Chapter 3a: Neurons, Neurotransmitters, and Drugs

The Biological Bases of Behaviour

Neurons

• Neurons are specialized cells that make up the nervous system

• The four main parts of a neuron are the cell body (soma), dendrites, axon, axon terminals

• There are different types of neurons: sensory neurons, interneurons, motor neurons

• Sensory signals travel from the dendrites through the axon to the axon terminals

• Glial cells hold neurons in place, they make and move nutrients, form the myelin sheath (schwann cells), remove toxins, and form the blood-brain barrier

• Neurons generate electricity (nerve impulses) and release chemicals (communicate with other cells)

• Neurons don’t touch they are separated by a small gap, which is part of the synapse across which signals are transmitted from one neuron to another

• Presynaptic and postsynaptic neuron

Action Potential

• https://www.khanacademy.org/test-prep/mcat/organ-systems/neuron-membrane-potentials/a/neuron-action-potentials-the-creation-of-a-brain-signal

• Are electrical impulses that send signals and travel along the axon of a neuron, leading to the release of neurotransmitters at the synapse, which then bind to receptors on the neighbouring neuron, facilitating communication within the nervous system.

• Are nothing more than a temporary shift (from negative to positive)

• Concentration gradients are key behind how action potentials work because they are the difference in ion concentrations between the inside of the neuron and the outside of the neuron (called extracellular fluid)

  

1. Resting Membrane Potential → more sodium ions (Na+) outside than inside the neuron, more potassium (K+) inside than outside

2. Depolarization →

3. Repolarization

4. Hyperpolarization

• Threshold level

Neurotransmitters

Drugs