What are the FUNCTIONS of the SKIN?
Protection Protects the body from infection, injury, and water loss.
Maintains body Temperature • helps us regulate body temperature through perspiration. • Without the nerve cells in our skin, we couldn't feel warmth, cold, or other sensations. • Sweat- Cools off the body • Goosebumps- keep the heat in.
Sense of Touch The nerve endings in your skin can tell you if something is hot, cold, smooth or rough . They can also feel if something is hurting you. Your body has about twenty different types of nerve endings that all send messages to your brain.
What are the three layers of the SKIN?
Epidermis • outer layer of our skin, • It is the tough, protective outer layer. • It is about as thick as a sheet of paper over most parts of the body. • Constantly flaking off and being renewed
Dermis Middle layer of skin The dermis contains…. Nerve endings-howthings feel Blood vessels- carryblood Oil glands- Produce Sebum Sweat glands- produce sweat
Subcutaneous Bottom layer made mostly of fat helps your body stay warm absorb shocks Each hair on your body grows out of a tiny tube in the skin called a follicle Every follicle has its roots way down in the subcutaneous layer and continues up through the dermis.
The Skin 1. Epidermis 4. Oil Gland 2. Dermis 5. Sweat Gland Nerves 7. 6. Hair 3. Subcutaneous Blood Vessels 8. Fat Cells 9.
What parts of the body give us our sense of taste? The Sense of Taste Tongue Brain Nose
The Tongue - Tongue is the sense organ that detects flavor. many grooveson the surface - Inside the grooves there are many taste buds which are taste receptors.
Papillae tastebud sensory cell food Magnified Microscopic view oftaste buds (x100) brain
The Sense of Taste What are the three functions of the tongue? The tongue moves and pushes a small bit of food along with saliva into your esophagus, which is a food pipe that leads from your throat to your stomach. Eat Speech Taste • The top of your tongue is covered with a layer of bumps called papillae • . Papillae help grip food and move it around while you chew. • They contain your taste buds, so you can taste everything.
Process to taste food • Flavoring chemicals in food dissolve in the saliva • Stimulates the taste buds to send messages to the brain. • Messages are sent to the brain to give us the taste of the food sensory cell chemicalsin food
bitter sour salty sweet • Humans have four kinds of taste buds. • They can detect four kinds of tastes: sweet, sour, salty and bitter. - Each kind of taste buds is not evenly distributed on the tongue. Thus, certain parts of the tongue are more sensitive to a particular taste than the others.
The Sense of Taste Areas of Taste on the Tongue
What parts of the body give us our sense of Smell? Nose Brain The Sense of Smell
nasal cavity How do we smell? • Noseis the sense organ that detects smell. • There are millions of smell receptors inside our nose.
What are the functions of the Nose? The Sense of Smell Smell Breathe Taste
Brain nerve nasal cavity sensory cell chemicalsin food Magnify mucus lininginside
Some chemicals in the food diffuse into the air. Process to smell food • When we breathe, some chemicals enter our nose • => chemicals dissolve in the mucus • => stimulate the smell receptors to produce messages • => These messages are sent to the brain to give us the odor of the food.
We use both smelland tasteto detect the flavor of food. Holding your nose can help take away unpleasant taste of food.
Do you know ? Why do warm foods have stronger flavorthan cold foods? This is because when food is heated, more chemicals in food diffuse into the air.
Some medicine is unpleasant to take. You can hold your nose while taking the medicine. This helps take awaythe unpleasant feeling.
Our tongue can only distinguish about 4 different tastes. But our nose can distinguish about 4000 different chemicals. Our nose can tell us not only the sweet taste of ice-cream, but also whether it is chocolate flavouror not. Thus, when our nose is also used to sense the food, the food ‘tastes’ better.
Do you know ? Why dothe elders like to take in food with strong flavor? It’s too salty!
This is because the senses of smell and taste ofthe elders are weaker. Food with strong flavor tastes good to the elders.
What parts of the body give us our sense of Hearing? Ear Brain The Sense of Hearing
What are the three functions of the Ear? The Sense of Hearing
Structures of the ear • The OUTER EAR • ________________: (pinna) Collects sound waves • ________________: sound waves pass through to the ear drum. Ear Lobe Ear Canal
Structures of the ear • The MIDDLE EAR • ________________: thin membrane that vibrates( stretched across the ear canal) • ________________: three small bones which help carry the sound waves (hammer, anvil, and stirrup) Ear Drum Ossicles
Structures of the ear • The Inner EAR • ________________: coiled tube in the inner ear (snail shaped) filled with liquid and hair like cells. • ________________: three small tubes in the inner ear which control your balance • ________________: carries impulses from the ear to the brain Cochlea Semicircular Canal Auditory Nerve
How does it all work? • ____________________ are collected in the outer ear. • Sound waves pass through our _________________ and cause our ear drum to vibrate. • These _________________________ are sent to our inner ear by the ossicles. (small bones in the middle ear) • The vibrations reach the ______________________. The fluid in the cochlea begins to move, this motion results in the hair cells sending a signal along the auditory nerve to the brain. • Our __________________ receives these impulses and interprets them as a type of sound. Sound Waves Ear Canal Vibrations Cochlea Brain
Ear Problems Infections • ____________________ in the middle ear are the most common ear problems. Germs from colds in the nose or throat can spread through the Eustachian tube in the middle and inner ear. • Hearing loss and deafness- This can result from injury, disease, birth defects, and very loud noises. • ___________________________: is someone who is specially trained to test and help with the problems related to hearing loss. Audiologist
What parts of the body give us our sense of Sight? The Sense of Sight Eye Brain
What is the function of the Eye? The Sense of Sight
Structures of the eye Cornea • ________________: Transparent coating which covers the iris and the pupil at the front of the eye. • ________________: The colored part of the eye that regulates the amount of light entering the eye. Cornea Optic Nerve Iris
Structures of the eye Cornea Optic Nerve Optic Nerve • ________________: The opening at the center of the iris.(hole) • ________________: A clear part of the eye behind the iris that helps to focus light, or an image on the retina Pupil Lens
Structures of the eye Cornea • ________________: The light-sensitive tissue lining at the back of the eye. The retina converts light into electrical impulses that are sent to the brain through the optic nerve) • ________________: A bundle of more than one million nerve fibers that carries visual messages from the retina to the brain. Optic Nerve Retina Optic Nerve
How does it all work? • ____________________ bounce off an object you are looking at. • Light then enters through the outer part of the eye, called the ___________________. • Next, light rays go through an opening called the _____________. • Light passes through the lens on its way to the back of the eye. • The retina sees the world upside down, but the ___________ turns it right side up. • When you look at an object, each eye sees a slightly different picture. The brain combines the images into one picture. Light Rays Cornea Pupil Brain
Eye Problems ____________________ It can cause redness, itching, inflammation or swelling, and a clear or white, yellow, or greenish gooey liquid to collect in the eyes. ____________________ someone can see stuff that's near, like a book, but has trouble seeing stuff that's far away. ____________________ someone can see stuff that's far away, but has trouble seeing up close, like reading the print in a book. ____________________ A misshaped cornea or lens causing objects to look blurry Pinkeye Nearsighted Farsighted Astigmatism
Eye Care • Visiting an ____________________ (a medical doctor who specializes in examining, diagnosing, and treating eyes)at least every 2 years • Wearing sunglasses • Wearing protective eyewear whenever you play sports • Take breaks from the computer, video games, or watching TV • staring for a long time — can strain your eyes. • Never share eye glasses or eye care products ophthalmologist