The Sense of Touch
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The skin allows us to have the sense of touch
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Protects the body
from infection,
injury, and water
loss.
•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.
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
Bottom layer
1. made mostly of fat
2. helps your body stay warm
3. absorb shocks
4. Each hair on your body grows out of
a tiny tube in the skin called a
follicle
5. 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
6. Hair
3. Subcutaneous
Nerves 7.
Blood Vessels 8.
Fat Cells 9.
Tongue
Brain
Nose
The Tongue
- Tongue is the sense organ that detects
flavor.
- Inside the grooves there are many taste buds which are
taste receptors.
Magnified
Papillae
taste
bud
sensory
cell
Microscopic
view
of
taste buds (x100)
food
brain
Eat
Speech
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.
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
chemicals
in food
- 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.
bitter
sour
salty
sweet
Nose
Brain
How do we smell ?
- Nose is the sense organ that detects smell.
- There are millions of smell receptors inside
our nose.
nasal cavity
Smell
Breathe
Taste
Brain
Magnify
nerve
nasal cavity
mucus lining
inside
sensory cell
chemicals
in food
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.
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?
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 away
the 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 flavour or not.
Thus, when our nose is also used to sense
the food, the food ‘tastes’ better.
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.
Ear
Brain
Balance
Hearing
Structures of the ear
The OUTER EAR
Ear Lobe
________________: (pinna) Collects sound waves
Ear Canal
________________: sound waves pass through to the
ear drum.
Structures of the ear
The MIDDLE EAR
Ear Drum
________________:
thin membrane that vibrates( stretched across
the ear canal)
Ossicles
________________:
three small bones which help carry the sound
waves (hammer, anvil, and stirrup)
Structures of the ear
The Inner EAR
Cochlea
________________: coiled tube in the inner ear (snail shaped) filled with liquid and
hair like cells.
Semicircular Canal
________________: three small tubes in the inner ear which control your
balance
Auditory Nerve
________________: carries impulses from the ear to the brain
How does it all work?
Sound Waves
1. ____________________
are collected in the outer ear.
Ear Canal
2. Sound waves pass through our _________________
and cause our
ear drum to vibrate.
Vibrations
3. These _________________________
are sent to our inner ear by
the ossicles. (small bones in the middle ear)
Cochlea
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.
Brain
5. Our __________________
receives these impulses and interprets
them as a type of sound.
Ear Problems
Infections
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.
Audiologist
• ___________________________:
is someone who is
specially trained to test and help with the problems
related to hearing loss.
Eye
Brain
Sight
Structures of the eye
Cornea
Optic Nerve
Cornea
________________: Transparent coating which covers
the iris and the pupil at the front of the eye.
Iris
________________: The colored part of the eye that
regulates the amount of light entering the eye.
Structures of the eye
Cornea
Optic Nerve
Pupil
________________: The opening at the center of the iris.(hole)
Lens
________________:
A clear part of the eye behind the iris that helps
to focus light, or an image on the retina
Structures of the eye
Cornea
Optic Nerve
Retina
________________:
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)
Optic Nerve
________________:
A bundle of more than one million nerve fibers
that carries visual messages from the retina to the brain.
How does it all work?
Light Rays
1. ____________________
bounce off an object you are looking at.
2. Light then enters through the outer part of the eye, called the
Cornea
___________________.
Pupil
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.
Brain
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.
Eye Problems
Pinkeye
1. ____________________
It can cause redness, itching,
inflammation or swelling, and a clear or white, yellow, or greenish
gooey liquid to collect in the eyes.
Nearsighted
2. ____________________
someone can see stuff that's near, like a
book, but has trouble seeing stuff that's far away.
Farsighted
3. ____________________
someone can see stuff that's far away, but
has trouble seeing up close, like reading the print in a book.
Astigmatism
4. ____________________
A misshaped cornea or lens causing
objects to look blurry
Eye Care
ophthalmologist
1.Visiting an ____________________
(a medical
doctor who specializes in examining, diagnosing,
and treating eyes)at least every 2 years
2.Wearing sunglasses
3.Wearing protective eyewear whenever you play
sports
4.Take breaks from the computer, video games, or
watching TV
1.staring for a long time — can strain your eyes.
5.Never share eye glasses or eye care products