Chapter II & III of Sensory System

7/24/2019 Chapter II & III of Sensory System

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ABSTRAK

Sistem penginderaan manusia adalah sistem organ yang dikhususkan untuk

menerima rangsangan tertentu yang terdiri dari indera penglihatan, indera

pendengar, indera penciuman, dan indera pengecap, dan keseimbangan. Semua

indra mempunyai peran dan fungsi masing-masing dalam tubuh manusia. Dan

apabila terjadi gangguan pada salah satu sistem indra di atas, maka akan terjadi

ketidakseimbangan dan ketidakmampuan pada aktivitas yang dilakukan manusia

sehubungan dengan fungsi sistem indra tersebut.

1. Organ penglihatan yaitu mata berfungsi untuk menerima rangsangan berkas

cahaya pada retina dengan perantaraan serabut nervus optikus,

menghantarkan rangsangan ini kepusat penglihatan pada otak untuk

ditafsirkan.2. Suara dapat terdengar melalui proses yang terjadi di telinga. elinga memiliki

tiga bagian yaitu telinga luar, telinga tengah dan telinga dalam. !elainan atau

penyakit yang sering terjadi pada indra pendengaran adalah otitis media akut.

". #ndera peraba membuat manusia dapat merasakan sentuhan, nyeri, dan suhu.

$. %ungsi alat pengecap merasakan makanan dan juga sebagai alat reflek

susunan saliva &kelenjar ludah'.

(. Sistem pengecapan dilakukan oleh organ lidah. )apila filiformis lebih

berfungsi untuk menerima rasa sentuhan dari rasa pengecapan yang

sebenarnya. Selaput 1* papila langit-langit dan faring juga bermuatan puting-

puting pengecap. +asalah yang sering terjadi pada daerah hidung adalah

polip.

. Sistem keseimbangan tubuh manusia berada di nervus auditori yang ada pada

telinga, yang berfungsi mengumpulkan sensibiltitas dan bagi vestibuler

rongga telingadalam yang mempunyai hubungan dengan keseimbangan.


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CHAPTER II

DISCUSSION

. Definition

he sensory system is a group of subsystems used for detecting and

understanding the orld around you. he sensory system is a part of the

nervous system responsible for processing sensory information. sensory

system consists of sensory receptors, neural pathays, and parts of the brain

involved in sensory perception. he system is stimulated by sensory

receptors/ these are the organs hich trigger action potentials on a sensory

neuron in response to a specific type of stimulus. here are three basic

classifications of sensory receptors. he first is somatic receptors0 receptors in

the skin, muscles, and tendons. Secondly, the visceral receptors. hese are

receptors in the internal organs. %inally, special receptors are the receptors

positioned in specific locations.

. natomy and )hisiology

ommonly recogni3ed sensory systems are those for vision, auditory

&hearing', somatic sensation &touch', gustatory &taste', olfaction &smell' and

vestibular &balance4movement'.

1. 5ision

he visual system is responsible for a person6s sight/ detecting light,

darkness, and color. he primary organs involved in sight are the eyes.

he eyes have many different components hich allo them to perform

the remarkable task of providing visual imagery. he parts of the eye are

assorted and e7ually varied in their purposes.


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)art of the eye0

ornea

ornea is the tissue hich covers the area of the eye over the

pupil and allos light to enter/ it is therefore transparent.

#ris

#ris is identifiable as being the colorful portion of the eye/

hoever it serves a higher purpose than just giving the eye its beauty.

he iris controls the amount of light hich enters into the eye. #t is

composed of smooth muscle hich ill constrict &condense' in bright

light and dilate &e8pand' in dim light.

)upil

he pupil is the black colored portion of the eye directly belo

the iris. he pupil ill appear to gro larger and smaller, but, as stated

previously, this is an illusion produced by the iris6s constriction anddilation.

9ens

9ight enters the eye through the lens. he lens focuses light

before it passes to the retina, covering the back of the eye.

:etina

he retina is full of blood vessels and also houses

photoreceptors called rods and cones. here are about 12; million

rods and * million cones located in the retina of each eye. here is one


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portion of the retina called the optic disk hich has no photoreceptors.

his is the part of the eye here the blood vessels enter the eye. #t is

also here the a8ons of the neuron in the eye e8it to join the optic

nerve, sending signals to the brain. his hole in the retina results in a

blind spot in the eye. he brain automatically compensates for this

blind spot and fills it in. he portion of the eye that gives us the

sharpest image is the fovea centralis. his is located in a small pit in

the macula lutea, a small yello spot in the center of the retina.

here are three main steps to an eye processing an image. %irst, the

light focuses on the retina here it stimulates the photoreceptors. Second,

the photoreceptors have a reaction to the stimulus. hird, action potentials

are created as result of the stimulus that are sent to the visual corte8, here

they are interpreted.

2. uditory

Sound can be heard through a process hich occurs in the ear. he ear

has three main sections0 the outer, the middle, and the inner ear. Sound

aves are vibrations in the air. hese vibrations journey don the

auditory canal and vibrate the tympanic membrane, the end of the e8ternal

ear.


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)art of the ears0

he +alleus

he malleus is connected through a tiny joint to the incus, hich

is attached to the stapes, both of hich vibrate in their turn as result of

the vibrations of the bone preceding them.


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orti

he organ of orti, hich is the actual =hearing> organ. #n the

cochlear duct is a li7uid called endolymph. he tectorial membrane

floats in this fluid and touches hair cells on the spiral organ.

he original sound vibrations, have no been converted through the

tympanic membrane, vibrated the auditory ossicles, traveled through the

oval indo, and are being sent don the perilymph in the inner ear. #f the

vibrations of the perilymph have originated from a sound ith a high

enough pitch, it ill cause a vibration in the basilar and vestibular

membrane in the scala vestibuli. s the tectorial membrane vibrates, itbrushes against hair cells in the spiral organ. hen activated, the hair cells

trigger action potentials in their sensory neurons. ontrastingly, if the

vibrations are of a lo-fre7uency origin, they cause a vibration in the

basilar membrane near its point, once again triggering a vibration in the

tectorial membrane, hich brushes the hair cells on the spiral organ, hich

results ultimately in action potentials. ?ssentially, the higher-fre7uency a

sound is the closer to the oval indo the basilar membrane ill vibrate,or if the sound is of lo-fre7uency origin, the farther from the oval

indo the basilar membrane ill vibrate.

". Somatic Sensation

here are to different types of somatic receptors in the

somatosensory system hich join together to allo a person to feel

sensations such as touch, pain, temperature, and proprioception &the

positioning of joints and muscles'. he first type is the cutaneous

receptors, hich are receptors in the skin. he second type isproprioceptors, receptors in the muscles and tendons.

here are different types of cutaneous receptors0

a. %ree nerve endings are the simplest and most common receptors. #n

these receptors, nerves rise to the epidermis here they branch out

until they end. Such nerves respond to heat, cold, movement, itch, and

pain.


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b. @air follicle receptors hich go deep into the dermis. lso deep in the

dermis are the )acinian corpuscles. hese are pressure and vibration

receptors and resemble miniscule onions.

c. :uffini6s organs can also be found in this part of the dermis. hey

respond to pressure of the surface of the skin and the stretching of the

skin.

d. he +eissner6s corpuscles hich are found throughout the dermal

papillae. hese assist in to-point discrimination, or being able to

distinguish ho many points of pressure there are ithin a specific

space.here are only to types of proprioceptors0

a. +uscle spindles, located ithin the skeletal muscle, these receptors

respond to the stretching of muscle.

b. he Aolgi tendon organ is found in the tendon and responds only to

tension.

ogether these receptors provide the brain ith the information it

re7uires to determine hether a muscle needs to be rela8ed or contracted.

echnically, this is called a sense of body position.

$. Austatory

aste is not only often pleasurable, but also plays a key role in

survival.


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a. %ungiform papillae 0 are spread irregularly over the entire surface of

the tongue.

b. %iliform papillae 0 are the most plentiful of all the types of papillae.

c. %oliate papillae 0 are situated in the sides of the tongue and contain the

most sensitive receptors.

d. ircumvallate papillae 0 are the largest but least numerous of the

papillae and are located on the back of the tongue.

he tongue is also covered ith taste buds, but, contrary to popular

opinion, they are located in other areas as ell. hey can also be found on

the palate, the lips, and the pharyn8 &throat', especially in children. #t is

estimated that each person has appro8imately ten thousand taste buds.

aste buds are located in the circumvallate, fungiform, and foliate papillae,

being most sensitive in the foliate papillae/ they are not present in the

filiform papillae. aste buds are called such due to their floer bud-like

appearance. #nside each of these floral-shaped bumps are to different

types of cells0 the gustatory cells and the supporting cells. ?ach taste bud

has a hole in its center appropriately named the taste pore. )rotruding from

the taste pore are the gustatory hairs. aste sensory cells are among the

shortest-lived cells in the body. During their brief e8istence of a fe days,

they migrate from the outside of the taste bud to its center, here they then

die. Berve fibers running out of the taste buds release neurotransmitters

hen stimulated. hese stimuli generate an action potential on an

associated afferent nerve. %ibers ith smaller diameters associate ith

only one sensory cell, hile larger fibers associate ith to or more. ny

given sensory cell may receive contacts from up to as many as thirty nervefibers. ?7ually impressive, a single nerve fiber can innervate up to nine

separate taste papillae. he afferent fibers carry the impulses directly from

the tongue to the brain stem via either the chorda tympani branch of the

seventh cranial verve, the lingual branch of the ninth nerve, or the

pharyngeal branches of the tenth nerve. he chorda tympani orks in

coordination ith the anterior &front' 24" portion of the tongue and the

lingual orks ith the posterior &back' 14". #n addition to taste signals,


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these nerves also transport information regarding temperature and te8ture.

%rom there, the nerve impulses are transferred beteen secondary cells in

the nucleus tractus solitarius, hich then transport them to the brain.

(. Olfactory

he olfactory system plays a very important role in a person6s life. #t

affects emotions, reproductive and maternal functions, aggression, and

food selection. he nose contains the receptors for the olfactory system.

hey are found in hat is called the olfactory epithelium, located in the

superior part of the nasal cavity. ?ach individual has to olfactory bulbs,

one located in each nostril. #n each nostril there is a bone, hich protectsthe olfactory bulbs. here are holes in the cribriform plates called olfactory

foramina hich allo the a8ons of the olfactory neurons to reach the

olfactory bulb. he other end of the olfactory neuron, the side e8posed to

the air inside the nasal cavity, has olfactory vesicles hich end in olfactory

hairs, encased in a mucous layer. ?ach olfactory neuron is bipolar and has

one dendrite and one a8on. Olfactory neurons are e8tremely uni7ue in that

they are not permanent and can be replaced by basal cells, unlike any other

variation of neuron. Cnlike other sensory systems, signals transmitted

from the olfactory hairs travel directly to the primary sensory cortical areas

and limbic system ithout ever involving the brain stem.


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#n order for a substance to be smelled, it must pass several 7ualifications.

%irstly, for a chemical to be smelled, it has to be airborne. volatile

substance is one that can evaporate into a vapor so that it becomes

airborne. his means that the only substances able to be smelled are those

hich are volatile. here are some volatile substances, hoever, that a

person cannot smell. his is because the substance must not only be

volatile, but it must also be able to reach the olfactory hairs. #n order for

this to happen, the chemical must transport through the atery, mucous

layer. his means that the substance must be at least somehat ater

soluble. On top of that, the chemical must also be moderately soluble in

lipids so that it can penetrate through the plasma membrane. #f the

chemical meets all of these re7uirements and is indeed able to reach the

olfactory hairs, it ill bind to a receptor molecule on the hair. he

receptor ill then generate an action potential. #t is believed that smell is a

result of the combining of as many as fifty primary sensations. #t does not

re7uire much stimulation to create an action potential. his allos people

to smell things that are floating even at a very, very lo concentration in


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the air. @oever, after the olfactory hairs have been stimulated

continuously for even a short period of time, the action potentials are no

longer sent.

. 5estibular

he vestibular sense refers to the bodys set of mechanisms that

monitor and adjusts the bodys sense of balance and orientation to the

orld. his sense is hat keeps the body upright hile standing, sitting or

alking. he vestibular sense is closely associated ith the inner ear and is

carried to the brain on a branch of the auditory sense. his is hy inner ear

infections can result in problems ith balance.

. he Disease and Disorder

1. +yopia &nearsightedness'

Bearsightedness is an eye condition in hich you can see nearby

objects clearly, but faraay objects appear fu33y or blurry.

Bearsightedness is also called myopia.2. %arsightedness

%arsightedness means that it6s easy for you to see things that are far

aay, but your close-up vision is blurry. he technical term for

farsightedness is hyperopia. )eople can have varying degrees of

farsightedness, depending on their eyes6 ability to focus on close-up

objects.

". stigmatism


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stigmatism is a common vision problem caused by an error in the

shape of the cornea. is an infection

or selling in the eye area. lood vessels in the conjunctiva, a thin

membrane that lines part of the eye, become inflamed. his gives the eye a

red or pink color that6s commonly associated ith conjunctivitis.

. ataract

he lens is used everyday, for everything from reading to driving to

bird atching.


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E. )olyp

polyp is an abnormal groth of tissue projecting from a mucous

membrane. #f it is attached to the surface by a narro elongated stalk, it is

said to be pedunculated. #f no stalk is present, it is said to be sessile.

F. Skin ancer

Skin cancer is the uncontrolled groth of cancer cells in the skin. 9eft

untreated, these cells can spread to other organs and tissues, such as lymph

nodes and bone.

1;. Austatory @allucination

gustatory hallucination is the perception of taste ithout a stimulus.

hese hallucinations, hich are typically strange or unpleasant, arerelatively common among individuals ho have certain types of focal

epilepsy, especially temporal lobe epilepsy. he regions of the brain

responsible for gustatory hallucination in this case are the insula and the

superior bank of the sylvian fissure.


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BAB III

CONCLUSSION

he sensory system is a group of subsystems used for detecting and

understanding the orld around you, that consists from vision, auditory &hearing',

somatic sensation &touch', gustatory &taste', olfaction &smell' and vestibular

&balance4movement'.

1. he visual system is responsible for a person6s sight/ detecting light,

darkness, and color, and the organ here is the eye. he disorder that

commonly happen to the vision are myopia &nearsightedness', farsightedness,

astigmatism, presbyopia, conjunctivitis &pink eyes', cataract, and etc.2. Sound can be heard through a process hich occurs in the ear. he ear has

three main sections0 the outer, the middle, and the inner ear. he disorder that

commonly happen to the auditory is acute otitis media.

". Somatic sensation allo a person to feel sensations such as touch, pain,

temperature, and proprioception &the positioning of joints and muscles'.

$. Austatory

he tongue houses the sensory receptors for the gustatory system. he

surface of the tongue is composed of tiny little bumps called papillae. he

tongue is also covered ith taste buds, but, contrary to popular opinion, they

are located in other areas as ell. he Disorded that commonly happen to

gustatory is gustatory hallucination.

(. Olfactory

Olfactory affects emotions, reproductive and maternal functions,

aggression, and food selection. he nose contains the receptors for the

olfactory system. he disease that commonly happen to olfactory is polyp.

. 5estibularhe vestibular sense refers to the bodys set of mechanisms that monitor

and adjusts the bodys sense of balance and orientation to the orld. his

sense is hat keeps the body upright hile standing, sitting or alking. he

vestibular sense is closely associated ith the inner ear and is carried to the

brain on a branch of the auditory sense.


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LITERATURE CITED

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1F.2;, 1$th October 2;1(.

@ealthline. &2;1('. #n http044.healthline.com4health4eye-health. ccessed at

12.22, 1(th October 2;1(.

)sychology glossary. &2;1('. #n http044.alleydog.com4glossary4definition.phpH

termI5estibularJ2;Sense. ccessed at 11.(*, 1(th October 2;1(.

)sychlopedia. &2;1('. #n https044psychlopedia.ikispaces.com45estibularKSense.

ccessed at 12.;", 1(th October 2;1(.

Study.com. &2;1('. #n http044study.com4academy4lesson4the-sensory-system-

definition-parts-functions.html. ccessed at 1E.(1, 1$th Oct 2;1(.

Chapter II & III of Sensory System

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