Intro to health

Special Senses

Description of the Special Senses• Smell–Smell occurs when specialized cells in the nose

(chemoreceptors) detect chemicals resulting in nerve impulses which are sent to the brain for interpretation.

Nose• In the upper part of the nasal cavity are specialized nerve

cells called olfactory receptor cells. The olfactory receptor cells contain hair called cilia to which the dissolved chemicals attach.

• Nerve impulses are transmitted from the olfactory receptors cells to the olfactory bulb, to the olfactory nerve to the brain where the sense of smell is interpreted.

• Basic smells:• putrid (rotting food)• pungent (spicy)• floral (flowers)• ethereal (medicine smell)• mint

TasteTaste occurs when specialized cells on the

tongue (chemoreceptors) detect chemicals resulting in nerve impulses which are sent to the brain for interpretation.

Mouth and TongueThe sense organs that detect dissolved chemicals for the

sense of taste are the taste buds. When the taste buds are stimulated by chemicals, they

generate nerve impulses which are sent to the brain for interpretation.

There are five basic tastes:◦ sweet (sugars and carbohydrates)◦ sour (acids)◦ salt (salt)◦ bitter (caffeine) ◦ umami (protein and amino acids).

HearingHearing involves the movement of sound vibrations through

the ear until they reach a specialized region in the inner ear where nerve impulses are generated by cells that detect movement (mechanoreceptors). These nerve impulses travel to the brain where they are interpreted as sound.

Outer Ear• Auricle– The visible portion of the ear on

the side of the head.– Composed of cartilage – Captures the sound waves from

the environment and directs them toward the auditory canal.

• Auditory Canal– Tube lined with hair and wax.– Assists in the passage of sound

waves to the middle ear.– Provides protection for the ear

as particles, debris and dust are trapped by the hair and wax.

Middle Ear• Tympanic Membrane– Known as the eardrum, it is the first

structure of the middle ear.– It vibrates with the sound waves and

passes the vibrations to the middle ear bones.

• Auditory Ossicles– Three tiny bones in the middle ear that

continue the passage of sound vibrations.– They also amplify the vibrations twenty

times.• Eustachian Tube (auditory tube)– Small tube extending from the middle ear

into the throat.– Helps to equalize pressure inside the ear.

Inner Ear• Cochlea– Snail shaped structure

composed of a series of membrane-lined fluid-filled canals that continue to pass along the sound vibrations.

– The sound vibrations eventually reach a specialized structure of the inner ear called the Organ of Corti where nerve impulses are generated. The impulses are transmitted to the brain where they are interpreted.

VisionThe sense organs that

respond to light are the eyes.

The light waves travel through the eyes until they reach the back of the eye called the retina where nerve impulses are generated by specialized cells that are sensitive to light (photoreceptors).

The impulses travel to the brain where they are interpreted as visual images and provide much information about the external world.

Eye• Eyelid–Structures composed of skin, muscles, and lashes–Protect the eye from foreign objects by the blink reflex.–Moves tears along the surface of the eyeball to keep

the eyeball moist.• Conjunctiva–Membrane lining the insides of the eyelids and eyeball.–Reduces friction during blinking

Eye• Sclera–The white part of the eye.–Provides protection and shape

to the eye.• Cornea–The clear window of the front

part of the eye.–Allows light waves to enter the

eye.–Helps to bend the light waves

on to the back of the eye (retina)

EyeIris–The colored portion of the eye which contains two sets of

muscles.–Regulates the size of the pupil to control the amount of light

entering the eye.• Pupil–An opening in the center of the iris.–Passage for light.

• Lens–Transparent disc shaped structure located behind the iris and

pupil.–Focuses light waves on to the retina.

EyeRetina–Most inner layer of the eyeball. Located under the

sclera.–Contains the photoreceptors that when stimulated

by light generate nerve impulses which are then sent to the brain for interpretation.

TouchTouch is the detection of various amounts of

pressure by the skin. Nerve impulses are generated by cells that

are sensitive to movement (mechanoreceptors) and sent to the brain for interpretation.

SkinThe skin contains several different types of nerve

receptors in the skin which are sensitive to deep pressure like poking or light touch.

All regions of the skin are sensitive to touch. The greatest number of touch receptors are found in the fingers, toes, and face.

Once the nerve impulses for touch are generated, they are sent to the brain for interpretation.

Disorders of the Special Senses• Conjunctivitis– Conjunctivitis is the

inflammation of the conjunctiva.

– Can be caused by viruses, bacteria, fungi, and allergies. The most common cause is viral.

– ”Pinkeye” is the common term for conjunctivitis.

Middle Ear Infection (Otitis Media)

Causes of otitis media include anything that causes the Eustachian (auditory) tubes to become blocked, inflamed or irritated.– Examples include colds, sinus

infections, allergies, tobacco smoke or other irritants, babies who spend a lot of time drinking on his or her back.

Most common symptom is earache

Treatment includes antibiotics for bactierial infections, use of warm cloths and analgesics to relieve pain and possible surgery if ear infections recur frequently.

Deafness

• Deafness is the complete or partial loss of hearing in one or both ears.

• May be caused by a blockage of the sound waves through the middle ear by wax build up, foreign objects, tumors or other matter. – This type of deafness generally improves

once the blockage is removed. • Deafness may also result from damage

to the nerves or to the Organ of Corti. – This type of deafness is usually irreversible

and may progressively get worse.• Treatment may include removal of the

blockage, hearing aids, or cochlear implants.

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Myopia

Nearsightedness; when a person sees near objects clearly and distant objects are blurred.

Occurs when the physical length of the eye is greater than the optical length.

Symptoms include blurred vision of distant objects, squinting, eyestrain, and sometimes headaches.

Treated with concave lenses or LASIK surgery

Hyperopia

Farsightedness; when a person sees far objects clearly and near objects are blurred.

Occurs when the physical length of the eyeball is too small or the focusing power of the lens is too weak.

Symptoms include blurred vision of close objects, eye strain, aching eyes, and headaches while reading.

Treated with convex lenses. Surgical options also available.

Presbyopia

• The normal loss of accommodation power of the eye which occurs as a consequence of aging. It occurs because the lens becomes less flexible and less able to bulge or accommodate for near vision.

• Symptoms are similar to those of farsightedness and include:– blurring of close objects– eye strain – holding objects further from the face to

focus– headaches or fatigue from focusing on

close objects. • Treatments may include the use of

reading glasses or bifocals.

Introduction to Health ScienceSpecial Senses

Vocabulary / Medical Terminology• Hearing – the sense by which sound is perceived.• Vision – the act or power of sensing with the eyes.• Taste – to distinguish flavor of using the mouth.• Touch - to bring a bodily part into contact with,

especially so as to perceive through the tactile sense

• Opthalmo – eye - Blepharo – eyelid• Audio – hearing - oto – ear• Glosso – tounge - ectasis – dilation• -rraphy - suturing

Description of the Special Senses• Smell–Smell occurs when chemicals are detected by

specialized cells in the nose resulting in nerve impulses which are sent to the brain for interpretation.

Nose• In the upper part of the nasal cavity, are

specialized nerve cells called olfactory receptor cells. The olfactory receptor cells contain hair called cilia to which the dissolved chemicals attach.

• Nerve impulses are transmitted from the olfactory receptors cells to the olfactory bulb, to the olfactory nerve to the brain where the sense of smell is interpreted.

Nose• Basic smells include –putrid (rotting food)– pungent (spicy)– floral (flowers)– ethereal (medicine smell)– and mint.

TasteTaste occurs when chemicals are detected by

specialized cells on the tongue resulting in nerve impulses which are sent to the brain for interpretation.

Mouth and TongueThe sense organs that detect dissolved

chemicals for the sense of taste are the taste buds. Taste buds are located in the tongue and throughout the mouth.

When the taste buds are stimulated by

chemicals, they generate nerve impulses which are sent to the brain for interpretation.

Mouth and Tongue• There are five basic tastes, although they are

not limited to specific parts of the tongue: • sweet (sugars and carbohydrates)• sour (acids)• salt (salt)• bitter (caffeine)• umami (protein and amino acids)

HearingHearing involves the movement of sound

vibrations through the ear until they reach a specialized region in the inner ear where nerve impulses are generated. These nerve impulses travel to the brain where they are interpreted as sound.

Ear and Hearing• Outer Ear• The outer ear is composed of cartilage covered

with skin and hair.• Captures the sound waves from the

environment.

Auditory CanalTube lined with hair and wax.Assists in the passage of sound waves to the

middle ear.Provides protection for the ear as particles,

debris, and dust are trapped by the hair and the wax.

Part of the outer ear

Tympanic Membrane• Known as the eardrum, it is the structure that

divides the outer ear with the middle ear.• It vibrates with the sound waves and passes the

vibrations to the middle ear bones.

Middle Ear and BonesContains the middle ear bones (3)

Malleus (hammer), Incus (anvil), Stapes (stirrup)

The middle ear bones continue the passage of sound vibrations. They also amplify the vibrations twenty times.

Eustachian Tube: is a tube that links the nasopharynx to the middle ear

Inner EarSemicircular Canals: • A series of membrane-lined fluid-filled canals that

continue to pass along the sound vibrations.Cochlea:• is filled with a watery liquid, which moves in

response to the vibrations coming from the middle ear

Organ of Corti :• The sound vibrations eventually reach a specialized structure

of the inner ear called the where nerve impulses are generated. The impulses are transmitted to the brain where they are interpreted.

TouchTouch is the detection of various amounts of

pressure by the skin. Nerve impulses are generated and sent to the brain for interpretation.

SkinThe skin contains several different types of nerve

receptors in the skin which are sensitive to deep pressure like poking or light touch.

All regions of the skin are sensitive to touch. The greatest number of touch receptors are found in the fingers, toes, and face.

Once the nerve impulses for touch are generated, they are sent to the brain for interpretation.

VisionThe sense organs that respond to light are the

eyes. The light waves travel through the eyes until

the reach the back of the eye called the retina where nerve impulses are transferred to the optic nerve.

The impulses travel to the brain where they are interpreted as visual images and provide much information about the external world.

Eye• Eyelid–Structures composed of skin, muscles, and lashes–Protect the eye from foreign objects by the blink

reflex.–Moves tears along the surface of the eyeball.

ConjunctivaMembrane lining the insides of the eyelids

and eyeball.Reduces friction during blinking

ScleraThe white part of the eye.Provides protection and shape to the eye.

CorneaThe clear window of the front part of the eye.Allows light waves to enter the eye.Helps to bend the light waves on the back of

the eye (retina)

IrisThe colored portion of the eye which contains

two sets of muscles.Regulates the size of the pupil.

PupilAn opening in the center of the iris.Passage for light.

LensTransparent structure located behind the iris

and pupil.Focuses light waves on to the retina.

RetinaMost inner layer of the eyeball. Located

under the sclera.Contains the nerves that when stimulated by

light generate nerve impulses which are then sent to the brain for interpretation.

Diseases and Disorders

Conjunctivitis– Conjunctivitis is the

inflammation of the conjunctiva.

– Can be caused by viruses, bacteria, fungi, and allergies. The most common cause is viral.

– ”Pinkeye” is the common term for conjunctivitis.

Otitis Media Otitis media is a middle

ear infection. Causes of otitis media

include anything that causes the Eustachian (auditory) tubes to become blocked, inflamed or irritated.

Examples include colds, sinus infections, allergies, tobacco smoke or other irritants, babies who spend a lot of time drinking on his or her back.

Tinnitus• Tinnitus is the term used for any ear noise when

there is not outside source for the sounds. • Is common. Most people have experienced it – and

it only lasts for a few minutes. • Causes are unknown but may be associated with an

ear infection, ear injury, and as a reaction to various drugs including alcohol, caffeine, antibiotics and aspirin.

• Also known as ringing in the ears.

Vertigo

Also known as dizziness, light headedness, or a feeling that the room is spinning or moving.

Occurs when: there is not enough

blood to the brain changing the position

of the head a viral infection of the

inner ear or Meniere’s disease

(an inner ear disease).

Myopia

Nearsightedness; when a person sees near objects clearly and distant objects are blurred.

Occurs when the physical length of the eye is greater than the optical length.

Symptoms include blurred vision of distant objects, squinting, eyestrain, and sometimes headaches.

Hyperopia

Farsightedness; when a person sees far objects clearly and near objects are blurred.

Occurs when the physical length of the eyeball is too small or the focusing power of the lens is too weak.

Symptoms include blurred vision of close objects, eye strain, aching eyes, and headaches while reading.

Careers Associated With the Special Senses

• Speech-Language Pathologist– Speech-language pathologists,

sometimes called speech therapists, assess, diagnose, treat, and help to prevent speech, language, cognitive-communication, voice, swallowing, fluency, and other related disorders.

– Education – Masters Degree – Salary – National Average

65,000/yr

Audiologist

Audiologists work with people who have hearing, balance, and related ear problems.

They examine individuals of all ages and identify those with the symptoms of hearing loss and other auditory, balance, and related sensory and neural problems.

They then assess the nature and extent of the problems and help the individuals manage them.

• Education – Doctoral degree. Usually takes 4 years of graduate school to earn an Au.D.

• Salary - National average 63,000

Optometrists

Optometrists provide most primary vision care. They examine people’s eyes to diagnose vision problems and eye diseases, and they test patients’ visual acuity, depth and color perception, and ability to focus and coordinate the eyes.

Optometrists prescribe eyeglasses and contact lenses and provide vision therapy and low-vision rehabilitation.

• Education – four year program at accredited optometry school.

• Salary - 96,000

Eye Doctor Clip