Lab 8 Endocrine Flashcards
endocrine axis basic pattern
hypothalamus –> pituitary –> gland –> final hormone
posterior pituitary - alternate name and hormones secreted
- neurohypophysis because of neural origin
- ADH and oxytocin storage and release
place where ADH and oxytocin made
- supraoptic nucleus = ADH
- paraventricular nucleus = oxytocin
- both are located in hypothalamus
ADH function, alternate name, and flow
- at high concentrations works as vasoconstrictor = vasopressin
- kidney reabsorb more water
- osmoreceptors in hypothalamus detect rise in osmolality –> ADH released –> kidneys reabsorb more water –> osmolality decreases
oxyotocin function
1) bonding between adults, children, and animals due to receptors in the brain
2) milk ejection from mammary glands
3) uterine contraction and labor
how is ADH and oxytocin brought to the posterior pituitary
hypothalamoi - hypophyseal tract = axon bundle in CNS
trophic hormones definition and affect if there is too much or too little
- trophic = nourishes a gland
- too much = hypertrophy and hyperplasia
- too little = atrophy
list all trophic hormones
- FSH and LH
- prolactin
- growth hormone
- TSH
- ACTH
hypothalamus releasing and inhibiting hormones
- GnRH
- PIH
- GHRH
- TRH
- CRH
hypothalamo-hypophyseal portal system
- brings releasing / inhibiting hormones from primary capillaries in hypothalamus to anterior pituitary
negative feedback of endocrine system
- end hormones made by glands inhibit hormones from hypothalamus and anterior pituitary
galactorrhea cause
prolactin secreting tumor in anterior pituitary –> inappropriate milk secretion in men, women, and children
2 hormones that don’t use negative feedback
prolactin and growth hormone
prolactin axis
PIH prolactin inhibiting hormone –> reduces prolactin secretion –> prolactin stimulates milk production
hypothalamo-pituitary-thyroid axis
TRH –> TSH –> T3 and T4
permissive hormone
thyroid hormone is permissive meaning it is necessary for other hormones to work
functions of thyroid hormone
metabolism, growth and development, heat generation
iodine deficiency and symptoms
iodine deficiency –> T3/T4 cannot be made –> low T3/T4 –> high TSH and TRH –> goiter aka thyroid swelling
thyroid follicle structure
- single layer of thyroid follicular cells
- inside is colloid and filled with thyroglobulin protein
T3/T4 production pathway
iodide (from diet, dairy, seafood) taken in to thyroid follicular cells –> iodide and thyroglobulin released into colloid –> iodide converted to iodine –> iodine binds to tyrosine on thyroglobulin to make MIT and DIT –> MIT and DIT combine to form T3/T4 still bound to thyroglobulin
T3/T4 release pathway
TSH stimulates follicular cells to take up T3/T4 –> T3/T4 cleaved off of thyroglobulin –> T3/T4 enter blood and bind to carrier proteins, thyroglobulin is recycled
hyperthyroidism symptoms
- always hot, nervous, excited, high heart rate, weight loss
hypothyroidism symptoms
- always cold, weight gain, lethargy, low heart rate
parafollicular cells
cells between follicles of thyroid that make calcitonin which decrease about of calcium in blood
name of carrier protein for thyroid hormone
thyroid binding globulin
percent of T3 vs T4
90% T4
10% T3
percent of bound thyroid hormone vs free
99% bound
<1% free
amount of free depends on concentration of hormones, carrier, and their chemical interaction
workflow of thyroid hormone / mechanism
- hydrophobic –> genomic mechanism
- T4/T3 enters cell –> T4 converted to T3 –> binds to receptor in cell –> receptor hormone complex forms heterodimer with retinoic acid –> gene expression modified
parathyroid gland shape, location, and main function and effects
- 4 beans on back of thyroid
- creates parathyroid releasing hormone which increases blood calcium
1) increases calcium reabsorption in kidneys
2) activates vitamin D so more calcium can be absorbed from food
3) stimulates bone resorption = break down
pancreas main function
- 99% acinar cells, exocrine production and secretion of pancreatic juices into duodenum of small intestines
alpha cells - hormone and effects
glucagon, released during low blood sugar
- gluconeogenesis, glycogenolysis, and lipolysis (to increase free fatty acids)
beta cells - hormone and effects
- insulin when high blood sugar
- skeletal muscle cells and fat cells take in glucose, amino acids
- STORE
type 1 diabetes
- autoimmune attack of beta cells so body cannot produce insulin
stages of follicle maturation
primordial follicle –> primary follicle –> secondary follicle –> graffian follicle
FSH and LH effect on ovaries
FSH –> estrogen released from granulosa cells –> follicle maturation
LH –> ovulation
corpus luteum function
- releases progesterone so endometrial lining thickens and vascularizes
granulosa cells - location and function
- surrounds egg, secretes estrogen to promote maturation of follicle
stroma vs parenchymal cells
- stroma = connective tissue
- parenchymal = cells / portion that does actual function of the tissue
seminiferous tubules - structure and brief function
- places where sperm are made
- as sperm mature move towards center of tubulues
interstitial cells of Leydig - stimulation and what does it produce
- found in between seminiferous tubules
- LH –> interstitial cells of Leydig –> testosterone production
sperm production - where and describe process
- seminiferous tubules
- FSH stimulates sperm maturation
- sperm mature and move closer to center of tubules
