part 3: Neurons and Electrochemical Signaling

resting membrane potential

-70mV

soduim-potassium pump

1. Moves Na+ and K+ ions across the cell membrane 2. Allow nerves to send electrical info. Allows muscles to contract. Allows for the absorption of food &urine

multiple sclerosis

A chronic disease of the central nervous system marked by damage to the myelin sheath. Plaques occur in the brain and spinal cord causing tremor, weakness, incoordination, paresthesia, and disturbances in vision and speech

myelin sheath

A layer of fatty tissue segmentally encasing the fibers of many neurons; enables vastly greater transmission speed of neural impulses as the impulse hops from one node to the next.

Glutamate

A major excitatory neurotransmitter; involved in memory

Dopamine

A neurotransmitter associated with movement, attention and learning and the brain's pleasure and reward system.

Norepinephrine

A neurotransmitter involved in arousal, as well as in learning and mood regulation

Serotonin

A neurotransmitter that affects hunger, sleep, arousal, and mood.

Acetylcholine (ACh)

A neurotransmitter that enables learning and memory and also triggers muscle contraction

GABA

An inhibitory neurotransmitter in the brain.

Dentrites

Branches that reach out from the cell body and receive signals from surrounding neurons

Nodes of Ranvier

Gaps in the myelin sheath to which voltage-gated sodium channels are confined.

axon hillock

The conical region of a neuron's axon where it joins the cell body; typically the region where nerve signals is generated.

synaptic cleft

The narrow gap that separates the presynaptic neuron from the postsynaptic cell.

nervous system

a collection of organs that are specialized for a common purpose, namely, the analysis of sensory information and the production of behavior.

presynaptic cell

a nerve cell that releases a transmitter substance into a synapse during transmission of an impulse

antonomic nervous system

a set of nerves that carries involuntary and automatic commands that control blood vessels, body organs, and glands

somatic nervous system

a set of nerves that conveys information between voluntary muscles and the central nervous system

sympathetic nervous system

a set of nerves that prepares the body for action in challenging and threatening situations

excitation messages

active, go

gets back to reseting potential

by using sodium potassium pump

motor neurons

carry signals from the spinal cord to the muscles to produce movement

Neurons

cells in the nervous system that communicate with each other to perform information processing tasks

glial cells

cells in the nervous system that support, nourish, and protect neurons

glial cells

cells in the nervous system that support, nourish, and protect neurons, allows some neurons to carry into more efficiently

absolute refraction period (peak)

charge on outside and inside are equal

Neurotransmitters

chemical messengers that cross the synaptic gaps between neurons

central nervous system (CNS)

composed of the brain and spinal cord, receives information from the external world, processes and coordinates this information and sends commands to the skeletal and muscular system for action

peripheral nervous system (PNS)

connects the central nervous system to the body's organs and muscles

2 general processes for movement of ions

delusion and electrostatic pressure

what happens when ions cross membrane

depolarization is occurring and potassium channels are opening

Nuerons communication is both:

electrical and chemical

2 kinds of messages neurotransmitters convey

excitation and inhibition

binding of molecules to specialized proteins can lead to...

excitation, leading to increase in likelihood for neurons to fire action potential; or inhibition, decrease likelihood

parasympathetic nervous system

helps the body return to a normal resting state

presynaptic state

high sodium and neg charged chlorines on outside, high potassium and protein inside

relative refractory period

hyper-polarization

call body (soma)

largest component of the neuron that coordinates the information processing tasks and keeps the cell alive

synaptic transmission process

molecules of neurotransmitters selectively bind to specialized proteins embedded in the dendrite

how action potential is propagated

moves like dominos or a wave, almost like it regenerates when moving from one axon region to the next

Endorphins

natural, opiate-like neurotransmitters linked to pain control and to pleasure

ions outside membrane well cell is at rest

negatively charged chlorine and sodium ions

Inerneurons

neurons within the brain and spinal cord that communicate internally and intervene between the sensory inputs and motor outputs

inhibition messages

not active, stop

Ions

positively and negatively charged atoms

ions inside membrane well cell is at rest

positively charged potassium and negatively charged proteins

postsynaptic state

potassium and sodium move outside the cell

refraction period

potassium leaving leads to decrease of potential, repolarization

Receptor

protein that detects a signal molecule and performs an action in response

sensory neurons

receives information from the external world and conveys this info to the brain via the spinal cord

Three types of neurons

sensory, motor, interneurons

what happens at stimulus threshhold

sodium channels open

action potential starter

sodium channels openning

two main major subdivides of PNS

somatic nervous system and the autonomic nervous system

2 major divides of autonomic nervous system

sympathetic and parasympathetic nervous system

Axon

the extension of a neuron, ending in branching terminal fibers, through which messages pass to other neurons or to muscles or glands

Synapes

the functional junction between two neurons at which point the impulse is transmitted.

synaptic transmission

the mechanisms that underlie the ability of a neurotransmitter to influence the electrical properties of the receiving cell

postsynaptic neuron

the neuron on the receiving end of the synapse