1.3a The Neuron and Neural Firing

Neurons

The base building blocks of the nervous system.

Dendrites

Receives messages from other cells

Cell Body

The cell's life-support system

Myelin Sheath

Covers the axon of some neurons and helps speed neural impulses

Axon

Passes messages away from the cell body to other neurons, muscles, or glands

Terminal Branches of Axon

Forms junctions with other cells

- connects to other dendrites

Multiple Sclerosis

Caused by myelin degeneration, a disease in which communication to muscles slow, and eventually the person loses muscle control

Glial Cells

Provides nutrients and insulating myelin

Refractory Period

Once a neuron fires, it needs time before it can fire again

- All-or-nothing

All-or-Nothing

Neurons either fire or they don't

Synapse

Meeting point between neurons

Neurotransmitters

Messages releases from neurons

- In mental illness, this is either low or high neurotransmitters.

Reuptake

Reabsorbed by the sending neuron

- excess neurotransmitters are present or too little are present to fill in spots

Agonist

Increase a neurotransmitter's action

Leptin

Hormone secreted by fat cells, when there is enough of it tells your body that it's full and speeds up metabolism to digest food

Antagonist

Decrease a neurotransmitter's action by blocking production or release

Adrenaline

Helps the body produce for stressful or dangerous situations

Ghrelin

Hormone secreted by empty stomach

Melatonin

Helps you sleep; produced by the brain when dark

Oxytocin

Manages key aspects of the female and male reproductive systems

Hormones

Influence our interest in sex, food, and aggression

Acetylcholine

Enables muscle action, learning, and memory. If not present, or in limited quantities, can be linked to Alzheimer’s disease.

Dopamine

Influences movement, learning, attention, and emotion. Oversupply links to schizophrenia, and undersupply can lead to tremors in Parkinson’s disease.

Serotonin

Affects mood, hunger, sleep, and arousal. Undersupply can be linked to depression.

Norepinephrine

Helps control alertness and arousal. Undersupply can depress mood.

GABA

A major inhibitory neurotransmitter. Undersupply can be linked to seizures, tremors, and insomnia.

Glutamate

A major excitatory neurotransmitter; involved in memory. Oversupply can overstimulate the brain; producing migrains or seizures.

Endorphins

Neurotransmitters that influence the perception of pain or pleasure. Oversupply with opiod drugs can suppress the body’s natural endorphin supply.

Substance P

Involved in pain perception and immune response. Oversupply can lead to chronic pain.