Chapter 12: Nervous System and Nervous Tissue (Quiz) Flashcards
Identify the functions of the nervous system (3).
Sensation - Taking information in from external stimulus, and sending electrical impulses down nervous system.
Response - When nervous system causes a target tissue (muscle or gland) to produce appropriate response, as a consequence of the external stimulus.
Integration - Combining information from external stimulus with higher cognitive functions (ex memory) and determines appropriate response.
What is the function of the afferent neurons?
They conduct impulses from the sensory cells to the central nervous system.
Name two subdivisions of the autonomic nervous system
- Sympathetic Nervous System
- Parasympathetic Nervous System.
What are the 4 different types of glial cells in the CNS? (AOME)
- Astrocyte
- Oligodendrocyte
- Microglia
- Ependymal Cells
What are the 2 types of glial cells in the PNS?
- Schwann Cells
- Satellite Cells
What are some ways that astrocytes support neurons in the CNS?
- Maintain concentration of chemicals in extracellular space.
- Remove excess signalling molecules.
- Reacting to tissue damage.
- Contributing to blood-brain barrier.
What do oligodendrocytes do?
They provides the myelin insulations for axons in tracts.
One oligodendrocyte provides myelin for multiple axon segments.
What do microglia do?
They ingest and digest any cells or pathogens that cause diseases.
What do ependymal cells do?
They create cerebrospinal fluid (CSF). They have cilia on their apical surfaces to help move CSF throughout the nervous system.
What do Satellite Cells do?
They surround the cell bodies of neurons.
- Provide support, performing similar functions in the periphery as astrocytes in the CNS
What do Schwann Cells do?
Insulates axons with myelin in the periphery.
What is a myelin sheath
It is a lipid rich layer that surrounds an axon in layers, which helps facilitate the speed of electrical signals.
Define dentrites
Processes at the end of a neuron, which provide locations foer other neurons to communicate with the cell body.
Define Grey Matter.
Regions of the nervous system containing cell bodies of neurons with few or zero myelinated axons.
Define White Matter.
Regions of the nervous system containing mostly myelinated axons, making the tissue appear whiter because of the high lipid content of myelin.
What is a nucleus?
A localized collection of neuron cell bodies in the CNS.
What are ganglion?
A cluster of neuron cell bodies in the PNS.
What is the meaning of the term resting potential membrane?
The difference in charge when ions are scattered across the membrane at concentrations (Usually -70mV).
What is the role of the sodium-Potassium Pump?
To actively carry out sodium ions out of the cell, and potassium ions into the cell. Powered by ATP.
How does a neuron become depolarized?
By the rapid influx of sodium ions through the nerve cell membrane.
What is a refractory period?
A time when an action potential is generated, and another action potential can’t be generated.
What is a threshold stimulus?
A stimulus that causes the membrane of a neuron to depolarize at -55mV, so an action potential can be generated.
What is the advantage of salatory conduction?
It is very fast, and requires less energy expenditure of the Na/K pump.
Why does the synaptic conduction of an impulse occur only in one direction?
Because neurotransmitters are released only from presynaptic terminals. Only postsynaptic membranes have appropriate neurotransmitter receptors.
Define: Neurotransmitter
A chemical signal that is released from the synaptic end bulb of a neuron to cause a change in the target cell.
Which neuroglia produce myelin in the CNS?
Oligodendrocytes.
What are the most important factors that determine the speed of impulse propogation?
Fibre diameter and the presence/absence of the myelin sheath.
With respect to synaptic facts, what is false?
The nerve impulses travel from postsynaptic to presynaptic.
It is the other way around.
what is a blood-brain barrier?
A physiological barrier that keeps substances that circulate in the rest of the body from getting into the CNS, restricting what can cross from circulating blood into the CNS.
