Endocrine Glands - Histo Flashcards
Type of secretion which involves in localized dispersal or through short loops of blood vessels
Paracrine
Type of secretion in which a signaling molecule remains on the secreting cell’s surface or adjacent extracellular matrix and affects the target cells when the cells make contact
Juxtacrine
Type pf secretion where cells may produce molecules that act on themselves or on cells of the same type
Autocrine
Cells that exhibit paracrine secretion
G cells
Cells that exhibit autocrine secretion
IGF
This signaling is particularly important in embryonic and regenerative tissue interactions
Juxtacrine
Hormones that can diffuse through the cell membrane and activate cytoplasmic receptors in target cells
Steroids and Thyroid Hormones
Weight and dimension of pituitary gland
0.5 g and 10x13x6mm
What part of the skull does pituitary gland lies?
Sphenoid bone - sella turcica
Its oral component arises from tge outpocketing of the ectoderm
Adenohypophysis
Part of pituitary that has neural component
Neurohypophysis
What part of pituitary rathke’s pouch develops?
Anterior part
What are the part of neurohypophysis?
- pars nervosa
- infundibulum
What are the parts of adenohypophysis?
- pars distalis
- para tuberalis
- pars intermedia
What part of adenohypophysis wraps around the infundibulum?
Pars tuberalis
What part of adenohypophysis adjacent to pars nervosa?
Pars inyermedia
A bundle of axons that courses into the neurohypophysis from two important hypothalamic nuclei
Hypothalamic-hypophyseal tract
What nuclei is responsible for the synthesis of ADH and oxytocin?
Supraoptic and paraventricular nuclei
Blood supply of median eminence and infundibular stalk?
Superior hypophyseal arteries
Main blood supply of neurohypohysis
Inferior hypophyseal arteries *from internal carotid artery
Has great importance because it carries neuropeptides from the median eminence the short distance to the adenohypophysis where they either stimulate or inhibit hormone release by endocrine cells
Hypothalamic-hypophyseal portal system
It accounts for 75% of adenohypophysis and has thin fibrous capsule
Pars distalis
These are secretory cells in which hormone is stored in cytoplasmic granules
Chromophils
What hormones does acidophils secrete?
- GH
- PRL
What hormones are the least and most abundant in pars distalis?
Least - thyrotrophs
Most - somatotrophs
What hormones does basophils secrete?
FLAT
What is the main protein does corticotrophs secrete?
POMC
Type of cell that stains weakly, with few or no secretory granules, and also represent a heterogenous group, including stem and undifferentiated progenitor cells as well as any degranulated cells
Chromophobes
What hormones does pars tuberalis secretes?
Gonadotrophs
A thin zone of basophilic cells between the pars distalis and the pars nervosa of the neurohypophysis
Pars intermedia
A smaller funnel-shaped region surrounding the infundibulum of the neurohypophysis, which is often invaded by basophils
Pars tuberalis
What ate the hormones does corticotrophs secrete?
ACTH and B LPH (lipotropin)
During fetal life, this part of adenohypophysis also express POMC
pars intermedia
Developed from the dorsal wall of the hypophyseal pouch and usually contains fluid-filled cysts of various sizes
Para intermedia
Cleaves by different peoteases to produce smaller peptide hormones
POMC
A polypeptide produced mainly by the gastric mucosa which also acts as a releasing hormone for somatotropin and oxytocin (also prolactin)
Ghrelin
Highly branched glial cells that resemble astrocytes and are most abundant cell type in the posterior pituitary
Pituicytes
It is an axonal dilation where ADH and oxytocin accumulate
Herring body
Chemical form of TRH
3 amino acid peptide
Aka modified amino acid
Dopamine
Aka 41 amino acid polypeptide
CRH
Aka 14 amino acid peptide
Somatostatin
Aka 10 amino acid peptide
GnRH
Wt. of adrenal medulla
8 g
Part of adrenal gland that mesoderm and the other from the neural crest
Mesoderm - cortex
Neural crest - medulla
Immediately inside the capsule and comprising 15% of the cortex, consist of closely packed rounded or arched cords of columnar pyramidal cells with many capillaries
Zona glomerulosa
Comprise about 10% of the cortex and consists of smaller cells in a network of irregular cords interspersed with wide capillaries
Zona reticularis
Occupies 65 to 80% of the cortex and consist of long cords of large polyhedral cells, one or two cells thick, separated by fenestrated sinusoidal capillaries
Zona fasciculata
Composed of large, pale-staining polyhedral cells arranged in cords or clumps and supported by a reticular fiber network
Adrenal medulla
A medullary parenchymal cells that arise from neural crest cells
Chromaffin cells
Cells that can be considered as modified sympathetic postganglionic neurons, lacking axons and dendrites and specialized as secretory cells
Chromaffin cells
Storage site of cathecolamines, ATP and calcium
Chromogranins
Collections of catechilamone-secreting cells adjacent to the autonomic ganglia
Paraganglia
Cells that ate innervated by cholinergic endings of preganglionic sympathetic neurons which trigger hormone release
Medullary chromaffin cells
