Parts of a Neuron
Identify letter L on the picture of the neuron on the board.
a. presynaptic terminals
A collection of neuron cell bodies that are outside of the CNS.
What is ganglia?
Sodium and potassium channels are closed. Na+ are concentrated outside the cell. K+ are concentrated inside the cell.
What is depolarization?
This type of neuroglia insulates PNS axons.
Schwann cells
This type of nerve contains axons that carry only sensory information from receptors to the CNS.
Sensory nerves
Why do myelinated axons carry action potentials faster than unmyelinated axons?
It skips from one node of Ranvier to another and in one direction only.
Also Myelinated axons allow saltatory transmission.
What is letter a?
calcium channels
Identify letter J on the picture of the neuron on the board.
b. node of Ranvier
The ability to undergo an action potential in response to a stimulus
What is excitability?
Na+ and K+ channels are closed. Sodium-potassium exchange pump moves Na+ out and Na+ in. Resting potential difference: -85 mV
What is resting conditions re-established?
Engage in phagocytosis to fight infections.
These axons carry signals only from the CNS to effector organs such as muscles and glands.
motor nerves
Myelinated axons.
What is letter b?
Synaptic vesicle or neurotransmitter
Identify letter F on the picture of the neuron on the board.
c. Golgi apparatus
A neuron that conducts neural signals from one neuron to another neuron within the CNS
What is an association neuron?
Sodium and potassium channels are closed. Na+ are concentrated outside the cell. K+ are concentrated inside the cell.
What is resting potential?
What do Oligodendrocytes do?
They bind CNS neurons together and insulate the axons.
Carries both sensory and motor nerves. And it is the most common nerve in the body.
Mixed nerves
Fill in the blank:
The frequency of the action potential determines the ____________________________
strength of the signal.
What is letter c?
Sodium channels
Identify letter A on the picture of the neuron on the board.
e. dendrites
Neurons that transmit action potentials from CNS to the effector organs.
What are efferent neurons?
Na+ channels close, and K+ channels open. K+ rush out of the cell according to the dictates of diffusion.
What is repolarization?
What do Astrocytes do?
IF an axon is covered by an oligodendrocyte, will it regenerate if severed?
No.
What kind of circuit is this?
Many inputs are reduced to a limited output.
Converging
What is letter d?
postsynaptic neuron
Identify letter H on the picture of the neuron on the board.
g. axon hillock
Neurons that transmit action potentials from the CNS to the skeletal muscles
What is the somatic motor nervous system?
There are three conditions that must be met in order for a severed axon to regenerate. Name one.
1. the cell body of the neuron must be alive.
2. the axon must be covered with Schwann cells.
3. the axon must be reasonably well aligned with its severed end.
What do Ciliated ependymal cells do?
They move cerebrospinal fluid around so that it stays homogeneous.
If an axon is covered by several Schwann cells and it is severed, what must happen in order for it to be healed?
It must be well aligned with its severed part in order for the Schwann cells to guide the regrowing.
What kind of circuit is this?
one input stimulates many outputs
Diverging circuit
What is letter e?
synaptic cleft