This document discusses the anatomy and function of the olfactory system. It notes that perception of odors depends on the state of the nasal epithelium and nervous system. It describes how odorant substances reach the olfactory cleft through diffusion or airflow in the nose. It outlines the structures involved in olfaction like the olfactory epithelium, receptor cells, and pathways in the brain. It also discusses clinical conditions that can affect smell and various diseases and medications that can impact the olfactory system.

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