Touch

TOUCHPosition, Movement, and the Skin

Senses

Essential Questions

• How does the brain translate touch? • What are the differences in the

vestibular, kinesthetic and cutaneous sense?

 • What are some common sensory

disorders related to touch and skin senses?

Cutaneous Sense (Skin Senses)What is it?• receptors that lie just below the surface of the skin

o  respond to touch, pressure, and temperature to varying degrees based on part of body affected

 How does it work?• connected to somato sensory cortex in the brain's parietal

lobe• information transmitted from receptors to nerve fibers

routed through spinal cord to brainstem  o adaptations can then be made or conditions are

toleratedEx: person's ability to feel pain

How does it work?• substance P used as a neurtransmitter• endorphins increase in concentration when body responds• 2 types of pathways information is sent to the brain by the

thalamus1.Fast parthway (myelinated): detects localized pain and

sends info rapidly to cortex2.Slow pathway (unmyelinated): carries less- localized,

longer- acting pain info• not merely the result of stimulation (ex: phantom limb)• yet to develop a theory that explains everything about pain

What is Pain?

Defined:• part of body's adaptive mechanism

o in response to conditions that threaten damage to the body

o alert that something is wrong• level of pain varies depending on a person's tolerance/

thresholdo perception of brain

Sensory Receptors

• 100 touch receptors in each fingertip• Cutaneous Receptors: Located in dermis or epidermis

o Cutaneous Receporso Thermoreceptors (temperature)o Nocioreceptors (pain)

Sensory Receptors Continued

Mechanoreceptorso Receptors of mechanical stimulio Initiates nerve impulses in sensory

neurons when it is physically deformed by an outside force like: Touch, pressure, stretching,

sound waves, motion

o Enable us to: Detect touch, changes in

pressure, position, acceleration Detect sounds and the motion of

the body Monitor the position of our

muscles, bones, and joints- sense of proprioception

• Specialized neurons which are sensitive and detect hot or cold temperatures

• Useful in alerting organisms od possible danger and changes in environmental conditions so they can react

• Provide brain with information about environmental temperatureo Alerts brain to cool or heat

body accordingly

Thermoreceptors

 • Free nerve endings that exist

in all body tissues• Responsible for sending

messages of paino caused by unpleasant

response by a combination of tissues damage and emotional reaction

o Sensations are warning messages

• Messages travel through afferent nerve tracts to the spinal cord

Nocioreceptors

Practical UsesLamaze method

o developed by French obstetrician Fernand Lamaze

o by work of psychologist Ivan Pavlov practical use of "conditioning"

o uses breathing and concentration techniques to help women during birth

 

Acupuncture• procedure developed by the

Chinese for controlling pain• method done by insertion of long

needles in various parts of the body

• One theory suggests that needles activate large nerve fibers and close the pain gate, other believe it releases endorphins

Theories relating to Touch

Control Theory: (1965)o Melzack and Wallo Represents balance in neural activity of cello Receives information from body and sends to braino Pain signals pass through "gate" in spinal cordo Can be closed by nonpain signals coming into the spinal cord

& by signals coming from brain

Control Theory: (1965)o William Glassero Also known as Choice Theoryo implies active role, or responsibility towards ones behavioro all behavior is made up of three components: what we do,

what we think, and what we feelo all behavior is an attempt to satisfy powerful forces within

ourselveso regardless of our circumstances, all we do, think, and feel, is

always or best attempted at the time to satisfy the forces within us

Vestibular SenseWhat is it?• sense of body orientation with respect to gravity

o person's fit in the environmento oriented in space and time

• shows us how we are moving and how our motion is changing o awareness of body balance and movement

 How does it work?• closely associated with the inner ear • information is carried to the brain on a branch of the

auditory nerveEx: body posture- straight, leaning, reclining, upside down..

ContinuedInner ear• portion of ear located within temporal bone that is

involved in hearing and balanceo includes the semicircular canals, vestibule, and

cochleao sound vibrations transmitted from cochlea to

the brain by the auditory nerves

Semicircular canals• Located in inner ear

o Movement of fluid in canals stimulates hair cells, located on the basilar membrane, which sends messages to the brain about speed and direction of body rotation

• Important for balance

Utricle• Membranous sac contained within the labyrinth of the inner ear• Connected with the semicircular canals

Kinesthetic SenseWhat is it?• movement of the body's muscles, tendons, and joints• helps us move with greater precision, avoid injuries, and

be fully present in the moment• ability to sense body position

 How does it work?• proprioceptors send messages to the brain and works

with sensory input to formulate feelingsEx: person playing soccer

Tober

DisordersPhantom limb sensation

o Occur to people that were born without a limb or have had a limb amputated

o pain that comes from missing part

o arise in the braino http://www.youtube.com/watch?v=hlQZ

mNlPdHQ

 

 

 

Tactile Sensory Dysfunctiono often found in children who are

bothered or fearful to touch things.

o examples:  certain clothing textures,

seams and/or materials A hug Bare feet touching grass or

sand 

Works Cited 

Boeree, George C. "The Senses: A Whirlwind Tour." General Psychology. webspace.ship.edu, 2009. Web. 30 Nov. 2011. http://webspace.ship.edu/cgboer/senses.html.  Brown, . Mistaken for ADHD blog. N.p., n.d. Web. 1 Dec. 2011. http://mistakenforadhd.com/tag/disorders-of-touch/.  Brown, David. "The Vestibular Sense." N.p., June 2007. Web. 30 Nov. 2011. <files.cadbs.org/200000353-9f7fca079e/2_vestibular_dbrown.pdf >.   Ciccarelli, Saundra K., and Glenn E. Meyer. Psychology: mypsychlab edition. Upper Saddle River, NJ: Pearson Prentice Hall, 2007.    "Touch the skin receptors." Think Quest. N.p., n.d. Web. 1 Dec. 2011. <http://library.thinkquest.org/05aug/00386/touch/sensoryreceptors.htm>.