Unit 2 Flashcards
chemical messenger, released by a neuron onto a target, causes an excitatory or inhibitory effect
Neurotransmitter
First step in neurotransmission
Synthesis
Second step in neurotransmission
Storage in Vesicles
3rd step in neurotransmission
Release
4th step in neurotransmission
Receptor Site Action
5th step in neurotransmission
Inactivation
action potential, activation of voltage sensitive Ca2+ channels, INFLUX of Ca2+ into presynaptic terminal, Ca2+ complexes with other proteins, complex induces synaptic vesicles to fuse to the membrane and release contents
Release
Neurotransmitter is released from vesicles on presynaptic membrane, diffuses across synaptic cleft, binds to specialized protein molecules embedded in the postsynaptic membrane, multiple things can happen, hyperpolarization, depolarization
Receptor Site Action
Diffusion, degradation by enzymes in the synaptic cleft, reuptake into the presynaptic terminal by membrane transporters, astrocyte uptake
Inactivation
5 classes of neurotransmitters
Small-molecule, peptide, lipid, gaseous, ion
Typically synthesized from dietary nutrients, synthesized in axon terminal, their level and activity can be influenced by diet, synthesized and packaged for use in axon terminals, following release, can quickly be replaced at presynaptic membrane, quick acting
Small-molecule transmitters
Small molecule, amino acid transmitters, used by many synapses, forebrain and cerebellum
Glutamate and GABA
GABA is formed from ___
Modification of glutamate
GABA is __
Inhibitory
Glutamate is __
Excitatory
Synthesized in cell body, transported to axon terminal, synthesis and transport are slow, action and replacement are not quick, numerous functions
Peptide Transmitters
What are the two major classes of receptor proteins
Ionotropic, Metabotropic
Two parts, binding site for neurotransmitter, a pore or channel opens, brings about rapid changes in membrane potential, usually excitatory
Ionotropic Receptors
Two parts, binding site for neurotransmitter, a G protein inside the cell is activated and coupled to the receptor protein
Metabotropic
Motor neurons in the brain and spinal cord send axons to skeletal muscles and synapse on them, ACh neurotransmitter, Nicotinic ACh receptor (nAChr), Ionotropic, excitatory
Neurotransmission in the Somatic Nervous System
Rest and digest,
SPINAL CORD —> ACh—> Ganglia—>ACh—> Target Organ
Neurotransmission in the Autonomic NS PARASYMPATHESTIC DIVISION
Fight or Flight,
SPINAL CORD—>ACh—>Ganglia—>NE—>Target organ
Neurotransmission in the Autonomic NS SYMPATHETIC
ACh in the parasympathetic division acts on organs in a way that produces ___
Calming
NE in the sympathetic division acts on organs in a way that produces ___
Arousal
___ excites digestive organs and inhibits other organs such as the heart
ACh
___ Excites the heart and inhibits other organs such as your digestive organs
NE
Neural pathway, cell bodies are clustered in a few brain stem nuclei, axons are widely distributed in the forebrain, brainstem, and spinal cord, coordinates activity of the brain and spinal cord, each uses ONE small-molecule transmitter
Activating Systems
Substances that alter mood, though, or behavior, are used to manage neuropsychological illness, may be taken recreationally, can act as toxins
Psychoactive Drugs
Most drugs that have psychoactive effects do so by ____
Influencing one of the steps in neurotransmission at the synapse
Agonists ____ muscles
Excite
Antagonists ___ muscles
Inhibit
Black Widow Venom affects what step in neurotransmission?
RELEASE