Matakuliah
Tahun
: L0044/Psikologi Faal
: 2009
Sistem Sensoris
Pendengaran dan Keseimbangan
Pertemuan 22
PENDENGARAN
TELINGA
• saraf kranial VIII (n. auditorius)
• terdiri dari 3 bagian : telinga luar, tengah dan dalam
• organ keseimbangan terdapat pada telinga dalam
Telinga Luar
• terdiri atas daun telinga (aurikula), lubang telinga, saluran telinga (meatus
akustikus eksternus), kelenjar sebasea dan serumen, serta selaput gendang
Structures of the Outer Ear
Auricle (Pinna)
• Outer funnel-like structure
• Collects sound waves
traveling through air and
directs them into the
external auditory meatus
• Aids in localization
• Amplifies sound approx. 56 dB
External Auditory Canal:
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Approx. 2,5 cm long
Also called external auditory
meatus
“S” shaped tube
Outer 1/3 surrounded by
cartilage; inner 2/3 by mastoid
bone
Allows air to warm before
reaching TM
Isolates TM from physical
damage
Cerumen glands
moisten/soften skin
Presence of some cerumen is
normal
Mastoid Process of Temporal Bone
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Bony ridge behind the auricle
Hardest bone in body, protects
cochlea and vestibular system
Provides support to the external
ear and posterior wall of the
middle ear cavity
Contains air cavities which can
be reservoir for infection
Tympanic Membrane
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(From Merck Manual)
Semitransparent thin membrane
covered by a thin layer of skin on the
outer surface and by mucous
membrane on the inside
Oval margin, cone-shaped with apex
directed inward toward the malleus
Forms boundary between outer and
middle ear
Vibrates in response to sound waves
Changes acoustical energy into
mechanical energy
Telinga Tengah
• berhubungan dengan rongga hidung melalui tuba eustachius, yang berfungsi
mengatur tekanan supaya sama
• terdapat tulang pendengaran : tulang martil, landasan, dan sanggurdi (malleus,
incus, stapes), yang meneruskan getaran pendengaran ke telinga dalam
Telinga Dalam (Labirin)
• sistem saluran yang tidak beraturan (labirin membranosa) yang dibatasi labirin
tulang
• Labirin tulang berisi perilimf
• Labirin membranosa berisi endolimf
• Di dalamnya terdapat dua macam alat : pendengaran dan keseimbangan
– Cochlea (Pendengaran)
– Vestibular Sacs / Vestibulum (Keseimbangan)
• utricle (little pouch) dan saccule (little sack)
– Semicircular canals (Keseimbangan)
The Ossicles
– Malleus, Incus, Stapes
– Stapes
• Smallest bone in the body
• Footplate inserts in oval window on
medial wall
– Tiny ligaments attach these bones to the
wall of the tympanic cavity
– Covered by mucous membrane
– Bridge the eardrum and inner ear,
transmitting vibrations between these parts
– Ligaments hold the stapes to an opening in
the wall of the tympanic cavity, called the
oval window, that leads to the inner ear
– Amplify (increase force of) vibrations as
they pass from eardrum to oval window.
Vibrations are concentrated as the move
from a relatively larger surface area to a
smaller area
Hole, Human Anatomy & Physiology, 10th ed
Auditory Ossicles bridge the tympanic membrane and the inner ear.
Eustachian Tube (AKA: “The Equalizer”)
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Hole, Human Anatomy & Physiology, 10th ed
Mucous-lined, connects middle ear
cavity to nasopharynx
Helps maintain equal air pressure on
both sides of the eardrum, which is
necessary for normal hearing (this
function is noticeable when you hear a
popping sound during rapid changes in
altitude)
Normally closed, opens under certain
conditions
Children “grow out of” most middle ear
problems as this tube lengthens and
becomes more vertical
Mucous membrane infections of the
throat may spread through these tubes
and cause middle ear infection
Stapedius Muscle
• Attaches to stapes
• Contracts in response to loud sounds; (the Acoustic Reflex)
• Changes stapes mode of vibration; makes it less efficient and
reduce loudness perceived
• Built-in earplugs!
• Absent acoustic reflex could signal
conductive
loss or marked sensorineural loss
Hole, Human Anatomy & Physiology, 10th ed
Inner Ear
• Labyrinth
– Complex system of communicating chambers and tubes
– 2 in each ear
• Osseous Labyrinth: bony canal in the temporal bone
• Membranous Labyrinth: tube that lies within the osseous labyrinth
Labirin tulang dibagi menjadi
VESTIBULUM
• terdapat dua kantung labirin bermembran (sakulus dan utrikulus)
• terdapat reseptor keseimbangan yang disebut makula, untuk memantau
perubahan posisi / orientasi kepala
KANALIS SEMISIRKULARIS
• Terdapat tiga kanalis semisirkularis yang berhubungan dengan tiga duktus
semisirkularis. Masing-masing duktus ujungnya melebar disebut ampula, yang
berisi reseptor keseimbangan, krista ampularis, berespons terhadap gerakan
anguler (rotasi) dari kepala
Structures of the Inner Ear:
The Cochlea
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Snail shaped cavity within mastoid bone
2 ½ turns, 3 fluid-filled chambers
Scala Media contains Organ of Corti Converts
mechanical energy to electrical energy
Cochlea
– 2 compartments
• Upper scala vestibuli leads from oval window to apex of the spiral
• Lower scala tympani extends from apex of cochlea to membrane-covered
opening in the wall of the inner ear, called the round window
– Cochlear duct
• Portion of the membranous labyrinth within the cochlea. Contains endolymph
• Lies between the 2 bony compartments and ends as a closed sac at the apex
of the cochlea
• Separated from the scala vestibuli by a vestibular membrane (Reissner’s
membrane)
• Separated from scala tympani by a basilar membrane
Hole, Human Anatomy & Physiology, 10th ed
Cross section of cochlea
Sherwood, Human Physiology From Cells to Systems, 6th ed
• Alat pendengaran berupa rumah siput / koklea, yang
kemudian getaran suara diteruskan ke alat penerima / alat
korti. Dari sini diteruskan melalui serabut saraf ke pusat
pendengaran.
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Oval Window – located at the footplate of the stapes; when the
footplate vibrates, the cochlear fluid is set into motion
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Round Window – functions as the pressure relief port for the
fluid set into motion initially by the movement of the stapes in
the oval window
Hole, Human Anatomy & Physiology, 10th ed
Hole, Human Anatomy & Physiology, 10th ed
Hole, Human Anatomy &
Physiology, 10th ed
Hole, Human Anatomy & Physiology, 10th ed
Organ Of Corti
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The end organ of hearing
– Contains stereocilia & receptor hair cells (hearing receptors)
– Located on the upper surface of the basilar membrane and stretches from the apex to
base of the cochlea
– Receptor cells (hair cells) are organized in rows and have many hairlike processes
that project into the cochlear duct
(From Augustana College, “Virtual Tour of the Ear”)
Hair Cells
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Frequency specific
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High pitches= base of cochlea
Low pitches= apex of cochlea
Fluid movement causes deflection of nerve
endings
Nerve impulses (electrical energy) are
generated and sent to the brain
Hole, Human Anatomy & Physiology, 10th ed
Sherwood, Human Physiology From Cells to Systems, 6th ed
Neil R. Carlson, Physiology of Behaviour, 9th ed
Properties of Sound Waves
Sherwood, Human Physiology From Cells to Systems, 6th ed
Sherwood, Human Physiology From Cells to Systems, 5th ed
Neil R. Carlson, Physiology of Behaviour, 9th ed
STRUKTUR DAN FUNGSI
TELINGA MANUSIA
a) Daun telinga dan saluran auditoris
telinga bagian luar mengumpulkan
gelombang suara
b) Gelombang suara menciptakan
vibrasi dalam membran timpanik
yang dihantarkan melalui tiga
tulang kecil pada telinga bagian
tengah ke bagian dalam yang ada
koklea
c) Penampang melintang koklea
menunjukkan tiga saluran
d) Sel-sel reseptor (sel-sel rambut)
adalah bagian dari organ Corti
Campbell & Reece, Biologi,
Edisi kelima jilid tiga
Neil R. Carlson,
Physiology of
Behaviour, 9th ed
Hole, Human Anatomy & Physiology, 10th ed
Sherwood, Human Physiology From Cells to Systems, 6th ed
Different regions of the basilar membrane vibrate maximally
at different frequencies
Sherwood, Human Physiology From Cells to Systems, 6th ed
Hole, Human Anatomy & Physiology, 10th ed
How Sound Travels Through The Ear...
Acoustic energy, in the form of sound waves, is channeled into
the ear canal by the pinna. Sound waves strike the tympanic
membrane, causing it to vibrate like a drum, and changing it
into mechanical energy. The malleus, which is attached to the
tympanic membrane, starts the ossicles into motion. (The
middle ear components mechanically amplify sound). The
stapes moves in and out of the oval window of the cochlea
creating a fluid motion. The fluid movement within the
cochlea causes membranes in the Organ of Corti to shear
against the hair cells. This creates an electrical signal which
is sent via the Auditory Nerve to the brain, where sound is
interpreted!
Neil R. Carlson,
Physiology of
Behaviour, 9th ed
Sound
Transduction
Sherwood, Human Physiology From Cells to Systems, 6th ed
Central Auditory System
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VIIIth Cranial Nerve or “Auditory Nerve”
– Bundle of nerve fibers (25-30K)
– Travels from cochlea through internal auditory meatus to skull cavity
and brain stem
– Carry signals from cochlea to primary auditory cortex, with continuous
processing along the way
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Auditory Cortex
– Wernicke’s Area within Temporal Lobe of the brain
– Sounds interpreted based on experience/association
Neil R. Carlson,
Physiology of
Behaviour, 9th ed
Gelombang suara : perubahan tekanan dan regangan dari molekul udara yang
disebabkan oleh bergetarnya suatu benda.
• Kecepatan suara : 344 m / s
• Kerasnya suara tergantung pada amplitudo ( besarnya getaran)
• Tinggi nada tergantung pada frekuensi dari suatu gelombang.
• Kerasnya (intensitas) suara dinyatakan dengan :
Desibel : 1/10 x 2 log tekanan
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tekanan standar suara : 0,000204 dyne / cm 2 = 0 desibel
Tekanan suara
Tekanan standar suara
Decibels (dB)
• Measure of sound intensity
• Scale begins at 0dB = intensity of sound least
perceptible by a normal human ear
• Scale is logarithmic: 10dB is 10x as intense as 0dB,
20dB is 100x more intense, 30dB is 1000x more intense
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batas pendengaran manusia : 0 - 20.000 Hertz
Intensitas 90-95 desibel dapat merusak pendengaran
Sherwood, Human Physiology From Cells to Systems, 5th ed
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Whisper = 40dB
Normal Conversation = 60-70dB
Heavy traffic = 80dB
Rock Concert = 120dB, causes discomfort
Jet plane take off = 140dB, pain
Frequent or prolonged exposure to sounds with intensities above
90dB can damage hearing receptors and cause permanent hearing
loss.
Hearing Loss
• Conductive deafness:
– Interference with transmission of vibrations to the inner ear
– May be due to plugging of the external auditory meatus or to changes in
the eardrum or auditory ossicles
• Ex. Eardrum may harden as a result of disease and be less responsive to
sound waves
• Ex. Disease or injury may tear or perforate the eardrum
• Sensorineural Deafness:
– Damage to the cochlea, auditory nerve or auditory nerve
pathways
– Can be caused by loud sounds, tumors in the CNS, brain
damage as a result of vascular accidents or use of certain drugs
– If the hair cells die, they do not regenerate and the hearing loss
is permanent
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WHO safe limit : 70 dBA
no more 85 dBA of noise over 8 hours for occupational health
noise over 100 dBA takes only 15 minutes to harm our hearing
noise damages the inner ear by causing injury to the hair cells that sense and
modulate sounds. If the hair cells die, they do not regenerate and the hearing
loss is permanent (sensorineural hearing loss) → deaf (gradually)
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loud noise → symptom of stress
our body prepares to react as if that noise is a threat or warning (fight or flight
response) → keeps the body in a state of agitation (raise blood pressure, heart
rates, level of stress hormones
loud noise → learning ability decreases
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Alat Keseimbangan
• Pada telinga dalam
– Vestibular Sacs / Vestibulum (Keseimbangan)
• utricle (little pouch) dan saccule (little sack)
– Semicircular canals (Keseimbangan)
• sagital, transversus, horizontal
The Vestibular Apparatus
Anatomy and Physiology
Components
a. Three semicircular canals (SCCs)
 Anterior
 Posterior
 Lateral
b. Utricle and Saccule
c. Vestibular nerve and nuclei
Vestibular System
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Consists of three semi-circular canals
Monitors the position of the head in space
Controls balance
Shares fluid with the cochlea
Cochlea & Vestibular system comprise the
inner ear
The Semicircular Canals
1. Fluid filled
2. Each canal has a dilated end = Ampulla
3. The ampulla houses the sensory hair cells which are
covered by a gelatinous material
a. Ampulla
b. Cristae = hair cells
c. Cupulae = gelatinous material
The Utricle and Saccule
• Present in the vestibule of the labyrinth
• Utricle is vertically oriented
• Saccule is horizontally oriented
• Sensory hair cells are embedded in the maculae of the
utricle and saccule
• Hair cells are covered by a membrane called otolithic
membrane
Hole, Human Anatomy & Physiology, 10th ed
Neil R. Carlson, Physiology of Behaviour, 9th ed
Utricle
(a) Receptor unit
in utricle
Sherwood, Human
Physiology From
Cells to Systems,
6th ed
Hole, Human Anatomy & Physiology, 10th ed
Sense of Equilibrium (Keseimbangan)
• Two senses that come from different sensory organs
• Static Equilibrium: senses position of the head,
maintaining stability and posture when the head and
body are still
• Dynamic Equilibrium: sense sudden movement or
rotation of the head and body. Aid in maintaining balance
Static Equilibrium
• Organs located within the vestibule, a bony chamber between the
semicircular canals and the cochlea
• There are two expanded chambers inside the vestibule – the utricle
and the saccule
• Each chamber has a tiny structure called a macula that contains
numerous hair cells which serve as sensory receptors
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When the head is upright, the hairs project upward into a mass of gelatinous
material containing grains of calcium carbonate (called otoliths)
When the head bends forward, backward, or to one side, the hair cells are
stimulated as the gelatinous masses of the maculae sag in response to
gravity causing the hair to bend
Stimulated hair cells signal nerve fibers resulting in impulses traveling to the
CNS on the vestibular branch of the vestibulocochlear nerve and informing
the brain of the head’s new position
Brain responds by sending motor impulses to skeletal muscles to
contract/relax to maintain balance
Utricle
(b) Activation of the utricle by a change in head position
(c) Activation of the utricle by horizontal linear acceleration
Sherwood, Human Physiology From Cells to Systems, 6th ed
Hole, Human Anatomy & Physiology,
10th ed
The macula responds to changes in head position. A.) Macula with the head in an
upright position. B.) Macula with the head bent forward.
Dynamic Equilibrium
• Semicircular canals are the organs of dynamic
equilibrium and are located in the labyrinth
• Detect motion of the head and aid in balancing the head
and body during sudden movement
• Semicircular canals lie at right angles to each other and
correspond to the different anatomical planes
• Ampulla: swelling at the end of a membranous canal that
is suspended in the perilymph of the bony portion of
each semicircular canal
– Contains sensory organs called crista ampullaris which are
made up of sensory hair cells and supporting cells
– Hair cells extend upward into a dome-shaped gelatinous mass
called the cupula
Hole, Human Anatomy & Physiology, 10th ed
A crista ampullaris is located within the ampulla of each semicircular canal.
• Rapid turns of the head or body stimulate the hair cells of the crista
ampullaris (semicircular canals move with the head but the fluid,
remains stationary)
• Hair cells signal associated nerve fibers to send impulses to the
brain – cerebellum
• Analysis of info allows the brain to predict the consequences of the
rapid body movements and signal appropriate skeletal muscle to
maintain balance
Neil R. Carlson,
Physiology of
Behaviour, 9th ed
Hole, Human Anatomy & Physiology, 10th ed
Equilibrium. A.) When the head is stationary, the cupula of the crista ampullaris remains
upright. B.) When the head is moving rapidly, C.) the cupula bends opposite the motion
of the head, stimulating sensory receptors.
Mechanism of Stimulation in SCCs
1- Angular acceleration of head
2- Motion of fluid in SCC
3- Pressure on cupula of SCC
4- Deflection of stereocilia to kinocilium
5- Deflection of stereocilia away from
kinocilium
6- Increase/decrease firing rate
K
K
Sherwood, Human Physiology From Cells to Systems, 6th ed
Activation of the hair cells in the semicircular canals
Sherwood, Human Physiology From Cells to Systems, 6th ed
Stimulus to the vestibular sensory organs
=
Motion
 Velocity
 Acceleration
Head acceleration in an angular fashion stimulates SCCs
Head acceleration in a linear fashion stimulates maculae in
utricle and saccule
Other Sensory Structures Aid in Maintaining
Equilibrium
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Keseimbangan kerjasama dari mata, otot, dan alat keseimbangan
Mata menyampaikan pesan apakah kita berdiri tegak atau miring
Otot menyampaikan pesan mengenai posisi badan dan anggota badan
Visual info is important. Even if organs of equilibrium are damaged, a
person may be able to maintain normal balance (eyes open and move
slowly)
Sherwood, Human Physiology From Cells to Systems, 5th ed
Motion Sickness
• Boat, airplane, car
• Caused by abnormal and irregular body motions that
disturb the organs of equilibrium
• Symptoms include nausea, vomiting, dizziness,
headache, and prostration (weakness, collapse,
exhaustion)
Systems regulating body balance
There are three components that regulate body balance
1. Senses from the environment
2. Summation and coordination of senses in the CNS
3. Motor commands to muscle regulation of body
balance
Systems regulating body balance
CNS
1-
1- Cerebral cortex
2- Brainstem
3- Cerebellum
Muscle commands
1-
2- Vestibular
3- Proprioceptive
2-
Campbell & Reece, Biologi, Edisi kelima jilid tiga
ORGAN KESEIMBANGAN PADA
TELINGA BAGIAN DALAM
a) Tiga struktur telinga bagian dalam, utrikel dan sakul di bagian vestibula dan saluran semisirkuler, mengandung
sel-sel rambut yang sensitif tehadap kesetimbangan dan posisi tubuh.
b) Masing-masing saluran mempunyai pembengkakan pada bagian dasarnya yang disebut ampula, yang
mengandung sekelompok sel rambut dengan rambut yang menjulur ke dalam tudung bergelatin yang disebut
kupula.
c) Ketika kepala mengubah laju rotasinya, kelembaman mencegah endolimfa dalam saluran semisirkuler agar
tidak bergerak seiring dengan gerakan kepala, sehingga cairan tersebut menekan kupula yang
membengkokkan sel rambut.
• Fungsi Sistem Vestibular adalah keseimbangan, mempertahankan
kepala pada posisi tegak, menyesuaikan pergerakan mata untuk
mengkompensasi gerakan kepala.
• Sistem vestibular mengontrol langsung pergerakan bola mata untuk
mengkompensasi pergerakan kepala yang tiba-tiba (Refleks Vestibuloocular), mempertahankan gambaran pada retina untuk tetap (steady)
• Stimulasi pada sistem vestibular belum mampu mengungkapkan
sensasi yang dapat dijelaskan dengan pasti.
• Stimulasi pada vestibular sacs
menyebabkan nausea, sedang
stimulasi pada kanalis semisirkularis
menyebabkan rasa pusing
(dizziness) dan pergerakan mata
yang ritmik (nystagmus)
Primary Reflexes of the Vestibular System
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Vestibulo-Ocular Reflex
– Maintains eye stability during
angular movement of head
Otolith-Ocular Reflex
– Maintains eye stability during
linear movement of head
Vestibulo-Colic Reflex
– Maintains stability of head on
shoulders
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Vestibulo-Spinal Reflex
– Maintains the stability of the
torso over your lower
extremities through various
tracts
- sends information
regarding gravity and linear
acceleration to
body
muscles
Vestibulo-Ocular Reflex (VOR)
Efferent = oculomotor nerves
Effector = Extra-ocular muscles
STIMULUS =
Head movement
Center
Afferent = vestibular nerve
Sensory =
Vestibular HC
Vestibulo-Spinal Reflex (VSR)
STIMULUS =
Gravity linear acceleration
Efferent = Spinal nerves
Effector = Neck and body muscles
Sensory =
Vestibular HC
Center
Afferent = vestibular nerve
Dizziness Defined
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Vertigo
– Sensation of spinning, tilting, whirling
Lightheadedness
– Sensation of possible passing-out (syncope)
Motion Sickness/Visual Sensitivity
– Body or environment movement increases symptoms
Dysequilibrium/Off-Balance
Anxiety/Fear Produced
– Hyperventilation, panic
Combinations of the Above
Meniere’s Disease
• Inner ear disorder that causes ringing in the ears,
increased sensitivity to sounds, dizziness, and hearing
loss
Meniere’s disease is a problem with the inner ear, the part of the ear responsible
for balance as well as hearing. When you have Meniere’s disease, too much
endolymph (fluid) backs up in the canals, a condition called endolymphatic
hydrops. Extra fluid causes pressure to build up, so the canals swell and can’t
work right. This leads to problems with the ear’s hearing and balance systems.
Otitis media
• Inflammation of the middle ear
Bacterial or viral infection occurs in the
fluid buildup after a respiratory illness
Otosclerosis
• Formation of spongy bone in the inner ear, which often
causes deafness by fixing the stapes to the oval window
Treatment
In the early stages of otosclerosis, or when the condition
is mild, you might not need any treatment. Hearing aids
are very useful initially. However, as the calcium buildup
on the stapes progresses you will gradually lose your
hearing. Sodium fluoride tablets have been shown to
help prevent the progression of otosclerosis, but only if
the condition has also affected the inner ear.
At some point, most people usually have an operation a stapedectomy or stapedotomy - where a tiny piston
replaces the stapes so that sound can travel to the inner
ear. This operation has a high success rate.
Tinnitus
• Ringing or buzzing noise in the ears.
Ringing, buzzing, whistling, or roaring
noises in the ear). These noises may
come and go or may always be present.
The noises may get louder just before a
vertigo attack.
Vertigo
• Sensation of dizziness
Daftar Pustaka
• Campbell & Reece, Biologi, Edisi kelima jilid tiga
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Diktat Faal, Fakultas Kedokteran Universitas Tarumanagara
Hole, Human Anatomy & Physiology, 10th ed
Neil R. Carlson, Physiology of Behaviour, 9th ed
Sherwood, Human Physiology From Cells to Systems, 6th ed