A&P Chapter 15

The sensory homunculus is __________.

A functional map of the somatosensory cortex

Which of the following is the best illustration for Golgi tendon organ activation?

A male gymnast performing an iron cross on the rings apparatus

The pyramidal system includes which of the following?

All of the listed responses are correct.

Which of the following serve as receptors to measure body position and balance?

All of the listed responses are correct.

Which of the following is a progressive degenerative disorder that affects motor neurons in the spinal cord, brain stem, and cerebral hemispheres?

Amyotrophic lateral sclerosis

Which of the following tracts are NOT involved in proprioception?

Anterior and lateral spinothalamic tracts

In motor pathways, the only portion of the pathway that is outside of the CNS is the

Axon of the lower motor neuron.

Which type of receptor detects pressure changes?

Baroreceptor

Mechanoreceptors that respond to changes in blood pressure are called

Baroreceptors

The ___________ nuclei provide the background patterns of movement involved in voluntary motor activities.

Basal

Chemoreceptors are located in __________.

Both the carotid arteries and the aorta

Chemoreceptors of the general senses do not send information to the primary sensory cortex but instead send information to the ________ to control autonomic function.

Brain stem

Unmyelinated Type C fibers carry slow pain sensations. What sensation is felt when an individual experiences slow pain?

Burning and aching pain

What part of the CNS uses proprioception sensations, visual information, and sensations of balance to fine tune movements making them precise, smooth, and efficient?

Cerebellum

Receptors in your stomach that determine when food enters because the pH changes would be classified as

Chemoreceptors

In somatic motor control, the cerebellum's role involves __________.

Coordinating complex motor patterns

The extrapyramidal tracts do NOT include which of the following?

Corticobulbar

___________ tracts of a descending motor pathway provide conscious control over skeletal muscles that move the eye, jaw, and face.

Corticobulbar

The anterior spinothalamic pathway carries the sensations of __________.

Crude touch and pressure

Peripheral adaptation ________ the number of action potentials that reach the CNS.

Decreases

Axons of second-order neurons (interneurons) crossover to the opposite side of the CNS. The crossing over from left to right side, or right to left side is known as a _______________.

Decussation

First-order sensory neurons deliver information to the CNS and synapse with certain interneurons called second-order neurons. Axons of the interneurons cross over to the opposite side of the CNS, and ascend to the thalamus where they synapse with third-order neurons. What is the result of the second order interneuron crossing over to the opposite side of the CNS?

Decussation

The relative proportions to the sensory and motor homunculus are __________.

Different because some sensitive areas have few muscles

Which of these types of sensory receptors is INCORRECTLY linked with its function?

Exteroceptor—monitors pressure in the lungs

The posterior column pathway carries the sensations of __________.

Fine touch and pressure

Which of the following best describes the sensory information provided by the fasciculus gracilis?

Fine touch, pressure, and vibration from the inferior half of the body

The afferent neuron that carries the sensation and enters the CNS is a ________ neuron.

First-order

Each sensory receptor has a characteristic sensitivity. For example, a touch receptor is very sensitive to pressure, but is relatively insensitive to chemical stimuli. This feature is called _______________.

General senses

A ________ potential is a depolarization of a sensory dendrite that can lead to an afferent nerve impulse if strong enough.

Generator

A receptor potential large enough to generate an action potential is called __________.

Generator potential

Sensory neurons that bring pain sensations into the CNS release the neurotransmitters, ___________ and/or ______________.

Glutamate, Substance P

The motor homunculus shows larger structures in areas of the body that

Have more motor units

Which of the following statements about the sensory homunculus is FALSE?

Hearing from the left ear is processed in the right sensory homunculus.

Which of the following INCORRECTLY pairs centers of somatic motor control with their activities?

Inferior medulla oblongata—coordinates complex motor patterns

Some neurons within the basal nuclei are known to

Inhibit neurons with GABA and stimulate neurons with acetylcholine.

Central adaptation refers to

Inhibition of nuclei located along a sensory pathway.

Which role does the medulla play in somatic motor control?

It balances reflexes and respiratory reflexes.

Which of the following statements about adaptation is FALSE?

It is a feature of tonic receptors but not of phasic receptors.

In order for a sensation to become a perception,

It must be received by the somatosensory cortex.

Which of the following INCORRECTLY pairs types of tactile receptors with their functions?

Lamellated corpuscles—Also called Meissner corpuscles, these measure fine touch and pressure and low-frequency vibrations in eyelids, fingertips, and lips.

In the corticospinal pathway, roughly 85% of the axons decussate to enter the ____________ corticospinal tracts.

Lateral

Which of the following correctly links components of the pyramidal motor pathways?

Lateral corticospinal tracts—descend without crossing to level of spinal nerves

Which descending motor neuron pathway helps control of muscle tone and more precise movements of distal limb muscles at the subconscious level?

Lateral pathway

The spinal tract that relays information concerning pain and temperature to the CNS is the

Lateral spinothalamic

Lucy is a 24-year-old who describes having severe pain emanating from her right upper chest and shoulder. She has no family history of heart disease. Which of the following is the most likely hypothesis for what she is experiencing?

Lucy is having referred pain from her gallbladder. The visceral sensory pathway that follows along the same spinal segments is most likely innervating the lateral spinothalamic tracts.

Which descending motor neuron pathway helps control gross movements of the neck, trunk and proximal limb muscles at the subconscious level?

Medial pathway

Descending tracts in the spinal cord relay ________ information.

Motor

Which receptors are common in superficial portions of the skin, in joint capsules, within the periostea of bones, and around the walls of blood vessels?

Nociceptors

A compound fracture of the femur results in tremendous sensations of prolonged pain. What type of sensory receptor would detect the stimulus of the bone breaking and state whether this receptor is tonic or phasic?

Nociceptors, phasic

Which of the following is NOT classified as a general sense?

Olfaction

Which of the following correctly defines referred pain?

Pain felt in an uninjured body area rather than in the area where the injury actually occurred

For the last few weeks, you have had an odd sensation on your upper thigh. When you touch the naked skin, it feels very strange, like you are touching your skin through layers of cloth. The surrounding area feels normal. Your doctor thinks that this may be related to spinal nerve damage related to a herniated disc. The doctor calls this change in sensation

Paresthesia

Your brain is not constantly bombarded with signals telling it that you are wearing socks. This is because the touch receptors around your ankle are

Phasic receptors and fast-adapting.

The gracile fasciculus and cuneate fasciculus are the spinal tracts of the ______________ pathway

Posterior column pathway

What somatic sensory pathway carries sensations of precise touch, vibration, and proprioception?

Posterior column pathway

Myelinated Type A fibers carry fast pain sensations. What sensation is felt when an individual experiences fast pain?

Prickling pain

Somatic sensory information does NOT travel to which of the following locations?

Primary motor cortex

The corticospinal pathway begins in which area of the brain?

Primary motor cortex

The spinocerebellar pathway carries the sensations of __________.

Proprioception

Which of the following is NOT considered a special sense?

Proprioception

You cannot tell when your small intestines shift position as food enters because you do not have any ________ there.

Proprioceptors

Which one of the following is NOT a correct linkage of a receptor type with the stimulus that excites it?

Proprioceptor—touch on skin surface

The neurons of the primary motor cortex are ________ cells.

Pyramidal

The corticospinal pathway can also be referred to as the __________ system.

Pyramidal system

The area monitored by a single receptor cell is its _______________.

Receptive field

The rubrospinal tracts originate in the

Red nuclei

Your uncle was just diagnosed with a heart attack. One of his major symptoms is left arm pain. You are not surprised because you are familiar with the phenomenon of ________ pain.

Referred pain

Each of the following is an ascending tract in the spinal cord except the

Reticulospinal tract

The spinal tract that normally plays a role in the subconscious regulation of the muscles of the arms is the ________ tract.

Rubrospinal

___________________ pathways carry sensory information from the skin and muscles of the body wall, head, neck, and limbs to the CNS.

Somatic sensory

The simplest reflexes are mediated at the level of the __________.

Spinal cord

Which somatic sensory pathway delivers proprioception input from Golgi tendon organs, muscle spindles, and joint capsule receptors?

Spinocerebellar pathway

Phantom limb syndrome and referred pain are a result of abnormalities in the ______________ pathway.

Spinothalamic

What somatic sensory pathway carries sensations of poorly localized crude touch, pressure, pain, and temperature?

Spinothalamic pathway

A highly sensitive tactile receptor composed of dendritic processes of a single myelinated fiber that makes contact with specialized cells of the stratum basale is a

Tactile (Merkel) disc

The medial pathway that controls involuntary movements of head, neck, and arm position in response to sudden visual and auditory stimuli is the ________ tract.

Tectospinal

Which of the following statements about levels of processing and motor control is correct?

The number of neurons in the cerebral cortex continues to increase until at least age four.

Your ability to localize sensations depends on __________.

The projection of sensation to the primary sensory cortex

The area monitored by a single receptor is called __________.

The receptive field

A high school senior dives into the unheated school swimming pool, and initially feels cold in the water. After a few minutes his body "gets used to it" and he feels comfortable. What type of general sensory receptor has been stimulated and indicate whether this receptor is tonic or phasic?

Thermoreceptors, tonic

Fine touch and pressure receptors provide detailed information about the source of stimulation, such as texture, size, and shape. What is the relationship between these types of tactile receptors and the receptive field?

These receptors are extremely sensitive and have narrow receptive fields

Thalamic neurons that project to the primary sensory cortex are ________ neurons.

Third-order

Visceral sensory information is collected by interoceptors monitoring visceral tissues and organs, primary located within _____________.

Thoracic and abdominopelvic cavities

How many major motor pathways are there?

Three

Sensory information requires __________ neuron(s) to reach the thalamus.

Three

There are __________ major sensory pathways.

Three

__________ receptors are always active and ___________ receptors are usually not active

Tonic, phasic

__________ receptors are slow-adapting and ___________ receptors are fast-adapting.

Tonic, phasic

The conversion of the stimulus into an action potential to be interpreted by the brain is called

Transduction

The spinal tract that unconsciously maintains balance and muscle tone is the ________ tract.

Vestibulospinal

We can localize sensations that originate in different areas of the body because

sensory neurons from specific body regions project to specific cortical regions.