Nervous system 3 & 4

Main part of the cell where the neucleous is

Recieving end of the neuron

Extention of thew cell body where electrical signals pass through

fatty insulation of axons that speeds up the speed of electrical signals

Contains vesicles filled with neurotransmitters

Drugs that strengthen the effect of a neurotransmitter

Drug that mimics the effect of the sympathetic nervous system

Drugs that disrupt signaling between two neurons (e.g., block receptors)

Pumps 2 potassium in for every 3 sodium out

Na K pumps, K leak channel, Na leak channel

-55mV; if reached, the neuron fires an action potential

Local changes in membrane potential that make a cell more or less likely to fire

Activated by neurotransmitter, allows more K to leave the cell making it more negative (hyperpolarized

Allows sodium to enter the cell making it more positive and more likely to fire (excitatory)

Voltage gated sodium channels open at -55mV letting in more sodium causing a chain reaction that travels down the axon

A neuron either sends an action potential or it doesn't; signal strength is the same every time

If an urgent signal needs to be sent, the frequency of action potentials goes up (e.g., 1

Go into overdrive to bring the neuron back to rest

White because of myelin around axons

Grey because it is where all the cell bodies are

On the anterior; contains cell bodies of somatic motor neurons

On the posterior; where all sensory information enters the spinal cord

Somatic neuron axons that merge to form a ventral root sending motor information to the body

Combine to form a dorsal root which sends sensory information to the brain

Formed when the ventral and dorsal roots combine

Cluster of cell bodies in the Peripheral Nervous System (bump where dorsal rootlets meet the root)

Cluster of neuron cell bodies in the Central Nervous System

Supplies a large part of the spinal cord with blood (roughly 80%)

Supply the back part of the spinal cord with blood (about 10% per artery)

Fast, involuntary, stereotyped motor response to a specific sensory stimulus

Support cells that enhance neurons so they can do their job

Maintain the blood brain barrier

Myelinate peripheral neurons

Myelinate central nervous system

Make cerebrospinal fluid (distributes nutrition and prevents brain trauma)

Immune cells in the central nervous system

Electrical charge along the membrane

Electrical charge at rest

Sodium and potassium

Potassium is mostly inside the cell, sodium is mostly outside the cell

Takes a lot of ATP (up to 70% of all ATP a cell makes)

Allow potassium to leave the cell or sodium to enter

Potassium is positively charged, so as it leaks out the cell becomes negative

Once the cell becomes negative, potassium slows down and reaches balance with the outside

If the cell were permeable to sodium, sodium would enter making the cell positive until repelled and balanced

+60mV

-90mV

-70mV because potassium has more channels so it tends toward potassium's resting number

The more myelinated a neuron is, the faster a signal is sent

Neuron can regrow if endoneurium scaffolding and myelin remain; grows about 1 millimeter per day

Many dendrites and one axon (most common)

One dendrite and one axon (rarest)

Cell body off to the side; single dendrite and axon look like a single line (all somatosensory neurons)