Chapter 18 Flashcards
One hormone can have many hormones as long as they have _____
the receptor for that hormone.
In both nervous and endocrine system:
function to maintain homeostasis
regulated by negative feedback
rely on release of chemicals that bind to specific receptors.
Differences between nervous system and endocrine system:
Nervous: Fast, but brief
Endocrine: Slow/long-term
Endocrine system is spread throughout the entire body + some organs that produce or do something else also can produce hormones used for communication.
Amino acid derivatives (changed slightly and become a hormone)
Small; not lipid soluble
Ex. thyroid hormone, serotonin, melatonin.
Can’t go lipid bilayer.
Peptide hormones
Chains of amino acids, not lipid soluble
Ex. insulin, growth hormone, ADH
Lipid derivative
Derived from fatty acids or cholesterol; lipid soluble, can cross plasma membrane, need a transport protein for this.
Hormones may circulate freely or travel bound to ___
special carrier proteins
When hormones become inactivated, they
diffuse out of bloodstream and bind to receptors on target cells
are absorbed and broken down by liver or kidneys
are broken down by enzymes in blood or interstitial fluids.
Mechanisms of hormone action
alter genetic activity
alter rate of protein synthesis
change membrane permeability
Catecholamines and peptide hormones:
not lipid soluble
unable to penetrate plasma membrane
bind to receptor proteins on outer surface of plasma membrane (extracellular receptors)
Steroid and thyroid hormones:
lipid soluble
diffuse across plasma membrane and bind to receptors inside cell.
Two cell types in the parathyroid glands
Parathyrioid cells: used for making PTH
Oxyphil cells: function is unknown.
Hormone producing cells of the gland.
Increased Calcitonin = _____ Calcitriol
decreased, responds to increased secretion of calcium.
Kidney’s help get rid of excess
ions to bring the body back to homeostasis
