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SENSE ORGANS

Dr. Gregory Budiman, MBiomed

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What is sense organs?

• General : ? Special: ?• Somatic : ? Visceral: ?• General sensory somatic – visceral

– GSA :– GVA :

• Special sense somatic – visceral– SSA :– SVA :

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What to study :

• Anatomy of the special sense organs• Tracts from the receptors up to the

cerebral cortex.• Applied anatomy

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VISION ORGAN

• OBJECTIVES:– Describe the anatomy of the eyeball and its

accessory organ– Explain the mechanism of eye movement

(extrinsic eye muscle)– Explain the neuronal pathways from retina up

to cerebral cortex

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Eye and Associated Structures

• Most of the eye is protected by a cushion of fat and the bony orbit

• Accessory structures include eyebrows, eyelids, conjungtiva, lacrimal apparatus, and extrinsic eye muscles

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• Conjuntiva: transparent mucous membrane that : – Lines the eyelids as the palpebral conj.– Lines the sclera as the scleral conj.

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Lacrimal gland excretory duct -> enter the eye lacrimal punctum lacrimal canaaliculus lacrimal sac nasolacrimal duct inferior meatus of nasal cavity

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INNERVATION OF LACRIMAL GLAND

• Afferent : via lacrimal nerve brain stem (spinal tr nucleus of n.V)

• Parasymphatetic eff : from nucleus salivatorius superior preganglionic fiber (n.VII, greater petrosal nerve) ganglion pterigopalatinum postganglionic fiber (zygomatic branch, lacrimal nerve)

• Sympathetic eff: thoracal segment preggl superior cervical ggl postggl (carotid plexus, ….lacrimal nerve)

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Inner Segment and Fluids

• The lens separates the internal eye into:• Anterior segment: filled with a plasmalike

fluid (Aqueous humor) drains via canal of Schlemm– Anterior chamber (COA) : cornea/iris– Posterior chamber (COP): iris/lens

• Posterior segment : filled with a clear gel (viteous humor)

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Scleral venous sinus

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• Intraocular pressure can increase and cause glaucoma. Can you explain the circulation of the fluid in the eyeball?

• Can you explain anatomical conditions that can cause increased intraocular pressure?

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Visual Pathways

• Axons of retinal ganglion cells form the optic nerve

• Medial fibers of the optic nerve decussate at the optic dhiasm

• Most fibers of the optic tracts continue to the thalamus (LGB)

• Fibers from LGB form the optic radiation• Optic radiations project to the visual cortex

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Describe the visual field of each lesion

(I-IV)

1.Ipsilateral anopia2.Bitemporal hemianopia3.Contralateral homonym hemianopia4.Upper contralateral quadranopia

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• A patient got left hemianopia of his visual field. Can you draw the visual pathways and show the lesion?

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Cortical Processing

• Primary visual cortex (corpus striatum)• Visual association area (prestriatum)• Visual information then proceeds anteriorly

to the:– Temporal lobe identification of objects– Parietal cortex spatial location

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EYE MUSCLES

EXTRINSIC EYE MUSCLES• Eyeball movement: RL, RM, RS, RI, OI,

OS• Elevate eyelid: m. levator palpebrae

INTRINSIC EYE MUSCLES:• To control covexity of the lens (m.cilliary)• To control diameter of pupil (m. sphincter

pupillae, m. dilatator pupillae)

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OTOT-OTOT INTRINSIK MATA

Muscle Location Innervation Function

Ciliary Muscle fibers in the ciliary body

Parasymphatetics from the occulomotor nerve [III]

Constrics ciliary body, relaxes tension on the lens, lens become rounded

Sphincter pupillae Circularly arranged fibers in the iris

Parasymphatetics from the occulomotor nerve [III]

Constrics pupil

Dilator pupillae Radially arranged fibers in the iris

Symphatetics form the superior cervical ganglion (T1)

Dilates pupil

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Light Reflex

• Some nerve fibers send tracts to the midbrain ending in the superior colliculi and pretectal nucleus.

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• If light is shined to left eye, then both the left and right pupil will constrict. How can this happen, show me the pathways!

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Accomodation Reflex• When the eyes follow the object directed

from a distance and get closer, the followings are occured:– Contraction of medial rectus muscles in order

to converge the eye’s axis.– Thickening of the lens– Constriction of the pupil in order to make the

light passes through the center of the lens (the thickest part of the lens)

• The pathways are as follows:

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• If the right cornea is touched then both right and left eyes will blink together. How can this happen, show me the pathways!

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REFLEKS KORNEA

Ggl. Semilunaris

Nucl.sensoris principalis n.V

korneam.orbicularis oculi

Nucl.motorik N.VII interneuron

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REFLEKS KORNEA

Ggl. Semilunaris

Nucl.sensoris principalis n.V

m.orbicularis oculi

Nucl.motorik N.VII interneuron

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• How can our eye do conjugate gaze? Explain the function of each extrinsic muscles!

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PRIMARY POSITION

ADDUCTION

L L

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PRIMARY POSITION

ADDUCTION

L L

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PRIMARY POSITION

ABDUCTION

L L

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PRIMARY POSITION

ABDUCTION

L L

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PRIMARY POSITION

ELEVATION

L L

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PRIMARY POSITION

ELEVATION

L L

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PRIMARY POSITION

DEPRESSION

L L

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PRIMARY POSITION

DEPRESSION

L L

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PRIMARY POSITION

INTORSION

L L

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PRIMARY POSITION

INTORSION

L L

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PRIMARY POSITION

EXTORTION

L L

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PRIMARY POSITION

EXTORSION

L L

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CONJUGATE GAZE

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CONJUGATE GAZE

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CONJUGATE GAZE

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CONJUGATE GAZE

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Conjugate gazeSaccadic movement :•Sudden eye movement to catch the moving object•Center : frontal lobeSmooth pursuit movement:•Continuous eye movement to follow the moving object

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HEARING AND BALANCE ORGAN

OBJECTIVES:• Explain the structures of outer ear, middlle

ear, and inner ear.• Explain the important ear structure related

to clinical case• Explain the neuronal pathways of hearing

and balance organs.

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The Ear : Hearing and Balance

• Part of the ear :– Outer ear : auricle – Ext auditory canal –

tympanic membrane– Middle ear: tympanic cavity – ear ossicles– Inner ear : bony and membranous labyrinth

(vestibule, cochlea, semicircular canals)

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The Outer Ear

•The auricle (pinna) is composed of helix (rim) and lobule (earlobe)•External auditory canal: short, curved tube filled with ceruminous gland (1/3 lateral cartilage part; 2/3 medial bony part)

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Tympanic membrane (eardrum)

• Boundary between outer and middle ear• Thin connective tissue mambrane that

vibrates in response to sound• Transfer sound energy to the middle ear

ossicles

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Middle Ear (tympanic cavity)

• A small, air-filled, mucosa-lined cavity– Flanked laterally by the eardrum– Lanked medially by the oval and round

windows• Middle ear communicates with :

– mastoid cells – Nasopharynx via pharyngotympanic tube :

equalizes pressure in the middle ear acvity with the external air pressure

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Wall of tympanic cavity

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Inner Ear

• The Vestibule : – central egg-shaped cavity of the bony

labyrinth– Suspended in its perilymph are two sacs :

saccule (extends into cochlea) and utricle (extends into semicircular canals)

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• Why children often get wet ear when he get flu?

• Infection of middle ear can cause tympanic bulging because of pus pressure. How can we drainage the pus out?

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• In case chronic mastoiditis, doctor should do mastoidectomy. Why procedure of mastoidectomy can cause facial paralysis (Bell’s palsy) or severe hemorrage?

• Why stimulation of the ear canal can cause cough, sneezing, or vomitus?

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A patient complained that he got vertigo. Can you mention what structures probably in trouble?

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Balance pathways

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OLFACTORY ORGAN

• Nasal structured (discussed in respiratory module)

• Explain the neuronal pathways from olfactory receptor up to the cerebral cortex

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• Why some odors can cause nausea?

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• Olfactory striae ends in primary olfactory cortex (uncus and prepyriform) which is connected to the limbic system.

Olfactory system

Limbic system

Hypothalamus

Reticular formation (brain stem)

Autonomic function and reflexes

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Gustatory Organ

• Tongue and oral cavity : discussed in Digestive Module

• Explain the special visceral pathways from taste receptor up to cerebral cortex

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• When someone drank black hot coffee he felt hot and bitter on his tongue. Explain the differences between the pathways of hot sensation and of bitter sensation!

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References

• Marrieb, Ellaine, Human Anatomy• Budiman, Gregory. Basic Neuroanatomical

Pathways. BP FKUI• Budiman, Gregory. Jaras-jaras

Neuroanatomi. Sagung Seto

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TULANG-TULANG PEMBENTUK RONGGA ORBITA

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