ch 15
What is the term for the crossing of second-order neurons to the opposite side of the CNS?
Decussation
The conversion of an arriving stimulus into an action potential by a sensory receptor is known as:
Transduction
The cerebellum monitors proprioceptive sensations, visual information, and vestibular sensations. What effect does learning patterns of cerebellar activity by trial and error have on complex movements?
Fine-tuning of complex movements improves.
Which of the following is NOT considered a general sense?
Vision
Which motor pathway provides voluntary control over skeletal muscles?
Corticospinal pathway
Which spinocerebellar tracts contain axons that do not cross to the opposite side of the spinal cord?
Posterior spinocerebellar tracts
Tactile discs (Merkel cells) are characterized by which of the following?
Extremely sensitive tonic receptors
What term describes the system that controls contractions of skeletal muscles?
Somatic nervous system
Lamellar corpuscles (Pacinian corpuscles) are most sensitive to which type of stimulus?
Pulsing or high-frequency vibrating stimuli
In a sensory pathway, which neuron is an interneuron located within the spinal cord or brainstem and receives information from the first-order neuron?
Second-order neuron
Which class of mechanoreceptors detects pressure changes in blood vessels and in digestive, respiratory, and urinary tracts?
Baroreceptors
Sensations of fast pain, such as a prickling pain from an injection, are carried by which type of nerve fibers?
Myelinated Type A fibers
Which of the following is NOT a major somatic sensory pathway?
Corticospinal pathway
The continued feeling of pain in an amputated limb is an example of what abnormality in the spinothalamic pathway?
Phantom limb syndrome
What is the conscious awareness of a sensation called?
Perception
Chemoreceptors in the carotid and aortic bodies monitor the levels of which three substances in arterial blood?
pH, carbon dioxide, and oxygen
Which proprioceptors monitor skeletal muscle length and trigger stretch reflexes?
Muscle spindles
Referred pain is described as:
Feeling pain in an uninjured part of the body when pain originates at another location.
What is the area monitored by a single receptor cell called?
Receptive field
What type of sensations does the posterior column pathway primarily carry?
Fine touch, vibration, pressure, and proprioception
Mechanoreceptors contain mechanically gated ion channels that open or close in response to what?
Physical distortion of the membrane
Sensory information reaches cortical neurons via a specific pathway where each line carries information about one type of stimulus. This pathway is referred to as a:
Labeled line
Sensations of slow pain (burning and aching pain) are carried by what type of nerve fibers?
Unmyelinated Type C fibers
What type of sensations does the spinothalamic pathway primarily carry?
Crude touch, pressure, pain, and temperature
Free nerve endings, one of the six types of tactile receptors in the skin, are described as:
Tonic receptors with small receptive fields
Name the special sense responsible for taste.
Gustation
Baroreceptors are characterized by their response to pressure changes and how they adapt. Which statement is true about baroreceptors?
They are free nerve endings within elastic tissues.
What type of tactile receptor monitors distortions and movements across the body surface wherever hairs are located?
Root hair plexus nerve endings
Which tactile corpuscles are abundant in eyelids, lips, fingertips, nipples, and external genitalia, and perceive fine touch, pressure, and low-frequency vibration?
Tactile corpuscles (Meissner corpuscles)
Nociceptors are sensitive to three main types of stimuli. Name one.
Temperature extremes
After second-order neurons of the gracile and cuneate nuclei decussate, their axons enter which tract?
Medial lemniscus
Which division of the nervous system is responsible for relaying sensory information from receptors to the Central Nervous System (CNS)?
Afferent division
What is the term for the reduction of receptor sensitivity in the presence of a constant stimulus?
Adaptation
When stimulated, a sensory receptor generates which of the following that are sent along sensory pathways?
Action potentials
Which type of receptor is always active and generates action potentials at a frequency that reflects the background level of stimulation?
Tonic receptor
Give an example of a type of receptor that reminds you of an injury long after the initial damage has occurred.
Pain receptors
What large nucleus on each side of the medulla oblongata serves as a major processing and sorting center for visceral sensory information?
Solitary nucleus
Phasic receptors are characterized by which of the following?
They respond strongly at first but then activity decreases.
Receptors that monitor internal organs and their functions are classified as what type of general sensory receptor?
Interoceptors
Thermoreceptors are free nerve endings found in several locations. Which of the following is NOT a location where thermoreceptors are found?
Thyroid gland
What is the functional map of the primary somatosensory cortex called?
Sensory homunculus
Which type of tactile receptor has large receptive fields and provides poor localization of a stimulus?
Crude touch and pressure receptors
Pain and temperature sensations are primarily carried by which tract within the spinothalamic pathway?
Lateral spinothalamic tract
Proprioceptors are found in what three locations in the body?
Joints, tendons, and muscles
Somatic motor pathways always involve at least how many motor neurons?
Two
The spinocerebellar pathway conveys information about positions of muscles, tendons, and joints, but this information typically does not reach:
Our conscious awareness
Which type of general sensory receptor is sensitive to physical distortion of plasma membranes?
Mechanoreceptors
Bulbous corpuscles (Ruffini corpuscles) are what type of receptors regarding adaptation?
Tonic receptors
Visceral sensory information is collected by interoceptors monitoring visceral tissues and organs, primarily within which cavities?
Thoracic and abdominopelvic
What happens to voluntary and reflex control over an innervated motor unit if its lower motor neuron is damaged?
It eliminates voluntary and reflex control over that motor unit.