Endocrine System Histology Flashcards
Where do exocrine glands secrete hormones?
Onto a surface, either directly or through a duct
Where do endocrine glands secrete their hormones?
Internally, ductless glands; utilize the cardiovascular system primarily for distribution
What are the two types of hormones?
Circulating and local
What are the two kinds of local hormones?
Paracrine and autocrine
What do paracrine excreted hormones end up interacting with?
nearby target cells
What do autocrine excreted hormones end up interacting with?
The same cell that secreted the hormone
What is the main role of the hypothalamus?
Main visceral control center for the body; the autonomic control center
What does the hypothalamus regulate? (6)
Body temperature, food intake, water balance/thirst, sleep-wake cycles, sexual behavior, and endocrine system functioning
The hypothalamus’s influence is vital to the body maintaining what?
Homeostasis
The hypothalamus is a major link between what two body systems?
The nervous system and the endocrine system
the hypothalamus is also called the command center for what?
The endocrine system
The hypothalamus secrets how many hormones?
9 hormones
The hypothalamus is connected to the pituitary gland via what?
The infundibulum
The pituitary gland is as the _______ gland of the endocrine system.
Master gland
The pituitary and the hypothalamus together regulate what?
Virtually all aspects of growth, development, metabolism, and homeostasis
The pituitary gland is also known as what?
Hypophysis
The pituitary gland sits in what?
The hypophyseal fossa within the sella turcica of sphenoid bone
What are the two significant parts of the pituitary gland?
The anterior lobe, (anterior pituitary, adenohypophysis) and the posterior pituitary (posterior lobe, neurohypophysis)
What are the three parts of the anterior pituitary?
Pars distalis, pars intermedia, pars tuberalis
Describe the pars distalis.
Bulk of anterior lobe of pituitary gland, cords of epithelial cells interspersed with fenestrated capillaries; develops from anterior wall of Rathke’s pouch
Describe the pars intermedia.
Thin remnant of posterior wall of Rathke’s pouch; next to pars distalis; the pars intermedia surrounds a series of colloid-filled follicles that represent the residual lumen of Rathke’s pouch
Describe the pars tuberalis.
From thickened lateral walls of Rathke’s pouch; forms a collar or sheath around infundibulum
Most cells around the pars tuberalis are what?
Basophilic gonadotropic cells
What are the two parts of the posterior pituitary?
Pars nervosa and infundibulum
Describe the pars nervosa.
Neurosecratory axons and their endings
Describe the infundibulum.
Contains neurosecratory axons forming the hypothalamo-hypophyseal tracts
The pituitary gland is derived in part from what two things?
An outpocketing of the ectoderm lining the roof the the mouth called the hypophyseal (Rathke’s) pouch and in part from an outpocketing of the neuroectoderm lining the floor of the hypothalamus called the neurohypophyseal bud
The anterior lobe develops from what?
The roof of the mouth (Rathke’s pouch)
The anterior pituitary is stimulated by what? (generally)
Releasing hormones (five of these)
The anterior pituitary is inhibited by what? (generally)
Inhibiting hormones (2) and negative feed back
How do the regulating hormones from the hypothalamus reach the anterior lobe of the pituitary?
The hypothalamo-hypophyseal portal system
What is the primary plexus of the hypothyseal portal system?
This is where the hypothalamic hormones secreted from the axon terminals will diffuse into the hypothyseal portal system
The hormones that enter the primary plexus of the hypophyseal portal system will eventually end up where?
In the cells of the pars distalis
There are what two cells in the pars distalis based on staining affinity and what volume do they contribute?
Chromophils and chromophobes (each contribute 50% total volume)
What are the two types of chromophils and what percent do they contribute to the total percent in the pars distalis?
Basophils (10%) and acidophils (40%)