Glands and Hormones Flashcards
endocrine system
for communication, slower but longer lasting than the nervous system bc every signal has to travel through the bloodstream, crucial in maintaining homeostasis
homeostasis
keeps usual state (endocrine- thermostat, nervous-light switch)
negative feedback system
occurs when some function of the output system is fed back in a manner that tends to reduce the fluctuations in the output, whether caused by changes in the input or by other disturbs
gap junctions
connected cells like in the heart for group coordinated contractions (diffusion-left to right, osmosis- right to left) move to higher concentration
paracrine
secretions affect neighboring cells (prostaglandins-contractions, vessel construction, inflammatory response and inducing pain/ nerve ending proliferation)
endocrine
hormone secretions into the bloodstream and act on distant tissues
synaptic
short lived neurotransmitters (secrete chemicals into synapse)
exocrine glands
not through blood, directly to target
hormones
synthesized by specific tissues, secreted into the blood stream, change the activities of target cells that possess the receptor for the hormone
hormones act on distant target cells through
amplification, bind to receptor changing activity at target cell
hormone actions
stimulate the synthesis of proteins such as enzymes, hormone goes to DNA in nucleus in the cell the increase production changing the rate of transcription and/or translation- switch protein on or off
neurosecretion
as a result of action potentials, direct response to environment
three types of secretory cells
neurons, neurosecretory cells, endocrine cells
neurons
many in brain that secrete on postsynaptic cell; stimulus induces (permeability increase, Na, Ca influx, depolarization) secretion follows (depolarization, permeability increase, Ca influx)
neurosecretory cells
when it has an action potential, synapses on capillary, goes straight through bloodstream
endocrine cells
when hormone comes into contact it moves across cell membrane to capillary
which of the following is a method of hormone action
all) control of enzymatic reaction rates, control of electrical signaling pathways, control of gene expression and protein synthesis, control of ion or molecule transport across cell membrane
amino acid derivatives
small hormones, thyroid hormones, epinephrine and NE, melatonin
melatonin
secreted in high amounts at night sleep time correction
peptides
glycoproteins (TSH, LH, FSH), diverse group (ADH, oxytocin, GH, prolactin)
lipid
eicosanoids, steroids; lipids don’t like water but cell wall is made up of lipids so they pass through better than carbs
eicosanoids
paracrine factors, such as blood clotting
steroids
estrogen, progestin, androgens, corticosteroids (adrenal cortex), calcitrol (kidney); last for weeks in bloodstream, bind to carrier proteins
transport proteins
bind to steroid hormones and prevent them from going into the cell so available when needed
