Chapter 17: The Endocrine System Flashcards
Nervous system uses _________
electrical signals
Endocrine system uses ________
hormones
Functions of the Endocrine System
Use of calories and nutrients
Secretion of wastes
Blood pressure and blood osmolarity
Growth
Fertility and sex drive
Lactation
Sleep
chemical messengers used by endocrine system
Hormones
hormone affects neighboring cells
Paracrine signaling
hormone affects same cell that released it
Autocrine signaling
hormone travels through blood to affect cells throughout body
Endocrine signaling
used by neurons and the nervous system
Neurotransmitters
releases product into bloodstream or extracellular fluid
Endocrine gland secretion
releases product into duct that carries product to a body surface
Exocrine gland secretion
Include the pituitary, thyroid, parathyroid, adrenal, and pineal glands
Endocrine Glands
cross cell membrane easily
Lipid-based hormones
Produced from cholesterol molecules
Require transport proteins to travel in blood
Examples include testosterone and estrogens
Steroid hormones
modified amino acids
Water-soluble; cannot cross cell membranes
Made from individual amino acids
Do not require transport proteins in blood
Examples include melatonin, epinephrine, and norepinephrine
Amine-based hormones
made from chains of amino acids
Water-soluble; cannot cross cell membranes
Do not require transport proteins in blood
Examples include antidiuretic hormone and insulin
Peptide and Protein hormones
made on demand by modifying cholesterol molecules
Steroid hormones
translated like other proteins
Peptide hormones
Receptors can be intracellular or on the cell surface
Hormone Receptors
Associated with steroid and thyroid hormones
Hormone must be lipid-soluble to pass through membrane
Results in increased transcription and increased protein synthesis
Intracellular Hormone Receptors
Associated with water-soluble hormones
Hormone serves as first messenger in the pathway
Membrane-bound Hormone Receptors
decrease in receptor number
Occurs when hormone level is chronically higher
Cells become less sensitive to hormone
Downregulation
increase in receptor number
Occurs when hormone levels are chronically low
Cells become more sensitive to hormone
Upregulation
_____ is regulated by a positive feedback loop
Oxytocin
