EX3 Histology - Endocrine System Flashcards
This type of gland secretes onto a surface; either directly or through a duct
exocrine
This type of gland secretes internally; ductless glands; secretes hormones; primarily uses cardiovascular system for distribution
endocrine
What are the two types of hormones
circulating hormones
local hormones
What are the two types of local hormones
paracrine
autocrine
In this type of feedback; the more I produce the less I do
negative feedback
This is the main visceral control center for the body “command center for the endocrine system”
hypothalmas
The hypothalmus regulated what
body temperature food intake water balance/thirst sleep/wake cycles sexual behavior endocrine functioning
What is the hypothalmus vital for maintaining
homeostasis
The hypothalms is a major link between what two systems
endocrine and nervous
The hypothalmus produces how many hormones
9; 7 anterior and 2 posterior which affect the anterior pituitary
How is the hypothalmus and pituitary gland connected
via the infundibulum
This is known as the “master gland for the endocrine system”
pituitary gland (hypophysis)
What are the three parts of the anterior pituitary
pars distalis
pars intermedia
pars tuberalis
this is the bulk of the anterior pituitary; cords of epithelial cells interspersed with fenestrated capillaries
pars distalis
This surrounds a series of colloid filled follicles that represent the residual lumen of rathke’s pouch
pars intermedia
This forms a collar or sheath around the infundibulum
pars tuberalis
This part of the anterior pituitary develops from the anterior wall of Rathke’s pouch
pars distalis
This part of the anterior pituitary develops from the thin remnant of posterior wall of Rathke’s pouch
pars intermedia
This part of the anterior pituitary develops from the thickened lateral walls of Rathke’s pouch
pars tuberalis
In which part of the anterior pituitary would you find basophilic gonadotrophic cells
pars tuberalis
What are the two parts of the posterior pituitary gland
pars nervosa
infundibulum
This is the part of the posterior pituitary where the neurosecretory axons and their endings lie
pars nervosa
This is the part of the posterior pituitary containing neurosecretory axons formed the hypothalamo-hypophyseal tract
infundibulum
What is the embryological origin of the pituitary
oral ectoderm outpocketing (Rathke’s pouch)
What is the embryological origin of the infudibulum
closing in of the lateral walls of the neurohypophyseal busd
The anterior lobe of the pituitary develops from where
the roof of the mouth
Regulating hormones acting upon the anterior lobe of the pituitary reach the anterior lobe via which system
hypothalamo-hpophyseal portal system
What are the four steps in the control of the anterior pituitary via the hypothalams
- neurosecretory neurons in the hypothalamus synthesize the hypothalamic releasing and inhibitory hormones in their cell body
- These hypothalmic hormones travel down the axon to the terminals and exit via exocytosis
- They diffuse into the hypophyseal portal system at primary plexus of hypophyseal portal system (fenestrated capillaries)
- Then pass from primary plexus to hypophyseal portal veins into secondary plexus bringing the hormones directly to the pars distalis
What are the two groups of secretory cells in the pars distalis
chromophils
chromophobes
What are the two types of chromophils
basophils
acidophils
In this type of cell, the hormone is stored in cytoplasmic granules
chromophils
This type of cell are undifferentiated stem-like cells and are clear
chromophobes
Gonadotropic, corticotropic, and thyrotropic cells are all what type of secretory cell
basophils
Somatotropic and mammotropic cells are what type of secretory cell
acidophils
This is an acidophil secreted by somatotrophs
human-growth-hormone (hGH)
This is a basophil secreted by thyrotrophs
thyroid-stimulating hormone (TSH)
These are basophils secreted by gonadtrophs
follicle-stimulaing hormone (FSH) luteinizing hormone (LH)
This is an acidophil secreted by lactrotrophs
prolactin (PRL)
These are basophils secreted by corticotrophs
adrenocorticotrphic hormone (ACTH) melanocyte-stimulating hormone (MSH)
50% of what are chromophobes
pars distalis
This is the growth hormone-inhibiting hormone, secreted by somatotrophs and thyrotrophs
somatostatin
Corticotrophs and lactotrophs secrete this inhibitory hormone
dopamine
Prolactin acts upon which “organ”
mammary glands and testes
adrenocorticotropic hormone acts upon this organ
adrenal cortex
growth hormone acts upon which organs
body tissues BONE muscle adipose *liver; insulin-like growth factor
follicle stimulating hormone acts upon this organ
gonads (testes and ovaries)
melanocyte-stimulating hormone acts upon this “organ”
melanocytes in the epidermis
True or False
The posterior pituitary does not synthesize hormones, but rather stores and releases two of them
True
What is the main component of the posterior pituitary
pars nervosa
This contains the axons and axon terminals of hypothalamic neurosecretory neurons, along with fibroblasts, mast cells, and pituicytes
pars nervosa
These are a type of glial cells, resembling the actrocyte that associates with fenestrated capillaries; many branches and pigmented vesicles, round/oval nuclei
pituicytes
What are the two hormones that are released from the posterior pituitary
ocytocin antidiuretic hormone (vasopressin)
Where is oxytocin and antidiuretic hormone synthezised
within the cell bodies of the neurosecretory neurons in the hypothalamus
What type of cells are the hormones stored in, prior to secretion, in the posterior pituitary in the avon terminal
Herring bodies (neurosecretory bodies)
This hormone stimulated the contraction of smooth muscle cells during childbirth and in milk ejection
oxytocin
This hormone conserved body water
antidiuretic hormone
What are the two parts of the adrenal gland
cortex
medulla
This part of the adrenal gland makes up 80-90% of the gland and the steroid secreting cells
cortex
This part of the adrenal gland is centrally located and contains catecholamine-secreting cells
medulla
What are the three regions of the adrenal cortex
zona glomerulosa
zona fasciculata
zona reticularis
This region of the adrenal cortex secretes androgens; dehydroepiandrosterone (DHEA)
zona reticularis
This region of the adrenal cortex secretes mineralocorticoid hormones; aldosterone
zona glomerulosa
This region of the adrenal cortex secretes glucocorticoid hormones; cortisol
zona fasciculata
This region of the adrenal gland secretes catecholamines; epinephrine and norepinephrine
adrenal medulla
This is a modified sympathetic ganglion of the ANS, with modified neurons (chromaffin cells) which cluster around blood vessels
adrenal medulla
chromaffin cells are controlled by what
sympathetic preganglionic neurons, which allow for release of hormones via exocytosis
This component of the pancreas synthesizes and secretes hormones
islets of Langerhans (endocrine)
Where do you find the islets of Langerhans in the pancreas
throughout but most numerous in the tail
What are the three principle cells of the islets of Langerhans
Beta (B)
Alpha (A)
Delta (D)
These cells make of 70% of the islet, synthesize and secrete insulin, found in the center of the islet
beta cells
These cells make 17% of the islet, synthesize and secrete glucagon, found in the periphery of the islet
alpha cells
These cells make up 7% of the islet, synthesize and secrete somatostatin, found towards the periphery of the islet
delta cells
This lowers blood glucose level as it signals for an acceleration of glucose transport into cells and the conversion of the glucose into glycogen
insulin
This raises blood glucose level as it signals for the breakdown of glycogen into glucose in the liver
glucagon
This inhibits insulin and glucagon secretion
somatostatin
These cells secrete pancreatic polypeptide, located near duodenum
F cells
Thyroid hormones are produced by what type of thyroid gland cell
thyroid follicles (follicular cells) filled with a gel-like mass of thyroglobulin
What are the thyroid hormones
thyroxine
tri-idothyronine
What are the thyroid hormones important for
growth, cell differentiation, and control of metabolic rate and oxygen consumption of body cells
These cells are ground in the thyroid gland and responsible for the production of calcitonin (CT)
parafollicular cells
Calcitonin works to do what
decrease the level of calcium in the blood by building bone and inhibiting osteoclasts
This system controls the secretion of calcitonin and parathyroid hormone
negative feedback;
high blood calcium stimulates secretion of calcitonin inhibits PTH
What are the two types of cells in the parathyroid gland
chief cells
oxyphil cells
These cells produce parathyroid hormone, small, numerous cells, slightly acidic
chief cells
These cells have an unknown function, very acidiophilic cytoplasm, common in old people
oxyphil cells
Parathyroid hormone works to do what
increase the level of calcium in the blood by stimulating osteoclases to resorb bone which releases calcium