Duck Flashcards
(103 cards)
Scattered through our organs are various _________that respond to stimuli in the internal or external environment of the organism
sensory receptors
All input to the CNS arrives in the same form as nerve impulses via
sensory neuron
are the physiological capacities within an organism that provide the inputs for perception
Senses
The information that the brain derives from sensory input is based on the frequency and pattern with which these impulses arrive on the identity of specific transmitting neuron
T or F
True
Topognosis aka….
Touch Localization
refers to the ability to localize stimuli to parts of the body
Touch Localization
occurs when the brain associates touch perception with sensory
nerve endings of a specific location on the ski
Touch Localization
🞂 due to differential density of distribution of the specific nerve
endings, touch sensitivity varies in one specific body regions
T or F
F
Different
T or R
sensitivity is greater in areas of the body with a high density of sensory nerve endings
T
Touch Discrimination is aka
Two-point discrimination
refers to the ability of the peripheral sensory nerves to recognize simultaneous stimulation by two blunt points (Walker, et al., 1990)
🞂 the point at which the patient can no longer differentiate one from two points once the two points are moved progressively closer
Touch Discrimination
TWO-POINT DISCRIMINATION DEPENDS ON:
◦ Activating two separate populations of neurons
◦ The receptive fields must be small
◦ The receptors must be densely packed in a sensitive area, so that two points very close together activate different receptors
Mechanisms of Touch Localization
Stimulus
Sensory Receptors
Afferent Nerve
CNS
Factors Affecting Sensitivity
◦ FACTORS:
HIGH
🞄 the large brain space devoted to
perception of touch in skin areas
🞄 the high density of touch sensory nerve fibers and receptor endings in a particular skin areas
◦ Glabrous (smooth and not hairy) areas of the skin are richly endowed with nerve endings which make them very sensitive (Culberson, 2006)
◦ i.e. fingertips and lips
LOW
◦ FACTORS:
🞄 less brain space in the cortex
🞄 lower density of sensory fibers and
receptor endings
◦ Hairy skin areas have fewer endings and different kinds with a low density of touch receptors which make them less sensitive to touch (Culberson, 2006).
◦ i.e. skin of the back and trunk
- Due to the large amount of mechanoreceptors specialized to provide information to the central nervous system about touch, this makes
the skin area to be highly
sensitive wherein even weak mechanical stimulation of the skin induces them to produce action potentials (Purves, et al., 2001).
true
Left Hemisphere section receives input from the body’s right side
for INPUT
Sensory Cortex
Left Hemisphere section controld the body’s right
OUTPUT
Motor Cortex
SOMATIC SENSORY RECEPTOR TYPES
Meissner’s Corpuscles
Pacinian C
Ruffini C
Hair Follicles
Merkel Complex
Free Nerve Ending
◦ Some are touch-sensitive (mechanoreceptors), while others are strictly pain-
sensitive (nociceptors).
◦ Others are temperature-sensitive (thermoreceptors) may be either cold- sensitive or heat-sensitive.
◦ Commonly found in hairy and smooth (glabrous) skin, cornea of the eye, pulp of teeth, mucous membranes, and many other locations.
Free nerve-endings
◦ Some are touch-sensitive
mechanoreceptors
others are strictly pain-
sensitive (
nociceptors
◦ Others are temperature-sensitive
thermoreceptors
◦ Commonly found in hairy and smooth (glabrous) skin, cornea of the eye, pulp of teeth, mucous membranes, and many other locations.
Free nerve-endings
◦ encapsulated and sensitive to pressure and vibration stimuli
Pacinian corpuscles
