Key Concepts in Neurotransmission and the Nervous System

acetylcholine signals where

neurotransmitter for signals in autonomic ganglia and at parasympathetic target organs

acetylcholinesterase

enzyme that breaks down acetylcholine in the synaptic cleft

adrenal glands

endocrine glands located at the top of each kidney, secreting adrenaline and noradrenaline due to sympathetic stimulation

adrenal medulla

inner part of the adrenal glands that release adrenaline and noradrenaline directly into the bloodstream during stress

are sensory neurons afferent or efferent

afferent

autonomic nervous system

branch of PNS, regulates involuntary processes

axon

long projection of neuron, transmits electrical signals

catechol

chemical structure consisting of a benzene ring with two adjacent hydroxyl groups, forms backbone of catecholamines

catecholamine

group of neurotransmitters and hormones including dopamine, noradrenaline

catechol-O-methyltransferase (COMT)

enzyme that metabolises catecholamines by adding a methyl group, reducing activity

CNS

brain and spinal cord, for processing and integrating sensory information, co-ordinating motor input

choline acetyltransferase

enzyme that synthesises acetylcholine from choline and acetyl-CoA

dopa decarboxylase

enzyme that converts L-DOPA into dopamine and catecholamine biosynthesis

dopamine

catecholamine neurotransmitter involved in motor control, reward and mood regulation

dopamine beta hydroxylase

enzyme that converts dopamine to noradrenaline

epinephrine

american for adrenaline

enteric nervous system

division of ANS located in gastrointestinal tract, capable of regulating digestion

fast synaptic transmission is mediated by

acetylcholine or glutamate

ganglion

cluster of nerve cell bodies in PNS

G protein

membrane associated protein that links G protein coupled receptors to intracellular signaling pathways

G protein coupled receptor

transduces extracellular signals into cellular responses via G proteins

L-DOPA

precursor to dopamine in dopamine synthesis, used in treatment of parkinsons disease

monoamine

class of neurotransmitters that includes catecholamines, serotonin, histamine and melatonin

monoamine oxidase

enzyme that degrades monoamines

motor

cns → muscles or glands

muscarinic acetylcholine receptor

acetylcholine receptor found on parasympathetic target tissues

NET

noradrenaline transporter, moves noradrenaline from synaptic cleft to terminate its action

nicotinic acetylcholine receptors location

ion channel receptors activated by acetylcholine,

• found at autonomic ganglia and on skeletal muscle at neuromuscular junctions

noradrenaline released by

sympathetic nerves and the adrenal medulla

norepinephrine

american for noradrenaline

paravertebral ganglia

sympathetic ganglia arranged in chains on either side of the vertebral column

pns

branch of cns, includes somatic and ans

Phenylethanolamine-N-methyltransferase

An enzyme that converts noradrenaline into adrenaline in the adrenal medulla.

Post-ganglionic neuron

A neuron in the autonomic nervous system that transmits signals from a ganglion to the target tissue.

Pre-ganglionic neuron

A neuron in the autonomic nervous system that transmits signals from the CNS to an autonomic ganglion.

Prevertebral ganglia

• Sympathetic ganglia located near major abdominal arteries

• innervating abdominal and pelvic organs

• unpaired

Somatic nervous system

The part of the peripheral nervous system that controls voluntary movements of skeletal muscles.

Sympathetic nervous system

A branch of the autonomic nervous system responsible for 'fight, fright or flight' responses, increasing heart rate, blood pressure, and energy mobilization.

Tyrosine hydroxylase

An enzyme that catalyzes the conversion of tyrosine to L-DOPA, the first step in catecholamine synthesis.

Uptake 2

A low-affinity transport mechanism for removing catecholamines from the extracellular space, primarily in non-neuronal tissues.