ENDOCRINE Flashcards
Exocrine
secretes products through a duct
Endocrine
directly into the bloodstream
No duct
Both endocrine and exocrine
Pancreas
Both hormone and neurotransmittres
NE, Dopamine and ADH
**ACTH (Adrenocorticotropic Hormone)
regulates response to stress, stimulates adrenal cortex
corticosteroids regulate glucose, fat and protein metabolism
Pituitary
Anterior (adenohypophysis : gland)
Posterior (neurohypophysis)
Prolactin
(prolactin-releasing factor stimulates anterior pituitary to produce it)
female - milk synthesis after delivery
male - increased LH sensitivity and increased testosterone secretion
Posterior Pituitary Hormones(produced by
hypothalamus)
Posterior Pituitary Hormones(produced by hypothalamus) are
ADH
Oxytocin
GnRH
**ADH targets
kidneys
incr. water retention, reduce urine
also functions as neurotransmitter
**Oxytocin
Causes uterine contractions and milk ejection (let-down)
***GnRH
(Gonadotropin-releasing hormone) stimulates production of FSH and LH
***Control of Pituitary: Feedback from Target Organ
Negative feedback
increased target organ hormone levels inhibits release of tropic hormones
Control of Pituitary: Feedback from Target Organ
Positive feedback
stretching of uterus OT release, causes more contraction/ stretching of uterus, until delivery
Thyroid Hormones
T3 (triiodothyronine)
T4 (tetraiodothyronine)
Thyroid hormones produced by
thyroid follicles - filled with colloid and lined with simple cuboidal epithelial “follicular cells”
***Increase body’s metabolic rate, O2 consumption
calorigenic effect - inc heat production
inc heart rate and contraction strength
inc respiratory rate
stimulates appetite and breakdown CHO, lipids and proteins
**Calcitonin produce by parafollicular “c” cells
increase blood Ca2+ , promotes Ca2+ deposition, antagonistic to parathyroid hormone
Posterior
Vasopressin
Oxytocin
Parathyroid hormone:
Increase blood Ca2+ levels stimulates osteoclast maturation and mobilization of calcium from bone. promotes synthesis of calcitriol Increase absorption of Ca2+ Decrease urinary excretion Increase bone resorption
Zona Glomerulosis produces
mineralocorticoids
control electrolyte balance, aldosterone promotes Na+ retention, water reabsorption and K+ excretion
Zona Fasiculata produces
glucocorticoids especially cortisol, stimulates fat and protein catabolism, gluconeogenesis (from a.a.’s and FA’s) and lipogenesis (release of fatty acids and glucose into blood) anti-inflammatory effect becomes immune suppression with long-term use
Adrenal medulla stimulation causes release of
“catecholamines” (epinephrine, NE)
Pheochromocytomas
Secrete
Clinical manifestations
caused by tumors derived from the chromaffin cells of the adrenal medulla.
catecholamines.
Hypertension, diaphoresis, tachycardia, palpitations,
and severe headache
Insulin (from Beta cells)
secreted after meal with carbohydrates raises glucose blood levels
*stimulates glucose and amino acid uptake
**nutrient storage effect (promotes glycogenesis and lipogenesis)
antagonizes glucagon
Glucagon (from alpha cells)
secreted when blood glucose is low, acts on liver cells to release glycogen, increases blood sugar
Somatostatin
(from delta cells)
Parathyroid on calcium levels
Increase
Pancreatic Hormones
Hyperglycemic hormones raise blood glucose
GH, epinephrine, NE, cortisol and corticosterone
Hyperglycemic hormones raise
blood glucose
GH, epinephrine, NE, cortisol and corticosterone
Steroids
derived from cholesterol:
sex steroids, corticosteroids
Hormone Transport
Monoamines and peptides are hydrophilic
protein hormones are transported in the bloodstream, transported free unbound as water soluble form
Cortisol
supresss inflammation
Hormones mode of action –> 2 types
Hydrophobic hormones
Hydrophilic hormones
Hydrophobic hormones
penetrate plasma membrane – bind to intracellular receptors ie. Estrogen, T3, aldosterone
Hydrophilic hormones
must bind to cell-surface receptors ie. epinephrine
Hydrophilic Hormones: Mode of Action
cAMP as Second Messenger ie. epinephrine
1) Hormone binding activates G protein
2) Activates adenylate cyclase
3) Produces cAMP
4) Activates kinases
5) Activates enzymes
6) Metabolic reactions:
- synthesis
- secretion
- change membrane potentials
Myxedema (adult hypothyroidism, low TH)
low metabolic rate, sluggishness, sleepiness, weight gain, bradycardia, constipation, dry skin and hair, cold sensitivity, HIGH blood pressure and tissue swelling
Modulation of Target Cell Sensitivity
UP-REGULATION
Low receptor density (weak response)
Increase receptor density / sensitivity –> stronger response
Modulation of Target Cell Sensitivity
DOWN-REGULATION
High receptor density (strong response)
reduce receptor density / sensitivity –> diminished response
Heart produces
ANP –> increase Na+ and H20 loss by kidneys
not red Hyposecretion
inadequate hormone release
Endocrine disorders
too much or too little
epipheaseal plate
Close 18-21
BEfore gigantism
After Dwarfism
excess corticol
cushing
