Endocrine I - Pituitary and Pineal Glands Flashcards Preview

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Flashcards in Endocrine I - Pituitary and Pineal Glands Deck (36)
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1
Q

How are endocrine signals transported throughout the body?

A

Blood and body fluids

2
Q

Which bone is the pituitary located within?

A

Sphenoid bone

3
Q

Which tissues are the pituitary derived from?

A

Oral cavity tissues and neural tissue

4
Q

What is another common name for the anterior pituitary?

A

Pars distalis

5
Q

What is another common name for the posterior pituitary?

A

Pars nervosa

6
Q

Which germ layer is the pars distalis derived from?

A

Oral ectoderm

7
Q

Name the three cell morphologies found in the pars distalis.

A
  1. Acidophils
  2. Basophils
  3. Chromophobes
8
Q

Name two pars distalis cell types that are acidophils.

A

Somatotropes and lactotropes/mammotropes.

9
Q

What do somatotropes do? How common are they? What stimulates them and what inhibits them?

A

Secrete GH. Account for 50% of pars distalis cells. Stimulated by GHRH and inhibited by somatostatin.

10
Q

What do lactotropes/mammotropes do? How common are they? What stimulates them?

A

Secrete prolactin, account for 15% of pars distalis cells but increase in number during pregnancy. Stimulated by thyroid releasing hormone (TRH) and vasoactive intestinal peptide.

11
Q

What do thyrotrophs do? How common are they? What stimulates them?

A

Secrete TSH, which in turn stimulates the thyroid gland to secrete T3 and T4. They make up 5% of paris distalis cells. Stimulated by TRH.

12
Q

What do gonadotrophs do? How common are they? What stimulates them?

A

Secrete FSH, LH. Make up less than 10% of paris distalis cells. Controlled by GnRH and LHRH.

13
Q

What do corticotrophs do? What stimulates them?

A

Secrete ACTH, stimulated by CRH.

14
Q

What do folliculostellate cells do?

A

They form an intrercellular network between endocrine cells of the pituitary with numerous gap junctions to coordinate distalis cells and perform phagocytic, neuro and immune regulation.

15
Q

What germ layer is the pars nervosa derived from?

A

Neural tissue

16
Q

What are the three parts of the pars nervosa?

A

Median eminence, infundibulum, pars distalis (?)

17
Q

In which part of the pituitary would one find unmyelinated axons and pituicytes?

A

Pars nervosa

18
Q

Name the two hypothalmic axons that extend into the pars nervosa.

A

Paraventricular and supraoptic.

19
Q

What do paraventricular axons release?

A

Oxytocin

20
Q

What do supraoptic axons release?

A

ADH

21
Q

What are Herring bodies?

A

Where oxytocin and ADH are stored in the axon terminals of paraventricular and supraoptic axons, respectively.

22
Q

What is the pars intermedia derived from?

A

Oral ectoderm.

23
Q

What structure separates the pars intermedia from the pars distalis?

A

Remnants of Rathke’s pouch

24
Q

Which hormone do pars intermedia cells secrete? What is the precursor to this hormone?

A

Melanocyte-stimulating hormone (MSH) made from precursor proopiomelanocortin

25
Q

What two cell types are found in the pineal gland?

A

Pinealocytes and interstitial cells (supporting glial cells)

26
Q

What do pinealocytes do? What are they derived from?

A

They produce melatonin from tryptophan. Epithelial-derived.

27
Q

What does melatonin do?

A

Maintains circadian rhythms and also is thought to be a tumor suppressor due to its ability to terminate hydroxyl radicals. May also play a role in the timimg of puberty.

28
Q

Describe how the pineal gland responds to light in maintaining circadian rhythms.

A

No light –> no norepinephrine from the sympathetic nerve fibers –> melatonin is made —> sleepy.

29
Q

What are the two types of calcifications of the pineal gland?

A

Corpora arenacea (brain sand) and myeloconia (brain dust)

30
Q

What is corpora arenacea (brain sand)?

A

Lumpy, dark staining aggregates that consist of hydroxyapatite and protein. They mark the midline of the pineal gland.

31
Q

What is myeloconia (brain dust)?

A

Small crystals of calcite and glycoprotein.

32
Q

What do pancreatic beta cells secrete?

A

Insulin

33
Q

What do pancreatic alpha cells secrete?

A

Glucagon

34
Q

What do pancreatic delta cells secrete?

A

Somatostatin

35
Q

What do pancreatic F (gamma) cells secrete? What does this hormone do?

A

Pancreatic polypeptide - regulates pancreas/GI functions

36
Q

What do pancreatic epsilon cells secrete?

A

Ghrelin (hunger hormone)