ch. 45 part 2 Flashcards
how does one hormone have different effects on target cells
- different receptors for hormone
- different signal transduction pathways
ex. of one hormone with multiple effects
epinephrine and fight/flight response
endocrine glands
endocrine cells grouped in ductless organs
ex. of endocrine glands
- thyroid/parathyroid glands
- testes/ovaries
- pituitary
- pineal
- stomach/small intestine
- adipose tissue
- pancreas
- adrenal glands
simple endocrine pathway of hormones
- released from endocrine cells
- travel through bloodstream
- interact with specific receptors
- cause physiological response
release of secretin
- release of acidic contents from stomach into duodenum stimulates secretin release
- target cells in pancreas raise pH in duodenum
simple neuroendocrine pathway
- stimulus received by sensory neuron
- then stimulates neurosecretory cell
- secretes neurohormone
- enters blood stream and travels to target cells
suckling of an infant
- stimulates signals in nervous system that reach hypothalamus
- hypothalamus triggers release of oxytocin from posterior pituitary
- mammary glands secrete milk
negative feedback loop
inhibits response by reducing the initial stimulus
- prevents excessive pathway activity
positive feedback
reinforces stimulus to produce even greater response
ex. of positive feedback
oxytocin in mammals causes release of milk, which causes greater suckling, which stimulates release of more oxytocin
endocrine pathway that controls molting of larva in invertebrates
- originates in larval brain, where neurosecretory cells produce PTTH
- in prothoracic gland, PTTH directs release of ecdysteroid
- bursts of ecdysteroid trigger each successive molt and metamorphosis
- metamorphosis not triggered until level of JH (juvenile hormone) drops
where is prothoracicotropic hormone (PTTH) stored
corpora cardiaca
what does PTTH stimulate the release of in the prothoracic gland
20-hydroxy-ecdysone in pulses
- triggers molting
hypothalamus function
coordinates endocrine signaling
where does the hypothalamus receive information from
the nerves throughout the body
- initiates appropriate neuroendocrine signals
what is at the base of the hypothalamus
pituitary gland
2 lobes of the pituitary
anterior and posterior
posterior pituitary
stores and secretes hormones made in the hypothalamus
anterior pituitary
makes and releases hormones under regulation of the hypothalamus
what synthesize the 2 posterior pituitary hormones
neurosecretory cells of the hypothalamus
2 hormones secreted by the posterior pituitary
- antidiuretic hormone
- oxytocin
antidiuretic hormone (ADH)
regulates water loss
oxytocin
regulates milk secretion by the mammary glands
target of ADH
kidney tubules
target of oxytocin
mammary glands, uterine muscles
anterior pituitary hormone overall function
diverse processes such as metabolism, osmoregulation, and reproduction
what do hormones secreted by the hypothalamus control
release of all anterior pituitary hormones
where is prolactin-releasing hormone secreted from
hypothalamus
what does release of prolactin-releasing hormone stimulate
anterior pituitary to secrete prolactin
prolactin (PRL)
role in milk production
hormones secreted by the anterior pituitary
- FSH/LH
- TSH
- ACTH
- prolactin
- MSH
- GH
targets of FSH and LH
testes or ovaries
targets of TSH
thyroid
targets of ACTH
adrenal cortex
targets of prolactin
mammary glands
targets of MSH
melanocytes
targets of GH
liver, bones, other tissues
tropic effect
stimulates other glands
trophic
affects growth
what are sets of hormones from the hypothalamus, anterior pituitary, and a target endocrine gland often organized into
hormone cascade
