sensory input: info gathered by sensory receptors about internal/ external changes

integration: processing and interpretation of sensory input

motor output: activation of effector organs (muscles and glands) produces a response

integration & control center: interprets sensory input and dictates motor output

somatic sensory fibers: convey impulses from skin, skeletal muscles, and joints TO CNS

visceral sensory fibers: convey impulses from visceral organs TO CNS

transmits impulses from CNS to effector organs (muscles & glands)

somatic nervous system (voluntary): somatic motor nerve fibers conduct impulses from CNS to skeletal muscle

autonomic nervous system (involuntary): consists visceral motor nerve fibers, regulates smooth/ cardiac muscles, glands

Parasympathetic division (rest & digest system): keeps body energy use low; directs digestion, diuresis, defacation

Sympathetic division (flight or flight system): mobilizes body during activity; exercise, excitement, emergency, embarrassment activates system

Multipolar: 3 or more processes (1 axon, others dendrites), most common, major neuron type in CNS

Sensory: transmit impulses from sensory receptors toward CNS, unipolar, cell bodies located in ganglia in PNS

Motor: carry impulses from CNS to effectors, multipolar, cell bodies located in CNS

Interneurons: lie between motor & sensory neurons, shuttle signals through CNS pathways, most within CNS, 99% body neurons

endoneurium: loose CT- encloses axons and their myelin sheaths

epineurium: tough fibrous sheath around fascicles to form nerve

Depolarization: depolarizing local currents open voltage-gated Na+ channels= Na+ rushes into cell

Na+ influx= more depolarization= more Na+ channels open

Repolarization: Na+ channels inactivating, K+ channels open

Hyperpolarization: some K+ channels remain open, Na+ channels reset

mimics natural opiates and binds to opiate receptors, turning off dopamine inhibition

dopamine is allowed to flood the synapse, producing feelings of sedation and well-being

mimics serotonin and is taken up by serotonin transporters; transporter becomes confused; transports serotonin out of cell causing it to bind to the receptors over and over, overstimulating the cell

affects serotonin pathways responsible for mood, sleep, perception, appetite

THC mimics anandamide and binds to cannabinoid receptors; inhibition turned off and dopamine is allowed to squirt into synapse

anandamide is responsible for slowing down movement- relaxed and calm; unlike THC, anandamide breaks down quickly in the body

causes transporters to work in reverse- pumping dopamine out of cell and into synapse; excess dopamine binds over and over, overstimulating the cell

interacts with GABA receptors to make them even more inhibitory; binds to glutamate receptors preventing glutamate from exciting the cell

affects areas of brain involved in memory formation, decision making, impulse control

blocks dopamine transporters leaving dopamine trapped in synaptic cleft; binds over and over, overstimulating the cell

excites locus coeruleus (responsible for wakefulness and evoking a startle response to unexpected stimulus)

Astrocytes: most abundant, versatile, highly branched of glial cells

function: support/ brace neurons, play role in exchanges between capillaries/neurons, guide migration of young neurons, control chemical environment around neurons

Microglial cells: small, ovoid cells with thorny processes that tough/ monitory neurons

function: regulate brain development, maintenance of neuronal networks, and injury repair

Ependymal cells: range in shape from squamous to columnar, may be ciliated

function: form permeable barrier between CSF in cavities & tissue fluid bathing CNS cells

function: processes wrap CNS nerve fibers, forming insulating myeline sheaths in thicker nerve fibers

Schwann cells (neurolemmocytes): surround all peripheral nerve fibers & form myelin sheaths in thicker nerve fibers

motor neurons that contain short, tapering, diffusely branched processes

convey incoming messages toward cell body as graded potentials (short) distance signals)

function: protect & electrically insulate axon, increase speed of nerve impulse transmission

in some neurons axons are short/absent; in others axon compromises almost entire length of cell

generates nerve impulses & transmits them along axolemma to axon terminal

dorsal horns: interneurons that receive somatic & visceral sensory input

ventral horns: some interneurons; somatic motor neurons

lateral horns: only in thoracic/superior lumbar regions; sympathetic neurons

ventral roots: bundle of motor neuron axons which exit spinal cord

dorsal root (spinal) ganglia: cell bodies of sensory neurons

gray commisure: bridge of gray matter that connects masses of gray matter on either side

FUNCTIONS: provide 2 way communication to/from brain and body, major reflex center: reflexes initiated/completed at spinal cord

gray matter is located in core, white matter is located outside