Hormonal Control and Exercise Flashcards
Characteristics of the Endocrine System
- all tissues and glands that secrete hormones
- hormones are often transported to specific target cells
- almost all cells and systems in the body are impacted by endocrine function
Autocrine
a cell targets itself
Signaling Across Gap Junctions
a cell targets a cell connected by gap junctions
Paracrine
a cell targets a nearby cell
Endocrine
a cell targets a distant cell through the bloodstream
Types of hormones
steroid and nonsteroid
Characteristics of Steroid Hormones
- lipid soluble
- most are derived from cholesterol
- includes reproductive hormones, cortisol, aldosterone
- receptors in cytoplasm or nucleus
Characteristics of Nonsteroid Hormones
- not lipid soluble
- amino acid derived hormones
- protein/peptide hormones
- have receptors on the cell wall
Amino Acid Derived Hormones
epinephrine, norepinephrine, thyroxine, triiodothyronine
Protein/Peptide Hormones
all other nonsteroid hormones
Process of Nonsteroid Hormones
can’t pass through cell membrane -> hormone binds to a specific receptor on the cell membrane -> hormone-receptor complex activates adenylate cyclase within the cell membrane -> the adenylate cyclase catalyzes the formation of cAMP -> the cAMP activates protein kinases (enzymes) that lead to cellular changes and hormonal effects
(binds to receptor -> intracellular second messenger activation)
What does lipid soluble mean for the ability to cross a cell membrane?
can cross the membrane easier (membrane is a phospholipid bilayer)
What type of activation do steroid hormones work through?
direct gene activation
How does direct gene activation work?
binds to cells DNA -> mRNA synthesizes in the nucleus -> protein synthesis
What might proteins be? (dependent on what they are needed for)
- enzymes (for cellular processes)
- structural proteins (tissues growth repair)
- regulatory proteins (alter enzyme function)