A&PII Endocrine System Flashcards
What are the two major regulatory systems of the body?
Nervous System
Endocrine System
How do our cells “know” when to alter their activity?
2 major regulatory systems
Nervous system releases…
Neurotransmitters
Endocrine System releases..
Hormones
The Nervous System and Endocrine System are..
Synergistic
What do the Nervous and Endocrine System do synergistically?
- use chemicals for communication
- bind to receptors to induce change
Nervous System’s neurons ________ effect target cells
Directly
What type of response does the nervous system have?
- Rapid Response
- Short lasting
Nervous system can target ________ tissue and have a ________ effect
- generalized
- localized
Endocrine System’s hormones travel via __________ to target cells
bloodstream
Endocrine System has a response range of __________ to _______ and has a ______ lasting response
- seconds
- days
- long
Endocrine System targets _______ receptors
specific
Endocrine System has a __________ effect
widespread
Endocrine Organs can be _______ or ________
primary or secondary
Primary Endocrine Organs function and example
- function: only make hormone
- ex.
-anterior pituitary gland, thyroid gland, parathyroid gland, adrenal cortex, pancreas, thymus, etc.
Secondary endocrine organs function and example
- does not only make hormone
- ex.
-heart, liver, kidneys, etc.
Methods of chemical signaling
autocrine, paracrine, and endocrine
Autocrine Method of signaling
chemical targets itself or same cell type
Paracrine Method of signaling
chemical targets nearby different cell types
Endocrine Method of signaling
- chemical targets far away different cell types
- a cell targets a distant cell through the bloodstream
- hormones were thought of as exclusively endocrine signals but can be all 3
Signaling across gap junctions
A cell targets a cell connected by gap junctions
3 types of stimuli that can initiate hormone secretion
- hormonal
- humoral
- neural
Hormonal Stimuli
- hormone stimulates hormone
-hypothalamus secretes GHRH, stimulates secretion of GH from ant. pituitary
Humoral Stimuli
- “humors” stimulate ions or molecules in the blood or extra cellular fluid stimulate
-high levels of glucose in the blood stimulate pancreas to release insulin
Neural Stimuli
- signals from the nervous system stimulate
-sympathetic neurons stimulate adrenal medulla to release epinephrine (adrenaline) and norepinephrine
Hydrophilic Hormone 🟣
- travels freely
- removed faster
- can’t readily pass through
- receptors embedded in membrane
Hydrophobic Hormone 🎀
- needs extra protein
- lipid soluble
- can readily pass through
- receptors in cytosol or nucleus
Hormones circulate until they are taken up by a _______ _____ or broken down by liver or kidney.
target cell
Receptors usually ahve 3 locations _______ ________, within the _________, or within the _________
- plasma membrane
- cytosol
- nucleus
Receptors are cotrolled via a ____/____ regulation
up/ down
What happens when we need more/ less of a hormone?
We can tailor the amount of receptors displayed on target cells to fit our needs
Upregulation
gradually more receptors displayed on target cells
Downregulation
gradually less receptors displayed on target cells
Amine Hormone
- Amino acids with modified groups (e.g. norepinephrine’s carboxyl group is replaced with a benzene ring)
- single AA
- usually hydrophilic, water soluble
Peptide Hormone
- short chains of linked amino acids (e.g. oxytocin)
- several AA
- usually hydrophilic, water soluble
Protein Hormone
- long chains of linked amino acids (e.g. human growth hormone)
- whole protein
- usually hydrophilic, water soluble
Steroid Hormones
- cholesterol derivative; hydrocarbon ring structure
- derived from the lipid cholesterol (e.g. testosterone and progesterone)
- always hydrophobic, lipid soluble
Thyroid Hormones
- EXCEPTION
- AA based BUT are hydrophobic
True or False? Hydrophilic hormones can pass through the phospholipid bilayer.
FALSE Hydrophilic hormones can’t pass through the phospholipid bilayer!
Hydrophilic Hormones mechanisms
-One method: bind to receptors that are ion channels (influence opening/ closing)
- Most popular: second messenger system (usually G protein mediated)
5 Steps of the Second Messenger System
1.) Hydrophilic hormone (first messenger) binds to its receptor in the plasma membrane
2.) The receptor activates a peripheral protein (like a G protein)
3.) The peripheral protein activates or inhibits an enzyme
4.) The enzyme catalyzes the formation of a second messenger
5.) The second messenger initiates a series of events that leads to a change in cellular activity
cAMP system
- cyclic adenosine monophosphate
- serves a vital role through activation of a protein kinase
- phosphorylates ATP; alters proteins
Mechanisms of Hormone Action HYDROPHOBIC
- can freely pass through membrane
- forms a hormone- receptor complex that usually interacts with DNA to change the rate of protein synthesis
4 Steps of Hydrophobic Hormone Action
1) Lipid- soluble hormone diffuses through the plasma membrane
2) Hormone binds with receptor in cytoplasm, forming a receptor- hormone complex
3) Receptor- hormone complex enters the nucleus and triggers gene transcription
4) Transcribed mRNA is translated into proteins that alter cell activity
Effects of Hormone Actions
- stimulating secretion from an endocrine or exocrine cell
- Activating or inhibiting enzymes
- Stimulating or inhibiting mitosis and/ or meiosis
- Opening or closing ion channels
- Altering membrane potential
- Activating or inhibiting transcription of genes that code for RNA or proteins
True or False? Different hormones can simultaneously bind to a cell, and their effects may interact
