Nervous system

Sensory function

signals are sent to the brain and spinal cord

somatic sensory input detects

stimuli you are conscious of

visceral sensory system detects

subconcious stimuli

motor function (output)

signals are sent away from the brain and spinal cord towards muscles or hormone glands

somatic motor division

conscious signals are sent to the skeletal system

autonomic motor division

subconcious motor control

what do neurons do

send signals to transmit and communicate

the 3 fundamental properties of a neuron

excitability, conductivity, and secretion

neurons lose the ability to replicate when

in adulthood except the hippocampus and olfactory nerves

the cell body (soma) houses

all organelles and manages essential processes

axon ends at synaptic knobs and stores

vesicles filled with neurotransmitters to release into synapse

neurofibril nodes

exposed region of axon between myelin sections

microtubules

active transport track for moving vesicles and molecules down the neuron

intermediate filaments

framework and anchor organelles

endoneurium

innermost ct layer, surrounds each axon/neuron cell for insulation

perineurium

middle ct, bundles axons together into fascicles

epineurium

outer ct, encloses the nerve

nerves are heavily

vascularized

sensory neurons carry signals along the

afferent pathway

motor neurons travel along the

efferent pathway

interneurons

act as connecters, facilitating communication between the sensory and nerves

the synapse is where

neurons meet

anterograde transport

transport away from the body

fast axonal transport

delivers materials by microtubule and protein transport, requires energy

retrograde transport

movement from synaptic knob to cell body

slow axonal transport

only occurs in anterograde direction (from soma to synapse)

resting membrane potential is

-70 mV

leak channels

allow associated ions to move along their electrochemical gradient

sodium potassium pump

3 Na+ out 2 K+ in

in a polarized state gated channels are

closed

chemically gated channels open due to

binding of neurotransmitters

postsynaptic potentials

localized, greatest potential electrical charge

temporal summation

rapid fire stimulation occurring at a single presynaptic neuron

spatial summation

combined effect of two or more different presynaptic neurons within a tiny range of time

action potential is initiated when

the threshold -55 mV is reached

action potentials trigger

the opening of volted gated channels

action potentials move from

initial segment to synaptic knobs

anterograde transport

movement of materials from the cell body towards synaptic knobs

retrograde transport

movement of materials from synaptic knobs toward cell bodies

fast axonal transport

uses ATP, movement along microtubules

slow axonal transport

results from the flow of axoplasm