The Sense of Touch =

The skin allows us to have the sense of touch =

Protects the body from infection, injury, and water loss.

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.

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

Middle layer of skin The dermis contains…. 1.Nerve endings-how things feel 2.Blood vessels- carry blood 3.Oil glands- Produce Sebum 4.Sweat glands- produce sweat

The Skin 1. Epidermis 2. Dermis 3. Subcutaneous 5. Sweat Gland 4. Oil Gland 6. Hair Nerves 7. Blood Vessels 8. Fat Cells 9.

Taste and Smell 1nslE 1nslE

Tongue Brain Nose

The Tongue - Tongue is the sense organ that detects flavor. many grooves on the surface - Inside the grooves there are many taste buds which are taste receptors.

Eat Speech Taste 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. 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. The tongue can move in many directions which controls language

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 chemicals in food sensory cell

-Humans have four-5 kinds of taste buds. sweetsoursalty bitter -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.

Umami and Glutamate IAo IAo

Nose Brain

How do we smell ? smell -Nose is the sense organ that detects smell. -There are millions of smell receptors inside our nose. nasal cavity

Smell Breathe Taste

Magnify chemicals in food nasal cavity nerve Brain Olfactory sensory cell

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. Some chemicals in the food diffuse into the air.

smell taste We use both smell and taste to detect the flavor of food. Holding your nose can help take away unpleasant taste of food.

Why do warm foods have stronger flavor than cold foods? chemicals This is because when food is heated, more chemicals in food diffuse into the air.

Our tongue can only distinguish about 4 different tastes. But our nose can distinguish about 4000 different chemicals. Thus, when our nose is also used to sense the food, the food ‘tastes’ better. chocolate flavor Our nose can tell us not only the sweet taste of ice-cream, but also whether it is chocolate flavor or not.

Why do the elders like to take in food with strong flavor? It’s too salty!

This is because the senses of smell and taste of the elders are weaker. Food with strong flavor tastes good to the elders.

Hearing and Balance 4JU 4JU

Ear Brain

HearingBalance

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 Ear Drum Ossicles 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)

Structures of the ear Cochlea Semicircular Canal 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 Auditory Nerve

How does it all work? 1.____________________ are collected in the outer ear. 2.Sound waves pass through our _________________ and cause our ear drum to vibrate. 3.These _________________________ are sent to our inner ear by the ossicles. (small bones in the middle ear) 4.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. 5.Our __________________ receives these impulses and interprets them as a type of sound. Sound Waves Ear Canal Vibrations Brain Cochlea

Balance Balance is maintained not only by the vestibular system found in your ears but also by your visual and sensory systems. If any one of these systems is damaged, you may experience dizziness or loss of balance.

The tubes and sacs within the vestibular system are filled with fluid. When we move our heads, this fluid also moves.

Cells within the system sense this movement and send signals to the brain The brain then tells the eyes and muscles to respond to this movement to maintain stability and balance

Dizziness If the signals sent to the brain by the vestibular system do not match those which the eyes and sensory system send then dizziness and motion sickness can result. This can happen, for example, if you travel on a boat but you are looking at the boat rather than at the horizon. Your eyes see that you are not moving relative to the boat but your ears and body can feel that you are moving. It's the discrepancy between the two that causes the motion sickness.

Ear Problems 1.____________________ 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. 2.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 Infections

Vision u1rNM u1rNM

Eye Brain

Sight

Structures of the eye Cornea Iris Cornea Optic Nerve ________________: 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

Iris

Structures of the eye Pupil Lens ________________: 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 Optic Nerve Cornea Optic Nerve

Pupil

Lens

________________: 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 Structures of the eye Retina Optic Nerve Cornea

Retina

Optic Nerve

How does it all work? 1.____________________ bounce off an object you are looking at. 2.Light then enters through the outer part of the eye, called the ___________________. 3.Next, light rays go through an opening called the _____________. 4.Light passes through the lens on its way to the back of the eye. 5.The retina sees the world upside down, but the ___________ turns it right side up. 6.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 Color Eye color is the result of variations in the amount of melanin, a pigment found in the front part of the iris of the eye. The lack of this pigment results in blue eyes, some pigment gives green and lots of pigment gives brown eyes. So light brown eyes just have a bit less melanin than darker brown eyes

Eye Problems Glaucoma: a group of diseases that damage the eye’s optic nerve and can result in vision loss and blindness. With early detection and treatment, you can often protect your eyes against serious vision loss. nB8 nB8

Eye-Brain Problems There are rare cases of people whose retinas or brains transmit or read information in the wrong direction

Eye Problems 1.____________________ It can cause redness, itching, inflammation or swelling, and a clear or white, yellow, or greenish gooey liquid to collect in the eyes. 2.____________________ someone can see stuff that's near, like a book, but has trouble seeing stuff that's far away. 3.____________________ someone can see stuff that's far away, but has trouble seeing up close, like reading the print in a book. 4.____________________ A misshaped cornea or lens causing objects to look blurry Pinkeye Farsighted Nearsighted Astigmatism