Nokea
An interneuron has _____________.
- A. long dendrites and a short axon
- B. long dendrites and a long axon
- C. short dendrites and a long axon
- D. short dendrites and a long or short axon
Correct Answer: D
Rationale: Interneurons, which are found within the CNS, typically have short dendrites and either a long or short axon. These neurons act as connectors between sensory and motor neurons, integrating and processing information to generate appropriate responses. The structure of interneurons allows them to facilitate communication within the CNS, enabling complex reflexes and higher-order cognitive functions.
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Which structure allows communication between the hemispheres?
- A. reticular formation
- B. temporal lobe
- C. contralateral bridge
- D. corpus callosum
Correct Answer: D
Rationale: The corpus callosum is a thick bundle of nerve fibers that connects the left and right hemispheres of the brain, allowing for communication and coordination between them. It enables the integration of information from both sides of the brain, facilitating complex cognitive processes and motor coordination. Damage to the corpus callosum can result in disconnection syndromes, where the hemispheres cannot communicate effectively.
The diameter of a motor nerve fibre is
- A. 1-2 micrometre
- B. 3-5 micrometre
- C. 5-12 micrometre
- D. 12-20 micrometre
Correct Answer: D
Rationale: Motor nerve fibers, such as alpha motor neurons, typically have a diameter of 12-20 micrometers. Larger diameters allow for faster conduction of action potentials.
Communication within neurons is ______, communication between neurons is ________.
- A. excitatory, inhibitory
- B. inhibitory, excitatory
- C. chemical, electrical
- D. electrical, chemical
Correct Answer: D
Rationale: Communication within neurons is electrical, involving the propagation of action potentials along the axon. Communication between neurons, however, is chemical, relying on the release of neurotransmitters at the synapse. This combination of electrical and chemical signaling allows for rapid and precise communication within the nervous system, enabling complex behaviors and cognitive processes.
A microscopic gap between a pair of adjacent neurons over which nerve impulses pass when going from one neuron to the next is called:
- A. Neurotransmitter
- B. Synapse
- C. Axon
- D. None of the above
Correct Answer: B
Rationale: Synapse is the correct answer because it is the junction between two neurons where electrical or chemical signals are transmitted. Neurotransmitters are the chemicals that facilitate this transmission, but the gap itself is called the synapse.
As the potassium ions move out of the axon, the oscilloscope records a ________.
- A. depolarization
- B. repolarization
- C. equalizing of negative and positive ions
- D. shutdown of the membrane pumps
Correct Answer: B
Rationale: As potassium ions move out of the axon during repolarization, the oscilloscope records a return of the membrane potential to its negative resting state. This phase of the action potential is called repolarization and is essential for resetting the neuron so it can fire another action potential. Repolarization ensures that the neuron is ready to transmit subsequent nerve impulses.