Post on 06-Sep-2020
Senses Guided Notes Name: ________________________
Do Now Which ‘fact’ is false?
1) Your eye muscles are the most active muscles in your body.2) Newborns don’t produce tears3) 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 MusclesControl movement of the eyes. Remember: rectus = straight, oblique = slanting
__________________________refers to tears. Tears __________ and _________________ the eyes, and also __________________________.
The lacrimal ducts empty into the nasal cavity
This is why nose and eye irritation is often linked. • you get the sniffles if cry and • you get watery eyes if congested
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
2. 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.
3. 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 __________________________.
4. 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.
PhotoreceptorsRods
• more abundant • sensitive to ______________________________• do not discriminate _______________________________________________
Cones - ________________________________________• 3 types, _______________________________________________________________________• triggering of more than one cone is interpreted 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
Responsible for night and peripheral vision – that’s why colors seem to be lost in the dark.
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.
• At rest, our eyes naturally focus on far-away objects.
• However, by contracting the ________________ ____________________, we can make the
lens bulge so that it has greater refractive ability – allowing us to focus on close items.
Color blindness is usually caused by the absence of one or more cones.
• Occurs in ~5% of population
• X-linked trait … much more common in men
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 special contact 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.
External Ear
Structures:
Function:
Middle Ear
Structures:
ooo
Function:
Inner Ear
Structures:
Function:
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 the middle 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 the inner 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 earOtitis 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
Hearing takes place within the cochlea of the inner ear.
Cochlea is a long, curled cavity with three layers
◦ 2 layers of _______________ – a plasma-like fluid
◦ In-between: a system of membranes that contain the ______________________ and the ______________________ _______________________ that create the nerve impulse
The top diagram is a cross-section of the cochlear cavity.
Take a moment to figure out …
◦ What fills the scala vestibuli?
◦ The scala tympani?
◦ The cochlear duct?
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 hairs are 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 are bent, 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 earSemicircular canals of earTendons, 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