Chapter 3 Flashcards
What are neurons?
Specialized cells that make up the nervous system
What are the 3 main parts of a neuron?
Cell body (soma); dendrites; axon
What is the cell body (soma)?
Structures that keep the cell alive
What are the dendrites in a cell?
“Branches” from cell body, receive signals
What does the axon in the cell do?
Conducts electrical impulses away from the soma
What are the functions of glial cells?
Hold neurons in place; make and move nutrients; form Meylin Sheath; remove toxins
What is the blood-brain barrier? And what cell is it associated with?
Wall of blood vessels that are covered in glial cells that protect toxins from entering our brain as the spaces are slightly larger in the brain
What are the 2 basic functions of a neuron?
- Generate electricity (Create nerve impulses)
- Release chemicals (Communicate with other cells)
What are the 3 steps of neural impulses?
- At rest with electrical resting potential
- Stimulated and electrical charges (ions) flow across cell membrane
- Restore distribution of ions, cell at rest again
What is the charge of a neuron at resting potential?
Pos outside + Neg inside with a -70mV difference
What are the 2 main elements that give charge to a neuron?
Sodium (Na+) and Potassium (K+)
What is depolarization?
When the cell is stimulated and electrical charges (ions) flow across cell membrane
What are the different stages that a neural impulse goes through when activated?
Resting potential->action potential->refractory period-> resting potential
What is the All-or-None Law?
Action potentials occur at a uniform and maximal intensity, or they don’t occur at all
When the rate of cell firing is increased what happens?
More action potentials are created
What is a myelin sheath?
A fatty, whitish insulation layer derived from glial cells during development (insulates neurons)
What are the Nodes of Ranvier?
Places where the myelin is either extremely thin or absent; Allows conduction to “skip ahead”
What are synapses?
Functional (not physical) connections between neurons and their target
What are neurotransmitters?
Chemical substances that carry messages across the synapse to either excite other neurons, or inhibit their firing
What are the 2 basic functions of a neurotransmitter?
- Generate electricity
- Release chemicals
What are the 5 stages of chemical communication?
- Synthesis
- Storage
- Release
- Binding
- Deactivation
In chemical communication, what is the synthesis stage?
Chemical communications are made in the neuron
In chemical communication, what happens in the storage stage?
Chem comm. is held in the synaptic vesicles
In chemical communication, what happens in the release stage?
Chem com. is released into the synaptic space
In chemical communication, what happens in the binding stage?
Chem com. attach to receptor sites
In chemical communication, what happens in the deactivation stage?
Stops the neurotransmitter signal