Lecture 9 Flashcards
hypothalamus
control of hormone secretion
pineal gland
reproductive maturation, body rhythms
anterior pituitary
hormone secretion by thyroid, adrenal cortex, gonads, growth
posterior pituitary
water balance, salt balance
thyroid
growth and development, metabolic rate
adrenal cortex
salt and carb metabolism, inflammatory reactions
adrenal medulla
emotional arousal
pancreas
sugar metabolism
gut
digestion and appetite control
gonads
body development, maintenance of reproductive organs in adults
Berthold’s classical experiment with roosters
group 1: left undisturbed
group 2: testes removed
group 3: testes removed and replaced in abdomen
group 1 formed large comb/wattles, mounted hens, was aggressive, and had normal crowning
group 2 formed small comb/wattles, didn’t mount hens, wasn’t aggressive, and had weak crowning
group 3 formed large comb/wattles, mounted hens, was aggressive, and had normal crowning
conclusion: testes release a chemical signal (hormone) that has widespread effects
canary example
gave female canaries testosterone, after one week started to sing, but stopped when weren’t given anymore testosterone
autocrine
affects self
paracrine
local diffusion
pheromone function
same species
allomone function
other species
neuroendocrine cell actions
blend neuronal and endocrine signal mechanisms
neuron acting on another neuron, in second neuron action potential causes a hormone to be released into blood stream to affect target cells
general principle of hormone systems
pulsatile (burst) secretion
hormonal effects depends on target system having receptors
some hormones affect more than one target
some targets are affected by more than one hormone
Neuronal vs hormonal communication
neuronal com: directed, restricted to specific targets (telephone) fast (milliseconds) APs, all or none hormonal com: widespread can affect many targets (TV) slow (seconds or minutes or longer) hormonal signals graded
how are hormones classified:
protein, amine, and steriod
classified by chemical structure
protein- amino acid chain
amine- single amino acid
steroid- carbon rings
protein hormone action
need a channel
rapid, short lived (min-hours)
steroid hormone action
always to go through membrane long lasting (hours days)
autocrine feedback loop
endocrine cells to target cells back to negative feedback
target cell feedback
endocrine cells to target cells to biological response then negative feedback
posterior pituitary (neurohypophysis)
1- neuroendocrine cell bodies in the hypothalamus produce oxytocin or vasopressin
2- axons from these neurons pass through the pituitary stalk
3- terminate on the capillaries of the posterior pituitary when the action potential arrives at terminal, oxytocin and vasopressin is released from the terminal directly into the blood stream
the milk let down reflex
1- stimulation of the mother’s nipple by the infant’s suckling response produces brain activity in the mother
2- the brain activity stimulates hypothalamic cells to release oxytocin from the posterior pituitary
3- the baby rewarded with milk continues suckling until satiated
4- the oxytocin causes the cells of the mammary glands to contract, thereby releasing milk
in a nursing women, hearing a baby cry can induce the reflex
tropic hormones
prolactin gonadotropic hormones (FSH, LH) thyroid stimulating hormone ACTH growth hormone
anterior pituitary (adenohypophesis)
1- neuroendocrine cell bodies in the hypothalamus produce releasing hormones
2- which are released from axons that terminate on the portal system. The hormones travel via the portal veins to the anterior pituitary
3- the anterior pituitary respond to the hypothalamic releasing hormones by increasing or decreasing the secretion of their own tropic hormones
4- tropic hormones travel through the blood stream and regulate endocrine glands throughout the body
what are the adrenal cortex and adrenal medulla controlled by
adrenal cortex by hormones
adrenal medulla controlled by nerves
oxytocin and vasopressin with social attachment
oxytocin and vasopressin are involved in parental care, grooming, sexual behavior, and pair bonding
prairie vole vs montane vole
prairie vole monogamous, more receptors for vasopressin
montane vole polygamous, less receptors
what happens when a male sees a female
male sees female, light goes into eye through retina, into brain, interpreted, stimulates hypothalamus to produce GnRH, causes pituitary to release FSH and LH, goes to testes, releases testosterone, goes back to brain to stimulate reproductive behavior (bowing and cooing)
Epinephrine and Norepinephrine are large molecules are cannot go into the brain due to blood brain barrier but brain parts including amygdala are still affected, how do they do it?
they act directly on the NE receptors on the inner walls of blood vessels, which are endings of the vagus nerve, that takes the info into the brain
