Chapter 35 Nervous System Flashcards Preview

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Flashcards in Chapter 35 Nervous System Deck (12):
1

Control of Physiological Systems

Hormones: -slower action (minutes)
-broader range of action (organs, glands)

Nervous system: -faster (ms)
-precise control of target (one single muscle action)

2

Glial Cells

Support for the nerve cells.
Glial = Glue
90% of all the cells in the nervous system.
Do not work in the signal transmission

-Microglia
-Oligodendrocytes
-Radial glia
-Ependymal cells

3

Microglia

Glial cell
scavenge and degrade dead cells and protect the brain from invading microorganisms.

4

Oligodendrocytes

Glial cell
form myelin sheaths around axonsin the CNS.
One axon can be myelinated by several oligodendrocytes, and one oligodendrocyte can provide myelin for multiple neurons.
This is distinctive from the PNS where a single Schwann cell provides myelin for only one axon as the entire Schwann cell surrounds the axon.

5

Radial glia

Glial cell
serve as scaffolds for developing neurons as they migrate to their end destinations.

6

Ependymal cells

Glial cell
cells line fluid-filled ventricles of the brain and the central canal of the spinal cord. They are involved in the production of cerebrospinal fluid, which serves as a cushion for the brain, moves the fluid between the spinal cord and the brain, and is a component for the choroid plexus.

7

Neuron

Cell body
Contains nucleus and most organelles

Dendrites
Reception of incoming information

Axon
Transmits electrical impulses called action potentials

Axon hillock
Where axon originates and action potentials initiated

Axon terminal
Releases neurotransmitter

8

Chemical and electrical synapses

Most synapses are chemical although some are electrical.

Electrical synapses are fast and usually bidirectional.

Chemical synapses are unidirectional presynaptic neuron releases neurotransmitters when stimulated and postsynaptic neuron (effector) has receptors that bind to neurotransmitters.


Neuron with myelin versus without.

9

What is an action potential?

the change in electrical potential associated with the passage of an impulse along the membrane of a muscle cell or nerve cell.

10

What is a neurotransmitter?

a chemical substance that is released at the end of a nerve fiber by the arrival of a nerve impulse and, by diffusing across the synapse or junction, causes the transfer of the impulse to another nerve fiber, a muscle fiber, or some other structure.

11

Central Nervous System (CNS)

BRAIN + spinal cord

12

Peripheral Nervous System (PNS)

Afferent information (input)