chapter 15: cutaneous senses Flashcards
the somatosensory system is broken down into 3 subcategories what are they?
- cutaneous senses
- proprioception
- kinesthesis
what is the heaviest and the largest organ of the body
skin
name the functions of the skin
- warning
- prevents bodily fluid from escaping and protects body from bacteria, chemical agents and dirt
- provides info about various stimuli that comes into contact with it
name the layers of the skin
- epidermis
- dermis
- hypodermis
mechanoreceptors are …
receptors that respond to mechanical stimulation such as pressure, stretching and vibration
name the 2 mechanoreceptors that are located near the epidermis
- Merkel receptor
- Meissner corpuscle
receptors located near the surface of the skin have … receptive fields, whereas receptors located deep within the skin have … receptive fields
small; large
why are Merkel receptors called slowly adapting (SA1) fiber, and Meissner corpuscles called rapidly adapting (RA1) fiber
- Merkel: fires continuously, as long as stimulus is on
- Meissner: fires only when stimulus is first applied and removed
what are the types of perception associated with Merkel receptors and Meissner corpuscles
Merkel: details, shape, texture
Meissner: controlling handgrip, and perceiving motion across the skin
Ruffini cylinders are to … as Pacinian corpuscles are to …
Merkel receptors; Meissner corpuscles
slowly adapting vs rapidly adapting
name the 2 pathways from somatosensory receptors to the brain
- medial lemniscal pathway
- spinothalamic pathway
what functions do each pathway carry
lemniscal: proprioception and perception of touch
spinothalamic: temperature and pain
in which part of the brain does both pathway synapse
ventrolateral nucleus of the thalamus
which brain region is important in sensing light touch
insula
which brain region is important in feeling pain
anterior cingulate cortex
what are the two regions that receive signals from the thalamus
primary somatosensory cortex (S1)
secondary somatosensory cortex (S2)
true or false? there is no communication between S1 and S2
false
what is the Jacksonian march
seizures progress over the body in an orderly way; seizure in one body part is followed by seizure in neighboring body part
- spread of neural activity across maps in motor area of brain
Penfield stimulated points in different part of the S1 causing participants to report sensations (touch and tingling) on various part of their bodies. in which part of their body did they perceive sensations if these regions were stimulated:
a. ventral
b. higher section
c. dorsal
a. lips and face
b. hands and fingers
c. legs and feet
how do we call the body map
homunculus
define tactile acuity
capacity to detect details of stimuli presented to the skin
explain the two-point threshold procedure that is used to measure tactile acuity
minimum separation between 2 points on the skin that when stimulated is perceived as 2 points
explain the procedure used to measure grating acuity
- grooved stimulus pressed onto skin
- Ps asked to indicate orientation of grating
- acuity measured by determining narrowest spacing for which orientation can be judged