Endocrine System 1: Pituitary, Pineal, Thyroid, & Parathyroid Flashcards
How does the endocrine system communicate?
- chemical messengers (hormone)
- carried by bloodstream
Endocrine organs are composed of
secretory cells of epithelial origin
Endocrine lack
DUCTS
Endocrine vs nervous control
endocrine is slower onset & longer duration
Hypothalamus
coordinates endocrine functions of body
acts as intermediary between autonomic nervous system & endocrine system
Most endocrine glands form
discreet organs
Anterior pituitary, pineal, thyroid and suprarenal (adrenal)
In the pancreaus
endocrine & exocrine tissue intermixe
Pituitary (hypophysis) is suspended by
a stalk from hypothalamus
The pituitary rest in the
sella turcica of the sphenoid bone
posterior to he optic chiasm (CN II)
WHat are the two major divisons of the Pituitary?
- Adenohypophysis (Anterior pituitary)
- Neurohypophysis (Posterior pituitary)
Secretion of pituitary hormones is conrolled by
hypothlamus
hypophyseal portal system allows
communication with hypothalamus
pititary
How does the Hypothalamus controls secretion of
anterior pituitary
hypothalamic regulating factors (hormone
Releasing factors stimulate
secretion
inhibitory factors inhibit
secretion
Direct acting hormones have
non-endocrine target organ
What are examples of direct acting hormones?
GH, ADH, MSH, oxytocin, prolactin
Trophic hormones
target organ is another endocrine gland
What are examples of trophic hormones?
TSH, ACTH, FSH, and LH
What are pituitary-dependent endocrine glands?
Thyroid gland, adrenal cortex, & gonads
Anterior portion of the pituitary contains
glandular epithelial tissue
posterior of the pituitary contains
neural secretory tissue
Anterior pituitary =
- “Master gland”
- adenohypophysis
- pars anterior
- pars distalis
Rathke’s pouch is
Specialized glandular tissue, arises from evagination of tissue from oral cavity in region of pharynx
What are the 3 regions of Rathke’s Pouch
- pars distalis
- pars intermedia
- pars tuberalis
pars distallis
bulk of anterior pituitary
What part of the pituitary is the Rathke’s Pouch?
anterior pituitary
pars intermedia
- thin layer between anterior & posterior pituitary
- Secretes MSH & ACTH
- Frequently contains cystic remnants of Rathke’s pouch
What secretes MSH and ACTH?
pars intermedia
pars tuberalis
- extension of anterior pituitary
- forms collar ~pituitary stalk (=infundibulum)
Pars distalis secretes
bulk of pituitary hormones, including both direct acting & trophic
hormones
What direct acting hormones does the pars distalis secrete
GH and prolactin
What trophic acting hormones does the pars distalis secrete
TSH, ACTH, FSH, LH
Secretory cells of anterior that stian
chromophils
Secretory cells of anterior that do not stain
chromophobes
what are the two types of chromophils
- Acidophils
- Basophils
chromophils -Acidophils
- stain with acidic dye
- pink on H&E
chromophils- Basophils
- stain with basic dye
- pale blue to light purple on H&E
Chromophobes are
- small cells
- don’t take up either dye
- clear on H&E
- represent inactive cells
What are the types of Acidophils?
*Somatotrophs
* Mammotrophs
Somatotrophs
secrete Growth Hormone (somatotropin)
What secrete growth hormones
Somatotrophs
is an Acidophils which is a subtype of chromophils
Somatotrophs make up
50% of cells
Mammotrophs secrete
prolactin
What secretes prolactin?
Mammotrophs
is an Acidophils which is a subtype of chromophils
Mammotrophs make up
20% of cells
Somatostatin inhibits
somatotropin
growth hormone hormone
ghrelin
- stomach enteroendocrine cells
- coordinates food intake with GH secretion