Study Notes for Anatomy & Physiology Neuron Structure & Function

This study guide is for the neuron in A & P  and will help you narrow down what information you need to study for your lecture exam. The neuron is made up of several parts that each function so the neuron can send signals throughout the body. The human body is absolutely amazing and was intricately designed by God. While designing this study guide, I was amazed at how complex everything works so well together.

After your review the study notes on the neutral structure, take the neuron quiz to test your knowledge on how well you grasp the material.

Study Notes for the Neuron Structure

The human body contains billions of neurons. Neurons make up the basic structure of our nervous system and conduct electrical signals from one part of the body to another.

The nervous system is made up of nervous tissue. Nervous tissue is made up of two main types of cells:

1. Neurons: these are excitable nerve cells that transmit electrical signals
2. Support cells: non-excitable cells that surround and wrap the neuron.

There are special characteristics of neurons:

1. They have extreme longevity (over a 100 years)
2. They do not divide (never can be replaced)
3. They have a high metabolic rate and require continuous and abundant amounts of oxygen and glucose.

Structure of a Neuron

Cell Body: called the soma or perikaryon and contains a single nucleolus surrounded by cytoplasma.

Inside the cell body are:

               Nucleus: this is spherical and clear and contains a dark nucleolus in the center….it resembles an owl’s eye

              Chromatophilic Nissl Bodies: found in the cytoplasm and continually renew the membrane of the cell and the protein part of the cytosol.

              Lysosome: digest free radicals

             Mitochondria: power-house of the cell body

Neurofibril: bundle of intermediate filament that runs in a network between the chromatophilic bodies and they keep the cell from being pulled apart.

Dendrites: looks like limbs on a tree. They are receptive sites that conduct electrical signals TOWARD the cell body

Axon: conducts nerve impulses AWAY from the cell body

Initial Segment: the axon arises from this area in the axon hillock

Axon Hillock: where the axon arises to the cell body…means “little hill” on the diagram the axon hillock go up in a hill formation in the cell body

Axon Collaterals: extends from the axon a right angles

Terminal Branches: This is where the axon branches and there can be ten of thousands of these branches per neuron

Axon Terminal: this is where the terminal branches end into these knob formations…they contact other neurons to form synapses.

Schwann Cells: Form myelin sheaths around axons

Quiz Questions:

1. The nervous system is made-up of _________?
   1. Nervous Tissue
   2. Nervous Muscle
   3. Fibularis longus
   4. Cells
2. This type of nervous tissue is excitable nerve cells that transmit electrical signals?
   1. Embryonic tissue
   2. Autonomic cells
   3. Support Cells
   4. Neurons

Take rest of the quiz

Answer Key:

1, 4