Transcript Introduction to Health Science

Introduction to Health Science
Special 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.
Taste
• Taste 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 Tongue
• The 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)
Hearing
• Hearing 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 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
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 Bones
• Contains 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 Ear- hearing
• 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.
Inner Ear- balance
• dynamic equilibrium - interprets balance when
one is moving
– Semicircular Canals
• static equilibrium - interprets the position of the
head to maintain stability and posture when the
head and body are not moving
– Vestibule
Inner Ear-balance
• Semicircular Canals:
– A series of membrane-lined fluid-filled canals
– Are the body's balance organs, detecting motion
in the three perpendicular planes.
• Vestibule:
– Contains the saccule and utricle
– Work with the eyes to maintain postural balance
Touch
• Touch is the detection of various amounts of
pressure by the skin. Nerve impulses are
generated and sent to the brain for
interpretation.
Skin
• The 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.
Vision
• The 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.
Conjunctiva
• Membrane lining the insides of the eyelids
and eyeball.
• Reduces friction during blinking
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 the back of
the eye (retina)
Iris
• The colored portion of the eye which contains
two sets of muscles.
• Regulates the size of the pupil.
Pupil
• An opening in the center of the iris.
• Passage for light.
Lens
• Transparent structure located behind the iris
and pupil.
• Focuses light waves on to the retina.
Retina
• Most 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.
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.
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
Audiologist
• Education – Doctoral
degree. Usually takes 4
years of graduate school
to earn an Au.D.
• Salary - National average
63,000
• 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.
Optometrists
• Education – four year
program at accredited
optometry school.
• Salary - 96,000
• 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.