Endocrine system Flashcards
what systems act together to maintain homeostasis
CNS and ES
the CNS is ___ term and the ES is ___ term
short(ms-s), longer(s,d,y)
what is used to coordinate both CNS and ES
extensive feedback loops
what are some features the nervous system has in common with the endocrine system
-both use chemical messangers (neurotransmitters) to signal effector cells
-simular mechanisms of messenger release
-similar mechanism at effector cell membrane
-similar biochemical diversity
what are some differences between the endocrine system and the nervous system
-all animals use endocrine system (even sponges)
-chemical signal carried in body fluid (endo=secretion into blood)
-provides longer term regulation (seconds to days, NS operates on msec time scale)
gland
organ/tissue responsible for synthesis and secretion of cellular products
endocrine
secretion of material into extracellular spaces of blood vessels; includes includes autocrine, paracrine & neuro-endocrine secretion
what is autocrine regulation
-acts of same cells that release it
-diffuses through extracellular fluid
-has receptor protein on the out side of cell
what is paracrine regulation
-acts on nearby (different) cells that release it
-there is a target cell
-with a receptor protein on it
what the different kinds of local regulation
-autocrine regulation
-paracrine regulation
distance regulation
-endocrine regulation
-neurogenic regulation
endocrine regulation
-endocrine cell releases hormone
-transported in blood
-goes to receptor protein
-onto the target cell
neurogenic regulation
-neurosecretory neuron
-release neurohormone
-transported in blood
-to target cell
-to receptor protein
what do hormones regulate
physiology, behavior, and development
what are hormones
signalling molecules secreted by endocrine cells
exocrine
secretions of material onto a body surface or into a duct
amines chemical properties
small, water coluble, derived form tyrosine or tryptophan
amines location of target cell receptor
plasma membrane (except thyroid hormones)
amines mechanism of action
second messengers (except thyroid hormones)
amines examples
epinephrine, norepinephrine, dopamine, melatonin, thyroid hormone
protein/pepides chemical properties
-water soluble
protein/pepides lacation of target cell receptor
plasma membrane
protein/pepides mechanism of action
secondary messengers
protein/pepides examples
insulin, glucogon, leptin
steroids chemical properties
derived from cholesterol, mostly lipid-soluble
steroids location of target cell receptors
cytosol or nucleus
steroids mechanism of action
usually stimulates gene transcription
steroids examples
cortisol, testosterone, estradiol
signalling mechanisms of non-steroid hormones
-reception=hydrophilic hormone binds to plasma membrane surface receptor and activates is
-transduction=activated receptor triggers a signal transduction pathway
-responce=transduction of the signal leads to cellular responce
non-steriod hormones exmples
epinephrine, insulin
signalling mechanism of steroid hormones
-hydrophobic hormone passes freely through plasma membrane and binds to receptor in cytoplasm activating it
-activated receptor binds to control sequence of gene, leading to gene activation of inhibition
-transduciton of signal leads to cellular responce
what are steroid hormones
lipids derived form cholesterol
what are some examples of steroid hormones
incest developmental hormones, human sex hormones
tyrosine can produce many hormones what are they
-L-dopa (inactie inter)
-dopamine (important neurotransmitter and hormone made by the brain)
-norepinephrine (important hormone for flight of fight reactions)
-epinephrine (important hormone for flight or fight reactions simular to epinephrine)
tyrosine can produce many hormones what are some characteristics of these
-can act as hormone of neurotransmitter or both
-molecule produced depends on enzyme gene expression in secretory cell
-hydrophilic hormones stored in secretory vesicles before secretion from cells
-regulation of: synthesis (enzyme expression), secretion (Ca++ mediated exocytosis)
what things can be made form cholesterol in a single pathway
-cortisol (regulates bodies stress response)
-aldosterone (regulates osmotic pressure)
-androgens (sex steroid responsible for the development and maintenance of male secondary sexual characteristics and repod)
-estrogens (sex steroids responsible for the development of female secondary sexual characteristics and repod)
-progesterone (sex steroid required for reporduction)
-ecdysone (stimulates molting and pupa formation)
what are some characteristics of the hormones made form cholesterol
-steroids
-tissues have different enzymes/intermediates to get specific outcomes
-(estradiol from testosterone)
-hydrophobic hormones diffuse out after sythesis (not stored in cells)
-regulation of: synthesis (enzyme expression)
what is the most common anderogen and estrogens
an- test
-estrogens- estradiol
what are the hormone levels in the blood/fluid regulated by
-altering rate of hormone syntesis
-altering rate of secretion (release from secratory vesicle)
-removal mechanisms (eg liver and kidney of vertebrates)
-converting inactive versions to active form of target tissue (eg T4 to T3 by deiodinase in liver)
-homeostatic feedback loops
what is the major difference between steroid and non-steroid hormones in terms of their chemical and functional structures
-different chemical properties
-different synthesis and storage (non steroid stored in secretory cells, steroids produced as needed
-different signalling mechanisms + target cell response (steroid hormone signalling=slower)
-difference in metabolism + elimination (lipids need to be turned into water soluble molecules to be excreted
what cells will respond to hormones
only cells wth specific receptor proteins
what tissues produce an endocrine messanger
virtually all
what organs are apart of the endocrine system
-hypothalmus
-pinal gland
-posterior pituitary
-parathyroids glands
-thyroid gland
-adreanal gland
-adreanal medualla
-islets of lagnerhans (in pancreas)
-ovaries
-testies
hypothalmus
-produces and secretes releasing and inhibiting hormones that regulate secretions by the anterior pituitary
-produces ADH and oxytocin, which are stored and released by posterior pituitary
-control center of ES
-acts through pituitary
pinal gland
secretes melatonin
anterior pituitary
secretes ACTH, TSH, FSH, and LH, which stimulates other glands, aswell as prolactin, GH, MSH, and endorphins
-glandular tissue
-processes and secretes its own hormones
posterior pituitary
-stores and releases ADH and oxytocin
-nervous tissue
-stores and secretes hypothalamus hormones
parathyroid glands
secretes parathyroid hormones
thyroid glands
-TRH
-TSH
-thyroxine- increases metabolic rate (inc body temp)
adrenal cortex
secretes cortisol and aldosterone and small amounts of androgens
adrenal medulla
secretes epinephrine and norepinephrine
islets of langerhans (in pancreas)
secretes insulin and glucogon
ovaries
secretes estrogen and progesterone
testes
secretes androgens
what are specialist endocrine organs
only have one function (thyroid pituitary)
what are the multifunction endocrine glands
-have multiple functions
-e.g. pancrease- endocrine, glucose mobilization, digestive enzymes
what are the only endocrine glands that produce steroid hormones
adrenal gland, sex organs
what are some endocrine systems that have a close relationship between endocrine and the nervous system
hypothalmus (basically a nervous tissue but major for signalling what to secrete)
brain-pituitary gland connection in vertebrates (posterior)
-neurosecratory cells(mod neurons) go from the hypothalmus to the post
-release hormones into it
-then post releases it in to blood vessels
-oxitocyn (uterine muscle, mammary glands)
-ADH (kidney tubules)
brain-pituitary gland connection in vertebrates (anterior)
-also have neurosecratory cells
-unlike posterior it is a true endocrine gland
-hypo releases hormones into the blood vessels which causes anterior pit to release hormones
-TSH (thyroid)
-ACTH (adrenal cortex)
-FSH and LH (testes of ovaries)
-growth hormone (entire body)
-prolactin (mammary glands in mammals)
-endorphins (pain receptor in brain)
growth hormone
-has very broad effect
-promotes synthesis and use of body fat for energy
-promotes development and enlargement of all body parts (especially muscle)
-essential for normal growth and development
-overproduction of GH causes gigantism
-less results in inadequate growth
thyroid gland charicteristics
-multifunctional role in body function and homeostasis
-controls metamorphosis in bull frogs
-in humans produces T4 (thyroxine) and T3
-maintains normal blood pressure, heart rate, muscle tone
-digestion, repo, calcium homeostasis (calcitonin)
-insufficent T3/T4:
-hypothyroidism (goiter)
-enlargement of thyroid
explain how goiter happens
-hypo secretes TRH
-causing anterior p to release TSH
-acting on thyroid but insufficent iodine to make t3,t4 so no inhibition
-build up of the TSH causes a large thyroid
endocrinology of stress in vertebrates 2
-body responds in two phases
-acute response (almost immediately, due to activation of sympathetic division
-chronic response (delayed by a few minutes, due to activation of hypothalamo-pituitary axis
-different adrenal gland hormones mediate both phases
acute phase endocrinology of stress in vertebrates
-adrenal gland secretes two hormones when sympathetic NS is maximally active
-epinephrine and norepinephrine in blood augment effects of sympathetic nerves
-prolongs bodys responce in flight or fight
epi (75%) norepi (25%)
what is the length of pre/post ganglionic nerve in para/sympathetic NS
-on average
-pre=longer in para
-post=longer in sympa
what is the response of the cardiovascular system for the acute phase of endocrinology of stress
increase in heart rate and strength of heart contractions to maximize pumping of blood to all parts of the body; dilate blood vessels entering tissues needing more O2 (eg skeletal muscle) and constriction of regions of less immediate importance (kidney, gut)
what is the response of the respiratory system for the acute phase of endocrinology of stress
dilate small airways (bronchioles) to reduce resistance to airflow in mammals; increase rate of depth of breathing to maximize O2 intake and CO2 elemination
what is the response of the metabolic system for the acute phase of endocrinology of stress
-increase in glycogenolysis in muscle to provide glucose for muscle cells and in liver to provide glucose to the blood where it can reach usable fuel (fatty acid) that can than enter the blood stream; stimulate glucagon secretion which acts on liver to promote gluconeogenesis
what is the response of the nervous system for the acute phase of endocrinology of stress
increase in arousal and alertness; inhibits non essential functions like appetite
endocrinology of stress in vertebrates
-form minutes to days
-prepares body to cope with stress over long term
-due to glucocorticoid hormones and adrenal cortex
-cortisol in humans, rodentsm and teleost fist
-corticosterone in all other vertabrates
livers response in endocrinology of stress in vertebrates for the chronic phase
stimulates gluconeogenesis, thus providing glucose into blood
adipose tissue response in endocrinology of stress in vertebrates for the chronic phase
stimulates breakdown of triglycerides into fatty acids and glycerol for fuel
muscle and adipose tissue response in endocrinology of stress in vertebrates for the chronic phase
inhibits sensitivity to insuli making more glucose available to brain cells which donnot require insulin to move glucose across their plasma membranes
bone response in endocrinology of stress in vertebrates for the chronic phase
inhibit bone growth and formation because such processes require large amounts of nutrients that could be used combat stress instead
lung response in endocrinology of stress in vertebrates for the chronic phase
stimulate lung maturation in the fetus
immume response in endocrinology of stress in vertebrates for the chronic phase
suppresses immune system function and reduces inflammation
other response in endocrinology of stress in vertebrates for the chronic phase
regulate sodium and chloride balance in migratory fish; stimulate nervous system development in most vertebrates; stimulares protein breakdown to provide amino acids to the liver for gluconeogenesis; inhibits reproduction
