The Special Senses

Pinna

Collects soundwaves & channels them into the ear canal (external auditory meatus), where the sound is implified.

Malleus

a small bone in the middle ear that transmits vibrations of the eardrum to the incus.

Incus

a small anvil-shaped bone in the middle ear, transmitting vibrations between the malleus and stapes.

Stapes

stirrup (middle ear), transmits vibration from the incus to the inner ear.

pharyngotympanic (auditory) tube

connects the middle ear to the nasopharynx; equalizes pressure in the middle ear cavity with the external air pressure

cochela

The fluid-filled, coiled tunnel in the inner ear that contains the receptors for hearing.

semi-circular canals

Three fluid-filled tubes that detect changes in angular acceleration. Also helps with balance.

CN Vlll- Vestibulocochlear

Sound & Balance

tensor tympani

A small skeletal muscle which limits movement of ossicles and increases tension of the tympanic membrane to prevent damage in response to loud, prolonged noises.

stapedius

the muscle attached to the stapes; tensing the stapedius decreases vibration

static equilibrium

maintains the position of the head in response to linear movements of the body. Ex. starting to walk or stopping.

Otoliths

Sense gravity & linear acceleration

Macula

(spot) detect vertical linear acceleration

Vestibular n.

the sense of body movement and position, including the sense of balance

dynamic equilibrium

maintains the position of the head in response to rotational motion of the body. Ex. rocking (as in a boat) or turning.

endolymph

fluid within the membranous labyrinth of the inner ear

crista ampullaris

A specialized receptor located within the semicircular canals that detects head movements

Cupula

a gelatinous mass found in the ampulla of the semicircular canals; moves in response to the flow of the fluid in the canals

Mechanoreceptors

detect mechanical or physical changes. Ex. touch, muscle tension, hearing, equilibrium, vibration, itch, pressure (baroreceptors)

Thermoreceptors

detect changes in temperature

Nocireceptors

detect pain

Photoreceptors

detect changes in the amount of light

Chemoreceptors

detect chemicals in dissolved in fluids

Lacrimal Apparatus

makes new tears & drains old ones out of your eyes

Lacrimal gland

continually release fluid which cleanses and protects the eye's surface as it lubricates & moistens it.

Excretory ducts of lacrimal gland

produce tears

Lacrimal punctum

The edge of each eyelid has a tiny opening, through which tears drain.

nasalacrimal duct

collects from lacrimal sac, empties tears into nasal cavity

lacrimal sac

structure that collects tears before emptying into the nasolacrimal duct

inferior meatus of nasal cavity

drains nasolacrimal duct

Nostril

(n.) one of the two holes at the end of your nose, through which you breathe and smell things

extraocular muscles

six muscles that control eye movement and eyelid elevation

superior rectus

elevates eye

superior oblique

depresses eye and turns it laterally

Medial rectus

moves eye medially

lateral rectus

moves eye laterally

Inferior rectus

depresses eye and turns it medially

inferior oblique

elevates eye and turns it laterally

Iris

The colored tissue at the front of the eye that contains the pupil in the center.

Sclera

(white of the eye) The supporting wall of the eyeball. Helps maintain eyeball's shape and is protection.

Cornea

the transparent outer covering of the eye (acts as structural barrier & protects the eye against infection.)

Anterior cavity

filled with aqueous humor, controls amount of light that enters the eye by opening & closing the pupil.

ciliary muscle

muscle that helps focus light on the retina by controlling the curvature of the lens of the eye

suspensory ligaments

hold the lens in place

Posterior cavity

filled with vitreous humor

hyloid canal

developmental remnant of hyloid artery that extended from the optic disk through the vitreous to lens

choroid

Brings oxygen & nutrients to the eye

Retina

Contains sensory receptors that process visual information and sends it to the brain

macula lutea with fovea centralis

highest concentration of cones, precise vision

Optic disc

Region at the back of the eye where the optic nerve meets the retina. It is the blind spot of the eye because it contains only nerve fibers, no rods or cones, and is thus insensitive to light.

Optic nerve

the nerve that carries neural impulses from the eye to the brain

Posterior chamber

space between the back of the iris and the front of the vitreous chamber; filled with aqueous humor

Anterior chamber

fluid-filled space between the cornea and iris

scleral venous sinus

drains the aqueous humor from the eye

emmetropic eye

normal eye

Myopic eye

nearsighted

hyperopia eye

farsightedness

astigmatism

a condition in which the eye does not focus properly because of uneven curvatures of the cornea

Gustation

sense of taste

Beta-Carotone

a pigment that gives color

Retinal

a chemical synthesized from vitamin A; joins with an opsin to form a photopigment

Polyene chromophore

known for their nonlinear optical properties

Nonlinear optical properties

Allows us to change the color of light beam, to change its shape in space and time, and to create the shortest events ever made by humans.

Fovea

the central focal point in the retina, around which the eye's cones cluster

ganglion cells

In the retina, the specialized neurons that connect to the bipolar cells; the bundled axons of the ganglion cells form the optic nerve.

Bipolar cells

eye neurons that receive information from the retinal cells and distribute information to the ganglion cells

Stimulus

any event or situation that evokes a response

cribriform plate

a portion of the ethmoid bone (transmits the olfactory nerves that carry the sense of smell) located at the base of the skull.

olfactory foramina

holes, olfactory nerves passes through, it enables your sense of smell.

How does the ear perceive sound?

nerve endings transform the vibrations into electrical imposes that then travel along the eight cranial nerve (auditory nerve) to the brain. The brain then interprets these signals.

How do we perceive smell?

The perception of a smell occurs when substances in the air pass through the nose and stimulate the olfactory (smell) nerve.

proprioceptor

senses changes in the tension of musles & tendons

Baroreceptors

detect changes in blood pressure

Strech receptors

In the lungs sense degree of inflation

How receptors stimulate sensory impulses?

All sensory signals begin as receptor potentials. These potentials lead to a release of a neurotransmitter that excites its corresponding nerve to send information to the brain.

How is sensation produced?

when sensory receptors detect physical sensory stimuli from the environment and encode the input into the nervous system.

somatic senses

touch, pressure, temperature, pain

special senses

smell, taste, vision, hearing, equilibrium

Extroreceptors

near body surface, provide info about external enviroment

How sense of pain is produced

nociceptors detect tissue damage and transmit information about the damage along the spinal cord to the brain.

The importance of stretch receptors in muscles & tendons

Stretch receptors are proprioceptors that send importation to the spinal cord and brain concerning the lengths and tension of muscles.

Relationship between smell & taste

the olfactory system plays a part in tasting food (taste what we smell)

How the eye refract light

The lens focuses the light on the retina. This is achieved by ciliary muscles in the eye. They change the shape of the lens, bending or flattening it to focus the light rays on the retina.

how the brain perceives depth and distance

The brain processes relative motion signals to perceive depth. Your two eyes viewing different images and your brain bringing them together to form one single image.

The visual nerve pathway

retina

Optic nerves

Optic chiasm

Optic tracts

Lateral geniculate bodies

Optic radiations

Visual cortex.

five tastes

sweet, salty, sour, bitter, umami

-aud

to hear

-choroid

skinlike

-cochlea

snail

-corn

horn

-Iris

rainbow

-labyrinth

maze

-lacri

tears

-lut

yellow

-macula

spot

-malle

hammer

-oculi

eye \[Definition\]

-olfact

smell

-palpebra

eyelid

-photo

light