Other senses

TasteSmell Touch

The Student will

• Complete the Graphic ORGANIZER Using the skill of cross referencing Cornell Notes

• Summarize :Smell, Taste and SKIN, PAIN AND Touch

• Analyze Pain and the Gate-Control Theory

Taste: savory sensations

Taste budsNests of taste-receptor cells

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Taste

• taste based on chemistry= soluble substances (stimuli)

• Have a cooperative working relationship with smell(onion taste is really mostly smell)

• Also when You have a cold, food has no taste because you cannot smell it

• Gustation- Sense of taste: Sweet, sour, bitter and salty

• Now Umani ( MSG in Asian foods) Found naturally in meats, seafood, cheese)

Taste description- tell me all about it

• Taste receptors- taste Buds, located on top and side of tongue

• Taste buds contain primary receptors• Receptors cluster in papillae a mucus membrane.• “Hotline” carries information to the brain• Taste is realized in the parietal lobe’s

somatosensory cortex.• Small children= sensitive taste buds, older=

loosing sensation

Five tastesFive basic tastesSalty, sour, bitter, sweet, umami

Different people have different tastes based on:GeneticsCultureLearningFood attractiveness

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Smell: the sense of scents

Airborne chemical molecules enter the nose and circulate through the nasal cavity.Vapors can also enter through the mouth and pass into nasal cavity.

Receptors on the roof of the nasal cavity detect these molecules.

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Smell

• Olfaction- Sense of smell; chain reaction of biochemical events. 1,000’s of volatile substances (stimuli)

• 1st odors (airborne chemicals) interact with receptor proteins (tiny hairs in the nose)

• 2nd Stimulated nerve cells (like the ear) convey information to the olfactory bulbs.

• Located in underside of the brain, by frontal lobes

More smell

• Olfaction has strong connection to memory.• In primitive organisms, used to detect decaying food• Animals use smell for communication: ants, termites,

dogs, cats • Pheromones: Secreting and detecting odors.• Primarily used for sexual receptivity (perfume),

territorial boundaries ( dog peeing) food sources (grandmas kitchen!)

Skin Senses

• Protects against injury, holds body fluids, regulates temp.

• Skin has nerve endings that produce sensations: touch, warm, cold (receptors)

• Skin Senses connected to somatosensory cortex (Like taste)

• 10x more sensitive in our fingers• Touch is primary stimulus for sexual arousal• External contact is stimuli

Sensitivity to touch

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Pain

• Gate-Control Theory: Melzack and Wall• Explains why pain can be blocked by drugs,

competing stimuli (as in acupuncture) or even the expectation of treatment effects

• 2 sensory pathways from organ to brain• Pain stimulus= tissue damage

Gate-control theory of pain

Experience of pain depends in part on whether the pain gets past a neurological “gate” in the spinal cord.

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Gate-control theory revised

The matrix of neurons in the brain is capable of generating pain (and other sensations) in the absence of signals from sensory nerves.

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Gate Control Theory (1st one)

• 1st route- has neurons with a fatty myelin covering their axons, handles methods quickly.

• Fast fibers- deliver most information to brain.• 2nd route- No fatty sheaths, slower• Hypothesis- Fast fibers can block slow

fibers=stop pain. Close gate

More GCT

• For example, when you hit hand with hammer, you immediately begin to shake it. Thus generating fast fibers to close the gate of pain

• “Gate” is a region in the brain stem called periaqueductal gray (PAG)

• Pain blocking opiates and endorphins act on PAG

Dealing with pain

• Pain is essential to survival-warns of harm, survive in hostile environments, treatments for illness.

• Congenital insensitivity do not feel what is hurting them= scars-deformation

• Analgesic drugs: aspirin, Ibuprofen, prescriptions- morphine =controls endorphins.

More pain

• Can control pain with hypnosis, deep relaxation or thought distracting procedures.

• Placebo- pill made of sugar/saline injection.• If you think you are receiving pain relief, your

brain releases painkilling endorphins• Show up on brain scans

Pain Tolerance

• Varies from person to person• Electro shocks are the testing method • Greater activation of thalamus= greater pain

tolerance

The environment within

KinesthesisThe sense of body position and movement of body parts

EquilibriumThe sense of balance

Semicircular canalsSense organs in the inner ear, which contribute to equilibrium by responding to rotation of the head

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Position and movement

• Need constant info. about body parts and relationships to our environment

• Vestibular sense- The body position sense that orients us with respect to gravity

• Used in posture of head, straight, leaning, tilted. Also tells us when we are moving or how motion is changing

• Receptors are tiny hairs, semicircular canals, like the basilar membrane in the ear.

Inside Body

• Kinesthetic sense- other sense of body position and movement. Keeps track of body parts relative to each other

• For example crossing your legs, knowing which hand is closest to the phone. Constant feedback

• Receptors are in joints, muscles, tendons.• Connect to parietal lobes in brain. • Automatic unless learning new skill. Golf swing or

playing an instrument

Summary

• TASTE• SMELL• SKIN• PAIN• KINESTHESIS