5 Written Questions
5 Matching Questions
- What is salutatory conduction of an action potential? Does it occur in all nerve fibers? How does diameter of a nerve fiber affect speed of conduction?
- How is the sodium-potassium pump related to the resting potential of the nerve fiber?
- What is summation? Temporal and spatial summation result in what?
- Axons are classified into 3 groups according to the relationship between diameter, myelination and propagation speed: define Type A, B and C fibers.
- You may recall that a muscle fiber is an entire muscle cell; is a nerve fiber an entire neuron? (explain)
- a In order to get back to polarization, they have to pump in 3 Na out, 2 K in
- b Type A - large-diameter, myelinated. Conduct at 15-120 m/s. Motor neurons supplying skeletal and most sensory neurons
Type B - medium-diameter, lightly myelinated. Conduct at 3-15 m/s. Part of ANS
Type C - small-diameter, unmyelinated. Conduct at 2 m/s or less. Part of ANS
- c Salutatory conduction of an action potential is when you jump from node to node.
- d No because the neuron consists of many other things that make up the neuron (dendrites, axons, cell bodies, axon terminals)
- e Certain stimulus happens repeatedly, and adds to threshold in order to get an action potential.
Results in threshold
5 Multiple Choice Questions
- Schwann cells can point the neuron in the right direction so it can regrow to the proper receptor sites.
- Not really.
- Voltage Gated Na+ Channels
- Schwann Cell wraps around the axon to form the myelin sheath.
Neurilemma is the plasma membrane of a neuron
Ranvier is the space between mylination
5 True/False Questions
Define excitability. What kinds of cells possess excitability? → Able to receive impulse from action potentials
How does nerve tissue respond to injury? What cells are responsible for the repair? Where can it occur? → In CNS, it doesn't heal.
In PNS, if mylineation cells are still in tact, they will reform a path for the neuron to grow.
Schwann Cells or Oligodendricites
What principle is applied to transmission of a nerve impulse (action potential)? What is a threshold stimulus? What is the ionic basis for threshold? → Threshold Stimulus is the all or none principle. Resting potential -55mv. Has to bring it positive with K+ ions.
Voltage Gated K+ Ions open up which allows K+ ions to enter the membrane.
What are the two major divisions of the nervous system? Name the three subdivisions of the PNS, and tell how they differ in functions. What are the two subdivisions of the Motor pathway system? → Central Nervous System (CNS) and Peripheral Nervous System (PNS)
Autonomic (involuntary). Within this, there are Sympathetic (Fight or Flight) and Parasympathetic (Rest and digest).
What is neuroglia? How do these cells compare (in structure, number, and function) to the neurons. What are the functions of each of the neuroglia? Which ones are in the CNS and which ones are in the PNS? → Neuroglia are cells that support and protect neurons
There are more neuroglia than neurons, they don't have dendrites or axons.
Astrocytes (CNS) - Forms blood brain barrier, protects neurons, allow the exchange of nutrients and waste
Oligodendricites - Mylinate the CNS
Epidymal (CNS) - Circulate the cerebral spinal fluid
Microglia - Eat debris in the CNS
Satellite and Schwann Cells are in the PNS.