SOMATIC AND SPECIAL SENSES

SPECIAL SENSES SOMTIC SENSES

1. Smell2. Taste3. Vision4. Hearing 5. Balance

1. Tactile (touch) Touch Pressure

2. Thermal (hot vs cold)3. Pain4. Proprioceptive

SENSORY RECEPTORS Detect environmental

changes Sensation occur via a

pathway Stimulus Sensory receptor Conduction Integration

What integrates the sensation? The brain!!!!!

TYPES OF RECEPTORS1. Mechanoreceptors

Touch, pressure, hearing

2. Nociceptors pain

3. Photoreceptors light

4. Chemoreceptors Chemicals in nose

and mouth 5. Osmoreceptors

Osmotic pressure

TYPES OF MECHANORECEPTORS

TYPES OF MECHANORECEPTORS

Merkel receptors Sense fine detail Fires

continuously

Meissner corpuscle Control hand

grip Fire when

stimulus is added and removed

TYPES OF MECHANORECEPTORS(CONTINUED)

Ruffini corpuscle Senses skin

stretching Fire continuously

Pacinian corpuscle Respond to fine

detail in fingers Fire when stimulus is

applied and removed

ADAPTATION Sensors adapt by

Perception of stimulus fades/disappears

“get use to it”

HOW SENSITIVE ARE YOU? Measure in mm!!

PAIN Fast Pain

Localized E.x

Slow Pain Localized in large area E.x

Why can’t the brain feel pain? Doesn’t have nocicptors

http://www.youtube.com/watch?v=tnABHy6tjL8

HOMUNUCLEUS

HOMUNUCLEUS Is a map that

corresponds body part to touch sensitivity

The proportion of the sensory cortex to the size of the body region is uneven.

EX. a relatively large cortical is devoted to the face and the lips, and a small area is devoted to sensations arising from the trunk.

MAKE YOUR OWN HOMUNUCLEUS ANALYSIS QUESTIONS

1. Is your skin’s sensitivity in proportion to the size of the body part? Is it reversed? Explain how/why this is the case.

2. What would happen if your skin’s sensitivity in your hands stopped working?

3. Why is a small portion of your cerebral cortex devoted to your arm while a large portion is devoted to your hands and fingers?

4. Which receptors allow you to feel fine detail? Where would you expect to find several of these receptors? Why?

5. Which type of receptors would you expect to find in your fingertips? Why?

6. How different is your homunucleus from your partners? Where are they different and where are they the same?

HOMUNUCLEUS ANALYSIS The hands and fingers are more useful for

gathering information and need more sensory receptors and area to integrate the info

Able to feel fine details with fingers

OLFACTION(AKA SENSE OF SMELL)

Detected by an olfactory receptor

Olfactory receptor Hair like

extensions Not nose hair

In olfactory epithelium

OLFACTORY PATHWAYHTTPS://WWW.YOUTUBE.COM/WATCH?V=SNJNO6OPJCS

Odor absorbed by receptor

Integrated by limbic system or temporal lobe

SMELL AND MEMORY

Odor + limbic system + parietal lobe = scent memory

TESTING OUR SENSE OF SMELL ANALYSIS

1. How many odors were you able to identify?

2. Were some odors easier to identify than others? Why?

3. Why do you think some odors elicited a memory?

HOW SMELL IS INTEGRATED BY THE BRAIN

GUSTATION(AKA SENSE OF TASTE)

1. Sour2. Sweet3. Bitter4. Salty5. Umami

(savory/meaty)

How does a cold affect your sense of taste?

TASTE BUDS(PAPILLAE)

On surface of tongue

Gustatory Pathway1. Taste receptors2. Cranial nerves3. Medulla oblongata4. Limbic system5. Parietal lobe

GUSTATORY PATHWAY

MAPPING TASTE BUDS Where are the receptors

for salt found? sweet ? sour? bitter? savory/umami?

What about the center of the tongue? Not many receptors=

does sense taste very well

HOW THE BRAIN UNDERSTANDS TASTE

Neurotransmitter is released

Foods taste different because Different

neurons are activated

ANATOMY OF THE EYEHTTP://WWW.HANDWRITTENTUTORIALS.COM/VIDEOS.PHP?ID=38

SCIENCE OF TEARS Tears

Salt, mucus, lysozyme (kills bacteria)

Are produced to: Clear, clean and

moistion the eye Emotions

FLOW OF TEARS

LAYERS OF THE EYEBALL1. Fibrous tunic

Cornea Sclera

2. Vascular tunic Choroid Ciliary body iris

3. Retina

FIBROUS TUNIC Cornea

Is curved This varies in

individuals and as you age

Sclera “White” of the eye Gives shape Protects Point of muscle

attachment

VASCULAR TUNIC Choroid

Lines the sclera Nourishes the retina

Cilliary body Muscle- controls the

shape of the lens Process- secretes

aqueous humor Aqueous humor

Nourishes the eye as it ciculates through both chambers

VASCULAR TUNIC Lens

Changes shape to focus light on retina

Clearer vision Held in place by zonular

fibers Iris

Is convex (curves outward)

Colored part of eye Pupil

Light enters here Diameter changes in

response to light

RETINA(CONTINUED)

Fovea centralis Sharp central vision Lots of cones and

zero rods Optic disk

“blind spot” Does not have

photoreceptors (rods and cones)

RETINA Photoreceptors

Light sensitive cells Transmit info to brain E.x. rods and cones

Rods Low light Sense shades of grey

Cones Need brighter light Sense color

INSIDE THE EYEBALL Vitreous body

Fluid that prevents the eye from collapsing

Intraocular pressure Refers to fluid inside

the eye Balance between

production and drainage of aqueous humor

MUSCLES OF THE EYEBALL Ciliary muscle

Controls diameter of pupil

Lateral rectus muscle Moves eye inward

Medial rectus muscle Moves eye outward

Orbicularis oculi Open and close the

eyelids

ANATOMY OF THE EYE ANSWER KEY2. Fiberous Tunic

Cornea and scleraRetinaVascular Tunic Choroid, ciliary body and iris

3. Cones4. Retina5. Choroid6. Lateral rectus muscle7. Sclera8. Aqueous Humor9. Medial rectus muscle10. Rods11. Pupil12. Ciliary muscle13. Intraocular pressure

14. Cornea15. Iris16. Orbicularis oculi17. Fovea Centralis18. Pupil19. Optic nerve20. Vitreous body, vitreous humor21. Optic disk22. Lens23. Rods and cones24. Hold the lens in place25. Superior rectus and inferior

rectus26. True

IRIS Bright light

Iris expands Pupil gets smaller

Low light Iris contracts Pupil bigger

RETINATypes of photoreceptors1. Rods

Low light Sense shades of

grey

2. Cones Need brighter

light Sense color

.

TYPES OF CONES

Red cones Sense red light

Green cones Sense green light

Blue cones Sense blue light

THE MANTIS SHRIMPHTTPS://WWW.YOUTUBE.COM/WATCH?V=PPW9RIY7GUS

Bullet like punch Punch heats the

water to 8,000 F Are able to see

cancer Cancer cells

scatter light differently It has 16

different photoreceptor cells

TESTING THE BLIND SPOTTrial Left Eye

DistanceRight Eye

Distance1

2

3

4

5

Average

1. At what distance did the dot disappear?

2. Why do you think the dot disappeared?

TESTING THE BLIND SPOT Close your right eye. Stand

about 20 inches away from the blind spot tester. With your left eye, look at the +. Slowly move toward the image while looking at the +. At a certain distance, the dot will disappear from sight. Measure how far away you were when the dot disappeared.

Reverse the process. Close your left eye and look at the dot with your right eye. Move slowly towards the image and the + should disappear. Measure how far away you were when the dot disappeared.

TESTING THE BLIND SPOT Measure how far away you

were when the dot disappeared.

This is when the dot fell on the blind spot of your retina

VISON RATINGS20/20 20 ft away you see

what the avg person sees

20/40 20 ft away you see

what the avg person sees from 40 ft away

20/10 20 feet away you see

what the avg person sees from 10 ft away

HAWKS Hawk’s have 20/2

vision What does this

mean?

VIEWING OBJECTS Distant objects (20 ft

away) Light rays are parallel Lens is flat

Near objects Light rays are

divergent Lens becomes

(rounder) =accommodation

HOW DOES ACCOMODATION WORK?

BINOCULAR VISION

Allows for Depth 3D vision

THE VISUAL PATHWAY

THE VISUAL PATHWAYImages (light rays):1. Enter the pupil2. Lens inverts image and

projects onto retina3. Optic nerve carries

message to brain (crosses over at optic chiasm) (chi-as-ma)

4. Brain integrates image5. Sends Info to eyes

TESTING BINOCULAR VISION1. Have your partner hold two different pencils

at different distances in front of you so that both pencils can be seen.

2. With both eyes open, try to grab the pencil that is furthest from you.

3. Repeat steps one and two twice. Have your partner change the pencils distance with each trial

4. Repeat steps one through three with one eye closed

OUTER EAR Pinna

Directs sound waves towards the external auditory canal

External auditory canal Funnels sound

toward the tympanic membrane

MIDDLE EAR Tympanic

membrane Vibrates due to sound

waves Auditory Ossicles

(bones) Deliver sound

vibrations Eustanchian Tube

Equalizes air pressure Drains middle ear

INNER EAR Oval Window

Transfers vibrations from ossicles to cochlea

Round Window Equalizes hydrolic

pressure Fluid motion

Cochlea Converts stimuli into

nerve impulses Semicircular Canal

Equilibrium and balance

WHAT PREVENTS FOREIGN OBJECTS FROM GETTING INTO THE EAR?

Cerumen

AKA Ear Wax

CERUMEN FAIL! http://

www.youtube.com/watch?v=ZgLWl1bjH84

RUPTURED TYMPANIC MEMBRANE What can cause it to

tear? Trauma or infection

Treatment Self healing May need surgery

DID YOU KNOW . . . . . Elephants can

hear with their feet! Have pancinian

corpuscles in their feet

Nerve impulses are sent directly to the brain

COCHLEA

COCHLEA Basilar membrane

Vibrates in same pattern as sound waves

Organ of Corti Short hairs = high

frequency Longer hairs = low

frequency What type of relationship

exists between hair length and frequency? Negative correlation

Cochlear Implanthttps://www.youtube.com/watch?v=zeg4qTnYOpw

https://www.youtube.com/watch?v=I8eHquhr52s

Use of Implanthttps://www.youtube.com/watch?v=HTzTt1VnHRM

BASILAR MEMBRANE VIBRATIONS https://

www.youtube.com/watch?v=K-nXFlLFsOk

PHYSIOLOGY OF HEARINGDescribe the process

HEARING AND AGING Hairs in inner ear

die or are damaged Do not regenerate

JUST A COUPLE OF QUESTIONS1. Explain the needed for popping your

ears2. Cliff works the night shift and

sometimes falls asleep in class. What is the effect on the structures of in his internal ear when his head falls backward as he slumps in his seat?