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Fall-Foundational Sciences Year 1 > Endocrine I and II > Flashcards

Endocrine I and II Flashcards

1
Q

hypothalamus

neurosecretory cell pathway

A

produce nuerosecretory hormones >

anterior glandular lobe of pituitary gland via primary and secondary fenestrated capillary plexus + hypophyseal portal veins

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2
Q

neurosecretory products

A

SRH/GHRH
TRH
CRH
GnRH

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3
Q

anterior lobe contains

A

chromophils (acid/basophils) + chromophobes

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4
Q

acidophils

A

somatotrophs + lactotrophs (mammotrophs)

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5
Q

somatotrophs

A

stimulated by SRH/GHRH
inhibited by somatostatin

release somatotropin (growth hormone)

excessive GH in KIDS=gigantism from somatotrophic adenoma/tumor
in ADULTS=acromegaly (enlarged face, jaw, tongue, hands, feet, organs)

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6
Q

lactotrophs

aka mammotrophs

A

stimulated by PRH and TRH
inhibited by dopamine

release prolactin (for mammary glands when pregnant)

prolactinoma most common benign pituitary tumor

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7
Q

basophils

A

corticotrophs + thyrotrophs + gonadotrophs

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8
Q

corticotrophs

A

stimulated by CRH

release ACTH precursor > adrenal cortex > cortisol and corticosterone

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9
Q

thyrotrophs

A

stimulated by T-RH

release TSH (thyrotropin) >thyroid>T3T4

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10
Q

gonadotrophs

A

stimulated by GnRH

release FSH and LH > ovary and testis

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11
Q

hypothalamohypophyseal tract

A

supraoptic and paraventricular nuclei of hypothalamus

have cell bodies of neurosecretory neurons > axons make up tract > terminates in posterior lobe/neural of pituitary gland

axons and terminals have vasopressin (ADH) and oxytocin

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12
Q

posterior lobe contains

A
  1. herring bodies (granules of ADH or oxytocin)
  2. pituicytes (glia-like support cells)
  3. fenestrated capillaries

ADH = yellow urine, oxytocin = contractions in childbirth

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13
Q

thyroid gland produces

A
  1. T3 (triiodothyronine) - follicular cells
  2. T4 (tetraiodothyronine)- follicular cells
    -both reg cell/tissue metabolism and heat production
  3. calcitonin- parafollicular cells
    -reg blood calcium levels
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14
Q

T3 and T4 production

A

T4 only from follicular cells in 20:1 ratio, T3 x5 more potent than T4

T3 converted from T4 by heart, liver, kidneys

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15
Q

thyroid hormone synthesis

A
  1. follicular cells syn thyroglobulin (glycoprotein) w/ 120 tyrosine residues
  2. release into follicular lumen
  3. iodide (inactive) from bloodstream pumped into follicular cells
  4. iodide oxidized on apical membrane/colloid facing side into iodine (active) and stays there
  5. iodine iodinates tyrosine residues = MIT + DIT
  6. MIT + DIT = triodinated thyronine
  7. DIT + DIT = tetraiodinated thyronine
  8. follicular cells uptake colloid from lumen
  9. proteases cleave iodinated tyrosine residues from thyroglobulin into cell cytoplasm = uncoupled MIT + uncoupled DIT + T3 + T4
  10. thyroid hormones (inactive) released from basal aspect into extracellular space
  11. fenestrated capillary network
  12. general circulation
  13. activated in target tissues and organs

lysosomal pathway, main

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16
Q

exocrine glands vs endocrine glands

A

exocrine = products released into ducts

endocrine = products/hormones released into extracellular space > bloodstream > organs

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17
Q

hypothalamus

A

nucleus in the brain

coordinates endocrine functions and integrates endocrine/ANS functions

has neurons = neurotransmitters AND
neurosecretory cells = hormones

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18
Q

neurosecretory hormone pathway

general

A
  1. syn in hypothalamus
  2. transported to axon terminals
  3. released into ECS
  4. pass into primary capillary plexus
  5. flow into hypophyseal portal veins
  6. secondary capillary plexus (sinusoidal) @anterior pituitary
  7. parenchyma of anterior pit to influence basophils/eosinophils
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19
Q

thyroid gland

general structure

A

R lobe + isthmus (bridge) + L lobe + pyramidal lobe

surrounded by capsule of dense irreg/coll CT from deep cervical fascia

trabeculae/septa- partion into lobules and carry vessels and nerves into gland

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20
Q

parathyroid glands

A

4 @ thyroid capsule on posterior surface of thyroid gland

21
Q

thyroid follicles

A

follicle is basic structural/functional unit of thyroid gland

spherical cyst like + lumen w/ colloid and thyroglobulin

22
Q

thyroid follicle histology

A

simple squamous = low level activity
simple cuboidal = normal activity
simple columnar = highly active

surrounded by basal lamina + reticular fibers + fenestrated capillary plexus

23
Q

parafollicular cells

A

from neural crest

b/t follicles so not exposed to colloid @ basal lamina near capillaries

syn calcitonin and store it in granules

24
Q

calcitonin

A

released when blood calcium levels elevated

lowers blood Ca levels to normal via inhibiting osteoclasts AND promote Ca deposition in bones

25
thyroglobulin synthesis
follicular cells syn in RER when activated by TSH glycosylation in RER and Golgi released into lumen via exocytosis
26
iodine pathway | thyroid hormone synthesis
1. iodine from diet > reduced to iodide in GI 2. bloodstream 3. pumped into follicular cells via sodium/iodide symporters 4. diffuses to apical cell membrane 5. iodide ions pumped into lumen via iodide/chloride transporter (pendrin) 6. thyroid peroxidase oxidizes iodide into iodine 7. thyroid peroxidase catalyzes iodination of thyroglobulin
27
thyroglobulin processing pathways
TSH binds @basal > filopodia form @luminal surface = endocytosis 1. lysosomal pathway 2. transepithelial pathway
28
transepithelial pathway
1. thyroglobulin binds megalin (TMP on apical membrane facing colloid) 2. evades lysosomes and transported to basolateral membrane 3. released into blood as T3T4 still bound to thyroglobulin
29
physiological effects T3T4
inc: cell metabolism, growth rate, mental activity, fatty acid syn stimulate: endocrine gland function, carb metabolism dec: formation of phospholipids, triglycerides, cholesterol
30
increase thyroid hormone
dec body weight inc heart rate, metabolism, respiration, muscle function, appetite | high levels = tremors, fatigue, impotence, menstrual irregularities
31
hyperthyroidism
aka toxic goiter or graves disease autoantibodies bind to TSH receptors = inc colloid uptake = xs thyroid hormones in circulation exophthalmos (bulging eyes from fibrosis of rectus muscles and acc of loose CT behind eyeball) and enlarged thyroid
32
cell types in parathyroid glands
1. principal- syn/store/release PTH 2. oxyphil- inactive principal/chief cells, don't know function 3. intermediate- inactive, don't know function
33
PTH
regulates calcium and phosphate levels in blood and ECF -influences bone, kidneys, GI inc blood calcium levels to normal if low serum -high serum Ca inhibits PTH | calcitonin is opposite
34
islets of langerhans cell types | pancreas
in endocrine portion 1. alpha = glucagon (inc blood glucose) 2. beta = insulin (dec blood glucose) and amylin (inhibit stomach emptying/glucagon release) 3. delta = D (somatostatin-reduce smooth muscle contractions of dig tract) or D1 (vasoactive intestinal peptide- induce glycogenolysis, control smooth muscle tonus and contraction of GI) 4. epsilon= ghrelin (induce hunger sensation) 5. PP = pancreatic polypeptide (inhibit digestive juices) 6. also gastrin by 1+ cells (stim HCl by parietal cells in stomach mucosa)
35
exocrine portion pancreas
acini + duct system produces digestive enzymes
36
suprarenal cortex zones
1. zonal glomerulosa- outer, **mineralcorticoids** (aldosterone main + deoxycorticosterone) -activate by ACTH and angiotensin II 2. zona fasciculata- middle/largest layer, **glucocorticoids** (cortisol + corticosterone) 3. zona reticularis- inner, weak **androgens** (DHEA, androstenedione, glucocorticoids)
37
suprarenal cortex zones | histology
1. zonal glomerulosa- cells in cords and clusters 2. zona fasciculata- cells in radial columns w/ capillaries running b/t 3. zona reticularis- anastomosing cords w/ lipofuscin
38
suprarenal medulla
from neural crest, sympathetics has chromaffin cells = epinephrine and norepinephrine (catecholamines) | release Ach
39
PTH synthesis
1. ribosomes on RER syn preproparathyroid hormone 2. @RER lumen = proparathyroid hormone + polypeptide 3. @Golgi lumen = parathyroid hormone (PTH) + polypeptide 4. stored in secretory granules
40
PTH in bone
1.binds osteoblast receptors (prolonged) 2.osteoblasts release osteoclast stimulating factor = triggers osteoclasts to breakdown and free Ca and P from bone or if intermittent = anabolic effect so inc bone mass to treat osteoporosis
41
PTH in kidneys
conserves Ca promotes activation of vitamin D
42
PTH in GI
regulates rate of Ca absorption from GI (directly) and activation of vitamin D (indirect in kidney) vitamin D facilitates Ca absorption in GI more great than PTH effect
43
thyroidectomy
complete removal of parathyroid glands = drop Ca levels tetanic contraction of muscles (laryngeal and respiratory) = death
44
tetany
hypoparathyroidism > hypocalcemia = tetany neuromuscular irritability, spontaneous twitching, numbness, tingling
45
urinary tract stones
from hyperparathyroidism > osteoclasts erode bone = hypercalcemia stones and calcification of lungs, myocardium, stomach, blood vessels
46
Diabetes Mellitus
hyperglycemic metabolic disorder from 1. beta cells not produce insulin 2. defective insulin receptors on targets
47
Type I Diabetes
insulin-dependent juvenile onset autoantibodies cause islets to atrophy and fibrotic, not enough insulin produces signs: polydipsia (thirst), polyphagia (eating), polyuria (urination)
48
Type II Diabetes
non insulin-dependent most common over 40 yr old
49
Cushing Syndrome
small tumors of basophils in anterior pituitary gland = excess ACTH suprarenal cortex overstimulated = excess cortisol obesity in face, neck, trunk, impotence (males) amenorrhea (females)

Fall-Foundational Sciences Year 1 (33 decks)

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