Chapter 12 And 13 Quiz

d Third-order sensory neurons relay ascending information from the thalamus to specific sensory areas of the cortex.

c association fibers communicate between gyri in the same cerebral hemisphere

b

d

c projection fibers connect the cerebral cortex to the brain stem and spinal cord

b the cerebral cortex is the "executive suite" of the nervous system, where most of our higher-level decision making occurs. It enables us to be aware of ourselves and our sensation, communicate, remember, understand, and initiate voluntary movements.

a the superior colliculus is at the inferior border of the diencephalon, located in the midbrain region of the brain stem

c the hypothalamus does not regulate the thalamus

d afferent impulses from all senses and all parts of the body converge on the thalamus and synapse with at least one of its nuclei. The thalamus- which sorts out and edits these afferent signals before relaying them to the appropriate cortical areas- is considered the gateway to the cerebral cortex. In summary, the thalamus plays a key role in mediating sensation, motor activities, and cortical arousal, learning, and memory.

d the pons is the point at which all information entering or exiting the cerebellum is collected. Descending motor input and ascending sensory input that feed the cerebellum and all cerebellar output enter or exit the cerebellum through several cerebellar peduncles located in the pons.

b

a

a

b

a The cerebellum does not operate at the conscious level of processing

b By processing and interpreting impulses from the motor cortex and brain stem nuclei, as well as sensory pathways, the cerebellum provides the precise timing and appropriate patterns of skeletal muscle contraction for the smooth, coordinated movements and agility needed for daily living (e.g., driving, typing, and tying our shoes). It also plays a poorly understood role in cognition. Cerebellar activity occurs subconsciously (we are not aware of it).

b

a

c the pia mater, meaning "gentle mother" is composed of delicate connective tissue and is richly invested with tiny blood vessels. It is the only meninx that clings tightly to the brain, like cellophane wrap, following its every convolution.

d

c The ventral roots carry motor commands out of the spinal cord. The dorsal roots carry sensory information into the spinal cord. The spinal nerves represent a fusion of these two elements.

b

c

d

d Axons constitute a small fraction of a nerve's bulk. The balance consists chiefly of myelin, the protective connective tissue wrappings, blood vessels, and lymphatic vessels.

d the hypoglossal nerve carries motor commands to the tongue.

a

d the abducens carries efferent (motor) signals to the extrinsic eye muscle that abducts the eye (turns it laterally)

d 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.

d the phrenic nerve, which arises from the cervical plexus, supplies both motor and sensory fibers to the diaphragm, the main breathing muscle.

False Dermatomes represent sensory innervations of the underlying skin.

True

includes a synapse between sensory and motor neurons without the involvement of an interneuron.

d When a muscle is contracted, its antagonist ("reciprocal") is reflexively relaxed.

c

b

b

c

b

d The grasped arm is withdrawn (via the flexor reflex) as the opposite arm pushes you away from the attacker (via crossed-extensor reflex). As in this scenario, the crossed-extensor reflex often accompanies the flexor reflex.