The Nervous System - Neurons and Neuroglial Cells

Neurons:

A typical neuron consists of several key components:

  1. Cell Body (Soma): This is the central part of the neuron that contains the nucleus and other organelles necessary for the cell's functioning.

  2. Dendrites: These are branch-like structures that extend from the cell body and receive incoming signals from other neurons or sensory receptors. Dendrites serve as the input sites for information.

  3. Axon: It is a long, slender projection that extends from the cell body and transmits electrical impulses, known as action potentials, away from the cell body toward other neurons, muscles, or glands.

  4. Axon Terminal: At the end of the axon, there are terminal branches that form synaptic connections with other neurons. These terminals release neurotransmitters, chemical messengers that transmit signals to the dendrites of neighboring neurons.

Neuroglial Cells (neuroglia)

- supportive tissue of the nervous system (more numerous than neurons). Five types

1. Microglial Cells - immune function
2. Oligodendrocytes (CNS) - produce myelin
3. Schwann cells (PNS) - produce myelin
4. Astrocytes - regulate blood flow, connect to capillaries
5. Ependymal Cells - line the ventricles of the brain and spinal cord

*Myelin Sheaths - protective covering that insulate axons

synapse

The Synapse

- gap between two communicating neurons
- neurotransmitters are released at the axon terminal

Types of Neurotransmitters

Here are some of the key neurotransmitters and their general functions:

  1. Acetylcholine (ACh): ACh is involved muscle contraction

  2. Dopamine: Involved in feelings of pleasure and reinforcement and plays a crucial role in movement and coordination.

  3. Serotonin: Serotonin regulates mood, appetite, sleep, and anxiety. I

  4. Gamma-aminobutyric acid (GABA): GABA is an inhibitory neurotransmitter that helps reduce neuronal excitability. It plays a key role in regulating anxiety and fear responses.

  5. Norepinephrine (noradrenaline): Norepinephrine is involved in the body's "fight or flight" response.

  6. Endorphins: Endorphins are natural painkillers produced in response to stress or pain.

  7. Oxytocin: Oxytocin is involved in social bonding, trust, empathy, and reproductive behaviors. It plays a role in childbirth and lactation.

 

Class Resources on Neurons and the Nervous System

Google Slides with Guided Notes

The Anatomy of a Synapse (Coloring)

Case Study: Neurons and Cell Communication

Neuron Labeling