Week 1 (Parts of a Neuron, Neuron Functions, Efferent vs. Afferent)

Start at page 33.

Cells of the Brain

There are two main cell types in the brain: Neurons and Glial cells, this focuses on Neurons.

Neurons are arranged into the circuits that control all types of behavior. Neurons receive, integrate, then send the information they gain to and from other cells. These neurons include:

  • Motor neurons

  • Sensory neurons

  • Interneurons

Parts of the neuron

Dendrites (Input Zone)

  • Branching fibers that receive information

  • They have specialized synaptic receptors.

  • Many dendrites have dendritic spines.'

    • Small projections from the surface that add additional space for synapses

  • Increased area for synapses

    • The greater the surface area the more information a neuron can receive.

Soma/Somata (Cell Body) (Integration Zone)

  • Performs functions that allow the cell to live

  • Contains the nucleus, ribosomes, and mitochondria

  • Also contains synaptic receptors on the surface can can receive information

Axon (Nerve Fiber) (Conduction Zone)

  • Sends information to other cells

  • Carries action potentials

  • Many vertebrate axons have myelin sheaths

    • Layers of fat that insulates the axon, improving the conduction of the signal

  • Presynaptic terminals at the tips of the branches

    • Where the axon releases chemicals so it can signal the next cell

Output Zone

  • Specialized swellings at the end of the axon called axon terminals (synaptic boutons)

    • Serves as the output zone

  • Transmit the neurons signals across synapses to other cells

Different Neuron Types (Builds)

Multipolar neuron

  • A nerve cell that has many dendrites and a single axon

Bipolar neuron

  • a nerve cell that has a single dendrite at one end and a single axon at the other end.

Unipolar neuron (monopolar neurons)

  • have a single extension (thought of as a axon) that branches in two different directions after leaving the cell body.

Different Neuron Types (Function)

Motor (moto) neurons receive information (motor commands) from the brain and send those signals to the muscles for movement.

Sensory neurons receive information from the outside environment and send those signals to the brain. They also have a specialized end that is sensitive to stimulation like light, sound, or touch.

Interneurons help to integrate signals from other neurons and facilitate communication between sensory and motor neurons.

Neural Communication

Form has function.

  • Neurons have parts that are specialized for different functions allowing for synaptic transmission.

  • Synaptic transmission is how neural cells communicate with one another.

Neural communication is relative

Efferent axons carry information away from a structure

  • Motor information is sent away from the brain to the muscles

  • efferent => exit

Afferent axons carry information to a structure

  • Sensory information carried from the body to the brain

  • afferent => Admissions