OLFACTION AND ITS PATHWAY

OLFACTION ANDITS PATHWAYDr.R.Ram ShankarM.S.Post graduate StudentUIORL,MMC&RGGGH,Chennai

OLFACTORY SYSTEMADD QUALITY OF LIFE

PERCEPTION OF ODOUR DEPEND ONANATOMICAL STATE OF NASAL EPITHELIUMSTATUS OF PERIPHERAL AND CENTRAL NERVOUS SYSTEMFOR OLFACTION CRANIAL NERVES 1,5,9,10 ARE INVOLVED

ODORANT SUBSTANCES REACH OLFACTORY CLEFT BYDIFFUSION

ORTHONASAL FLOW

RETRONASAL FLOW

AMOUNT OF AIR FLOW50% AIR FLOW THROUGH MIDDLE MEATUS

35% AIR FLOW THROUGH INFERIOR MEATUS

15% AIRFLOW THROUGH OLFACTORY CLEFT

MUCOSAL LAYER OF OLFACTORY EPITHELIUMPRODUCED BY BOWMANS GLANDS DEEP IN LAMINA PROPRIA AND RESPIRATORY GOBLET CELLS

NECESSARY FOR CONCENTRATION OF ODORANT SUBSTANCES

FOR SUBSTANCE TO PRODUCE ODOUR IT MUST BE LIPID SOLUBLE AND VOLATILE

OLFACTORY EPITHELIUMLOCATION-POSTEROSUPERIOR PART OF NOSE

AREA OF OLFACTORY EPITHELIUM-5 SQ.CM

PSEUDOSTRATIFIED COLUMNAR EPITHELIUM

4 TYPES OF CELLS-CILIATED OLFACTORY RECEPTOR,MICROVILLI CELLS,SUSTENTACULAR CELLS,BASAL CELLS

BASAL CELLSHORIZONTAL BASAL CELL

GLOBOSE BASAL CELL-STEM CELL

OLFACTORY PATHWAYCILIATED OLFACTORY RECEPTORAXONS CONDENSE TOFORM OLFACTORY NERVE10-15 FORAMINA IN CRIBRIFORM PLATEOF ETHMOID CONVERGE ON MITRAL CELLS OF GLOMERULI IN OLFACTORY BULBOLFACTORY TRACT PASS CROSSING OPTIC NERVEAND OPTIC CHIASMA END IN PYRIFORM CORTEX

.

.

OLFACTORY CORTEXPRIMARY OLFACTORY CORTEX

SECONDARY OLFACTORY CORTEX

TERTIARY OLFACTORY CORTEX

VOMERONASAL ORGAN OF JACOBSONGROOVE IN ANTEROINFERIOR PART OF NASAL SEPTUM

PHERMONES

DO NOT DISTURB UNLESS NECESSARY IN SEPTAL SURGERY

ODOUR TRANSDUCTION AND PROCESSING

RECOGNITION AND DISCRIMINATION OF ODOURS

ODOUR MAPS

HUMANS HAVE RECEPTOR GLOMERULUS RATIO OF 1:16

IDENTIFICATION TESTPHENYL ETHYL ALCOHOL

PYRIDINE

1-BUTANOL

TESTS4 ODORANTS AT GIVEN CONCENTRATION

2 ALTERNATIVE FORCED CHOICE PROCEDURE

SCREENING TEST USING ALCOHOL PAD

ELECTROPHYSIOLOGICAL TESTSELECTROOLFACTOGRAM

BRAIN EVOKED POTENTIALS *EXCITATION OF TRIGEMINAL NERVE *EXCITATION OF OLFACTORY NERVE

CONTINGENT NEGATIVE VARIATION

UPSITUNIVERSITY OF PENNSYLVANIA SMELL IDENTIFICATION TEST

MOST WIDELY USED

40 POINT CARD TEST

6 CATEGORIES

CLINICAL CONDITIONSANOSMIA

HYPOSMIA

PAROSMIA

PHANTOSMIA

HYPEROSMIAHETEROSMIA

PRESBYOSMIA

OSMOPHOBIA

OLFACTORY AGNOSIA

DISEASES AFFECTING OLFACTION

OBSTRUCTIVE NASAL AND SINUS DISEASEMEDIAL AND ANTERIOR TO LOWER PART OF MIDDLE TURBINATE

1-2 WEEKS OF STEROIDS

AFTER URILAST FOR 1-3 DAYS

DECREASED NUMBER OF OLFACTORY RECEPTORS

HEAD TRAUMA5-10%

ANOSMIA COMMON ONSET IMMEDIATE

MC IN FRONTAL BLOWS

AGEINCREASED AGE CAUSE DECREASE IN MITRAL CELLS OF OLFACTORY BULB

CONGENITALRECOGNISE NEARING AGE OF 8

KALLMAN SYNDROME

TOXINSFORMALINE

POLLUTANTS

CONDITION IS PROGRESSIVE

NEOPLASMSINTRANASAL TUMOURS

INTRACRANIAL TUMOURS

MEDICATIONSMETROCLORFIBRATECPMAMPHOTERICIN BAMPI,TETRACYCLINE, STREPTOMYCINDOXORUBICIN,AZAPTU,CARBIMAZOLEALLOPURINOLCAPTOPRILGLIPIZIDECOEDINEMORPHINECARBAMAZEPINE, LITHIUM,PHENYTOIN

HIV

EPILEPSY

PSYCHAITRIC DISTURBANCES

SURGERIESNOW RARE DUE TO FESS

MORE COMMON IN CRANIAL AND SKULL BASE SX

LESS WITH ENDOSCOPIC PITUITARY SX

MANAGEMENTTREAT THE CAUSE

MEDICATIONS TRIED-STEROIDS VITAMIN A

THANK YOU