Edit · Neurotransmitters, Brain Structures, and Nervous System Functions

Acetylcholine (ACh)

Enables muscle action; excitatory (causes neurons to fire); undersupply marks Alzheimer's disease.

Dopamine

Influences movement, attention, and emotion (pleasure); inhibitory (causes neurons to not fire); excess linked to schizophrenia, limited dopamine produces tremors and decreased mobility of Parkinson's disease.

Serotonin

Affects mood, hunger, sleep onset, and arousal; inhibitory; undersupply linked to depression; Prozac and other antidepressants raise serotonin levels.

Norepinephrine

Helps control alertness and arousal; excitatory; undersupply can depress mood.

GABA

Inhibitory; decreases anxiety; undersupply linked to seizures, tremors, and insomnia.

Glutamate

Excitatory; involved in memory; oversupply can stimulate the brain, producing migraines.

Endorphins

Inhibits transmission of pain messages; oversupply with opioid drugs can suppress the body's endorphin supply.

Substance P

Modulation of pain; oversupply can lead to chronic pain.

Reuptake

Process where neurotransmitters are reabsorbed into axon terminals to be used again.

Botulism toxin

Prevents the release of ACh, causing paralysis and death.

Black widow toxin

Causes too much ACh to be released, resulting in spasms and tremors.

Cocaine

Blocks the reabsorption of dopamine, increasing its concentration in the synaptic cleft.

Agonist

Binds directly to a receptor site that mimics a neurotransmitter.

Antagonist

Blocks receptor sites.

Schizophrenia

Associated with an overactivity of dopamine; some drugs block dopamine receptors.

Depression

Linked to reduced serotonin; antidepressants like Prozac block the reuptake of serotonin.

All or none principle

The toilet either flushes or it doesn't; it doesn't half flush.

Direction of impulse

The water goes down the toilet and away.

Refractory period

After a toilet flushes, there is a time where the tank has to fill up again before it can flush again.

Threshold

It takes a certain amount of pressure on the handles before the toilet flushes; not enough pressure and it won't flush.

Central nervous system

Consists of the brain and spinal cord.

Peripheral nervous system

Relays messages from the central nervous system to the rest of the body.

Autonomic nervous system

Controls self-regulated actions of internal organs and glands; involuntary processes.

Somatic nervous system

Controls voluntary movement and sensory input.

Sympathetic nervous system

Causes arousal when frightened or threatened.

Parasympathetic nervous system

Calming when a threat has passed.

Neuron

Individual cells that are the smallest unit of the nervous system.

Cell Body

Soma; contains a nucleus where metabolism takes place.

Dendrites

Short fibers that extend from the cell body and pick up incoming messages.

Axon

Long fiber that extends out from the cell body; carries outgoing messages.

Myelin Sheath

White fatty covering found on some axons; acts as insulation and conductor to speed the electrical impulse.

Terminal Buttons

Small knobs that store and secrete neurotransmitters.

Multiple Sclerosis

A disease in which the immune system attacks the myelin of neurons in the central nervous system.

Reflex

When you put your hand on a hot stove, receptors send messages from afferent neurons through interneurons to the spinal cord, where efferent neurons send a message to your muscles causing you to pull your hand away.

Mirror neurons

Important for observational learning.

Resting Potential

The cell's stable negative charge when the neuron is inactive.

Action Potential

A brief change in the neuron's electrical charge or depolarization.

Threshold of excitation

The minimum number of impulses received from neighboring neurons to cause the cell to fire.

Sodium ions

Positively charged ions that enter the cell during an action potential.

Absolute refractory period

The minimum length of time after an action potential before another action potential can begin.

All or none law

A neuron either fires or it doesn't; it can't half fire.

Neuroplasticity

The structural and functional organization of the brain is more malleable than previously thought.

MEG (magnetoencephalography)

A technique that measures magnetic fields from the brain's natural electrical activity.

Myasthenia gravis (MG)

A rare autoimmune disorder that causes muscle weakness due to antibodies forming against acetylcholine receptors.

Endocrine system

Consists of glands that secrete chemicals into the bloodstream to help control bodily functions.

Hormones

Chemical substances released by the endocrine glands.

Hypothalamus

Controls the endocrine system by activating the pituitary gland.

Pituitary gland

The master gland of the endocrine system that releases a variety of hormones.

Leptin

A hormone that reduces appetite and hunger.

Ghrelin

A hormone that increases appetite and food intake while reducing metabolic rate.

Melatonin

A hormone that regulates the sleep-wake cycle.

Oxytocin

A hormone that plays a role in sexual arousal, trust, and mother-infant bonding.

Cortisol

A hormone released in response to stress.

Frontal lobe

Controls motor area, reasoning, planning, organizing, and speaking language.

Occipital lobe

Contains the primary visual cortex where visual processing begins.

Parietal lobe

Processes and organizes information, including touch and pain registration.

Temporal lobe

Involved in hearing, understanding language, and object recognition.

Brain lateralization

The specialization of the right and left hemispheres of the brain for different functions.

Broca's area

Involved in the production of speech.

Wernicke's area

Involved in the comprehension of language.

Aphasia

Loss of ability to understand or express speech due to brain damage.

Split brain studies

Research on patients with severed corpus callosum to understand lateralization.

Medulla

Part of the brainstem responsible for breathing, heartbeat, and circulation.

Reticular formation

Modulates muscle reflexes, breathing, and sleep/wakefulness.

Pons

Part of the hindbrain associated with sleep and arousal.

Thalamus

Relays sensory information except for smell.

Cerebellum

Coordinates movement, balance, and equilibrium.

Limbic system

Regulates emotion, memory, and motivation.

Hippocampus

Involved in learning and memory.

Clinical observation

The oldest method of studying brain-mind connections through observing effects of brain disease.

Lesioning

Involves destroying a piece of the brain to study behavior relationships.

EEG (Electroencephalograph)

Monitors electrical activity of the brain over time.

CT Scan

A computer-enhanced x-ray of brain structure.

PET Scan

Monitors brain activity over time using radioactively labeled glucose.

MRI (Magnetic Resonance Imaging)

Uses magnetic fields and radio waves to map out brain structure.

fMRI (Functional MRI)

Monitors blood and oxygen flow in the brain to identify areas of high activity.