All Unit 2 Vocab

Neuron

Individual cells which provide basic communication within the nervous system.

Dendrites

Receive information from other neurons

Cell Body (Soma)

contains nucleus with chromosomes

Axon

transmits information to other neurons

Myelin Sheath

Insulating layer of fatty material- Glial Cells

multiple sclerosis

immune system attacks the myelin

Messages don't travel efficiently- scar like

Glial Cells

support system for neurons, facilitate message transmission, remove damaged/dead neurons.

Action potential

A brief electrical signal that travels down the axon of a neuron, caused by the movement of ions across the cell membrane.

Autonomic nervous system (ANS)

The part of the peripheral nervous system that controls involuntary body functions, like heart rate, digestion, and breathing.

Axons

Long, thin extensions of neurons that carry electrical impulses away from the cell body toward other neurons, muscles, or glands.

Central nervous system (CNS)

Made up of the brain and spinal cord; it processes and interprets information from the body and environment.

Depolarization

The process during an action potential when sodium ions rush into the neuron, making the inside less negative and causing the electrical signal to fire.

Interneurons

Nerve cells in the brain and spinal cord that connect sensory neurons to motor neurons; they handle processing and reflexes.

Neurons

The basic cells of the nervous system that send and receive information using electrical and chemical signals.

Parasympathetic nervous system

A branch of the autonomic nervous system that calms the body and conserves energy ("rest and digest").

Peripheral nervous system (PNS)

All the nerves outside the brain and spinal cord; it links the CNS to the rest of the body.

Polarization

When a neuron is at rest, with the inside of the cell being more negatively charged than the outside.

Receptor sites

Locations on a neuron's dendrites where neurotransmitters bind to pass along a signal.

Reflex arc

A simple pathway involving sensory neurons, interneurons, and motor neurons that produces an automatic response without the brain's direct involvement.

Refractory period

The short time after an action potential when a neuron cannot fire again until it resets.

Resting potential

The stable, negative electrical charge of a neuron when it is not firing (around -70 mV).

Reuptake

The process by which neurotransmitters are reabsorbed back into the presynaptic neuron after sending a signal.

Somatic nervous system

The part of the peripheral nervous system that controls voluntary muscle movements and carries sensory information.

Sympathetic nervous system

A branch of the autonomic nervous system that prepares the body for action in stressful situations ("fight or flight").

Threshold

The level of stimulation a neuron needs to reach before it will fire an action potential.

Vesicles

Small sacs in the axon terminals that store neurotransmitters and release them into the synapse during communication.

Neurotransmitters

a chemical messenger that transmits information

Excitatory Neurotransmitters

Excite connections neurons and cause them to fire

Inhibitory Neurotransmitters

Prevent the next neuron from firing

Agonists

Drugs that excite by mimicking a particular Neurotransmitter or blocking its reuptake

Antagonists

Substances that inhibit, or block action of Neurotransmitter

Dopamine (Reward Neurotransmitter)

Excitatory

Pleasure, movement, (learning, attention)

Abnormally high: linked to schizophrenia, addiction

Cocaine & amphetamines agonist drugs

Low levels: Parkinson's disease, muscle rigidity

Serotonin (Mood Neurotransmitter)

Inhibitory

Mood, (hunger, sleep, arousal, pain perception)

Abnormally low levels: linked to depression, anxiety, mood disorders, OCD

Antidepressants - SSRI's

High levels: shivering, seizures, hallucinations

GABA (calming neurotransmitter)

GABA (gamma-aminobutyric acid) - Inhibitory

Balances excitatory messages

Contributes to regulation of anxiety

Regulates daily sleep and wake cycles

Low levels: anxiety and tremors

High levels: sleep and eating disorders

Glutamate (memory neurotransmitter)

Excitatory

(opposite of GABA)

Thinking, memory, learning - strengthening neural connections

High levels: agitation, memory loss, migraines, seizures *msg

Low levels: anxiety, restlessness, insomnia

Norepinephrine - The Fight or Flight Neurotransmitter

Excitatory

Alertness & arousal

Increasing heartbeat, arousal, memory, learning, and eating

Abnormally low levels: linked to depression

High levels: Anxiety

*also known as adrenaline

Acetylcholine (Movement and Memory Neurotransmitter)

Excitatory

Muscle action/contractions; learning/memory

Messenger at every junction between motor neuron & skeletal muscle

High levels: violent muscles contractions, convulsions, death (agonist - Black Widow spider venom)

Low levels: Paralysis, Alzheimer's Disease - dementia (memory impairment)

Myasthenia Gravis Immune system destroys the muscles receptor sites for Acetylcholine

fewer receptors lead to fewer messages sent and extreme muscle weakness

Substance P (Pain Preceptor)

excitatory neuromodulator

Sends pain signals in central nervous system

Released from sensory neurons in skin, muscles, joints

stress response, mood regulation, inflammation

High levels: inflammation, depression

Low levels: reduced pain sensitivity and motor control

Endorphins (euphoria neurotransmitter)

Inhibitory

"morphine within" - natural opiates

pain control and pleasure

released in response to pain and vigorous exercise (!)

Low levels: pain

High levels: body may not give warning about pain/danger - artificial high

Cerebral Cortex

Outer covering of two hemispheres of the brain, responsible for the most complex aspects of perception, emotion, movement and thought

Frontal Lobe

planning, judgment, reasoning, abstract thinking, impulse control, movement (motor cortex) *cues amygdala for emotions

-Last to develop and myelinate

Prefrontal Cortex

higher order thinking, executive functions

Motor Cortex

Larger areas of motor cortex= more precise control

Broca's area

LEFT only - responsible for speech production

Damage to Broca's Area can lead to speech disruption known as aphasia.

Broca's aphasia

makes speech very slow, slurred and labored, no comprehension problems

Parietal Lobe

nformation about touch (sensory cortex) and pain perception

governs spatial awareness and navigation

Left hemisphere involved in mathematics, reading, writing and understanding symbols.

Sensory (Somatosensory) Cortex

The sensory cortex interprets sensations such as touch, temperature and pain on the body

Temporal Lobe

hearing, language

auditory cortex:

detection of sound, pitch, and frequency, and language switching

Wernicke's Area

LEFT ONLY - responsible for comprehension of written and spoken language

Wernicke's Aphasia

Speech is incomprehensible

patients have great difficulty understanding

Speech is NOT slurred

Occipital Lobe

visual processing

Visual Cortex

specialized for different aspects of vision - sends info out to other parts of the brain

Corpus Callosum

The brain is separated into two hemispheres that:

control the opposite sides of the body (contralateral control)

are connected by corpus callosum - think bundle of nerve fibers

Limbic System

They hypothalamus, hippocampus, thalamus and amygdala

Hippocampus

Creates new memories

Integrates, consolidates, and stores memories

Amygdala - emotion center

tip of each side of the hippocampus

central role in emotional processes

formation of emotional memories

associated with fear and reward

Hypothalamus - "regulator"

Regulates body temperature, sleep-wake cycles

Helps govern endocrine system

Houses "reward centers"

Controls maintenance functions, such as eating and drinking

Thalamus - "relay station

Processing and relaying information from sensory receptors to other parts of the brain (*except smell).

Pituitary Gland

Receives signals from hypothalamus

Releases hormonal signals - activate sympathetic and parasympathetic nervous system

Cerebellum

coordinates voluntary movements and balance - enables nonverbal learning (classical conditioning)

Reticular activating system

ends messages to thalamus, hypothalamus and cortex to activate arousal levels

Medulla

Controls heartbeat and breathing

Spinal Cord

Tubular bundle of nervous tissue and support cells (central nervous system)

Extends from medulla to the lumbar region

Transmission of nerve signals

Split Brain Contralaterality

Right visual field is connected to the left hemisphere (language center)

Can talk about it

Left visual field is connected to the right hemisphere

Can't talk about it but CAN "draw" (left hand)

EEG

(Electroencephalogram)

Measures the electrical activity in the brain

Can show which areas of the brain are active or have abnormalities

CAT Scan

Xray images, combined

Can detect abnormalities like tumors

MRI

Magnetic fields to construct image

fMRI

Detects un/oxygenated blood

Identifies areas in the brain that are most active

Transcranial Magnetic Stimulation (TMS)

Non-invasive - wand alters the magnetic fields and affects how the brain processes "reset"

Can help with depression and PTSD

Lesioning

Destruction of brain tissue - can be extreme treatment or experimental

Heredity

Genetics

Predisposed characteristics

Brain Plasticity

Brains change as a result of experience

Hemispherectomy

EXTREME - Used to treat behavioral disorders or severe seizures

Removal of one hemisphere of the brain

Lobectomy

removal of a lobe

multiple sclerosis

a chronic autoimmune disease that affects the central nervous system(brain and spinal cord)

myasthenia gravis