A & P MASTERING: CHAPTER 13

FALSE All of the sensory information is considered afferent, or flowing toward the CNS. Efferent means "from the CNS."
Explanation: The efferent division of the PNS is also known as the motor division. This is because the efferent division is responsible for sending signals from the brain to the muscles, which results in movement.

C. Nociceptors respond to potentially damaging stimuli that result in pain.
Explanation: C. Nociceptors are receptors that can respond to painful stimuli.

A. Mechanoreceptors respond to mechanical force such as pressure, vibration, stretch, and touch, allowing us to feel an insect landing on our skin.

C. Processing at the circuit level involves the transmission of action potentials along ascending pathways. These pathways deliver impulses to the appropriate regions of the cerebral cortex for localization and perception of the stimulus.
Explanation: The integrative level of the somatosensory system involves the spinal cord. This level is responsible for integrating information from the various receptors in the body and transmitting it to the brain. The perceptual level is responsible for processing this information and creating a conscious awareness of it. The circuit level is responsible for organizing this information and sending it to the appropriate areas of the brain.

C. The perceptual level is the third (final) level of neural integration in the somatosensory system. This is when you become aware of a stimulus.
Explanation: The correct answer is C. perceptual. In order for you to realize there has been a sensory change, it has to reach the perceptual level of processing. This is because the perceptual level is where information from the senses is interpreted and organized.

B. Transduction is converting a stimulus into a nervous signal; this happens at the receptor level.
Explanation: A. detection is NOT representative of receptor-level processing because it is the ability to see or hear something. B. transduction is NOT representative of receptor-level processing because it is the process of converting one form of energy into another. C. magnitude is NOT representative of receptor-level processing because it is the size or intensity of a stimulus. D. spatial discrimination is NOT representative of receptor-level processing because it is the ability to perceive the location of a stimulus in space.

C.
Explanation: Magnitude estimation is the ability to judge the intensity of a sensation. Spatial discrimination allows us to recognize the location of a stimulus. Pattern recognition allows us to see familiar shapes and recognize them as being meaningful. Perceptual detection is the ability to detect the presence of a stimulus.

B. Within a nerve, each axon is surrounded by endoneurium, a delicate layer of loose connective tissue that also encloses the fiber's associated Schwann cells.
Explanation: The endoneurium directly surrounds every axon in a nerve. The endoneurium is a layer of connective tissue that is made up of cells called Schwann cells. Schwann cells wrap around the axons of nerve cells and provide support and protection. The endoneurium also helps to keep the axons of nerve cells hydrated and nourished.

FALSE PNS nerve fibers regenerate because of the actions of Schwann cells.
Explanation: The answer is True. Schwann cells are a type of glial cell that wraps around and provides support to nerve fibers in the peripheral nervous system. When a nerve fiber is damaged, Schwann cells are important for helping the nerve to regenerate by providing support and guidance for the growing nerve fibers.

A. The vestibular branch of the vestibulocochlear nerve transmits afferent impulses for the sense of equilibrium. The cochlear branch transmits afferent impulses for the sense of hearing.
Explanation: The vestibulocochlear nerve is the cranial nerve that transmits information about audition. This nerve has two main functions: to provide information about the position and movement of the head, and to transmit auditory information from the inner ear to the brain. The vestibulocochlear nerve is responsible for the sense of balance and for hearing.

B. The vagus nerve has many targets in the thoracic and abdominal cavities and innervates many of the visceral organs.
Explanation:The vestibulocochlear nerve is the cranial nerve that transmits information about audition. This nerve has two main functions: to provide information about the position and movement of the head, and to transmit auditory information from the inner ear to the brain. The vestibulocochlear nerve is responsible for the sense of balance and for hearing.

C. The abducens carries efferent (motor) signals to the extrinsic eye muscle that abducts the eye (turns it laterally).
Explanation: The correct answer is D. The trigeminal nerve is the only cranial nerve that carries only motor information. The other cranial nerves carry both motor and sensory information.

C. The hypoglossal nerve carries motor commands to the tongue.
Explanation: The trigeminal nerve carries information from the face, including the teeth. The optic nerve carries information from the eye. The hypoglossal nerve carries information from the tongue. The vestibulocochlear nerve carries information from the ear.

A.
Explanation: The olfactory nerve (I) is responsible for the sense of smell. The vagus nerve (X) and hypoglossal nerve (XII) are responsible for the movement of the muscles of the throat and tongue, respectively. The facial nerve (VIII) is responsible for the movement of the facial muscles.

C.
Explanation: The emergency medical technician is examining a trauma victim by shining a pen light into her patient's eye. She records the reactivity of the patients pupils as they constrict when stimulated by the light. This test supports that the patient has function of the oculomotor nerve (III).