Special Senses Anatomy

What percent of inhaled air makes it to the receptor sites?

2%

Gustation

Taste receptors are also chemo receptors

Filiform

provide friction to help move food around but has no taste buds

Fungiform

small bumps on the tongue surface with about 5 taste buds each

Circumvallate

Back of the tongue forming a “v” about 100 taste buds on the sides of the pegs

Bitter

Alcolloids

What are the eyes moved by?

extrinsic eye muscles

Pathway of tears from the lacrimal gland to the nasal cavity

1.Lacrimal gland

2. Lacrimal gland ducts

3. Washes across the eye

4. Lacrimal canaliculi

5. lacrimal sac

6. nasolacrimal duct

What is the purpose of tears?

To keep conjunctival surfaces moist and clean, to reduce friction, remove debris, prevent bacteria infection, and provide oxygen and nutrients to portions of the conjuctival epithelium.

Conjunctivitis

Damage to and irritation of the conjuctival surface

Three layers of the eye

1. Fibrous Tunic

2. Vascular tunic

3. Neural tunic

Fibrous Tunic

-Comprised on cornea and sclera(white of the eye)
It’s the attachment point for the 6 extrinsic eye muscles

-The cornea has no blood vessels

Vascular tunic

• Has much blood flowing through it

• In charge of regulating the amount of light that enters the eye

Neural Tunic

• The part that turns light into a visual message

• Comprised of rods and cones

• Contains the optic disc (blind spot)

Pupil dilation

• the pupil gets larger

• In low light, during emotional arousal (like fear or excitement)

Pupil Constriction

The pupil gets smaller

What is the eye color with the least amount of melanin?

Blue eyes

How is the fovea centralis different from other parts of the retina?

• The fovea centralis is the site of sharpest vision

Rods

Enable use to see in dimly lit rooms and at twilight

Cones

Provides us with color vision

what is the difference between the fluid in the anterior and posterior cavities?

The anterior chamber contains aquous humor, the posterior cavity contains vitreous humor

Canal of Schlemm

Drains aqueous humor from the anterior chamber of the eye into the bloodstream.

What happens to the lens when we focus from near to far?

• Near focus-lens become more rounder

• Far focus-lens become flatter

Cataract

the lens of the eye becomes cloudy or opaque, leading to blurred or dim vision.

What are the 3 kinds of cones on the retina?

• Blue

• Green

• Red

How do we see yellow?

A combination of inputs from highly stimulated green cones, less stimulated red cones and unaffected blue cones

Hearing

• Since nerves are stimulated by physical movement they are mechanoreceptors

Hearing involves?

External, Middle and Inner ear

Sense on balance?

Inner ear only

External ear

• the auricle is the part we see

• Tympanic membrane vibrates with the frequency of the sound that hits it

Middle Ear

• Small air-filled chamber that houses the 3 tiny bones (ossicles)

• Auditory tube can allow infections to move to the middle ear

Inner ear

• Located deep in the temporal lobe

• Contains: Cochlea, vestibule, and semicircular canals

Mechanism of Equilibrium

• Response to the force of gravity and head movement

Static Equilibrium

• Detects the position of the head compared to gravity

• Takes place in the vestibule

Dynamic Equilibrium

• Detects changes in motion

• As fluid move out of the tube it causes bending of receptor cells