48 Flashcards
(33 cards)
What structures are in the central nervous system?
Brain and nerve cord (spinal cord in vertebrates).
What makes up the peripheral nervous system?
All neurons and projections of their plasma membranes that are outside of the CNS.
What are neurons?
Cells that send and receive electrical and chemical signals to and from other neurons or other cells throughout the body.
Which animal does not have neurons?
Sponges.
Number of neurons varies widely as a function of [1] and [2].
- size
- behavioral complexity
What are the three many parts of neuron structure?
- Cell body or soma
- Dendrites
- Axons
What is the neurolemma?
The outer portion of the myelin sheath created by Schwann cells.
What does the cell body or soma contain?
Nucleus and organelles
Three characteristics of dendrites.
- Extensions of plasma membrane
- May be single or branching
- Incoming signals
Five characteristics of axons.
- Extension of plasma membrane
- Typically single
- Sending signals
- Axon hillock near cell body (go/no go)
- Axon terminals convey electrical or chemical massage to other cells
What can glia cells function as?
Stem cells to produce more glial cells and neurons.
What do astrocytes provide?
Metabolic support (star-cell)
What do microglia do?
Remove cellular debris (litte-glue)
The Myelin Sheath is interrupted by…?
Nodes of Ranvier
What are nodes of Ranvier produced by?
Oligodendrocytes (CNS) and Schwann cells (PNS) (few-tree-cells).
Where are satellite cells found and what do they do?
Found in the PNS, these cells:
1. surround neuron cell bodies in the ganglia and
2. regulate O2, CO2, nutrient, and neurotransmitter levels around neurons in the ganglia.
Where are Schwann cells found, and what do they do?
Found in the PNS, they:
1. surround axons in the PNS,
2. are responsible for the myelination of peripheral axons, and
3. participate in the repair process after injury.
Where are oligodendrocytes found and what do they do?
Found in the CNS, they myelinate CNS axons and provide structural framework.
Where are astrocytes found, and what do they do?
Found in the CNS, they:
1. maintain blood-brain barrier,
2. provide structural support, regulate ion, nutrient, and dissolved gas concentrations,
3. absorb and recycle neurotransmitters, and
4. form scar tissue after injury
Where are microglia found, and what do they do?
Found in the CNS, they remove cell debris, wastes, and pathogens by phagocytosis.
Where are ependymal cells found and what do they do?
Found in the CNS, they
1. line ventricles (brain) and central canal (spinal cord) and
2. assist in producing, circulation, and monitoring of cerebrospinal fluid
What are the peripheral nervous system cells?
Satellite cells and Schwann cells
What are the central nervous system cells?
Oligodendrocytes, astrocytes, microglia, and ependymal cells
What is a synapse?
A junction between an axon and another cell.
