Chapter 13: The Endocrine System Flashcards
endocrine glands
- ductless
- secrete hormones into bloodstream
- hormones act only on target cells
exocrine glands
- glands that secrete into ducts or tubes that lead to a body surface
- secrete externally
- deliver products directly to a specific cell
hormones
chemical signals
similarities of nervous & endocrine system
- function in communication
- nervous sys. releases neurotransmitters into synapse
- endocrine sys. secretes hormones into blood via chemicals that bind to receptors
which system is slower?
endocrine; snail mail
which system is faster?
nervous; email
are major endocrine glands connected?
no
what type of compounds are hormones?
organic; two types
two types of hormones
- steroid/steroid like
- nonsteroid
steroid/steroid like hormones
- lipids w/ complex rings of carbon & hydrogen
- produced from cholesterol
- ex. sex hormones & adrenal cortex hormones
non steroid hormones
- amines
- proteins
- peptides
- glycoproteins
amines
non steroid; derived from tyrosine (epinephrine/norepinephrine)
proteins
composed of long chains of amino acids (growth hormone)
peptides
short chains of amino acids (oxytocin)
glycoproteins
carbs joined to proteins (TSH)
how to hormones alter metabolic processes?
- may alter enzyme activity
- may alter rate of membrane transport of a substance
what does # of receptors determine?
strength of response; can be changed to alter response
upregulation
increase in # of receptors, response to a decrease in hormone level
downregulation
decrease in # of receptors on target cell, due to increase in hormone level
characteristics of steroid hormones
- poor water solubility
- can diffuse through lipid bilayer of cell membranes
- thyroid hormones thought to enter cell by specific transport methods
- bind to receptors inside cell, usually in nucleus
characteristics of non steroid hormones
- can’t penetrate through bilayer
- bind to receptors on target cell membrane
- hormone considered first messenger
- use cyclic adenosine monophosphate as second messenger
- signal transduction
signal transduction
non steroid; chemical communication process from outside to inside cell
second messenger
chemical that induces changes leading to hormones effect
which process is faster?
non-steroid
steroid process
new protein
non steroid process
activating existing protein
prostglandins
- paracrine substances
- potent in small amounts, like hormones
- NOT stored in cells, synthesized just before release
- rapidly inactivated after use
- regulate cellular responses to hormones
- can activate or inhibit adenylate cyclase
- control cAMP activity
- alter a cell’s response to hormones
