1. 1.3 SENSE OF SMELL
Sense of smell detects the presence of chemical substances in the air. Its sensory organ is the nose.

2. Structure of Human NOSE
Sinus
Nasal cavity
Nostril
Sinus
Hard palate
Opening of auditory nerve
Nasopharynx
Oral cavity
Uvula
Tongue
Tonsil
Epiglottis
Pharynx
Glottis
Vocal cords
Larynx
Esophagus
Trachea

3. Structure of Human NOSE
In the nasal cavity, there are :-
a. Sensory cells to
detect smell
b. Glandular
cells
which
secrete
mucus
Smell receptors : Olfactory bulb
Hard palate
Olfactory Nerve Fibres

4. Certain smells are more easily detected than others. Do you know why?
Detection of Smell
Certain smells are more easily detected than others. Do you know why?

5. Detection of Smell
Certain smells are more easily detected than others. For instance smell of durian is more easily detected than the smell of watermelon. Do you know why?

6. Detection of Smell
Why do we sneeze? What happen when we are having flu? What’s the effect of it?