Nose anatomy & physiology sensory system

Nose anatomy & physiology

1. NOSE

2. The Nose
•Thenoseconsistsof
theexternalnose
andthenasal
cavity.
•Botharedividedby
aseptumintoright
andlefthalves.

3. External Nose
•Theexternalnosehas
twoellipticalorifices
calledthe naris
(nostrils),whichare
separatedfromeach
otherbythenasal
septum.
•Thelateralmargin,the
alanasi,isroundedand
mobile.

4. External Nose

5. External Nose
Theframeworkof
theexternalnoseis
madeupbythe,
•nasalbone
•frontalprocessesof
themaxillae
•thenasalpartofthe
frontalbone

6. External Nose

7. SENSE OF SMELL

8. Anatomy of Olfactory Receptors
•Itisestimatedthathumanscanrecognize
about10,000differentodors.
•Thenosecontains10millionsto100millions
receptorsforthesenseofsmellcontained
withinaregioncalledtheolfactory
epithelium.

9. Cont..
•Olfactoryepitheliumoccupiesthesuperior
partofthenasalcavity,coveringtheinferior
surfaceofthecribriformplateandextending
alongthesuperiornasalconchae.
•Itconsistsofthreekindsofcells:olfactory
receptors,supportingcells,andbasalcells.

11. Olfactory Receptors
•OlfactoryReceptorsarethefirst-orderneurons
oftheolfactorypathway.
•Eacholfactoryreceptorisabipolarneurons
withanexposedknob-shapeddendriteandan
axonprojectingthroughthecribriformplate
andendingintheolfactorybulb.
•Thepartsoftheolfactoryreceptorsthat
respondtoinhaledchemicalsaretheolfactory
hair(cilia)thatprojectfromthedendrite.

13. Supporting Cells
•Supportingcellsarecolumnarepithelialcells
ofthemucousmembraneliningthenose.
•Theyprovidephysicalsupportand
nourishmenttotheolfactoryreceptors.

15. Basal Cells
•Basalcellsarethestemcellslocatedbetween
thebasesofthesupportingcells.
•Theycontinuallyundergocelldivisionto
producenewolfactoryreceptors.
•Withintheconnectivetissuethatsupportsthe
olfactoryepitheliumareolfactory(Bowman’s)
glands,whichproducesmucusthatiscarried
tothesurfaceofepitheliumbyducts.

16. PHYSIOLOGY OF OLFACTION

19. 19
Overview of Olfactory Pathway
send the information along olfactory
bulbs and tracts
different areas of the cerebrum
cerebrum interprets the information as
a particular type of smell
Smell receptors are activated, they send their
information to the olfactory nerves

20. Olfactory Pathway