2.1.3 The Neuron HBS Human Body Systems PLTW WCHS Mr. Alasti

What does a neuron generally do?

Enables your body to send signals to and from the brain

Clinical Researchers

Works with humans to determine the safety and effectiveness of medications, devices, diagnostic products, and treatment regimens intended for human use. Clinical research can be used for prevention, treatment, diagnosis, or relief from symptoms of a disease

Experimental Researchers

Focus on cells and model organisms to study the properties of drugs and materials

How do clinical researchers and experimental researchers work together?

They work together to expand the knowledge base about the brain and nervous system to reduce the burden of neurological diseases

Label the image

1. Neuron

2. Glia

Neurons

Primary signaling cells of the nervous system; they send and receive electrical and chemical signals to communicate with each other in the nervous system and with other types of cells in the body

Glial Cells

Cells in the nervous system that provide protection and maintain homeostasis for neurons 

What are neurons and glial cells responsible for when working together?

All sensations, movements, thoughts, memories, and feelings

What are the three essential parts of all neurons?

1. A cell body

2. An axon

3. Dendrites

Cell Body

Central part of a neuron that contains the nucleus and is the main structural component of gray matter 

Axon

A long nerve cell process that usually conducts impulses away from the cell body

Dendrites

Any of the usually branching protoplasmic processes that conduct impulses toward the cell body of a neuron

Label the image

1. Axon

2. Cell Body

3. Dendrite

Label the image

1. Dendrite

2. Nucleus

3. Node of Ranvier

4. Axon

5. Soma (Cell Body)

6. Normal Myelin Sheath

7. Node of Ranvier

8. Axon Terminal

Schwann Cell

The cell that produces the myelin sheath

Axon Terminals

The ending of axons; the location where axons make contact with other nerve or effector cells 

Myelin Sheath

In a neuron, an insulating coat of cell membrane from Schwann cells that is interrupted by nodes of Ranvier

Nodes of Ranvier

The gaps in the myelin sheath of nerve cells found between neighboring Schwann cells

What do glial cells (or neuroglia) care for?

Neurons; they also maintain the environment neurons are in

Do glial cells have axons or dendrites?

No

Can glial cells generate action potentials or nerve impulses?

No

What are the 6 major types of glial cells?

1. Ependymal Cells

2. Oligodendrocytes

3. Satellite Cells

4. Astrocytes

5. Microglial Cells

6. Schwann Cells 

What can happen when glial cells do not function properly?

Various problems can occur, including diseases and tumors

What causes most brain tumors?

Mutations in glial cells

What do many neurodegenerative diseases (multiple sclerosis) involve?

Damage to myelin sheaths 

Which cells produce the myelin sheaths that are damaged in diseases like multiple sclerosis?

Schwann cells

What neurons are pictured?

Rat hypothalamus neurons

What neurons are pictured?

Rat neonatal retinal cells, bipolar

What neurons are pictured?

Mouse CD1 cortex neurons, multipolar

What neurons are pictured?

Normal human astrocytes

What neurons are pictured? 

Rat brain cortex neurons 

What neurons are pictured?

Rat brain microglia

What neurons are pictured?

Rat cerebellar cells, unipolar

How are neurons classified?

By their function

What are the three basic groups of neurons?

1. Sensory

2. Motor

3. Interneurons

Synapse

The place at which a nervous impulse passes from one neuron to another

Neurotransmitter

A substance (as norepinephrine or acetylcholine) that transmits nerve impulses across a synapse 

Multipolar Neuron

Makes multiple connections with other cells using dendrites, and is the most common kind of motor and interneuron

What type of neuron are 99% of neurons?

Multipolar

Bipolar Neuron

A rare neuron used for your main senses in the eyes, ears, and nose (sight, hearing, and smell)

Pseudounipolar Neuron

The most common type of sensory neuron found within our hands, feet, and skin

Unipolar Neuron

A neuron not found in humans

What are the three broad types or three main categories of neurons?

Sensory, motor, and interneurons 

Job of sensory neurons

Sense what’s in the environment and send signals to the spinal column (CNS)

Job of interneurons

Receive signals sent from sensory neurons, and process and send a signal to motor neurons

Job of motor neurons

Act upon the signal sent from interneurons

Afferent neurons

Carry information to the CNS

Efferent neurons

Carry information away from the CNS

How are hormones similar to radio signals?

It takes a long time for them to get going and land on their target cells, which act like antennas to receive the signal, and then it lasts a long time

How are nerves similar to old-school telephone lines?

They are fast acting and fast finishing, and the only way to stimulate it again is to send another nerve signal 

What are the myelin sheaths made out of?

Fat

What are the gaps between the myelin sheaths?

Nodes of Ranvier

What subsystem of the nervous system are interneurons (association neurons) part of?

CNS