Neurons and Cell Signaling

Neuron

A nerve cell that transfers information within the body

Dendrites

Highly branched extensions that receive signals from other neurons

Axon

A longer extension, transmits signals to other cells

Axon hillock

The cone-shaped vase of an axon where signal is generated

Synapse

The branched ends of axons transmit signals to to other cells at a junction

Synaptic terminal

The part of each exon branch that forms the specialized junction

Neurotransmitters

Chemical messengers that pass information from the transmitting neuron to the receiving cell

Glial cells

Neurons of vertebrates and many invertebrates require supporting cells

Roles of Glial cells

Nourish neurons, insulate the axon of neurons, and regulate the fluid surrounding neurons

Replenish some groups of neurons and in transmitting information

Three nervous systems process

Sensory input, integration, motor output

Higher order processing is carried out in large groups of neurons are

Organized into a brain or into simpler clusters called ganglia

Sensory neurons

Transport information about eternal stimuli or internal conditions

Interneurons

Integrate (analyze and interpret ) the sensory input , which form local circulates connecting neurons in brain or ganglia

Motor neurons

Transmit signals to muscle cells causing them to contract , extra neurons extend to trigger gland activity

Central nervous system

The neurons that carry out integration are often organized

Peripheral nervous system

The neurons that carry information into and out o the CNS

What is the inside of the cell charged?

Negative

Membrane potential

The charge difference or voltage is a source of potential energy

Resting potential

The membrane potential of a neuron that is not sending signals

Potassium ions and sodium ions play a. Role

In forming the resting potential

Sodium-potassium pumps

Use the energy of ATP to maintain these gradients across the plasma membrane

Ion channels

Are pores formed by specialized proteins that span the membrane

Ion channels are selectively permeable allows

Only certain ions to pass

Leak channels

A resting neuron that has many open potassium channels allowing to flow out