5 Written questions
5 Matching questions
- Define excitability. What kinds of cells possess excitability?
- Axons are classified into 3 groups according to the relationship between diameter, myelination and propagation speed: define Type A, B and C fibers.
- What is a presynaptic neuron? Postsynaptic neuron? Define converge, divergence of neurons.
- You may recall that a muscle fiber is an entire muscle cell; is a nerve fiber an entire neuron? (explain)
- What parts of neurons are found in gray matter? White matter? Why is it white?
- a Presynaptic - The neuron that sends the action potential to the next dendrite
Postsynaptic - Receives the message
Convergence of Neurons - First one neuron is influenced by many others, resulting in a convergence of input.
Divergence of Neurons - When the neuron fires, the signal is sent to many other neurons, resulting in a divergence of output.
- b No because the neuron consists of many other things that make up the neuron (dendrites, axons, cell bodies, axon terminals)
- c Able to receive impulse from action potentials
- d Cell bodies found in gray matter
Because the tissue is composed of fatty tissue.
- e 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
5 Multiple choice questions
- Schwann cells can point the neuron in the right direction so it can regrow to the proper receptor sites.
- spatial variation of both electrical potential and chemical concentration across a membrane.
- 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
- 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.
5 True/False questions
How are electrical potentials of cell membranes measured? → mV
Are nerve fiber in the CNS mylelinated? Do they have a neurilemma? → Not really.
Describe the structure of a typical neuron. Identify as to structure and function: a cell body; dendrite; axon; microtubules; Nissl bodies; axon hillock. → Unipolar
What gives peripheral nerves their white appearance? → Only allows certain things through.
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? → Salutatory conduction of an action potential is when you jump from node to node.