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 / ActionLateral 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
- 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
- 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.
- 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 ______.
- 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 / LocationVision / ______/ 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