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Endocrine System
Endocrine System
92
Biology
Professional
05/04/2012

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Term
All endocrine cells are ____ cells. The glands (have/don't have) ducts. The glands lie in a ________.
Definition
-Epithelial
-Don't have
-Large vascular bed
Term
What are the 2 types of specialized capillaries? What do they do?
Definition
-Fenstrated capillary w/ diaphragm, Sinusoidal capillary
-Allows leakiness and permeability
-SC gave no tight junctions or BMs
-SC are lined with non-phagocytic fixed macrophages
Term
What do the cells look like that secrete modified amino acids? What are some examples?
Definition
Eosinophilic non-granular cytoplasm
Epi, norepi, thyroid hormones
Term
What do the cells look like that secrete pure polypeptides/proteins?
Definition
Serous cells with granular cytoplasm
Term
What do the cells look like that secrete glycoproteins
Definition
Serous cells with granular cytoplasm, hormones are glycosylated
Term
What do the cells look like that secrete steroids?
Definition
Large SER, foamy eosinophilic non-granular cytoplasm
Term
What is the difference between endocrine, paracrine, and autocrine factors?
Definition
Endo- travels through blood, effect far
Para-spreads through CT matrix, effect close by on different tissue
Auto-receptor on same gland, effect on same type of tissue
Term
How does a ligand-gated channel work?
Definition
Receptor binds
Ca+ gates open
Ca+ influx
Activates protein kinases
Term
A transmembrane receptor an example of what type of receptor?
Definition
Enzymatic, catalytic
Term
What happens when a Gs hormone binds?
Definition
Cleaves GTP
Activates Adenylyl Cyclase
Inc cAMP
Activates protein kinases
Term
What happens when a Gi hormone binds?
Definition
Cleaves GTP
Inactivates adenylyl cyclase
Dec cAMP
Inactivates protein kinases
Term
What happens when a Gp hormone binds?
Definition
Cleaves GTP
Activation of Phospholipase-C
Splits membrane phospholipids
(other stuff)
Inc cGMP
Activates protein kinases
Term
What are the 4 parts that Rathke's pouch develops into?
Definition
Pars Tuberalis-wrapped around infund.
Pars Distalis-anterior, swells
Pars Intermedia-didn't grow
Residual lumen
Term
What does the infundibulum develop into?
Definition
Neural stalk-outpocking growing down
Pars Nervosa-swollen bulbous part
Term
Hypertrophy of the pituitary may cause what?
Definition
Visual impairments - sits very close to optic chiasm
Term
What makes up the anterior and posterior lobes of the pituitary? What about the stalk?
Definition
Ant = Pars distalis
Post = Pars nervosa, Pars Intermedia
Stalk = Pars tuberalis, Neural stalk
Term
What does adenohyphsis and neurohypohysis associate with?
Definition
Adeno - from Rathke's pouch: Pars Intermedia, Pars tuberalis, Pars distalis

Neuro-from infundibulum : Neural stalk and pars nervosa
Term
What is the only organ where you'll find both fenestrated and sinusoidal capillaries?
Definition
Pituitary gland
Term
What is the only organ where you'll find both fenestrated and sinusoidal capillaries?
Definition
Pituitary gland
Term
Where do the capillaries that nourish the gland originate from? What about those that transport hormones?
Definition
Nourish - from Circle of Willis
Transport - from Hypothalamus
Term
Where are the interconnecing veins between the 2 capillary beds of the pituitary located?
Definition
Pars tuberalis
Term
Where is the 1st capillary bed of the pituitary located and which type of capillaries?
Definition
Hypothalamus, fenestrated
Term
Where is the 2nd capillary bed of the pituitary located and which type of capillaries?
Definition
Pars distalis, sinusoidal
Term
What are the 2 types of cells in the pars distalis?
Definition
Chromophobes and Chromophiles
Term
Which cells in the pars distalis are inactive/don't produce horomes, and are reserve cells until activated?
Definition
Chromophobes
Term
How many different chromophile cells are there? How many stain?
Definition
7 types for 7 hormones
-only 2 different stain, red (3/4)and blue (1/4)
Term
What do acidophile cells looks like?
Definition
Polyhedral
Larger than chromophobes, smaller than basophiles
Cluster in center of pars distalis
Eosinophilic serous granules @ top
Term
What do mammotroph cells produce? What type of cell are they?
Definition
Prolactin
Acidophile
Term
What do Somatotroph cells produce? What type of cell are they?
Definition
Somatotropin/GH
Acidophile
Term
How do mammotroph and somatotroph cell appearances differ?
Definition
Mammo-large irregular granules, stains with erthrosin

Soma-smaller regular granules, stains with orange-g
Term
What is the function of prolactin?
Definition
-Induce breasts to produce milk (not secrete)
-Mitogenic for ova and sperm
-Maternal behavioral patterns
Term
Where do somatostatins come from?
Definition
Delta cells of pancreas
Term
What do somatomedins do?
Definition
Amplify the effect of GH
Term
Under-production of GH affects what?
Definition
Growth of long bones but not really flat bones - normal trunk with small limbs, different from midget
Term
Tumor of the somatotroph cells leads to what?
Definition
Acromegaly - plate have already fused, height not affected but has extra bone deposition
Term
Which cells are the largest of the pars distalis?
Definition
Basophiles - more irregular and oval than acidophiles
Term
Where do basophiles tend to sit? What do they stain with?
Definition
Cluster together at outer edges of pars distalis
-PAS
Term
What do throtroph cells produce? What type of cell are they?
Definition
TSH
Basophile
Term
What do gonadotroph cells produce? What type of cell are they?
Definition
FSH, LH
Basophile
Term
What do Corticotroph cells produce? What type of cell are they?
Definition
ACTH and MSH
Basophile
Term
How do thyrotroph, gonadotroph, and corticotroph cell appearances differ?
Definition
Thyro-long spindle shape, irregular purple granules
Gonado-Round w/ medium blue granules
Cort-small red granules
Term
What does TSH do?
Definition
Induces production and secretion of thyroid hormones
Term
For normal production of testosterone what hormones must both be present?
Definition
FSH and LH
Term
In women, what do FSH and LH do?
Definition
FSH - induces growth of ovarian follicle
LH - Induces ovulation
Term
What does ACTH do?
Definition
Stimulates adrenal cortex to secrete its steroid hormones
Term
What does MSH do?
Definition
Stumulates melanocytes to produce melanin
Term
What does MSH do?
Definition
Stumulates melanocytes to produce melanin
Term
What is Addison's disease?
Definition
Too much ACTH activity, skin gets darker
-ACTH has some MSH activity
Term
T or F: The cells in the pars tuberalis produce hormones
Definition
False
Term
T or F: The pars intermedia secretes hormones
Definition
False, except in fish amphibians and chameleons where they produce MSH equivalent Intermedin
Term
What type of tissue is in the pars nervosa?
Definition
Grey matter, with unmyelinated nerve fibers in parallel, no cell bodies
Term
What are pitulcytes?
Definition
Large supporting glial cells in the pars nervosa
Term
What are herring bodies? What do they store?
Definition
Dilated endings of golgi-type 1 unmyelinated axons with storage granules in the pars nervosa

-Store hormones produced in hypothalamus
Term
Where is oxytocin produced? What does it do?
Definition
-PVC, some in SON
-Induces smooth muscle contractions for labor and milk secretion
Term
Where is ADH produced? What does it do?
Definition
-SON, some in PVN
-Conserves water and sodium to inc BP
Term
What is the general structure of the thyroid gland? What surrounds it? What holds it in place/supports it?
Definition
-Bi-lobed, connected by isthmus
-Dense irregular fibro-elastic CT
-Superior cervical fascia
Term
What is the stroma of the thyroid gland made of?
Definition
Areolar CT surrounded by fenestrated capillaries
Term
What is the basic functional unit of the thyroid gland? What type of tissue is it?
Definition
-Follicle
-Simple cuboidal on BM
But changes with activity
TSH - columnar
Storage phase - low cuboidal
Term
What does the follicle cells of the thyroid gland produce?
Definition
Thyroglobulin, proteases, iodinases
Term
What do thyroglobulin, proteases, and iodinases do?
Definition
-Thyroglobulin acts as carrier until hormones are needed
-Proteases split them when ready
-Iodinases attach onto thyroid hormone precursors
Term
What is progressive iodinization?
Definition
-Follicle picks up tyrosine
-Converts to Thyronin
-Thyronin gets 1st iodinization
-1st always in cytosol
-T1 released out apical end to colloid
-T1 binds to thyroglobulin
-Gets iodinized 3 more times = T4, remains bound until needed
Term
What is the most potent form of thyroid hormones?
Definition
T3, but T4 controls TSH feedback loop
Term
T or F: Thyroid hormones do not require membrane-bound receptors
Definition
True - they are membrane soluble
Term
How is specificity dictated with thyroid hormones? What does it do?
Definition
NOT receptors
Presence of tetra-iodo-thronin-delodonase
-CONVERTS TO T3
Term
What must thyroid tests test for?
Definition
TSH, T3 and T4
Term
What do parafollicular cells look like, what do they do, and where are they?
Definition
Thyroid gland
Clear cell
Come from endoderm of pharyngeal pouch
Calcium homeostasis
Term
What does the parafollicular cells secrete? When?
Definition
Calcitonin (produce and secrete)
When plasma Ca levels are high
Term
What does calcitonin do?
Definition
Inactivates osteoclasts - inhibit bone resorption
Stimulates osteoblasts - deposit more Ca into bone

*binds to osteoclasts
Term
Which trigeminal layer do follicular cells come from? What about parafollicular cells?
Definition
Mesoderm
Endoderm
Term
What is the basic structure of the parathyroid glands? What are they enclosed by? What's the stroma made of?
Definition
-4 separate lobes, each adhere to posterior of thyroid
-Areolar fibro-elastic CT
-Reticular CT
Term
T or F: Thyroid and parathyroid glands share circulation
Definition
True
Term
What are the 3 types of cells in the parathyroid gland?
Definition
Dark Chief Cells, Pale Chief cells, Oxyphil cells

*chief or principle
Term
How do the dark and pale chief cells of the parathyroid gland differ? What stages are they in?
Definition
Dark-small dark nucleus, has granules, active storage phase

Pale-large light nucleus, no granules, active production phase (making more PTH, it's already been secreted)
Term
What do oxyphil cells look like? What are they?
Definition
-Large clustered cells
-Dark nucleus
-Pink non-granular cytoplasm
"Reserve" cells in inactive phase
Can be activated on demand
Term
What does PTH do? When is it secreted?
Definition
Inactivates osteoblasts
Activates osteoclasts
When low plasma Ca levels
Term
What can decrease skeletal mass?
Definition
Low estrogen
High PTH
High thyroid hormones
High glucocorticoids
Term
Where does the adrenal cortex come from? the medulla?
Definition
Cortex - mesoderm
Medull - ectoderm
Term
What is the adrenal cortex covered by?
Definition
Dense irregular fibro-elastic CT
Term
What are the 3 layers of the adrenal cortex?
Definition
Zona: glomerulosa, fasiculata, reticularis
Term
What does the zona glomerulosa look like and what is it involved in?
Definition
Knots of columnar EP
True fenestrated capillaries
Produces Aldosterone under control of angiotensin II

SALT
Term
What does the zona fasiculata look like and what does it do?
Definition
Single layer of tall-cuboidal EP
Sinusoidal capillaries
Produces glucocorticoids by spongiocytes under control of ACTH

SUGAR
Term
What does the zona reticularis look like and what does it do?
Definition
Networking cords of low-cuboidal EP
Sinusoidal capillaries
Produces sex androgens

SEX
Term
What is the basic structure of the adrenal medulla?
Definition
Golgi type II motor ganglia of ANA synapsing with chromaffin cells
Term
Of the adrenal glands which has venous system which has arterial?
Definition
Cortex - arterial
Medulla - venous
Term
T or F: The adrenal gland is under control of ACTH
Definition
False - NOT medulla, functions as a ganglion, synapses w/ chromaffin cells, then they secrete
Term
What does the adrenal medulla secrete?
Definition
Catecholamines - epi and norepi
Term
What does the pineal gland develop from?
Definition
Epiphysis of the diencephalon
Derived from grey matter of brain but does not have any perikarya
Term
What are pinealocytes involved in?
Definition
Light-dependent metabolism of tryptophan -> serotonin -> melatonin
Term
What occurs in the pineal gland at night? day?
Definition
Night - no light, serotonin dec melatonin inc

Day - Light, serotonin inc, melatonin dec

Get diurnal rhythms
Term
When do melatonin and seratonin peak?
Definition
Melatonin - 11pm to 7am
Seratonin - light hours
Term
How is wakefulness controlled?
Definition
By serotonin
-goes to hypothalamus' SCN's RAS
-Active RAS = you wake up
-Inactive RAS = get sleepy
Term
What happens if you have elevated melatonin chronically?
Definition
Male - Dec FSHRH and LHRH, dec FSH&LH, decreases testosterone (decreased sperm and sex drive)

Female - dec LHRH only, dec estrogens, no ovulation (decreased fertility and sex drive)
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