Cell-cell communication: Neurons

what is the nervous system consisted of?

brain, spinal cord and peripheral nerves

Central Nervous System (CNS)

brain and spinal cord

Peripheral Nervous System (PNS)

the sensory and motor neurons that connect the central nervous system to the rest of the body

somatic nervous system

the division of the peripheral nervous system that controls the body's skeletal muscles; controls voluntary activity

autonomic nervous system

the part of the peripheral nervous system that controls the glands and the muscles of the internal organs such as the heart; controls involuntary activity

sympathetic nervous system

the division of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations (fight or flight)

parasympathetic nervous system

the division of the autonomic nervous system that calms the body, conserving its energy (rest and digest)

reflex

a simple, automatic response to a sensory stimulus

what are the 3 types of neurons?

sensory (afferent), motor (efferent), interneurons

sensory neuron

neurons that carry incoming information from the sensory receptors to the brain and spinal cord

afferent neurons

Nerve cells that carry impulses towards the central nervous system

efferent neurons

Nerve cells that conduct impulses away from the central nervous system

motor neurons

control the activity of muscles

interneurons

pass signal from one neuron to another

Neuroglia

cells that support and protect neurons; can divide but cannot transmit cell signals

components of a neuron

cell body, dendrites, axon, myelin

cell body

Largest part of a typical neuron; contains the nucleus and much of the cytoplasm

dendrites

receive chemical signals from other neurons and convert them into electrical signals

axons

a part of a neuron that carries impulses away from the cell body

axon terminal

The endpoint of a neuron where neurotransmitters are stored

myelin sheath

covers the axon of some neurons and helps speed neural impulses

Nodes of Ranvier

gaps in myelin sheath along the axon

membrane potential

the voltage difference across a membrane

diffusion

Movement of molecules from an area of higher concentration to an area of lower concentration.

resting potential of a neuron

stable, negative charge when the cell is inactive

action potential

a neural impulse; a brief electrical charge that travels down an axon

Electrical vs. chemical signals

Inside neuron - electrical

In between neurons - chemical

Neurotransmitters

chemical messengers that cross the synaptic gaps between neurons

Depolarization

The process during the action potential when sodium is rushing into the cell causing the interior to become more positive.

Repolarization

Return of the cell to resting state

Synapse

the junction between the axon terminal of the sending neuron and the dendrite or cell body of the receiving neuron

Nodes of Ranvier

gaps in the myelin sheath