Unit 2 Synapes Flashcards
what is the sequence of events at a synapse
1- neurotransmitter synthesis
2- ap and NT release
3 - NT binding and post synaptic effects
4 - NT detachment
5- NT removal or recycling
6 - feedback and regulation
neurotransmitter
chemical messengers that transmit signals between neurons
nitric oxide
chemical formula NO, is a gas released by many small local neurons
○ Poisonous, but many neurons release it when they are stimulated
○ Dilates vessels in highly active brain, increasing blood flow
what are the 6 types of neurotransmitters
amino acids, modified amino acid, monoamines, neuropeptides, purines, gases
amino acids
acids containing an amine group
Neurons synthesize nearly all neurotransmitters from amino acids
Catecholamines
compounds that contain a catechol and an amine group
Relationship among epinephrine, norepinephrine, and dopamine compounds
where are most NTs synthesized
presynaptic terminal
vesicles
tiny nearly spherical packets found in presynaptic terminal that store and release NTs
MAO (Monamine oxidase)
enzyme that converts catecholamines and serotonin into synaptically inactive chemicals MAOIs, prevents the transmitters to accumulate to harmful levels
Exocytosis
bursts of release of neurotransmitter from presynaptic neuron to synaptic cleft, caused by calcium entering terminal
synaptic cleft
the space between the presynaptic and postsynaptic neurons to the post synaptic membrane
what can the receptor do when a NT attaches to it? (1 of 2 things)
Ionotropic Effects or Metabotropic Effects
Ionotropic Effects
synaptic effects that depend on the rapid opening of some kind of gate in the
membrane, produce brief on/off effects when NTs bind (fast and short lasting)
Metabotropic effects
a sequence of metabolic reactions that produce slow and long-lasting effects at a synapse
what is the sequence of events that happens during metabotropic effects
NT binds –> receptor bends –> G protein detaches –> Result of a G protein is a second messenger
G protein
a protein coupled to guanosine triphosphate (GTP), an energy-storing molecule, part of metabotropic effects and results in a second messenger
neuropeptides
chains of amino acids (often referred to as neuromodulators)
hallucinogenic drigs
drugs that distort perception, such as lysergic acid diethylamide (LSD)
Chemically resemble serotonin, and attach to serotonin receptors
nicotine
a compound found in tobacco
opiates
drugs that are derived from, or chemically derived from, the opium poppy
auto receptors
a mechanism that prevents excess NT release, respond to the neurotransmitter they release, providing negative feedback to reduce further release, located on presynaptic terminal
reverse transmission
a mechanism that prevents excess NT release, where post synaptic neurons release chemicals like NO, that travel back to inhibit NT release
what are the reverse transmitters
nitric oxide, hydrogen ions, anandamide, 2-AG
2-AG
a reverse transmitter, chemical that binds to cannabinoid receptors
anandamide
chemical that binds to cannabinoid receptors
acetylecholine
a chemical similar to an amino acid, except that it includes an N(CH3)3 group instead of an NH2, group,
Acetylcholinesterase
enzyme that breaks down acetylcholine into acetate and choline,
cannabinoids
the active chemicals in marijuana, bind to anandamide or 2-AG receptors on presynaptic neurons
gap junction
at an electrical synapse, the membrane of one neuron comes into contact with as another (gap between)
5 differences between neuropeptides and neurotransmitters
NPs
- synthesized in cell body, than transport to other parts of cell
- diffuse widely, slowly affecting more neurons
- released mostly by dendrites
- released by repeated depolarization/ repeated stimulation
-neighbouring cells release the NP to
NT
- synthesized in presynaptic terminal
- effects are limited to receptors of adjacent post synaptic cell, duration is quick
- can be released by a single action potential
- released by axon terminal
- no effect on neighbouring cells
hormone
chemical secreted by cells in one part of the body and conveyed by the blood to influence other cells.
two types of hormones
protein hormones and peptide hormones
protein hormones
hormones composed of long amino chains
peptide hormones
hormones composed of short chains of amino acids
endocrine (hormone producing glands)
organs that release hormones directly into the bloodstream, influencing various bodily functions like growth, metabolism, and reproduction
include hypothalamus, pineal gland, pituitary gland, thyroid, liver, adrenal gland, kidney, pancrease, ovary/testes, placenta
anterior pituitary
made up of glandular tissue, produces six hormones nut is controlled by the hypothalamus through releasing hormone
posterior pituitary
composed of neural tissues, extension of hypothalamus, Stores and releases oxytocin and vasopressin, which are synthesized by the hypothalamus.
negative feedback
homeostatic processes that reduce discrepancies from the set point, how the hypothalamus maintains balance
oxytocin
hormone made in the brain, synthesized in hypothalamus, migrate down to posterior pit where its released into blood, controls uterine contractions, milk release, sexual pleasure
vasopressin
aka antidiuretic hormone, also synthesized in hypothalamus and released by post. pit. raises blood pressure, decreases urine volume
releasing hormones
secreted by the hypothalamus, which flow through the blood to ant pit, where they stimulate or inhibit the release of other hormones
6 hormones that ant. pituitary releases
Thyroid-stimulating hormone
Luteinizing hormone
Follicle-stimulating hormone
ACTH
Prolactin
Growth hormone
what hormone does the pineal gland release and whats the function
melatonin, sleepiness
what hormones are released in the adrenel cortex
aldosterone and cortisol
what hormones are released in the adrenal medulla
epinephrine and norepinephrine
what hormones are released in the pancrease
insulin and glucagon
what hormones are released in the overies
estrogen and progesterone
what hormone is released in the testes
testosterone
what hormone is released in the kidney
renin - regulates blood pressure
what hormones do fat cells release
leptin - decreases appetite
amphetamine
a drug that blocks reuptake of dopamine and other neurotransmitters
COMT
(catechol-o-methyltransferase) enzyme that breaks down excess dopamine into inactive chemicals that cannot stimulate the dopamine receptors
ligand-gated channel
channel that opens when a neurotransmitter attaches,
reuptake
reabsorption of a neurotransmitter by the presynaptic terminal
second messenger
a chemical that, when activated by a neurotransmitter, initiates communication to many areas within the neuron
transmitter gated channels
same thing as ligand-gated: channels that open when a NT binds
voltage gated channels
found along axons, open from electrical signals
what is the most abundant NT in the nervous system
glutamate
what are some key neurotransmitters that inhibitory ionotropic synapse use
GABA and Glycine
common neurotransmitter at excitatory ionotropic receptors
acetylcholine and glutamate
what things contribute to the firing rates of neurons
depends on the balance of EPSPs and IPSPS it receives, if excitatory inputs dominate, neuron fires more frequently, if inhibitory inputs dominate, neuron firing is suppressed
how do synaptic potentials contribute to the integration of information
neurons typically integrate both spatial and temporal inputs
that integration enables processing of complex sensory info such as decision making and learning
the order effects results
what is the significance of the pituitary gland
is essentially the master gland, influences all endocrine glands, produces and releases hormones that are crucial to regulating many bodily functions such as growth, metabolism, reproduction, and body’s response to stress, especially crucial during puberty
how do the pituitary gland and hypothalamus work together (2 main points)
hypothalamus controls pituitary gland by sending it hormones (inhibitory and releasing) , where the pit gland releases those hormones and influences nearly all endocrine glands
what is the significance of the hypothalamus (4 main points)
the hypothalamus is link between the endocrine system, and neurotransmitters
it produces
produces various releasing hormones which promote/inhibit release of hormones from pit gland
maintain balance with negative feedback loop
regulates homeostasis
