5 Written Questions
5 Matching Questions
- What is the role of the Schwann Cell in the formation of the myelin sheath. What is the neurilemma? What is a node of Ranvier? Are nodes of Ranvier in both the CNS and the PNS?
- What parts of neurons are found in gray matter? White matter? Why is it white?
- What is the refractory period (absolute and relative)? What are the ligand gated channels doing at this time?
- What is an EPSP and a IPSP? Are these graded potentials, action potentials, or can they be both?
- How are electrical potentials of cell membranes measured?
- a Absolute Refractory Period - complete insensitivity exists to another stimulus. Voltage gated Na+ Channels open and close.
Relative Refractory Period - follows the absolute period, membrane is more permeable to K+ because many voltage gated K+ channels are open.
- b mV
- c 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
- d EPSP - Excitatory Post Synaptic Potential; potential of the cell to reach threshold again after it has been through a cycle.
IPSP - Inhibitory Post Synaptic Potential; Hyperpolarize on purpose to prevent a response to every stimulus.
- e Cell bodies found in gray matter
Because the tissue is composed of fatty tissue.
5 Multiple Choice Questions
- 3 Na out, 2 K in
- 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.
- 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
- To travel across the synapse and get the action potential to the next neuron
Ach is acetylcholine
Cholinergic synapses -
- Axonal transport is a cellular process responsible for movement of mitochondria, lipids, synaptic vesicles, proteins, and other cell parts (i.e. organelles) to and from a neuron's cell body, through the cytoplasm of its axon
5 True/False Questions
What is an electrochemical gradient? → Only allows certain things through.
What gives peripheral nerves their white appearance? → Only allows certain things through.
Describe the ionic basis for an action potential (depolarization). What is the ionic basis for repolarization? What is hyperpolarization? What ions are involved? → Voltage Gated Na+ Channels
If a neuron synapses on a second neuron and drives the resting membrane potential further from threshold, what is this called? Where does it occur? → IPSP, Inhibitory Post Synaptic Potential.
Axons are classified into 3 groups according to the relationship between diameter, myelination and propagation speed: define Type A, B and C fibers. → 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