Chapter 7 Nerve Cells and Electrical Signaling

Peripheral nervous system

Consists of neurons that provide communication between the central nervous system and organs throughout the body.

Somatic senses

Skin, muscles, and joints

Special Senses

Vision, hearing, equilibrium, smell, and taste

Visceral senses

Internal environment (fullness of the stomach, blood pressure, and blood pH).

Table 7.1 be able to draw this out!

What does it mean that neurons are “excitable cells”

Cells that can produce large, rapid electrical signals called action potentials.

Figure 7.2 anatomy of a neuron

1) Cell body (soma)=contains the nucleus and most organelles

2) Dendrites=branch from the cell body and receive input from other neurons at synapses.

3) Axon=Transmits electrical pulses called action potentials

4) Axon hillock = where the axon originates, and action potentials are initiated.

5) Axon terminal=Releases neurotransmitter

Synapse

Site of communication between two neurons or between a neuron and an effector organ

Transport in neurons

1) Anterograde transport:From cell body/soma to axon terminal

2) Retrograde transport: From axon terminal to cell body/soma

Figure 7.4 fast axonal transport of vesicles

Role of ion channels

-They contribute to the resting membrane potential and facilitate signaling in Neurons

-The opening or closing of ion channels changes the permeability of the plasma membrane for a specific ion, resulting in a change in electrical properties or release of a neurotransmitter.

Leak channels

1) Always open

2) Throughout the neuron

3) Resting membrane potential

Ligand-gated channels

1) Open or close in response to ligand binding

2) Dendrites and cell body

3) Synaptic potentils

Voltage-gated channels open/close with changes in membrane potential

1) Sodium and Potassium channels: mostly in the axon; action potentials

2) Calcium channels: axon terminal; release of neurotransmitters.

Structural classes of neurons

1)