The Endocrine System: Hypothalamus and Pituitary Gland Flashcards

1
Q

Hypothalamus and Pituitary

What is the generalized function of the hypothalamus and pituitary?

A

Relay stations that act in sequence

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2
Q

Hypothalamus

What is the anatomy of the Hypothalamus?

A

Essentially just two nuclei with processes that extend down into the posterior pituitary

Histology = brain/nervous tissue

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3
Q

Hypothalamus

What is the function of the Hypothalamus?

A

Releases peptide hormones that stimulate the pituitary

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4
Q

Hypothalamus

What triggers release of hormones from the Hypothalamus?

A

Sensory stimuli: Light, olfactory, autonomic, etc.
Other stimuli: Blood-bourne sterioids, hormones, blood glucose, blood pressure, stress, etc.

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5
Q

Hypothalamus

What happens to hormones released by the Hypothalamus?

A
  • They accumulate in the axons fo the neurohypophysis
  • Release in the median eminence that diffuse into the adenohypophysis
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6
Q

Hypothalamus

What hormones, from the Hypothalamus, accumulate in the axons in the neurohypophysis?

A
  • Oxytocin
  • Vasopressin
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7
Q

Hypothalamus

What hormones, from the Hypothalamus, diffuse into the adenohypophysis?

A
  • Somatostatin
  • Dopamine
  • GHRH
  • CRH
  • GnRH
  • TRH
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8
Q

Hypothalamus

Somatostatin

A

Inhibits GH and insulin secretion

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9
Q

Hypothalamus

Dopamine

A

Inhibits prolactin secretion by the pituitary

Directly impacts pituitary

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10
Q

Hypothalamus

Growth Hormone Releasing Hormone (GHRH)

A

Stimulates GH secretion by pituitary

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11
Q

Hypothalamus

Corticotropin-Releasing Hormone (CRH)

A

Stimulates ACTH secretion by the pituitary

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12
Q

Hypothalamus

Gonadotropin-Releasing Hormone (GnRH)

A

Stimulates LH/FSH secretion by the pituitary

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13
Q

Hypothalamus

Thyrotropin-Releasing Hormone (TRH)

A

Stimulates TSH secretion by the pituitary

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14
Q

The Pituitary Gland

What is the function of The Pituitary Gland?

A
  • Receives signals from the CNS (specifically the hypothalamus)
  • Sends signals to other endocrine glands and organs
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15
Q

The Pituitary Gland

What are the two parts of The Pituitary Gland?

A
  • Neurohypophysis - posterior pituitary (nerve tissue) - Pars nervosa
  • Adenohypophysis - anterior pituitary (glandular tissue - Pars distalis
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16
Q

The Pituitary Gland

What is the Pars intermedia?

A

Thin layer between the neurohypophysis and adenohypophysis containing colloid filled sacs (remnants of rathke’s pouch)
It also contains basophils and chromophobes from the adenohypophysis

17
Q

The Pituitary Gland

The Neurohypophysis

A

Axons of nerves from hypothalamus
Pituicytes (supportive glial cells)
Neurosecretory bodies (herring bodies) containing hormones (Oxytocin and ADH (vasopressin)

18
Q

The Pituitary Gland

What is the function of Antidiuretic Hormone?

aka ADH/Vasopressin

A

Increases water absorption in kidneys
Induces vasoconstriction
Increases Blood Volume/BP

19
Q

The Pituitary Gland

What is the function of Oxytocin?

A

Stimulates smooth muscle contraction

Myoepithelial cells in lactating brest

20
Q

The Pituitary Gland

Basophils produce…

A

endorphins

21
Q

The Pituitary Gland

What three cell types are found in the adenohypophysis?

A

Acidophils
Basophils
Chromophobes

22
Q

The Pituitary Gland

What type of hormones do acidophils produce?

A

Somatotropic
Mammotropic

23
Q

The Pituitary Gland

What type of hormones do basophils produce?

A

Gonadotropic
Corticotropic
Thyrotropic

24
Q

The Pituitary Gland

What are chromophobes?

A

They are thought to be stem cells or depleted cells

25
Q

The Pituitary Gland

Describe Acidophils histologically

A

Trichrome: Highly magenta
H&E: Very eosinophilic

26
Q

The Pituitary Gland

Describe basophils histologically

A

Blueish purple

27
Q

The Pituitary Gland

Describe chromophobes histologically

A

Empty cytoplasm (resistant to dye)
Stem cells or Acidophils/basophils that have released all their contents

28
Q

The Pituitary Gland

Do i need to know the major functions for the hormones on slide 32? She said just for reference?

A
29
Q

The Pituitary Gland

What is the function of corticotropin - releasing hormone?

A

Stimulates release of proopiomelanocortin (POMC) by corticotropic basophils

30
Q

Where is corticotropin-releasing hormone produced?

A

Hypothalamus

31
Q

The Pituitary Gland

What happens once POMC is released by corticoptropic basophils?

A

POMC is cleaved to
* β - lipotropin (β-LPH) → β-LPH stimulates melanocytes to produce melanin → induces lipolysis and steriodogenesis
* ACTH