Senses Guided NotesName: ______

Do Now

Which ‘fact’ is false?

1) Your eye muscles are the most active muscles in your body.

2)Newborns don’t produce tears

3)Corneal scratches heal in about 48 hours.

4)If you sit too close to a TV , computer, or tablet, you will damage your eyes.

External Eye and Accessory Structures

______ are the membranes the line the eyelid and eyeball.

______inflammation of these membranes, caused by irritants, allergies, or infection (e.g. “pink eye”).

Extrinsic Eye Muscles

Control movement of the eyes. Remember: rectus = straight, oblique = slanting

Eye muscle names and actions

Name / Action
Lateral rectus
Medial rectus
Superior rectus
Inferior rectus
Inferior oblique
Superior oblique

Eyeball

The eye has three ______, or coats.

•______– “whites of the eye” , outermost, thick connective tissue.

•______– has blood vessels, middle layer

•______– contains the photoreceptors (rods & cones), inner layer

The eye is divided into two fluid-filled chambers:

•The anterior chamber is filled with ______

• The posterior chamber is filled with ______

• Both fluids ______, and the aqueous humor ______.

•______occurs when the aqueous humor doesn’t drain properly, resulting in increased eye pressure and blindness

Pathway of Light

  1. Light enters the eye at the ______– a clear, hard part of the sclera.

Functions: protects eye and focuses light

Fun fact: the cornea is responsible for ~70% of the eye’s focusing ability

  1. Light passes through the ______which is the opening in front of the lens.

•The size of the pupil is controlled by the muscles of the ______(the colored part of the eye).

• The pupil dilates or contracts to vary the amount of light hitting the retina.

  1. The light passes through the ______which focuses the light onto the retina.

•The ______are muscles which change the shape of the lens to focus on nearby items, a process called ______.

  1. The light passes through the ______to land on the retina, which contains the photoreceptors.

There are no photoreceptors on the ______, which is where the optic nerve exits the eye – this causes a small blind spot.

Photoreceptors

Rods

• more abundant

• sensitive to ______

• do not discriminate ______

Cones - ______

•3 types, ______

•triggering of more than one cone isinterpreted by brain as different colors

e.g. if both red and green are activated, the brain will interpret the light as yellow or orange

•______than cones

•mostly found in ______

Responsible for color and fine detail vision – including reading

Refraction and Accommodation

Light is bent – or ______– by nearly every eye structure that it passes through on the way to the retina.

However the lens is the only structure that can vary how much the light is bent in order to allow us to focus on different objects – a process called ______.

As we get older, our lens loses elasticity – making it harder to focus on nearby items.

This condition is called ______(old eyes)

Refraction flips and reverses the light rays, forming an upside down and reversed image on the retina … but the brain learns to interpret visual information correctly.

Refractive Errors

Myopia

Common name:

Causes:

Diagram:

Why can myopic individuals see ______objects better?

Because light from ______to properly hit the retina

Correction:

______corrective lenses / contacts magnify the image (make the light diverge more), before it enters the eye

Lasik surgery to flatten cornea makes the light focus less so it can properly reach the

retina.

Hyperopia

Common name:

Causes:

Diagram:

Why can hyperopic individuals see ______objects better?

Because light from ______to properly hit the retina

Correction:

______corrective lenses / contacts

Cornea surgery to make the cornea more ______

Both focus the light ______so that it properly reaches retina

Astigmatism

A-stigma = ______(light focuses unevenly on retina)

Causes:

Diagram:

Signs of astigmatism:

Fine details are blurry – whether ______or ______

“Halo”effects or glare from lights

Correction

Corrective lenses or contacts

Shape of lens /contact ______to counteract irregular shape of the eye

Contact lenses are often ______so that they align properly with the eye

Ortho-K / cornea surgery

______with specialcontact lenses worn at night or with laser surgery

Ear Structure and Function Guided Notes

Ear Anatomy

Overview

NOTE: Diagrams are misleading.

The entire inner is bony, except for the labyrinth which is a series of cavities (spaces) within the bone.

Outer Ear

Function: ______

Pinna collect sound waves and direct to the tympanic membranes … but in humans, not very effectively.

Cerumen (ear wax) lines the external auditory canal.

◦Antibacterial

◦Also discourages bugs, mold, etc.

◦Lubricates ears

◦Helps trap / remove foreign particles

The tympanic membrane (ear drum)vibrates when sound waves hit it,

transmitting the sound to themiddle ear

Disorders of the outer ear

Ear Wax Blockage

Ear wax can become impacted, usually from hear aid use or inappropriate methods of cleaning the ears

Can cause temporary loss of hearing

Otitis Externa (Swimmer’s Ear)

Infection of external auditory ear canal, usually due to excess moisture in the ear canal (such as from swimming), though cuts and scrapes to the ear canal can also become infected.

Middle Ear

Function: ______

How? The tympanic membrane transmits sound to the three ossicles. The ossicles act like levers, amplifying the sound and transmitting it to the oval window, a membrane-covered opening to theinner ear.

Eustachian tubes

Structure

Tube that connects the middle ear to the nose and throat

Mostly closed, but opens when we move our jaw

Why do we have it?

Equalize pressure in the middle ear

Drain fluids to the throat

Disorders of the middle ear

Otitis media (middle ear inflammation / infection) –

Inflammation (often with the buildup of infected fluids) within the middle ear

Visible with an otoscope as a bulging eardrum

Usually caused from a respiratory infection

Babies who are allowed to drink bottles while lying down are also very likely to get ear infections

Much more common in young children, because their Eustachian tubes are narrower and more horizontal

Ear tubes are often recommended for children who experience chronic middle ear infections or fluid build-up

The tube is placed in the ear drum, but performs the functions of a eustachian tube – ventilating and draining the middle ear.

Hearing and the inner ear

When the stapes beats against the oval window, it causes pressure waves within the perilymph

The movement of the perilymph disturbs the cilia (receptors) of the Organ of Corti, generating a nerve impulse

Different frequencies (pitch) vibrate the membrane in different locations.High pitches are heard that the front, low at the back.

The round window is a membrane-covered opening just below the oval window. It bulges to keep the pressure waves from bouncing back.

Balance and Aging Guided Notes

How do we maintain balance?

Cerebellum monitors and controls balance.

It receives input from four main sources:

______

______

______

______

______

Static vs Dynamic Equilibrium

Static equilibrium has to do with our ______

e.g. upside down, tilted to the left, slowing down, etc.

Sensed by the ______of the ______

Dynamic equilibrium has do to with ______

E.g. spinning, roller coasters, boat rides

Sensed by the ______of the ______

Static Equilibrium

The ______contains hair cells surrounded by an ______(a jelly-like material) that contains ______(tiny calcium stones)

The otolithic membrane slides due to gravity or linear acceleration, bending the hairs

When the hairsare bent, the hair cell generates a nerve impulse

Dynamic Equilibrium

3 canals, oriented in the three planes of space

At the base of each is a receptor region called the ______, which consists of hair cells covered with a gelatinous cap called the ______.

During angular / rotational movements, the ______in one or more canals will move, pushing against the hair cells

When the hair cells arebent, they generate a nerve impulse.

Types of Receptors

Sense / Type of Sensor / Name / Location
Vision / ______/ Retina of eye
Hearing / ______( on organ of Corti) / Cochlea of ear
Balance / ______(on crista ampullaris)
______/ Vestibule of ear
Semicircular canals of ear
Tendons, muscles, joints
Smell / Olfactory receptor / Top of nasal cavity
Taste / Taste buds / Papillae of tongue
Pain / nocioreceptors / Skin, muscles, bladder, digestive system, mucus membranes, cornea
Temp / Thermoreceptors / Skin
Pressure / Pacinian corpuscle / Skin & internal organs
Touch / Meissner’s corpuscle / Skin

Senses and Aging

Vision

Develops slowly in babies

Kids are far-sighted until around 6 because the eye needs to grow

In old age

______, causing ______– an inability to accommodate and focus on near items

Other factors which reduce visual acuity include ______, inability to fully dilate pupil, loss of photoreceptors

Many diseases more common with age: cataracts, glaucoma, macular degeneration, etc.

Hearing

______–

a loss of hearing, especially speech sounds and high pitches – due to damage to the organ of Corti

A type of ______l hearing loss

Associated with age and noise exposure

______hearing loss -

Anything that prevents sound from getting to the inner ear, including fusion of ossicles

Smell & Taste

Very sharp at birth

Declines starting around age 40

Most people over 80 have poor taste sensation and almost no ability to smell

Balance, Touch, Pain

Begin to decline around age 50

Leads to increased risk of falls

Inability to recognize injury