Unit 1 (Neurons and Neurotransmitters)

Soma

The cell body of a neuron, the cell’s life support center.

Dendrites

Tentacle structure that receive messages.

Axon

Pass messages away from the soma to other neurons muscles, and glands. Functions like a mouth that talks.

Myelin Sheath

Fatty tissue over the the axon of neurons that insulate the axon and speeds up the neural impulse. Remains underdeveloped until age 25.

Multiple Sclerosis

When your body attacks myelin, you have develop slowed communication between muscles and brain. Leads to muscle degeneration and control loss. There is no cure. Mainly affects women.

Schwann Cell

Myelin sheath is made up of individual ones of these cells.

Nodes of Ranvier

Gaps in myelin sheath, information hops between fatty schwann cells.

Glial Cells

Support cells of the neuron.

Axon Terminals

Ends of the axons. Forms the junction to another neuron.

Axon Hillock

Lock for the axon, decides whether the neuron fires from the information collected by the dendrites.

Synaptic Vesicles

Lives inside the axon terminals and are containers for neurotransmitters that are released into the synapse.

Neurotransmitters

Body’s chemical messenger that transmit messages to the next neuron. All have a different chemical make-up.

Receptor Site

On the post-synaptic neuron and is the location where neurotransmitters bind, and then return to pre-synaptic neuron.

Excitatory Synapse

Action potential is more likely.

Inhibitory synapse

Action potential is less likely

Serotonin

Can be excitatory or inhibitory. Not enough leads to depression and too much leads to anxiety.

Selective Serotonin Reuptake Inhibitor

Some serotonin is not allowed to re-uptake after release and thus continuously binds to other receptor sites. Usually takes a couple of weeks to work.

Norepinephrine

Hormone or neurotransmitter. Can be excitatory or inhibitory. Not enough causes depression. Helps release glucose to support your body’s flight or fight response.

GABA (Gaba-aminobutyric acid)

Only inhibitory, helps to calm anxiety. Not enough can lead to seizure tremors and insomnia.

Glutamate

Only excitatory. Too much can overstimulate brain, causes migraines and seizures. Affects synaptic plasticity, learning, memory, and nervous system development.

Endorphins

Creates pain relief and are natural opiates. No established problems, unless man-made.

Substance P

Excitatory and inhibitory. Helps create pain perception. In excess causes chronic inflammation.

Acetylcholine (ACh)

Excitatory and Inhibitory, causes Alzheimer’s and Myasthenia Gravis (autoimmune disorder where body mistakenly attacks ACh especially facial muscles)

Dopamine

Mainly excitatory. Not enough creates Parkinson’s Disease while too much causes Schizophrenia.

Epinephrine

Hormone and neurotransmitter, Adrenaline as a hormone. Mainly excitatory. Too much leads to cardiovascular problems, anxiety, or tremors.

Resting Potential

Neuron is at rest, ot firing. At homeostasis. Polar.

Graded Potential

Slight shift in charge, not enough for it to fire.

Threshold of Excitation

the level of impulse must exceed to cause a neuron to fire.

Neural Firing

Action Potential. Depolarizes.

Transduction in Neuronal Firing

conversion of energy from one form to another (electrical → chemical → electrical)

Synaptic Vesicles

Release neurotransmitters and pass the impulse on to the next neuron

Refractory Period

Where the neuron recharges and returns back to polar state. Cannot fire at this state.

Intensity of Neural Firing

Remains the same throughout the axon

All or Nothing

Neuron has a complete response or gives no response.

Action potential is fueled by…

Sequential Na+ and K- pumps.

Saltatory Conduction

When the message hops from node to nodeRe

Reuptake

Where the neurotransmitter is returned to the original neuron

Agonist

Mimics the neurotransmitters and its effects

Antagonist

These inhibit, with a structure similar enough to the neurotransmitter to occupy the receptor but not similar enough to stimulate it

Psychoactive Drug

A chemical substance that alters perception or mood

Substance-Use Disorder

Professional word for a drug addict

Tolerance

Repeated exposure to a drug creates more of a tolerance and requires more of the drug to reach the same high.

depressants

Reduce neural activity and slow you down

Examples of Depressants

Alcohol, Barbiturates (tranquilizers), opioids, and heroin

Stimulants

Excite neural activity and speeds your body up

Examples of Stimulants

Meth, caffeine, and nicotine

Ectasy can be categorized as…

a stimulant or mild hallucinogen

Hallucinogen

Psychedelic drugs that distort perceptions and evoke sensory images in the absence of sensory perception

Examples of Hallucinogens

LSD and Marijuana

Withdrawal

Your body’s reaction when a substance it’s reliant on is taken away

Central Nervous System

Body’s Ultimate decision maker, made up of the spinal cord and the brain

Peripheral Nervous System

Anything that is not on your CNS; connects your CNS to the rest of the body

Autonomic Nervous System

Controls glands and muscles of internal organs

Sympathetic Nervous System

Expends energy and speeds you. Stress management, fight, flight, freeze. Arousing.

Parasympathetic Nervous System

Anything that is not your CNS; connects your CNS to the rest of the body. Calming.

Somatic Nervous System

Body’s nervous system; controls body’s skelatal muscles

Sensory/Afferent Neurons

Sends info to CNS

Motor/Efferent Neurons

Info comes from the CNS

Interneurons

Connects sensor to motor

Melatonin

Makes you sleep, regulates circadian rythms

Ghrelin

Released when you’re hungry

Leptin

Tells you when you’re full

Oxytocin

Love hormone, helps with positive emotions