Bell Work!Use pages 266-274 in your science book to answer

the following questions.1. Draw and label the parts of a neuron. pg.267

2. Compare and contrast the central and peripheral nervous system.

3. Explain why you have trouble falling asleep after drinking several cups of hot cocoa.

4. Explain the advantage of having reflexes controlled by the spinal cord.

5. Think critically. Explain why many medications caution the consumer no to operate heavy machinery.

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Your body

has five senses.

Danger …danger… code red alert! An unidentified vessel has entered the spaceship’s energy force field. All crew members are to be on alert!”

Just like a spaceship in the movies, your body has an alert system too.

Light rays, sound waves, heat, chemicals, or pressure that come into your personal territory will stimulate your sense organs.

http://www.faizani.com/online_library/G1/images/brain_senses.jpg

Sense organs carry

messages about the

environment to the central

nervous system.

Vision is your ability to see.• Light enters your eye, and

the cornea and lens focus it onto the retina.

• The light stimulates the rods and cones, two types of cells found in your retina.– Retina is a tissue at

the back of the eye that is sensitive to light

– Rods respond to dim light

– Cones respond to bright light and color

• The rods and cones send impulses to the optic nerve, which carries them to the visual area of the cortex.

• The image transmitted from the retina to the brain is upside down and reversed.

• Your brain interprets the image correctly, and you “see.”

https://www.dratiq.co.uk/catalog/images/2020%20Vision%20Mix.jpg

The colored part of the eye is

the iris.

The black part of the eye is the

pupil.

The pupil becomes

larger and smaller as it controls the light coming into the

eye.

Iris

Pupil

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• Light is refracted when it passes through a lens. • Concave lens, thicker at edge than in middle,

corrects nearsightedness.• Convex lens, thicker in middle than at edge,

corrects farsightedness. • Nearsightedness occurs when light is focused in

front of the retina.• Farsightedness occurs when light is focused behind

the retina.

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• Do you wear contact lenses or eyeglasses to correct your vision?

• Are you nearsighted or farsighted?• When the eyeball is too long from front to

back the light from the object is focused in front of the retina not being able to focus a sharp image this is nearsightedness.

• When the eyeball is too short from front to back the light from the object is focused behind the retina, being able to see a clearer image further this is farsightedness.

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When a sound is made, the air around the sound vibrates.

Hearing is when an object vibrates, it produces sound waves necessary for

hearing soundhttp://farm1.static.flickr.com/27/43319090_7ce7949585_o.jpg

• Your outer ear catches sound waves and funnels them down the ear canal to the middle ear.

•In the middle ear, the sound waves cause the eardrum to vibrate, and these vibrations move through tiny bones—the hammer, anvil, and stirrup.

http://www.health.state.ny.us/nysdoh/antibiotic/ear.gif

The inner ear is made of the cochlea and liquid.

The cochlea is a fluid-filled structure that looks

like a snail’s shell.

In the inner ear, the vibrations cause the fluids in the cochlea

to vibrate, stimulatingnerve endings.

http://courses.cit.cornell.edu/psych431_nbb421/student2005/vbs5/inner%20ear.jpg

The ear works with the brain to control your balance.

The stimulated nerve endings send impulses to the brain, where the stimulus is interpreted.

The cristae ampullaris and maculae in the middle ear control the body’s movement.

The liquid in your ear moves when we move. The liquid movement sends information to the brain to

tell it how we are moving.http://thumb2.visualizeus.com/thumbs/08/11/01/balance,black,and,white,dress,girl,photography,rails,railway,tracks,walking,woman-e3b0a57db379f7e933dd1f0153e4aaea_m.jpg

The nose controls your sense of smell.

•The nose is able to smell 80 different kinds of smells.

•Smell can determine which foods you eat, strong memories, or feelings.

•Food and other objects give off molecules into the air.•These molecules stimulate nerve cells, called olfactory

cells, in your nasal passages.•The olfactory cells send impulses to the brain,

where the stimulus is interpreted.

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Your sense of taste comes from the taste buds in the tongue.

Taste buds on your tongue are the major sensory receptors for taste.

You have about 10,000 taste buds all over your tongue.

When the solution of saliva and food washes over the taste buds, impulses are sent to the brain, where the

stimulus is interpreted.

The five kinds of taste sensations on your tongue are sweet, sour, bitter, salty, and MSG.

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•Smell and taste are related.

•The sense of smell is needed to identify some foods such as chocolate.

•When saliva is mixed with food, odors travel up the nasal passage in the back of your throat.

•So when you have a stuffy nose and some foods seem tasteless, it may be because the food’s molecules are

blocked from contacting the olfactory cells in your nasal passages.

http://www-psych.stanford.edu/~lera/psych115s/notes/lecture11/images/tongue2.jpg

The sense of touch is located in the skin.

The nerves in the skin allow us to feel texture, pressure, heat, cold, and pain.

Sensory receptors are found in our internal organs and brain.

Sensory receptors pick up changes in touch, pressure, pain, and temperature and send impulses to the brain or

spinal cord.

Sensory receptors are also throughout your skin.

All of your body’s senses work together to protect itself from harm.

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