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Flashcards in Hypothalamus and Pituitary Microstructure Deck (23)
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1

Another name for Pituitary

Hypophyseal

2

Another name for posterior pituitary

neurohypophysis (because its hormones are delivered to it via neuron axons)

3

Another name for anterior pituitary

adenohypophysis

4

Parts of the anterior pituitary

pars distalis
pars intermedia
pars tuberalis

5

Parts of the posterior pituitary

pars nervosa
infundibular stalk
median eminence

6

Pars distalis

Anterior. Continuous with pars tuberalis. Looks darker staining pink because highly cellular and vascularized. Cells are organized in hoards that are closely associated with capillaries (fenestrated).

7

Median eminence

posterior. 2 halves of hypothalamus come together to form it. It is continuous with the infundibular stalk. Part of the posterior pituitary.

8

Pars tuberalis

Anterior. continuous with pars distalis. Forms a sleeve around the infundibular stalk.

9

How is the nucleus in the CNS different?

Is simply a group of nerve cell bodies

10

Supraoptic and Paraventricular nuclei

produce ADH and oxytocin which are carrier via the neurons axons to the pars nervosa of the posterior pituitary. Run in the infundibular stalk.

11

Defining histological feature of pars intermedia?

cysts whose function is unknown (appear clear on the slide). Cells look basophilic like they are filled with granules. Thin section.

12

Histology of pars nervosa?

Looks like a much lighter pink, looser organization. Axons are unmyelinated and carry ADH and oxytocin to be stored in the terminal axons in the nervosa. Axon terminals end on the fenestrated capillaries without diaphragms which carry the hormones to the rest of the body. See lots of nuclei (glial cells aka pituicytes) nerve cell bodies are in the hypothalamus.

13

Cells types of the pars distalis?

chromophils (basophil and acidophil) and chromophobes

14

Basophil

Dark blue staining. Secretes a single hormone and are arranged in cords, surrounded by thin layer of CT.

15

Acidophil

Pink/red staining. Arranged in cords. Secretes one type of homrone

16

Chromophobes

Are chromophils that are colorless because they have released their hormones and no longer have granules. Is a transient state, will accumulate granules again and become stained.

17

2 types of acidophils?

Growth Hormone (GH or Somatoropin- involved in growth and fuel metabolism) and prolactin (PRL- involved in mammary gland milk production)

18

4 types of basophils?

1. Thyroid stimulating hormone (TSH)
2. Follicle stimulating hormone (FSH)
3. POMC
4. Luteinizing hormone (LH)

19

How are hormones carried to the pars distalis?

via the hypophyseal portal system--blood supply. Hormones are produced by the hypothalamus and are either releasing or release-inhibiting hormones. This venous portal system allows the hormones to be transported without getting diluted too much.

20

What does the superior hypophyseal artery supply?

- median eminence
- infundiubular stalk
- pars tuberalis

21

What does the inferior hypophyseal artery supply?

pars nervosa

22

Where is the primary and secondary plexus located?

primary plexus- median eminence and infundibulum
secondary plexus- pars distalis

23

What is the hypophyseal portal system composed of?

1. primary plexus
2. portal venules
3. secondary plexus