The nervous system works in conjunction with what?
endocrine system
Nervous System
responds to both internal and external environment change and maintainshomeostasis within the body
Glial Cell
structural and nutritional support
Neurons
conduct nerve impulses throughout the body. they are supported by the glial cells
Dendrites
branches which accept nerve impulses form other neurons and carry them towards the cell body
Axon
longer branches which carry nerve impulses away from the cell body
Myelin Sheath
around the axon, speeds up the rate of impulse transmission
Schwann Cell
produces the myelin
Nodes of Ranvier
gaps between the Schwann cells
Axon Terminal
end of the axon and passes the electrical signal to other neurons
Myelinated Neurons
"white matter" which conducts nerve impulses, can regenerate after injury
Unmyelinated Neurons
"grey matter" responsible for processing information, cannot regenerate after injury
Sensory Neurons (afferent)
gather information from sensory receptors, transmit the impulses to the brain
Interneurons
process and integrate sensory information from sensory neurons and relay information to motor neurons
Motor Neurons (efferent)
transmit information from the brain to muscles(effectors)
Reflex Arc
neural circuit that passes through interneurons in the spinal cord for immediate response
Summation
sum of multiple neurons leads to greater stimulation
What are the four stages of a nerve impulse?
polarized, depolarization, repolarization, and refractory period
Resting State/Polarized
inside of neuron has a slight positive charge at rest and the outside has a slight negative charge. has a potential at -70mV
Does sodium ions go in or out?
in
Does potassium ions go in or out?
out
Depolarization
an impulse causes the sodium gates to open and sodium rushes into the cell, causing a morepositive charge and reverses the membrane potential to +40mV
Threshold
any stimulus that does not reach a potential of -55mV will have no effect
Stimulus Strength
if an increase of stimulus strength occurs, there will not be an increase of impulsestrength. there will only be an increased frequency of nerve impulses
Repolarization
once action potential is reached sodium gates close and the potassium gates open, K+ rushes out of the axon and restores the positive charge on the outside and goes back to the initial resting potential of -70mV
Hyperpolarization
will become too negative (-70mV to -90mV) until the resting potential has been restored by the sodium-potassium pump. a second action potential cannot be conducted along the axon
Neurotransmitters
help "carry" the electrical impulse from one neuron to another
Pre-Synaptic Membrane
axon terminal
Post-Synaptic Membrane
dendrites
First step of Synapse
action potential reaches the axon terminal and the calcium gates open causing calcium ions to flow into the cell triggering the vesicle to fuse into the membrane
Second step of Synapse
neurotransmitters diffuse across the synaptic cleft to the post-synaptic membrane then bind to the receptors and induces or inhibits an action potentail