Week 4: Micro-Neuroanatomy

Neurons

individual nerve cells that transmit electrochemical impulses

electrical communication

• within neurons, action potentials

• intra-neuronal communication

chemical communication

• between neurons, neurotransmitters

• inter-neuronal communication

Sensory neurons

transmit info from sensory receptors to brain

Motor neurons

transmit info from brain to muscles and organs

Interneurons

transmit info between neurons

unipolar neuron

one projection from the cell body, which can sometimes be a dendrite or axon, depending on its function

bipolar neuron

has two projections and plays an important role in the visual system

multipolar neuron

many projections and most commonly found in the brain

pseudo-unipolar neurons

one projection that splits into a dendrite and axon. most commonly long sensory and motor neurons that traverse the whole body

Glial cells

provide nutrients to neurons and structural support to the nervous system

Neural signalling

how info is transmitted

grey matter

cell bodies and dendrites, outer brain, processing info

white matter

myelinated axons, inside brain, transmission of info

Cell body

heart of neurons, receives inputs from nearby neurons

nucleus

Contains cell DNA; control house containing info about how cell should structure and function

Dendrites

receive inputs from surrounding neurons via receptors

Axon

long extension from cell body; transmits action potentials

Axon Hillock

Region connecting axon to cell body

Myelin

fatty deposit covering axon; insulation for electrical signal

Nodes of Ranvier

Sections of unmyelinated axon

Terminal Buttons

ends of axon; site where neurons chemically communicate with surrounding neurons

Synapse/Synaptic Cleft

tiny space between terminal button and dendrites

Glutamate

• Excitatory

• Epilepsy and seizures

• Learning and memory

GABA

• Inhibitory

• Affected by alcohol (GABA blocked; cause of disinhibition)

• Anxiety, relaxes muscles

• Xanax/ Valium (muscle relaxants) inhibit anxiety areas

Dopamine

• Pleasure & motivation

• May be released during eating, sex and drinking behaviours

• Addictive drugs – methamphetamine & cocaine (↑ ↑ ↑ dopamine)

• Movement, emotional arousal, learning

• Parkinson’s disease (low lvls), Schizophrenia (high lvls)

Serotonin

• Involved in mood regulation, sleep, eating and arousal

• Major Depression (↓ serotonin)

• May also underlie pleasure and pain (SSRIs)

• Associated with ecstasy use (↑ serotonin)

Acetylcholine

• Important for muscle control between nerves and muscles

• Involved with cognition, learning, memory, sleeping and dreaming

• Alzheimer’s Disease

Endorphins

• Pain reduction, reward, mood

• Released when in immense pain

• Morphine and heroin