Ch18 Flashcards
____system : -Nerve impulses/ Neurotransmitters -Faster responses, briefer effects, acts on specific target
Nervous
____ system: -Hormone-mediator molecule released in one part of the body but regulates activity of cells in other parts -Slower responses, effects last longer, broader influence
endocrine
ducted glands are..
exocrine (endocrine)
ductless glands that secrete products into interstitial fluid; diffuse into blood
endocrine gland
pituitary, thyroid, parathyroid, adrenal and pineal glands are all ____ glands
endocrine
Hypothalamus, thymus, pancreas, ovaries, testes, kidneys, stomach, liver, small intestine, skin, heart, adipose tissue, and placenta
exceptions : organs and tissues not exclusively endocrine
affect only specific target tissues with specific receptors in which constantly synthesize and break down -Down-regulation – decrease in receptors -Up-regulation – increase in receptors
hormones
regulation in endocrine system can be activated or inhibited by:
neural regulation, hormonal regulation, or humoral regulation
2 hormone types are
- Circulating – circulate in blood throughout body
- Local hormones – act locally
- Paracrine – act on neighboring cells
- Autocrine – act on the same cell that secreted them
lipid soluble -use transport proteins- hormones include
- steroid hormones
- thryoid hormones
- nitric oxide
water soluble hormones that circulate in free form include:
- amines
- peptides/proteins
- eicosanoids
- Water-soluble hormones bind to receptors on the plasma membrane and …
- Activate second messenger system
- Amplification of original small signal
Responsiveness of target cell depends on what 3 things
- Hormone’s concentration
- Abundance of target cell receptors
- Influence exerted by other hormones
- lipid soluble hormones binding to receptors inside target cells
mechanism of action of lipid soluble steroid and thyroid hormones
water soluble hormones bind to receptors on the plasma membrane ; then …
- activate second messenger system
- amplification of original small signal
responsiveness of target cell depends on …
- hormone’s concentration
- abundance of target cell receptors
- influence exerted by other hormones(permissive, synergistic and antagonistic effects)
- lipid soluble hormone diffuses into cell
- activated receptor hormone compelx alters gene expression
- newly formed mRNA directs synthesis of specific proteins on ribosomes
lipid soluble hormone action
- first messenger binds to its receptor activates G protein activating adenylate cyclase
- activated adenylate cyclase converts ATP to cAMP
- cAMP serves as 2nd messenger to activate protein kinases
- activated protein kinases phosphorylate cellular proteins
- millions of phosphorylated proteins cause reactions that produce physiological responses
water soluble hormone action
control of hormone secretion regulated by:
- signals from nervous system
- chemical changes in the blood
- other hormones
[most hormonal regulation by negative feedback]
major link btwn nervous and endocrine system
hypothalamus
- somatotrophs
- thyrotrophs
- gonadotrophs
- lactotrophs
- corticotrophs
ADENOHYPOPHYSIS cells
human growth hormone and insulin like growth factors are what type of anterior pituitary cells
somatotrophs
thyroid stimulating hormone is what type of adenohypophysis cell/ lactotrophs include ___
thryotrophs; prolactin
adrenocorticotropic hormone and melanocyte stimulating hormone are what type of anterior pitutary cells
corticotrophs
- hormone release stimulated by releasing and inhibiting hormones from hypothatlamus (regulated by negative feedback)
- hypothalamic hormones made by neurosecretory cells transported by hypophyseal portal system
- tropic hormones acting on other endocrine systems
anterior pituitary= adenohypophysis
stimulates secretion of insulin like growth factors that promote growth, protein synthesis; targets cartilage, bone, skeletal muscle cells
human growth hormone or somatostatin
ovaries initiate development of oocytes; tests stimulate testosterone production (hormone)
follicle stimulating hormone FSH
(hormone) ovaries stimulate ovulation; tests stimulate testosterone production
luteinizing hormone
long-term condition in which there is too much growth hormone and the body tissues get larger over time.
acramegaly
- decline in blood glucose concentration stimulates corticotropic cells in the anterior pitutiary to produce ___being with zona fasciculata of adrenal cortex
- targets liver cells causing glycogenolysis
- relaease of glucose into blood restores blood glucose levels
ACTH- adrenocorticotropic hormone
- causes liver cells to undergo glucogenesis
- causes adipose cells to undergo lipolysis
- cause muscle cells to breakdown proteins to amino acids
- response is to increase blood glucose levels
- supression of immune responses
- reduces stress
cortisol
syndrome :too much CRH, ACTH, cortisol
cushings syndrome
disease: too little CRH, ACTH, cortisol
addison’s disease
- doesnt synthesize hormone, stores and releases hormones made by hypothalamus
- oxytocin
- ADH (vasopressin)
neurohypophysis
- high blood osmotic pressure stimulates hypothalmic osmoreceptors
- osmoeceptors activate the neurosecretory cells that syn and release ADH
- nerve impules liberate ADHfrom axon terminals the posterior pituitary into bloodsteam
- kidneys retain more water
- low blood osmotic presuure inhibits hypolthalmaaic receopters
ADH regulation
- located inferior to the larynx
- 2 lobes connected by isthmus
- produce t3 and t4
- parafollicular cells or C cells produce calcitonin
thyroid gland
increased ___ hormones: increase oxygen use and basal metabolic rate; and inc in body temp
thyroid hormones
thyroid hormones use oxygen,lipid and glucose to fuel a faster production of ___ within cells in order to reduce stress
ATP
thryotropin is released from hypothalamus and tsh from anterior pituitary; situations that increase ATP demand also increase secrtion of___ hormones
thyroid
- low blood levels of t3 or low metabolic rate stimulate release of trh
- trh carried by hypophyseal portal veins to adenohypophysis; stimulating release of tsh by thryotropins
- tsh released into blood stimulates throid follicular cells
- t3 and t4 released into blood by follicular cells
- elevated t3 inhibits release of trh and tsh (negative feedback)
thyroid hormone regulation
- cretinism =stunted mental/physical growth
- goiter=enlargement of thyroid gland
- exophthalmia=protruding eyeballs
iodine deficiency disorders
- embedded in lobes of thyroid gland
- usually 2 pairs
- pth=regulator of Ca,Mg, and phosphate iions in blood
- increases number and activity of osteoclasts
- elevates bone resorption
parathyroid glands
- high level of Ca in blood stimulates thyroid gland
- calcitonin inhibits osteoclasts, thus decreasing blood ca levels
- low level of Ca in blood stimulates parathyroid gland cheif cells to release more pth
- pth promotes release of Ca from bone extracellular matrix into blood and slows loss of Ca in urine, increasing Ca level
- pth stimulates the kidneys to release caicitrol
- calcitrol stimulates increased of absorption of Ca from foods increasing Ca level
calcium regulation
decrease of Ca > chemical receptiors of parathyroid(afferent) > PTH(control center) > bone osteoclasts/kidney reabsorption(efferent) > Ca increase
blood calcium homeostasis
inc of Ca > chemical receptiors of thyroid(afferent) > thryoid releases calcitonin(control center) > bone osteoclasts/kidney excretion (efferent)> Decrease in Ca
blood calcium homeostasis
- contains mineralcorticoids(affect mineral homeostasis) [aldosterone]
- glucocorticoids(affect glucose homeostasis) [cortisol]
- androgens(masculinzing effects) [DHEA in females]
adrenal cortex
- contains modified sympathetic ganglion of autonomic nervous system
- intensifies sympathetic responses
- epinephrine and norepinephrine
adernal medulla in the adrenal glands
chronic adrenal insufficiency, hypocortiolism, and hypoadrenalism causes
addison’s disease
- endocrine and exocrine gland
- Roughly 99% of cells produce digestive enzymes
- Pancreatic islets or islets of Langerhans
- Alpha or A cells secrete glucagon – raise blood sugar
- Beta or B cells secrete insulin – lower blood sugar
- Delta or D cells secrete somatostatin – inhibit both insulin and glucagon
- F cells secrete pancreatic polypeptide – inhibit somatostatin, gallbladder contraction, and secretion of pancreatic digestive enzymes
pancreatic islets
- hypoglycemia stimulates alpha cells to secrete
- glucagon acts on liver cells for glycogenolysis and gluconeogenesis
- glucose released by heptocytes raises blood glucose levels to normal
- if glucose cont to rise, hyperglycemia inhibits release of glucagon
- hyperglycemia stim beta cells to secrete
- insulin acts on body cells to speed gly…
- blood glucose level falls
- if blood cont to fall, hypoglycemia inhibits release of insulin
glucose/insulin regulation
produce gametes and hormones
gonads
- Produce two estrogens (estradiol and estrone) and progesterone
- With FSH and LH, regulate menstrual cycle, maintain pregnancy, prepare mammary glands for lactation, maintain female secondary sex characteristics
- Inhibin - inhibits FSH
- Relaxin - produced during pregnancy
ovaries
- Regulates sperm production
- Maintains male secondary sex characteristics
- Inhibin inhibits FSH
- produces testosterone
testes
- attached to roof of 3rd ventricle of brain at midline
- masses of neuroglia and pinealocytes
- produces melatonin(more during darkness)
pineal gland
located behind sternum btwn the lungs
- produces thymosin, thymic humoral factor, thmic factor, thymopoietin
- all involved in t cell maturation
Prolonged exposure to ___ can result in wasting of muscles, suppression of immune system, ulceration of GI tract, and failure of pancreatic beta cells
cortisol
