Nokea
Compared with myelinated nerve fibres, non-myelinated nerve fibres:
- A. have a higher threshold for stimulation
- B. have a longer refractory period
- C. transmit impulses at a lower frequency
- D. all above
Correct Answer: D
Rationale: Non-myelinated nerve fibers have a higher stimulation threshold, longer refractory period, and lower impulse transmission frequency compared to myelinated fibers. These differences are due to the lack of saltatory conduction in non-myelinated fibers.
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Autonomic dysreflexia can best be described as a
- A. serious complication occurring in patients with cord damage below the T-6 level
- B. frequent cause of cerebral hemorrhage and myocardial infarction
- C. normal sequelae of spinal cord injury
- D. sudden exaggerated sympathetic discharge
Correct Answer: D
Rationale: Autonomic dysreflexia involves an exaggerated sympathetic response in spinal cord injury patients.
Like other systems in the body, the nervous system is composed of organs, principally the brain, spinal cord, nerves, and _______.
- A. ganglia
- B. axon
- C. neurons
- D. dura mater
Correct Answer: A
Rationale: The nervous system is composed of several key organs, including the brain, spinal cord, nerves, and ganglia. Ganglia are clusters of nerve cell bodies located outside the central nervous system and play a role in processing and transmitting nerve signals. Axons and neurons are components of nerves, while the dura mater is a protective membrane surrounding the brain and spinal cord. Ganglia are the correct answer as they are distinct organs within the nervous system.
In planning community education for prevention of spinal cord injuries, what group should the nurse target?
- A. Older men
- B. Teenage girls
- C. Elementary school€“age children
- D. Adolescent and young adult men
Correct Answer: D
Rationale: Young men are at higher risk for traumatic spinal cord injuries.
The joint position sense of the right leg is impaired in damage of:
- A. the superior colliculi
- B. the cerebellum
- C. the thalamus of the right
- D. the post-central gyrus of the left cerebral hemisphere
Correct Answer: D
Rationale: Joint position sense (proprioception) is processed in the post-central gyrus of the contralateral cerebral hemisphere. Damage to the left post-central gyrus impairs proprioception in the right leg. The superior colliculi, cerebellum, and thalamus are not primarily involved in joint position sense.
The 'synaptic cleft' of a neuromuscular junction is
- A. a groove in the muscle cell plasma membrane through which neurons grow
- B. that portion of the cell surface receptor molecule on the surface of a muscle cell, into which the ligand binds
- C. a depression at the end of an axon from which neurotransmitters are secreted
- D. the space between the plasma membrane of a neuron on the pre-synaptic side of the synapse, and the plasma membrane of the muscle cell on the post-synaptic side of the synapse
Correct Answer: D
Rationale: The synaptic cleft is the narrow space between the presynaptic neuron and the postsynaptic muscle cell. It is where neurotransmitters are released and diffuse to bind receptors on the muscle cell, initiating muscle contraction. This structure is essential for signal transmission at the neuromuscular junction.