BIO 242 Study Guide with Questions and Answers

The threshold of a neuron is the: d. total amount of neurotransmitter it takes to cause an action potential. An neuronal circuit in which one presynaptic neuron stimulates a group of neurons, each of which then synapses with a common postsynaptic cell is a: d. parallel after-discharge circuit. Following injury to a peripheral neuron, chromatolysis occurs, which is: b. breakup of the Nissl bodies. Cerebrospinal fluid normally circulates in the: c. subarachnoid space. The part of a spinal nerve that contains only efferent fibers is the: b. ventral root. The nerve that stimulates the diaphragm to contract arises from the: a. cervical plexus. Spinal nerves emerge from the vertebral column via: c. intervertebral foramina. The highly vascular, innermost layer of the meninges is the: c. pia mater. Ascending tracts contain: b. sensory neurons. Efferent neurons transmit impulses from: a. the CNS to effectors. Neuroglia in the central nervous system that produce the myelin sheath are the: b. oligodendrocytes. Nissl bodies are: b. clusters of rough ER in the cell body. The function of Schwann cells is to: a. form the myelin sheaths of neurons in the PNS ALL of the following are TRUE concerning action potentials EXCEPT: a. according to the all-or-none principle, all action potentials fired by a given neuron are of the same amplitude.