Ch 17 Endocrine Intro Flashcards
functions of endocrine system
regulate growth, development, metabolism
maintain homeostasis of blood composition and volume
controlling digestive process
control reproductive activities
autocrines and paracrines are what?
not hormones!
autocrines
chemicals that exert their effects on the same cells that secrete them
paracrines
locally acting chemicals that affect cells other than those that secrete them
how are hormones broken down?
kidneys, primarily liver
what are hormones
signaling molecules released by multicellular glands into blood and transported throughout body
amino acid hormones
hydrophilic
hormone binds to receptor cell surface
binding triggers a change in activity of enzyme inside cell
most hormones
(amines, thyroxine, peptide, protein)
steroid hormones
small nonpolar
most diffuse across the plasma membrane - bind to receptor
hormone receptor complex acts in nucleus to inhibit or enhance transcription
(gonadal, adrenocortical)
eicosanoids
biologically active lipids w local hormone like activity
(leukotrines, prostaglandins)
types of hormones
amino acid, steroid, eicosanoids
properties of hormones
regulate metabolic function of cell
maintain homeostasis
have lag times ranging from seconds to hours
tend to have prolonged effects
hormones produce one or more of the following cellular changes
alter plasma membrane permeability
activate or deactivate enzyme systems
stimulate protein synthesis
induce secretory activity
stimulate mitosis
how are hormones synthesized and released
humoral
neural
hormonal stimuli
humoral stimuli
secretion of hormones in direct response to changing blood levels of ions and nutrients
(Ca levels in blood)
neural stimuli
nerve fibers stimulate hormone release
(SNS stimulates the adrenal medulla)
nervous system can override normal endocrine control
