1 other important senses module 15. 2 other important senses sense of touch is a mix of four...

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Other Important Senses

Module 15

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Other Important Senses

Sense of touch is a mix of four distinct skin senses- pressure, warmth, cold, and pain.

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Skin Senses

Only pressure has identifiable receptors, all other skin sensations are variations of

pressures, warmth, cold and pain.

Burning hot

Pressure Vibration Vibration

Cold, warmth and pain

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Pain

Pain tells the body that something has gone wrong. Usually pain results from damage to the skin and other tissues. There is a rare disease in which the person feels no pain.

Ashley Blocker (right) feels neither painnor extreme hot or cold.

AP Photo/ Stephen M

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Biopsychosocial Influences

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Pain

• Phantom Limb: Missing limb feels like it is present, like always, before amputation

• Visceral Pain: Pain fibers located in internal organs

• Referred Pain: Pain felt on surface of body, away from origin point

• Somatic Pain: Sharp, bright, fast

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Fig.5.28 Visceral pain often seems to come fro m the surface of the body, even though its true origin is internal. Referred pain is believed to result from the fact that pain fibers from internal organs enter the spinal cord at the same location as sensory fibers from the skin. Apparently, the brain misinterprets the visceral pain messages as impulses from the body’s surface.

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Gate-Control Theory

Melzak and Wall (1965, 1983) proposed that our spinal cord contains neurological

“gates” that either block pain or allow it to be sensed.

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Types of Pain

• Warning System: Pain carried by large nerve fibers; sharp, bright, fast pain that tells you body damage may be occurring (e.g., knife cut)

• Reminding System: Small Nerve Fibers: Slower, nagging, aching, widespread; gets worse if stimulus is repeated; reminds system that body has been injured

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Pain Control

Pain can be controlled by a number of therapies including, drugs, surgery,

acupuncture, exercise, hypnosis and even thought distraction.

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How do we taste?

•Taste (and smell) are chemical senses.

What is the central muscle involved in taste?

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Papillae

• Those bumps on our tongue are called Papillae.

• Papillae help grip food while your teeth are chewing. They also have another special job - they contain your taste buds

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Taste Buds

Map out the tongue

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Taste

Traditionally taste sensations consisted of sweet, salty, sour and bitter tastes. Recently

receptors for a fifth taste have been discovered called “Umami”.

Sweet Sour Salty Bitter Umami(Fresh

Chicken)

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Taste

• Taste cells absorb chemicals in saliva and trigger neural impulses routed through the thalamus.

• Taste preferences are largely learned and heavily shaped by social processes.

• Sensitivity to tastes are distributed somewhat unevenly across the tongue, but the variations are small.

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Sensory Interaction

When one sense affects another sense sensory interaction takes place. So the taste of strawberry interacts with its smell and its

texture on the tongue to produce flavor.

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Smell and Taste

• Olfaction: Sense of smell• Anosmia: Defective sense of smell for a single

odor • Taste Buds: Taste-receptor cells• Gustation: Sense of taste

– Four Taste Sensations: sweet, salt, sour, bitter – Most sensitive to bitter, least sensitive to sweet– Umami: Possible fifth taste sensation; brothy taste

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Smell

Like taste smell is a chemical sense. Odorants enter the nasal cavity to stimulate 5 millions receptors to sense smell. Unlike

taste there are many different forms of smells.

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Age, Gender and Smell

Ability to identify smell peaks during early adulthood but steadily decline after that. Women are better at detecting odors than

men.

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Smell and Memories

Brain region (red) for smell is closely

connected with brain regions (limbic

system) involved with memory, that is

why strong memories are made through the sense of

smell.

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Gender related odors• Can you smell the difference between?

Hands, Breath, Shirts

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So can we smell the difference?

• Well….yes and no.

Pheromones•Chemical messengers that are picked up through our sense of smell.

•Founded in the early 1930’s by studying silkworms.

•Jury is still out on whether they exist in humans. Best evidence we have comes out of the university of Chicago.

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Body Position and Movement

The sense of our body parts’ position and movement is called kinesthesis. And the vestibular sense monitors the head (and

body’s) position.

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Kinesthetic Sense

• Tells us where our body parts are.

• Receptors located in our muscles and joints.

Without the kinesthetic sense you could not touch the button to make copies of your buttocks.

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Vestibular System

• Otolith Organs: Sensitive to movement, acceleration, and gravity

• Semicircular Canals: Fluid-filled tubes in ears that are sensory organs for balance

• Crista: “Float” that detects movement in semicircular canals

• Ampulla: A wider part of the canal

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Fig. 5.30 The vestibular system.

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Fig. 5.29 Hold a variety of elongated objects upright between your fingertips. Close your eyes and move each object about. Your ability to estimate the size, length, shape, and orientation of each object will be quite accurate. (after Turvey, 1996)

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Vestibular Sense

• Semicircular canals and the vestibular sacs, which connect the canals with the cochlea.

• Contain fluid that moves when the head rotates or tilts.

• Sends messages to the cerebellum at the back of your brain

• Enables you to sense your body position and to maintain your balance.

Vestibular Sense

• Tells us where our body is oriented in space.

• Our sense of balance.

• Located in our semicircular canals in our ears.

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Vestibular System and Motion Sickness

• Motion sickness is directly related to vestibular system

• Sensory Conflict Theory: Motion sickness occurs because vestibular system sensations do not match sensations from the eyes and body – After spinning and stopping, fluid in semicircular

canals is still spinning, but head is not– Mismatch leads to sickness

• Medications, relaxation, and lying down might help

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