiple hormones

A

true

28
Q

true or false
there are no unique cell that only secrete TSH

A

true

29
Q

true or false
60-70% GH cells do not express only GH

A

FALSE
60-70% GH cells do EXPRESS ONLY GH

30
Q

what is the sexual dimorphism about GH and PRL in males and females

A

males produce more GH than females and females produce more PRL than males

31
Q

hormones excreted by the hypothalamus that goes to ME will bind to what.
Explain the process and give an example of ACTH

A

Hormones are secreted by neurons that will have an effect on the target cells that will release hormones granules

For example, CRH affect corticotroph cell that will secrete ACTH

32
Q

What are some of the inhibitory hormones

A

somatostatin and dopamine (an decrease in dopamine will have an effect on prolactin)

33
Q

true or false
GH is coded by various genes

A

true

34
Q

what are the genes that code for GH

A

hcs-a, cs-B, cs-V and cs-L

35
Q

human growth hormone is used for treatment of

A

dwarfism

36
Q

hCS’s is found in the

A

placenta it will produce an hormone similar to GH

37
Q

GHRH will make GH and what will happen

A

GH will stimulate FFA that will ahev an inhibitory response
it will stimulate IGF-1 in the liver which will have an inhibitory response

38
Q

npy will have a … in sst (somatostatin)

A

will have a positive influence and sst will inhibit GH

39
Q

what will increase or decrease GH

A
  • stress will increase GH
  • insulin and amino acids will increase GH
  • oral glucose, FFAs will decrease GH
  • leptin and ghrelin will increase GH
40
Q

what somatostatin do to GH secretion

A

it inhibits Gh secretion but not synthesis

41
Q

What itme is GH more secreted

A

at night - during sleep

42
Q

levels of GH depend on the development so expalin that

A

level fetus > child< adolescent > adult

43
Q

how does GH signals

A

by the Jack stats.
They will make IGF-1

44
Q

what does SOCS do

A

inhibit GHR, so without SOCS we would grow very big

45
Q

where does GH act on the bone to make it grow

A

in the epiphyseal plate

46
Q

what are the direct action of gh on growth

A

promote cell differentiation

47
Q

what are the indirect action of gh

A
  • induce IGF-1 in the liver that promotes cell division
  • GH and IGF-1 promote growth of long bones
  • epiphysis fuse at the end of puberty and longitudinal growth ceases
48
Q

Difference between IGF 1 and IGF2

A

IGF1: Gh dependent
produced by the liver and t is released into bloodstream
IGF2 : GH independent important in fetal development

49
Q

true or false
Structure of IGF-s is similar to insulin

A

true

50
Q

true or false
IGF remain constant over long periods despite fluctuation of GH

A

true

51
Q

GH vs IGF receptor

A

GH : tyrosine kinase, JAK 2 and MAPK or IP3K

IGF1: insulin recptor - tyrosine kinase activity

52
Q

what is the role of growth hormone in adults

A
  • optimized body composition, physical function and substrate metabolism
  • interacts with insulin to regulate lipid protein and glucose metabolism
    – enhances lipolysis and FA oxidation
  • reduces urea synthesis and excretion
  • increase AA uptake and protein synthesis
  • inhibits insulin-stimulated glucose uptake
53
Q

Gh treatment induces what

A

insulin so more glucose uptake