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Glial cells

• support cells in the nervous system

• protect, nourish, and clean up neurons

• help with myelin formation

Dendrites

• receive messages from other neurons

• branch-like parts of a neuron

• carry signals toward the cell body

Axon

• long part of neuron that sends signals

• carries electrical impulses away from cell body

• ends in terminals that communicate with other neurons

Order of a neuron firing

• dendrites receive signal

• cell body processes signal

• axon sends electrical impulse

• axon terminals release neurotransmitters

• signal crosses synapse to next neuron

Myelin sheath

• fatty covering around axon

• speeds up neural transmission

• prevents signal loss

Action potential

• electrical impulse fired by neuron

• travels down axon

• all-or-nothing signal

Threshold

• level of stimulation needed to fire neuron

• if not reached, neuron does not fire

• “trigger point” for action potential

All-or-none response

• neuron either fires fully or not at all

• no partial firing

• intensity does not change strength of signal

Synapse

• gap between neurons
• site of communication
• neurotransmitters cross here

Synaptic gap

• tiny space between neurons
• where neurotransmitters travel
• separates sending and receiving neurons

Endorphins

• natural painkillers in brain
• reduce pain and increase pleasure
• released during stress or exercise

Serotonin

• affects mood, sleep, appetite
• low levels linked to depression
• helps regulate emotional stability

Acetylcholine

• involved in muscle movement

• helps memory and learning

• important in nervous system signaling

Dopamine

• linked to reward and pleasure

• involved in motivation and addiction

• affects movement and reinforcement learning

GABA

• main inhibitory neurotransmitter

• reduces neural activity

• helps calm brain activity

Agonists

• increase neurotransmitter effect

• mimic or boost neurotransmitters

• can activate receptor sites

Antagonists

• block neurotransmitter effects
• prevent neurotransmitters from working
• reduce neural activity

Pituitary gland

• “master gland” of endocrine system
• controls other hormone glands
• releases hormones affecting growth and stress

Adrenal glands

• release stress hormones like adrenaline

• involved in fight-or-flight response

• increase heart rate and energy

Reuptake

• neurotransmitter is reabsorbed by sending neuron

• stops signal between neurons

• recycles chemicals

Prozac

• SSRI antidepressant drug

• increases serotonin availability

• blocks reuptake of serotonin

Somatic nervous system

• controls voluntary movements

• carries messages to skeletal muscles

• allows conscious control of body

Peripheral nervous system

• all nerves outside brain and spinal cord

• connects CNS to body

• includes somatic and autonomic systems

Sympathetic nervous system

• activates fight-or-flight response

• increases heart rate and energy

• prepares body for stress

Parasympathetic nervous system

• calms body after stress

• slows heart rate

• restores rest-and-digest state

Oldest to newest brain regions

• brainstem (medulla first)

• cerebellum

• limbic system (thalamus included)

• cortex (frontal, parietal, temporal, occipital newest)

• newer regions handle complex thinking

Medulla

• controls breathing and heartbeat
• basic life functions
• located in brainstem

Thalamus

• sensory relay station
• sends info to correct brain areas
• located above brainstem

Cerebellum

• coordinates balance and movement
• helps with motor learning
• fine motor control

Parietal lobes

• processes touch and spatial awareness
• helps body position understanding
• integrates sensory info

Occipital lobes

• processes vision

• visual information center

• located at back of brain

Frontal lobes

• decision making and planning

• personality and impulse control

• contains motor cortex

Motor cortex

• controls voluntary movement

• sends signals to muscles

• located in frontal lobe

Temporal lobes

• processes hearing

• involved in language and memory

• located near ears

Brain plasticity

• brain’s ability to change and adapt

• forms new neural connections

• especially strong in learning and recovery

Corpus callosum

• connects left and right brain hemispheres

• allows communication between sides

• damage can affect coordination

Epileptic seizures

• uncontrolled brain electrical activity

• can cause convulsions or loss of awareness

• sometimes linked to split corpus callosum

Identical vs fraternal twins

• identical

Nature and nurture

• nature = genetics and biology
• nurture = environment and experience
• both influence behavior

Absolute threshold

• smallest stimulus detected 50% of the time
• minimum detectable level
• varies by sense

Difference threshold

• smallest detectable difference between stimuli
• also called just noticeable difference (JND)
• depends on stimulus strength

Retina

• light-sensitive layer in eye
• contains rods and cones
• converts light into neural signals

Pupil

• opening in eye that lets light in
• changes size with light levels
• controlled by iris

Cornea

• clear outer covering of eye

• helps focus light

• protects eye

Iris

• colored part of eye

• controls pupil size

• regulates light entry

Lens

• focuses light onto retina

• changes shape for near/far vision

• helps image clarity

Rods and cones

• rods

Young-Helmholtz theory of color

• three cone types (red, green, blue)

• colors come from combination of cones

• explains color vision

Opponent-process theory of color

• colors processed in opposing pairs

• red-green, blue-yellow, black-white

• explains afterimages

Relative height

• objects higher in visual field seem farther

• depth cue

• used in perception

Linear perspective

• parallel lines converge in distance

• depth cue for distance

• used in art and vision

Interposition

• closer objects block farther ones

• depth perception cue

• object overlap

Relative size

• smaller object assumed farther away

• compares known object sizes

• depth perception cue

Basilar membrane

• structure in cochlea

• contains hair cells for hearing

• vibrates with sound

Cochlea

• spiral-shaped inner ear structure

• converts sound waves to signals

• filled with fluid

Hair cells in basilar membrane

• sensory receptors for sound

• convert vibration into neural signals

• damaged cells cause hearing loss

Place theory of sound

• pitch depends on location on basilar membrane

• high pitches at base

• low pitches at tip

Frequency theory of sound

• pitch based on firing rate of neurons

• works for low-frequency sounds

• neurons match sound wave frequency

Volley principle of pitch

• groups of neurons fire in sequence

• helps process high-frequency sounds

• improves frequency theory limits

Gate-control theory

• spinal cord acts as “gate” for pain

• brain can open or close pain signals

• explains psychological pain control

Umami

• savory taste (meaty, rich foods)

• fifth basic taste

• detects amino acids

Olfaction

• sense of smell

• detects airborne chemicals

• directly linked to memory

Semicircular canals

• fluid-filled inner ear structures
• detect head movement
• help balance

Vestibular sense

• sense of balance and body position

• inner ear system

• helps maintain equilibrium

Sensory interaction

• senses influence each other

• smell affects taste

• brain combines sensory info

Endorphins

• function-reduce pain and create feelings of pleasure

• released during exercise, stress, or excitement

• malfunction

Serotonin

• function-regulates mood, sleep, and appetite

• helps emotional stability and well-being

• malfunction

Acetylcholine (ACh)

• function- enables muscle movement

• important for learning and memory

• malfunction

Dopamine

• function- controls movement, reward, and motivation

• involved in pleasure and reinforcement

• malfunction

GABA

• function- main inhibitory neurotransmitter (calms brain activity)

• reduces anxiety and overexcitement

• malfunction

Norepinephrine

* function- controls alertness and arousal
* involved in stress response (fight-or-flight)
* malfunction

Glutamate

* function-main excitatory neurotransmitter
* involved in learning and memory
* malfunction

Substance P

* function- involved in pain perception
* sends pain signals to the brain
* malfunction