pathway of olfaction and its pathology

1. Dr.R.Ram Shankar
M.S.Post graduate Student
UIORL,MMC&RGGGH,Chennai

2. OLFACTORY SYSTEM
ADD QUALITY OF LIFE
PERCEPTION OF ODOUR DEPEND ON
 ANATOMICAL STATE OF NASAL EPITHELIUM
 STATUS OF PERIPHERAL AND CENTRAL NERVOUS
SYSTEM
 FOR OLFACTION CRANIAL NERVES 1,5,9,10 ARE
INVOLVED

3. ODORANT SUBSTANCES REACH
OLFACTORY CLEFT BY
 DIFFUSION
 ORTHONASAL FLOW
 RETRONASAL FLOW

4. AMOUNT OF AIR FLOW
 50% AIR FLOW THROUGH MIDDLE MEATUS
 35% AIR FLOW THROUGH INFERIOR MEATUS
 15% AIRFLOW THROUGH OLFACTORY CLEFT

5. MUCOSAL LAYER OF OLFACTORY
EPITHELIUM
 PRODUCED BY BOWMAN’S 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

6. OLFACTORY EPITHELIUM
 LOCATION-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

7. BASAL CELLS
 HORIZONTAL BASAL CELL
 GLOBOSE BASAL CELL-STEM CELL

8. OLFACTORY PATHWAY
CILIATED OLFACTORY RECEPTORAXONS CONDENSE
TO
FORM OLFACTORY NERVE10-15 FORAMINA IN
CRIBRIFORM PLATE
OF ETHMOID CONVERGE ON MITRAL CELLS OF
GLOMERULI IN OLFACTORY BULBOLFACTORY TRACT
PASS CROSSING OPTIC NERVEAND OPTIC CHIASMA
END IN PYRIFORM CORTEX
 .

10. OLFACTORY CORTEX
 PRIMARY OLFACTORY CORTEX
 SECONDARY OLFACTORY CORTEX
 TERTIARY OLFACTORY CORTEX

11. VOMERONASAL ORGAN OF
JACOBSON
 GROOVE IN ANTEROINFERIOR PART OF NASAL
SEPTUM
 PHERMONES
 DO NOT DISTURB UNLESS NECESSARY IN SEPTAL
SURGERY

12. ODOUR TRANSDUCTION AND
PROCESSING

13. RECOGNITION AND
DISCRIMINATION OF ODOURS
 ODOUR MAPS
 HUMANS HAVE RECEPTOR GLOMERULUS RATIO
OF 1:16

14. IDENTIFICATION TEST
 PHENYL ETHYL ALCOHOL
 PYRIDINE
 1-BUTANOL

15. TESTS
 4 ODORANTS AT GIVEN CONCENTRATION
 2 ALTERNATIVE FORCED CHOICE PROCEDURE
 SCREENING TEST USING ALCOHOL PAD

16. ELECTROPHYSIOLOGICAL TESTS
 ELECTROOLFACTOGRAM
 BRAIN EVOKED POTENTIALS
*EXCITATION OF TRIGEMINAL NERVE
*EXCITATION OF OLFACTORY NERVE
 CONTINGENT NEGATIVE VARIATION

17. UPSIT
 UNIVERSITY OF PENNSYLVANIA SMELL
IDENTIFICATION TEST
 MOST WIDELY USED
 40 POINT CARD TEST
 6 CATEGORIES

18. CLINICAL CONDITIONS
 ANOSMIA
 HYPOSMIA
 PAROSMIA
 PHANTOSMIA
 HYPEROSMIA
 HETEROSMIA
 PRESBYOSMIA
 OSMOPHOBIA
 OLFACTORY AGNOSIA

19. DISEASES AFFECTING
OLFACTION

20. OBSTRUCTIVE NASAL AND SINUS
DISEASE
 MEDIAL AND ANTERIOR TO LOWER PART OF
MIDDLE TURBINATE
 1-2 WEEKS OF STEROIDS

21. AFTER URI
 LAST FOR 1-3 DAYS
 DECREASED NUMBER OF OLFACTORY RECEPTORS

22. HEAD TRAUMA
 5-10%
 ANOSMIA COMMON ONSET IMMEDIATE
 MC IN FRONTAL BLOWS

23. AGE
 INCREASED AGE CAUSE DECREASE IN MITRAL
CELLS OF OLFACTORY BULB

24. CONGENITAL
 RECOGNISE NEARING AGE OF 8
 KALLMAN SYNDROME

25. TOXINS
 FORMALINE
 POLLUTANTS
 CONDITION IS PROGRESSIVE

26. NEOPLASMS
 INTRANASAL TUMOURS
 INTRACRANIAL TUMOURS

27. MEDICATIONS
 METRO
 CLORFIBRATE
 CPM
 AMPHOTERICIN B
 AMPI,TETRACYCLINE,
STREPTOMYCIN
 DOXORUBICIN,AZA
 PTU,CARBIMAZOLE
 ALLOPURINOL
 CAPTOPRIL
 GLIPIZIDE
 COEDINE
 MORPHINE
 CARBAMAZEPINE,
LITHIUM,PHENYTOIN

28.  HIV
 EPILEPSY
 PSYCHAITRIC DISTURBANCES

29. SURGERIES
 NOW RARE DUE TO FESS
 MORE COMMON IN CRANIAL AND SKULL BASE SX
 LESS WITH ENDOSCOPIC PITUITARY SX

30. MANAGEMENT
 TREAT THE CAUSE
 MEDICATIONS TRIED-STEROIDS VITAMIN A

31. THANK YOU