This document discusses the five basic senses - sight, hearing, taste, smell, and touch. It provides details on: - The key components of each sense, including the stimulus, receptor cells, and parts of the sensory organs (eyes, ears, tongue, nose). - Common vision and hearing problems and how to care for the eyes and ears. - The importance of taste, smell, and their roles in detecting chemicals, preparing for digestion, and providing sensory input. - Thresholds, transduction, and how each sense detects and interprets sensory information.

1. SENSATION
SENSATION
- awareness or a mental process which is aroused
because of the stimulation of a sense organ
STIMULUS
- anything that initiates an organic activity
RECEPTOR CELLS
- receiving mechanisms that are sensitive to
certain stimuli in the environment
TRANSDUCTION
- The process of converting physical energy into
activity in the nervous system
THRESHOLD
- The level stimulus energy which must be
exceeded before a response occurs
KINDS OF THRESHOLD
1. ABSOLUTE THRESHOLD
- The smallest intensity of a stimulus that must be
present for it to be detected
2. DIFFERENCE THRESHOLD
(Just Noticeable Difference)
- The smallest detectable difference between two
stimuli
I. SENSE OF SIGHT
 Your eyes only see colours and light and dark.
 You can see shapes, motion and proportions
because your eyes move and work together
with the senses of movement and balance.
 You are an organism with conscious thought,
which is intricately involved with the act of
seeing.
 This also means that it is easier to be
mistaken about what you see than what you
smell
A. STIMULUS FOR SIGHT: LIGHT
B. RECEPTOR CELL: RODS AND CONES
C. PARTS OF THE EYE
1. SCLERA - white part of the eye protecting the
eyeballs
2. PUPIL - black dot at the center of the, a hole
through which light can enter the eye
3. IRIS - colored part of the eye surrounding the
pupil, controls how much light enters the eye by
changing the size of the pupil
4. CORNEA - a clear window at the front of the
eye, covers the iris and the pupil.
5. CLEAR LENS - located behind the pupil, acts
like a camera lens by focusing light onto the
retina at the back of the eye.
6. RETINA - a light-sensitive inner lining at the
back of the eye
D. VISION PROBLEMS
1. MYOPIA - When an image is focused behind
the retina, this is referred to as far-sightedness.
When an image is focused in front of the retina,
this is referred to near-sightedness.
2. SCOTOMAS - Only their macular vision is
affected, which can lead to the formation of blind
spots.
3. CATARACT -Vision problems include
cloudiness in the lens
4. GLAUCOMA - increased eye pressure.
5. PRESBYOPIA- Farsightedness caused by loss
of elasticity of the lens of the eye, occurring
typically in middle and old age.
6. HYPEROPIA - farsightedness.
7. ASTIGMATISM - a defect in the eye or in a
lens caused by a deviation from spherical
curvature, which results in distorted images, as
light rays are prevented from meeting at a
common focus.
8. COLOR BLINDNESS - There are
different causes of colour blindness. For the vast
majority of people with deficient colour vision
the condition is genetic and has been inherited
from their mother.
E. CARE FOR THE EYES
1. Find out if you are at higher risk for eye
diseases.
2. Have regular physical exams to check for
diabetes and high blood pressure.
3. Look for warning signs of changes in your
vision.
4. Exercise more frequently.
5. Protect your eyes from harmful UV light.
6. Eat a healthy and balanced diet.
7. Get your eyes checked at least every two
years.
8. Don't smoke.
II. SENSE OF HEARING
- The state of being able to hear.
- Ability to perceive sound by detecting
vibrations, through an organ such as the ear
* IMPORTANCE OF HEARING
oHearing may initially have been important to
vertebrate as a mechanism to alert them to
dangerous activities
oIt is also important in search for food and
mates and in communication

2. * FACTS ABOUT EARS
 Ever wondered why every time you catch
cold, you go dumb? I mean, you lose your
voice! That’s because middle ear is connected
to the throat using a tube named Eustachian
tube.
 Human ear functions even when a person
sleeps. The ears will continue to pick up
sound but brain blocks them out.
A. STIMULUS FOR EARS: SOUND
- Sound, the stimulus for hearing, is made up of
a series of pressures, usually of air, that can be
represented as waves.
B. RECEPTOR FOR EARS: ORGAN OF CORTI
The Organ of Corti is the sensory receptor
inside the cochlea which holds the hair cells,
the nerve receptors for hearing.
C. PARTS OF THE EAR
IT IS DIVIDED INTO 3 PARTS:
1. OUTER EARS - The outer ear includes an ear
canal that is lined with hairs and glands that
secrete wax. This part of the ear provides
protection and channels sound.
The auricle or pinna is the most visible part
of the outer ear and what most people are
referring to when they use the word “ear.”
2. MIDDLE EAR - Three tiny bones —
the malleus, incus, and stapes — within the
middle ear transfer sound vibrations from the
eardrum to the inner ear.
• MALLEUS (Hammer) - The malleus or
hammer of the ear is one of the smallest
bones in the body.
• INCUS (Anvil) - The anvil bone or the incus
sits on top of the hammer, and will collect the
vibrations coming from the ear drum,
sending them on to the stirrup.
• STAPES (Stirrup) - The stirrup or stapes sits
below the anvil, and is the final bone in the
inner ear to collect and pass on sound.
3. INNER EAR - The inner ear, also called
the labyrinth, operates the body’s sense of
balance and contains the hearing organ.
• COCHLEA - This is a spiral tube that is
covered in a stiff membrane. This membrane
is filled with nerve cells, commonly known as
ear hairs. These are each designed to pick up
on a different type of vibration, which hits in
different frequencies.
• AUDITORY NERVE - These nerves receive
the electrical impulses generated by the ear
and pass this information up to the brain so it
can be interpreted.
D. HEARING LOSS TO BEHAVIOR
 Hearing loss is not just an ailment of old age.
It can strike at any time and any age, even
childhood. For the young, even a mild or
moderate case of hearing loss could bring
difficulty learning, developing speech and
building the important interpersonal skills
necessary to foster self-esteem and succeed
in school and life.
 irritability, negativism and anger
 fatigue, tension, stress and depression
 avoidance or withdrawal from social
situations
 social rejection and loneliness
 reduced alertness and increased risk to
personal safety
 impaired memory and ability to learn new
tasks
 reduced job performance and earning power
 diminished psychological and overall health
E. CARE FOR THE EARS
1. Clean your ears with extra care.
2. Wipe the outer ear with a washcloth or tissue.
3. Do not put anything into your ear smaller than
your elbow.
4. Do not use Q-tips, bobby pins or sharp pointed
objects to clean your ears. These objects may
injure the ear canal or eardrum.
5. Earwax is the ear's mechanism for self
cleaning. you have a build-up of wax that is
blocking your hearing, see your doctor to have it
removed.
6. If you experience itching or pain in your ears,
consult with your primary care physician to
determine the appropriate treatment and to
determine if you need to see a specialist
7. If you have pierced ears, clean your earrings
and earlobes regularly with rubbing alcohol.
8. Reduce the risk of ear infections by treating
upper respiratory (ears, nose, throat) infections
promptly.
9. Some illnesses and medical conditions can
affect your hearing. If you experience sudden
hearing loss or have constant noise in your ears
or head, see an ear doctor promptly.
III. SENSE OF TASTE
FACTS ON TASTING AND TONGUE
 Everyone has a different number of taste
buds.
 You can't taste well if you can't smell.
 Your tongue print is as unique as a
fingerprint.
 Temperature affects taste intensity.

3. IMPORTANCE OF TASTE
• Taste are chemical substances dissolved in
water or other fluid. Taste can be described
as four basic sensations, sweet(cane sugar),
sour(hydrochloric acid), salty(sodium
chloride), and bitter(quinine), which can be
combined in various ways to make all
other taste sensations.
• Taste sensation prepare our bodies for
digesting food, it provide information about
our food
• Taste receptors (called taste buds) about
10,000, are situated primarily in or around
the bumps (papillae) on the tongue.
Each papilla contains several taste buds,
from which information is sent by afferent
nerves to the thalamus and, ultimately, to
areas in the cortex.
COMPONENTS OF OBSERVATION OF TASTE
SMELL
- Its smell can change as new particles are releases.
- Olfactory observation(contributing to the sense
of smell).
ACTUAL TASTE
- Taste is limited to four possibilities: Sweet,
sour, salty, and bitter.
FOUR ZONES OF TONGUE
1. Zone of the bitter taste
2. Zone of the salty taste
3. Zone of the sour taste
4. Zone of the sweet taste
DEFECTS ON SENSE OF TASTE
• The decreased ability to taste certain types of
foods is known medically as HYPOGEUSIA.
• The absence of taste entirely is termed
AGEUSIA.
• DYSGEUSIA refers to the presence of a
metallic, rancid, or foul taste in the mouth.
• PARAGEUSIA is a distortion of the sense of
taste.
IV. SENSE OF SMELL
SMELL
• Ability of perceiving odors or scents by means
of the organs in the nose
• Perceive or detect the odor or scent of
(something)
IMPORTANCE OF SMELLING
Smell is an important sense as it can alert us to
danger like gas leak, fire or rotten food but also
is closely linked to parts of the brain that process
emotion and memory.
FACTS ABOUT SENSE OF SMELL
Smell and Health Care
Creating a comfortable and relaxing atmosphere
for patients is a challenge for every health care
facility, be it large or small.
Studies have shown that people can remember a
scent with 65% accuracy after 1 year while visual
memory sinks to 50% after only a few months.
The smells we experience play a crucial role in
how we associate with memories and places.
A. STIMULUS FOR SMELL: Chemical Substances
The stimuli for smell are volatile chemical
substances suspended in the air. These molecules
stimulate the olfactory receptors, which are in the
upper portions of the nasal passages.
B. RECEPTOR CELL: Olfactory Bulbs
Olfaction is a chemoreception that forms
the sense of smell. Olfaction has many purposes,
such as the detection of hazards, pheremones, and
food. It integrates with other senses to form the
sense of flavor.
C. PARTS OF THE NOSE
1. NASAL CAVITY - is a large air filled space above
and behind the nose in the middle of the face.
2. OLFACTORY NEURONS - is a transduction cell
within the olfactory system.
3. OLFACTORY BULB - They are formed from the
branching ends of axons of receptor cells that pass
information to other parts of the brain.
D. PROCESS OF SMELLING
AROMATIC SUBSTANCES  NASAL CAVITY 
OLFACTORY NEURONS  OLFACTORY BULB 
LIMBIC SYSTEM OF THE BRAIN
E. DEFECTS
1. ANOSMIA - It's usually caused by a nasal
condition or brain injury, but some people are
born without a sense of smell (congenital
anosmia).
2. HYPOSMIA - is a reduced ability to smell and to
detect odors
3. PAROSMIA - is an olfactory dysfunction that is
characterized by the inability of the brain to
properly identify an odor's "natural" smell.
3. PHANTOSMIA is the medical term for an
imaginary odour (phantom smell). It is also known
as an "olfactory hallucination".
F. EFFECTS ON BEHAVIOR
1. Smells have the power to drive your behavior on
an instinctive and subconscious level.
2. Fragrances have the ability to evoke both
positive and negative psychological states of mind
and reactions in milliseconds.

4. 3. Smell is often the first warning of safety
or danger, friend or foe.
CARE FOR THE NOSE
1. Do not blow your nose hard
2. Clean your nose with a soft, wet cloth
3. Cover your nose with a clean handkerchief when
in dusty place.
V. SENSE OF TOUCH
A. STIMULUS FOR TOUCH
1. Pressure
2. Pain
3. Warmth & Cold
4. Touch
B. RECEPTOR CELL : Free Nerve Endings
(Dendrites)
SUBDIVISION OF CUTANEOUS RECEPTORS
1. NONICEPTORS - receptor for pain
2. MECHANORECEPTORS - receptor for
pressure
and texture
3. THERMORECEPTORS- receptor for warmth
and cold
C. PARTS OF THE SKIN
1. EPIDERMIS - It is the outermost layer of the
skin that provides a protective barrier over the
body's surface, responsible for keeping water in
the body and preventing pathogens from
entering.
2. DERMIS - It is underneath the epidermis
which contains tough connective tissue, hair
follicles and sweat glands
3. HYPODERMIS (SUBCUTANEOUS TISSUE) -
It is made of fats and connective tissues that
attaches the skin to underlying bone and
muscles as well as supplying it with blood
vessels and nerves.
D. TRANSDUCTION IN THE SENSE OF TOUCH
STIMULUS (Pain/Warmth/Cold/Touch/Pressure)
 SPINAL CORD  BRAINSTEM  CEREBRUM
E. SOMATOFORM DISORDERS
Somatoform disorders are a group of
psychological disorders in which patients are
convinced that their sufferings come from
undetected and untreated bodily derangement.
1. SOMATIZATION DISORDER (HYSTERIA)
It is an illness if multiple somatic complaints in
multiple organ systems that occurs over a
several years and results in significant
impairment or treatment, or both.
EFFECTS ON BEHAVIOR:
 Suicide threats
 Complaints in a dramatic, emotional, and
exaggerated fashion
 Female patients may dress in an
exhibitionistic manner
 Patients may be perceived as dependent, self-
centered, hungry for admiration or praise,
and manipulative
2.HYPOCHONDRIASIS
(ILLNESS ANXIETY DISORDER)
- Is a condition where the patient misinterprets
trivial symptoms as having a serious disease.
- The idea is non-delusional and usually last at
least 6 months
EFFECTS ON BEHAVIOR:
 The condition interferes with the patient’s
daily life and causes him distress
 Disability and physical dysfunction
E. CARE FOR THE SKIN
1. Keep your skin soft, clean, and moisturized
2. Drink 6 to 8 glasses of water each day
3. Eat fruits and vegetables because they are
rich in vitamins and antioxidant.
4. Get 7 to 9 hours of sleep each night
5. Reduce your stress levels
6. Make sure to get a few hours of exercise each
week
VI. KINESTHESIS SENSE
It is the sensory system that tells us of position
and movement of the parts of the body.
A. STIMULUS: Body Movements
B. RECEPTOR CELLS: Nerves in muscle, tendons
and joint. (Proprioceptors)
Muscle Spindles: Stretch and Speed of stretch
Golgi Tendon Organs: Tension
C. PARTS OF KINESTHESIS SENSE
1. MUSCLES
2. TENDONS
3. JOINTS
D. KINESTHESIS SENSE DISORDERS
1. HYPERKINETIC CONDUCT DISORDER
A psychiatric syndrome emerging in early
childhood that features an enduring pattern of
severe, developmentally inappropriate inattention,
hyperactivity and impulsivity across different
settings
EFFECTS ON BEHAVIOR
• Impair academic life, social and work
performance

5. • Display disorganized, poorly controlled and
excessive activity
• Lack perseverance in task involving thought and
attention
• Experience low self esteem and engage in
dissocial behavior
2. PHANTOM LIMB DISORDER
• The sensation that an amputated or missing limb
is still attached.
• It occurs after the removal of body parts other
than limbs, extraction of a tooth or removal of an
eye
3. TABES DORSALIS
• Involves the destruction of the various tracts
through which impulses from the kinesthetic
receptors pass to the brain.
E. CARE FOR KINESTHETICS
1. Practice daily exercise
2. Drink beverages rich in calcium
3. Eat fruits rich in potassium
4. Sleep for at least 7 hours
VII. STATIC SENSE
• A form of proprioception and kinaesthesis
providing information about orientation,
balance, and acceleration, mediated by the
vestibular system.
• It was also known as Sense of Equilibrium.
A. STIMULUS: Body Movement
B. RECEPTOR: Proprioceptor
C. PARTS OF EAR CANAL
• The ear canal, also called the external acoustic
meatus, is a passage comprised of bone and
skin leading to the eardrum. The ear is
comprised of the ear canal, the middle ear, and
the inner ear.
• The ear canal functions as an entryway for
sound waves, which get propelled toward the
tympanic membrane, known as the eardrum.
• Oval window – connects the middle ear with
the inner ear
• Semicircular ducts – filled with fluid; attached
to cochlea and nerves; send information on
balance and head position to the brain
• Cochlea – spiral-shaped organ of hearing;
transforms sound into signals that get sent to
the brain
• Auditory tube – drains fluid from the middle
ear into the throat behind the nose.
• When the stapes moves, it pushes the oval
window, which then moves the cochlea. The
cochlea takes the fluid vibration of sounds
from the surrounding semicircular ducts and
translates them into signals that are sent to the
brain by nerves like the vestibular nerve and
cochlear nerve
Vestibular Portion
• Saccule
• Utricle
• Semi – circular canals
o Movement Forward & Backward
o Movement Leftward & Rightward
o Rotating
DEFECTS IN EAR CANAL (MOTION SICKNESS)
1. MÉNIÈRE'S DISEASE
This is an inner ear disorder thought to be caused
by a buildup of fluid and changing pressure in the
ear. It can cause episodes of vertigo along
with ringing in the ears (tinnitus) and hearing loss.
2. VERTIGO
• Vertigo is a sensation of feeling off balance.
Vertigo is often caused by an inner ear
problem.
• BPPV - These initials stand for benign
paroxysmal positional vertigo. BPPV occurs
when tiny calcium particles (canaliths) clump
up in canals of the inner ear.
VERTIGO IS OFTEN TRIGGERED BY A
CHANGE IN THE POSITION OF YOUR HEAD.
• Spinning
• Tilting
• Swaying
• Unbalanced
• Pulled to one direction
3. VESTIBULAR NEURITIS OR LABYRINTHITIS
This is an inner ear problem usually related to
infection (usually viral). The infection causes
inflammation in the inner ear around nerves that
are important for helping the body sense balance
CARE OF THE EAR FLUIDS
Fluid often builds up inside the ear during a
cold or allergies. Usually the fluid drains away,
but sometimes a small tube in the ear, called
the eustachian tube, stays blocked for months.
Symptoms of fluid buildup may include:
• Popping, ringing, or a feeling of fullness
or pressure in the ear.
• Trouble hearing.
• Balance problems and dizziness.
Follow-up care is a key part of your treatment
and safety.
Be sure to make and go to all appointments, and
call your doctor or nurse call line if you are
having problems. It's also a good idea to know
your test results and keep a list of the medicines
you take.

6. When should you call for help?
• Watch closely for changes in your health, and
be sure to contact your doctor or nurse call line
if:
• You have pain or a fever.
• You have any new symptoms, such as hearing
problems.
• You do not get better as expected.
• Ask your doctor to remove the wax in their
office.
• Clean the outside of your ear with a damp
cloth.
• If you choose to use cotton swabs, don't insert
them into the ear canal.
• You can use earwax softener to soften earwax
for easier removal.
• You can use a syringe to irrigate your ears.
VIII. ORGANIC SENSE
A. STIMULUS: Sensitivity of visceral and other
internal organs
B. RECEPTOR CELLS: Internal Organs
(Interoceptors)
C. PARTS OF THE ORGANIC SENSE:
1. Heart
2. Lungs
3. Intestines
4. Stomach
5. Kidney
6. Liver
D. TRANSDUCTION:
When sensory fiber of organs are stimulated,
nerve impulses are send to the brain thus giving
rise to organic sensation
* You are not consciously aware of your body or
organ
* Organic sense gives information about physical
situation, your health, vitality, illness or pain
* Psychological perspective of organic sense deals
with behaviorism;
Behaviorism is concerned with the effect of
environmental factors on observable
observation.
* With organic sense we may feel hungry, thirsty
and drowsy.
E. ORGANIC SENSE DISORDER
 LEPROSY - If organic sense isn't
functioning properly(do not feel pain) or
simply insensitivity is symptom of leprosy.
F. CARE FOR ORGANIC SENSE
1. HEART : Avoid foods rich in fats and cholesterol
2. LUNGS : Avoid smoking
4. KIDNEY : Avoid foods with large amount of salt
5. LIVER : Avoid alcoholic beverages