OCAT 2

Afferent

"Input"; neurons that carry incoming signals TOWARD a central point

Processing Unit

"Decider"; central hub that receives and interprets signal (brain & spinal cord)

Efferent

"Output"; neurons that carry signals AWAY from the central point, commands

Nervous System

The body's communication network; Made up of the central and peripheral nervous systems

Central Nervous System/CNS

The brain and spinal cord

Peripheral Nervous System/PNS

All nervous structures outside the brain and spinal cord that carry signals between the CNS and body

Somatic Nervous System/SNS

Part of PNS; controls skeletal muscles

Autonomic Nervous System/ANS

"Automatic" part of PNS; regulates involuntary organs, glands, smooth, and cardiac muscle

Parasympathetic

Associated with 'rest and digest'; pre is short

Sympathetic

Associated with 'fight or flight'; pre is long

Enteric

Neurons in the GI tract

Neuron

A nerve cell; make up the nervous system

Dendrite

Receives signals from other cells and carries their effects toward the cell body

Cell Body

Main part of neuron that contains organelles, integrates incoming signals

Nucleus

Inside cell body that contains DNA

Axon

Extension of a neuron that carries action potentials AWAY from the CELL BODY

Schwann cell

A PNS cell that produces myelin around axons to speed up signal transmission

Myelin Sheath

An insulating layer around an axon that increases the speed of electrical signal transmission

Node of Ranvier

A gap between myelin segments where action potentials are regenerated

Axon Terminal

The end of an axon that releases neurotransmitters to communicate with another cell

Myelination

Formation of myelin around axons to increase the speed of action potential propagation

Saltatory Conduction

The rapid conduction of an action potential as it is regnerated at successive nodes of Ranvier

Resting Membrane Potential/RMP

-70 mV; The voltage across a resting neuron's membrane

K+

Ion concentrated INSIDE neurons that helps establish RMP and repolarise the membrane

Na+

Ion concentrated OUTSIDE neurons that enters during depolarization

Leaky Potassium Channels

Passive channels that allow K+ to cross the membrane and help maintain RMP

ATPase (Na+/K+ pump)

ATP-powered pump that moves 3 Na+ out/ 2 K+ in to maintain ion concentration gradients

Depolarizing

Step in which MP becomes more + from Na+ entering the cell

Hyperpolarizing

Step in which MP becomes very -, making action potential less likely

Action Potential

A rapid electrical signal that travels along an axon to transmit information

Voltage Gated Sodium Channel

A channel that opens at threshold and allows Na+ to enter, causing rapid depolarization

Synapse

The junction where neurons release neurotransmitters across a small gap

Presynaptic Terminal Bulb

The signal-sending bulb of a neuron that releases neurotransmitters across a small gap

Voltage Gated Ca+2 Channel

A channel that opens during depolarization, allowing an ion into the terminal to trigger neurotransmitter release

Ca+2

A positively charged ion whose entry into the presynaptic terminal triggers vesicle fusion

Neurosecretory Vesicle

A membrane-bound sac that stores neurotransmitters until they are released

v-SNARE

A vesicle protein that helps attach the vesicle to its target membrane for fusion

t-SNARE

A target-membrane protein that works with v-SNARE to bring the vesicle and membrane together

Synaptic Transmission/Vesicular Fusion

The process in which Ca2+ triggers vesicles to fuse with the presynaptic membrane and release neurotransmitters

Postsynaptic Terminal Bulb

The bulb on the receiving side of a synapse where receptors detect neurotransmitters and initiate a cellular response

Choline

A molecule taken up by neurons and used to synthesize acetylcholine

Acetyl CoA

A molecule produced by cellular metabolism that supplies the acetyl group needed to make acetylcholine

Choline Acetyltransferase/ChAT

The enzyme that combines choline and acetyl CoA to produce acetylcholine

Acetylcholine/ACh

A neurotransmitter that communicates with other cells and is involved in REST & DIGEST

Vesicular Acetylcholine Transporter/VAT

A transporter that packages acetylcholine into vesicles for storage and release

Cholinoceptor

A receptor activated by acetylcholine that produces a response depending on its subtype

Muscarinic Receptors

Acetylcholine receptors that uses G proteins and intracellular signaling pathways to affect cell activity

M1

A muscarinic receptor that commonly activates the Gq pathway; CNS, ↑IP3, ↑DAG

M2

A muscarinic receptor that ↓cAMP signaling and slows heart rate

M3

A muscarinic receptor that increases intracellular Ca2+ signaling; ↑IP3, ↑DAG, Lungs, Urinary, GI, Eye

M4

A muscarinic receptor that inhibits adenylyl cyclase; CNS, ↓cAMP

M5

A muscarinic receptor that activates the Gq pathway; CNS, ↑IP3, ↑DAG; the other one

Nicotinic Neuronal ACh Receptor/NN

An acetylcholine-gated ion channel found in autonomic ganglia and the CNS that usually depolarizes the receiving cell

Neuromuscular Junction Receptor/NMJ

An acetylcholine-gated ion channel at the neuromuscular junction that initiates skeletal muscle activation

Acetylcholinesterase/AChE

The enzyme that breaks acetylcholine into choline and acetate, terminating its signal

Anticholinesterase

A substance that inhibits acetylcholinesterase, allowing acetylcholine to remain active longer

Hexamethonium

NN receptor antagonist that blocks signal transmission through autonomic ganglia

Tubocurarine

A nicotinic receptor antagonist at the neuromuscular junction that prevents skeletal muscle activation

Catecholamine

Dopamine, noradrenaline, adrenaline

Phenylalanine

An amino acid that can be converted into tyrosine, the starting precursor for catecholamine synthesis

Tyrosine

An amino acid used to produce dopamine, noradrenaline, and adrenaline

Enzymatic Conversion

A series of enzyme-controlled reactions that transform tyrosine into catecholamines

Tyrosine Hydroxylase

The enzyme that converts tyrosine into L-DOPA and controls the rate-limiting step of catecholamine synthesis

L-DOPA

An intermediate in catecholamine synthesis that is converted into dopamine

Dopa Decarboxylase

The enzyme that converts L-DOPA into dopamine

Dopamine

A catecholamine involved in movement, motivation, reward, and arousal that also serves as a precursor to noradrenaline

Dopamine Beta Hydroxylase

The enzyme that converts dopamine into noradrenaline

Noradrenaline/Norepinephrine

A catecholamine and sympathetic neurotransmitter that helps regulate alertness, blood vessel tone, and organ responses; SLOW & WIDESPREAD

Phenylethanolamine N-methyltransferase/PNMT

Converts Noradrenaline into Adrenaline

Adrenaline/Epinephrine

A catecholamine released mainly by the adrenal medulla that helps coordinate the fight-or-flight response; FAST & FEW ORGANS

Dopaminergic Neurons

Neurons that produce and release dopamine to regulate functions such as movement and reward

Noradrenergic Neurons

Neurons that produce and release noradrenaline to help regulate alertness and sympathetic responses

Adrenal Medulla

The inner part of the adrenal gland that releases adrenaline and noradrenaline into the bloodstream

Alpha Receptors

Adrenergic receptors that help regulate blood vessel constriction and other autonomic responses

Alpha 1

A receptor that is: Constriction, Gq, ↑IP3,↑DAG; works w/ Phospholipase C

Alpha 2

A receptor that is: Constriction, Gi, ↓cAMP, ↓noradrenaline; works w/ ACi

Beta Receptors

Adrenergic receptors that generally increase cAMP signaling and regulate heart, smooth muscle, and metabolic functions; relaxation

Beta 1

A receptor that is: Heart Constriction, Gs, ↑cAMP; works w/ ACs

Beta 2

A receptor that is: Lung Relaxation, Gs, ↑cAMP, works w/ ACs

Beta 3

A receptor that is: Bladder Relaxation, Gs, ↑cAMP, works w/ ACs

Reuptake (Nervous System)

The removal of neurotransmitters from the synaptic space by transporters, helping terminate their signals; done by NET

Norepinephrine Transporter/NET

A transporter that takes noradrenaline back into nerve terminals to end its signaling

Enzymatic Degradation (Nervous System)

The chemical breakdown of neurotransmitters by enzymes to help terminate their effects

Monoamine Oxidase/MAO

An enzyme that breaks down monoamines, including catecholamines, and helps regulate their levels inside cells

Catechol-O-Methyltransferase/COMT

An enzyme that chemically modifies catecholamines and contributes to their breakdown

Receptor Desensitization

A decrease in a cell's response to a signal despite continued or repeated exposure

Receptor Internalization

A process in which receptor phosphorylation and beta-arrestin binding reduce GPCR signaling and may cause receptors to be removed from the cell surface

Nernst

Calculates equilibrium potential for one specific ion; the voltage at which concentration gradient and electrical gradient balance

Goldman

Calculates membrane potential by considering multiple ions; Cl- as the major anion and also included a permeability term in the equation

Somatic Neurons

Neurons that have a long nerve from spinal cord to muscle, uses ACh to signal to muscles, causing contraction

Sympathetic Neurons

Preganglionic short (nicotinic), long postganglionic (adrenergic); Catecholamine (norepinephrine) signal to organs

Parasympathetic Neurons

Preganglionic long (nicotinic), short postganglionic (muscarinic); ACh signal to organs

Ganglion/Ganglia

An area with a collection of neuron cell bodies. Forms a relay point between CNS and PNS

VX Agent

Organophosphate; North korean leader brother death

Mule

Drug mules

Organophosphate Insecticide

Anticholinesterase (AChE inhibitor) example

Botulinum Neurotoxin/Toxin/Botox

Neuromuscular toxin; Taken into the presynaptic terminal, cleaves SNARE proteins, blocking ACh release.

Snake Venom

Neuromuscular toxin; cause paralysis in different ways

Bungarotoxin

A toxin found in krait snake venom; block NMJ receptors, causing paralysis

Atropine

Parasympathetic toxin; Blocks M receptors, also described by this poem: “Hot as a hare, Blind as a bat, Red as a beet, Dry as a bone, Mad as a hatter