5 Written questions
5 Matching questions
- How are nerve impulses transmitted across synapses? Compare this to transmission of an impulse from nerve fiber to muscle fiber. Is transmission of the impulse across a synapse one-way? What role does calcium play in the release of a neurotransmitter?
- Describe the importance of the Schwann cells in regeneration of the nerve fiber following injury.
- How does nerve tissue respond to injury? What cells are responsible for the repair? Where can it occur?
- Define excitability. What kinds of cells possess excitability?
- What is the refractory period (absolute and relative)? What are the ligand gated channels doing at this time?
- a 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
- b 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.
- c Through Neurotransmitters
Calcium has to go into the synapse to stimulate the vessels to open.
- d Schwann cells can point the neuron in the right direction so it can regrow to the proper receptor sites.
- e Able to receive impulse from action potentials
5 Multiple choice questions
- 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
- In order to get back to polarization, they have to pump in 3 Na out, 2 K in
- Channels that are somehow opened to allow specific ions to enter and exit.
- Means that action potential doesn't have to travel down the entire axon, just jumps from node to node.
- Voltage Gated Na+ Channels
5 True/False questions
Describe two conditions that allow maintenance of the resting membrane potential. How are concentration gradients involved? → IPSP, Inhibitory Post Synaptic Potential.
How are electrical potentials of cell membranes measured? → spatial variation of both electrical potential and chemical concentration across a membrane.
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? → Schwann cells can point the neuron in the right direction so it can regrow to the proper receptor sites.
What principle is applied to transmission of a nerve impulse (action potential)? What is a threshold stimulus? What is the ionic basis for threshold? → 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.
What is an electrochemical gradient? → spatial variation of both electrical potential and chemical concentration across a membrane.