Ex 4 - Pituitary and Adrenal Glands Flashcards Preview

742 - Biology of Disease III > Ex 4 - Pituitary and Adrenal Glands > Flashcards

Flashcards in Ex 4 - Pituitary and Adrenal Glands Deck (20):
1

What are hormones comprised of?

Proteins, aa derivatives, or steroids

2

Describe hormone release

1. Immediate release (preformed substrate)

2. Stimulation of synthesis and delayed release

3

Describe hormones as controlling elements

The hormone that is produced acts as its own negative feedback loop

4

Describe hormones as controlled variables

Secondary hormones feedback to primary endocrine organs to shut down production of 'primary' hormones

5

What bone is poorly formed in the head of the horse?

(allows for compression of the overlying structures)

Sella turcica bone

6

Name 3 regions in the pituitary gland

1. Pars nervosa
2. Pars intermedia
3. Pars distalis

7

What are the 3 cells of the pars distalis?

1. Acidophils
- Prolactin
- Growth hormone (major counter regulatory hormone to insulin)

2. Basophils
- FSH/LH
- TSH
- ACTH

3. Chromophobes
- lack secretory content

8

What is released from the pars intermedia?

Melanocyte-stimulating hormone (MSH)

*important in the dopamine regulatory pathway and pathogenies of equine PPID

9

What are the 3 zones of the adrenal cortex (outer to inner)? and what hormones do each release?

1. Zona glomerulosa = salt
- mineralocorticoids (e.g. aldosterone)

2. Zona fasciculata = sugar
- glucocorticoids (e.g. cortisol)

3. Zona reticularis = sex
- androgens (e.g. DHA)

*Remember GFR = layers

10

What stimulates the release of ADH?

Hyperosmolarity and hypovolemia

11

ADH and Nephrogenic diabetes insipidus

Kidney's don't respond to ADH

Congenital defect

12

Mineralcorticoid regulation (aldosterone)

Release stimulated by falling or rising BP and high K+

Promotes salt retention and promotes RAAS activation

13

What is the primary function of Gucocorticoids?

induce hepatic gluconeogenesis

- inhibits glucose uptake and metabolism in peripheral tissues
- synergies with glucagon actions
- directly increases lipolysis and redistributes fats

14

What are some other functions of glucocorticoids?

- promotes protein catabolism
- promotes diuresis (increases GFR)
- prevents arachidonic acid metabolism
- surpasses lymphocyte and MO fxn

15

How do animals with glucocorticoid abnormalities present?

1. Pot belly appearance
2. Hepatomegaly
3. PU/PD (ADH is inhibited)
4. Secondary infections (immune system suppressed)

16

Four major mechanisms of Endocrine dz

1. Primary hyperfunction (most common)
- commonly caused by neoplasia

2. Primary hypofunction

3. Secondary hyper function

4. Secondary hypo function
- loss of a trophic stimulus leads to a loss of stimulation/feedback & atrophy
- target tissue is unable to respond to hormone --> endocrine organ works harder --> eventually fails

17

Hyperfunction

Almost always due to some proliferative disease

*neoplasia

18

Hypofunction

Usually a degenerative or hypo plastic process

19

How do we classify lesions?

Proliferative
- hyperplasia
- neoplasia (functional)

Destructive
- hypoplasia
- atrophy
- inflammatory
- neoplasia (non-functional)
- degenerative

20

Key points - mechanisms of endocrine dz

1. Since hormones often have multiple fxns, secondary lesions in distant organs is common

2. There are key clinical/pathologic features that should suggest a particular endocrine disease.

3. Neoplasia is a common process causing endocrine disease

4. Other neuro manifestations may be present with primary disease of the pituitary