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4/10/2015
The Senses!
Smelling
Sight
Taste
Touch
Hearing
Proprioception / Relative position
Vestibulation / Balance
Because sensing what is around you is half the fun!
Purpose of Sensory Organs
• Allows the body to receive information from the outside world
• Have specialized receptors for specific stimuli
• All information transmitted is to the brain
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Purpose of Sensory Organs
Key sensory organs
1. Skin → Touch
2. Tongue → Taste
3. Nose → Smell
4. Ears → Hearing and Balance
5. Eyes → Seeing
The Skin
Largest organ of the body (16% body mass)
Function:
1. Protect body
• Defense against pathogens
• Waterproofing
2. Allow for sensation of touch (temperature, pain, pressure and
touch)
3. Waste removal
• Sweating has waste in it
4. Temperature regulation
• Sweating cools you down
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Did you know?!?
• Adults have approximately 3.6 kilograms of skin on them
• That’s approx. 32 iPhone 5’s stacked on top of each other
Skin. Health and the Human Body. Retrieved April 6, 2015, from
http://science.nationalgeographic.com/science/health-and-human-body/human-body/skin-article.html
The Skin
Shape: Three layers, one on top of the other
Outer layer: Epidermis (“epi” = over)
• Dead skin cells; protect living cells underneath
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The Skin
Shape: Three layers, one on top of the other
Middle layer: Dermis
• Living cells
• Key structures in the dermis
1.
2.
3.
4.
Blood vessels
Sensory receptors
Glands
Hair
The Skin
Shape: Three layers, one on top of the other
Inner layer: Hypodermis (“hypo”= low)
• Living cells
• Contains fat cells that has two roles
1.
2.
Helps insulate body
Emergency energy reserve
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The Skin- Cross section
Hair
Epidermis
Blood vessels
Sensory Receptor
Dermis
Hypodermis
Fat cells
Nerve
The Skin- Types of Sensory Receptors
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The Skin- How it “interprets” stimuli
• Sensory receptors on skin sense stimuli
• Sensory receptors transform stimuli into nerve impulse
• Impulse sent to brain
Did you know?!?
Not all areas of the skin have an equal amount of sensory
receptors! “Homunculus”
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The Tongue
Muscle in mouth; key in digestion
Function:
1. Allow for food to be swallowed
2. Sense taste
3. Create sounds
Did you know?!?
Taste and flavor are not same!
Flavor → combination of taste and smell
Taste → chemical stimulation of the tongue
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Tongue
Tastes humans can detect
1. Sweet
2. Sour
3. Salty
4. Bitter
5. Umami (savory; cheese, soy sauce, cured meat)
The Tongue – Cross Section
Papillae
Taste bud
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The Tongue- How it “interprets” stimuli
• Taste buds are found on structures called papillae
• They are the “bumps” on the tongue
• Saliva mixed with chemicals from food flow through the taste pore
• Taste buds sense the chemicals, transforming the chemical stimulus
to nerve impulse
• Impulse sent to brain
Did you know?!?
Besides the five basic tastes, your tongue can sense
• Spiciness
• Coolness
• Numbness (numbing and hot; Asian foods)
• Puckering (astringency)
• Metallicness
• Calcium
• Temperature
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The Nose
Organ ; key in respiration
Function:
1. Allow for gas to be exchanged
2. Sense smell
Key receptor in nose
• Olfactory bulb (on tip of olfactory nerve)
Did you know?!?
90% of the sensation of taste is due to smelling the food you
ingest?!?!
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The Nose – Cross Section
The Nose- How it “interprets” stimuli
• Odorants (chemicals carried by gas) enter the nose
• Cilia (hairs) on olfactory bulb pick up odorant, transforming the
chemical stimulus to nerve impulse
• Impulse sent by olfactory nerve to brain
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