Chapter 17
Neurons conveying somatosensory information from the head to the brainstem are ___-order
1st
Neurons of the somatosensory pathway that convey information from the brainstem to the contralateral side of the thalamus are ___-order
2nd
Identify the three modalities detected by free nerve endings.
Falling temperatures (cold receptors) Rising temperatures (warm receptors) Pain (nociceptors)
Identify the type of unencapsulated nerve endings that include temperature receptors (warm and cold), and nociceptors (pain).
Free nerve endings
Tactile receptors that are located in the mucous membranes of the lips and tongue, in the conjunctiva of the anterior surface of the eye, and the epineurium of large nerves are the ______.
Krause corpuscles
Tactile receptors responsible for sensing deep pressure, stretch, tickle and vibration stimuli are the
Lamellar (Pacinian) corpuscles
These receptors are defined by the type of stimulus (modality) that stimulates them. (Mark all that apply.)
Nociceptors Photoreceptors Chemoreceptors Mechanoreceptors
Identify the senses that are stimulated by environmental chemicals.
Olfaction Gustation
___ is a sensation mediated by specialized receptors called nociceptors.
Pain
___ is discomfort resulting from tissue damage or exposure to noxious stimuli.
Pain
Identify the location where first order pain neurons are inhibited by descending analgesic fibers thereby blocking pain signals from reaching the brain.
Posterior horn of the spinal cord
The sensation felt along the medial aspect of the left arm during a heart attack, which in reality occurs due to the stimulation of visceral pain pathways, is an example of what?
Referred pain
What is pain from the skin, muscles, and joints called?
Somatic
Indicate the two terms that describe the type of senses that utilize receptors that are widely distributed throughout the body.
Somesthetic senses General senses
Which two types of encapsulated nerve endings are responsible for detecting light touch and texture? (Mark two.)
Tactile (Meissner) corpuscles End bulbs (Krause corpuscles)
Identify the modalities detected by tactile (Merkel) discs. Select all that apply.
Texture Light touch
Describe the projection pathway of pain occurring in the head. Select all that apply.
Third-order neurons convey signals from the thalamus to the cerebral cortex Second-order neurons ascend to the thalamus where they synapse third order neurons First-order neurons synapse with second order neurons in the medulla
Proprioceptors respond to which stimuli?
Those pertaining to the position or movements of body parts
List four cranial nerves that function as first-order neurons in the projection pathway for pain that occurs in the head.
Trigeminal (V) Vagus (X) Glossopharyngeal (IX) Facial (VII)
True or false: First order pain neurons conveying nociceptive information can be inhibited by enkephalins and dynorphins from descending analgesic fibers.
True
The receptive field is the ______.
area of stimulus detected by a single sensory neuron
Sensory receptors are found in all of the following forms EXCEPT ______.
axons
First-order somatosensory fibers from the head carry information to the ______.
brainstem
Tactile receptors that sense heavy touch, pressure, stretching of the skin, and joint movement are the ______.
bulbous (Ruffini) corpuscles
Third-order fibers of somatosensory projection pathways from the head ______.
carry signals to the cerebrum
Projection pathways are sensory signals that end in the ______.
central nervous system
A receptor that is stimulated by interaction with chemicals such as in taste or smell is classified as a
chemoreceptor
In an area that has high two-point touch discrimination receptor fields are located _____.
closer together
Papillae that look like tiny spikes without taste buds are called ______.
filiform papillae
The type of lingual papillae that lacks taste buds but aids in the sense of texture is the ______ papillae and the lingual papillae that contains taste buds that degenerate by the age of 2 or 3 is the _____ papillae.
filiform, foliate
Areas where the tactile (Meissner) corpuscles are abundant include ______. (Mark all that apply.)
fingertips nipples palms
The somatosensory signals travel by way of three neurons called ______.
first-order, second-order, and third-order neurons
Interoceptors respond to stimuli _______.
from internal organs
The two senses determine by environment chemicals are the senses of _____.
gustation and olfaction
Imagine that a mosquito landed on your arm. The unencapsulated nerve endings that would sense the presence of the insect are the ______.
hair receptors
The receptors that are classified as encapsulated nerve endings are ______. (Mark all that apply.)
lamellar (Pacinian) corpuscles end bulbs tactile (Meissner) corpuscles bulbous (Ruffini) corpuscles
First order fibers for touch, pressure and proprioception are ______.
large, myelinated, fast
The stimulus that triggers photoreceptors is ______.
light
The modalities detected by Krause corpuscles (end bulbs) are ______.. Mark all that apply.
light touch texture
Four types of surface projections of the tongue are collectively referred to as ___ papillae
lingual
A receptor that is stimulated by touch, pressure, stretching, or vibration is classified as a
mechanoreceptor
Spinal gating is a mechanism in which ______.
pain signals never reach the brain
Receptors that respond to light stimuli are classified as ______.
photoreceptors
Somesthetic senses include the ______. (Mark all that apply.)
pressure pain touch stretch
The pathways followed by sensory signals to their ultimate destinations in the CNS are called ______.
projection pathways
The type of sensory receptor that detects information pertaining to the position and movement of body parts is the
proprioceptor
The ______ is the area of stimulus that is detected by a single sensory neuron.
receptive field
Pain that results from convergent neural pathways that leads to visceral pain mistakenly thought to originate from the skin is called ___ pain
referred
Free nerve endings are most abundant in ______.
skin and mucous membranes
Unencapsulated nerve endings that include receptors for detecting textures, edges and shapes are the ______.
tactile (Merkel) discs
Receptors that are unencapsulated nerve endings include ______. (Mark all that apply.)
tactile (Merkel) discs hair receptors free nerve endings
Sensory receptors for taste located primarily on lingual papillae are the ___ ___
taste buds
Taste cells, supporting cells and basal cells form lemon-shaped structures located on the lingual papillae. These lemon-shaped structures are referred to as ___ ___
taste buds
Stretch receptors in tendons are called ______.
tendon organs
Within somatosensory projection pathways, most third-order fibers synapse with the second-order fibers in the ___
thalamus
Pain fibers that are ___ conduct impulses that travel 0.5-2 m/sec and produce the slow (second) pain.
unmyelinated
Identify the four modalities detected by lamellar (Pacinian) corpuscles.
vibration stretch deep pressure tickle
The sensations that result from input by exteroceptors are ______. (Mark all that apply.)
vision pain in the skin touch hearing
Identify the most abundant lingual papillae.
Filiform papillae
Which of the following sites contains the most taste buds?
Lingual papillae
Indicate the type of pain fibers that produce the fast (first) pain.
Myelinated fibers
Receptors are found in which of the following forms? Select all that apply.
Receptors in eyes Receptors in skin Receptors in joints Receptors in viscera
Identify the projection pathway for pain from below the neck responsible for eliciting the emotional response to pain including fear and nausea.
Spinoreticular tract
Which of the following is the projection pathway for pain from below the neck responsible for carrying most of the somatic pain information?
Spinothalamic tract
True or false: First-order fibers from below the head may decussate at or near the point of entry into the spinal cord.
True
Name the type of pain fibers associated with slow (second) pain.
Unmyelinated fibers
______ pain is the pain that results from stretch receptors, chemical irritants or ischemia to the abdominal organs.
Visceral
Which sensations result from input by interoceptors? (Mark all that apply.)
Visceral pain Bladder pressure
Flattened elongated capsules capable of detecting heavy touch, stretching of the skin and joint movement are the ___ corpuscles
bulbous
Receptors that detect specific molecules related to smell or taste, for example are classified as ______.
chemoreceptors
As the diameter of a receptive field increases, the ability to have a two-point touch discrimination ______.
decreases
Second-order fibers carrying somatosensory signals ______.
decussate and end in the contralateral thalamus
Nerve endings that consist of nerve fibers surrounded by glial cells or a connective tissue covering are referred to as
encapsulated
muscle spindles
encapsulated receptor detecting tension if skeletal muscle
tendon organs
encapsulated receptor detecting tension in tendons
end bulb
encapsulated tactile receptor of mucous membranes
Special senses which are mediated by relatively complex sense organs of the head include ______. (Mark all that apply.)
equilibrium smell vision
Nerve endings that detect deflection (bending) of body hair are the unencapsulated ______.
hair receptors
An area with a higher two-point touch discrimination will have a _______ number of receptor fields.
higher
As the diameter of a receptive field decreases, the ability to have a two-point touch discrimination ______.
increases
Tendon organs protect against tendon or muscle injury by ______.
inhibiting muscle contraction
Muscle spindles are stretch receptors containing ______.
intrafusal fibers and sensory nerves
Receptors that detect touch, pressure, stretch, or vibration stimuli are classified as ______.
mechanoreceptors
One system for classifying receptors is by the type of stimulus such as temperature, pressure, pain, touch, light, and vibration. The type of stimulus is referred to as
modality
Stretch receptors in the muscles are called ______.
muscle spindles
Pain fibers that are ___ conduct signals 12-30 m/sec and produce fast (first) pain.
myelinated
A pain receptor which is stimulated by tissue damage is referred to as a
nociceptor
Receptors that respond to pain stimuli are classified as ______.
nociceptors
Any structure, either nerve endings or nerve endings combined with other tissue, that is specialized to detect a stimulus is a(n) _____.
sensory receptor
Touch, pressure, stretch, hot, cold, pain, blood pressure and blood chemistry are all examples of ______. (Mark all that apply.)
somatosensory senses somesthetic senses general senses
The type of senses that utilize receptors that are specific to a particular area of the body is classified as ______.
special
First-order somatosensory fibers carrying signals from below the head enter the central nervous system at the level of the _____.
spinal cord
Mortally wounded people often do not feel pain. This may be due to ______.
spinal gating
Exteroceptors respond to ______.
stimuli external to the body
Special senses include all of the following EXCEPT
stretch
A receptor that responds to temperature (heat and cold) stimuli is classified as a
thermoreceptor
The receptor that is specialized to respond to hot and cold stimuli is referred to as a ______.
thermoreceptor
"Naked" sensory dendrites, lacking connective tissue coverings are referred to as ___ nerve endings. They include free nerve endings, tactile (Merkel) discs, and hair receptors.
unencapsulated
free nerve endings
unencapsulated pain, heat and cold receptor of epithelial and connective tissue
hair receptors
unencapsulated receptor located around hair follicles