2. Fatima Fareesa siddiqui
Roll no 51
Biological sciences

3. Nose
 Smell and taste are chemical
senses
Sound and taste are physical sense
 Both smell and taste depend on the
chemical nature of the substance.

4. .
We can
neither smell
not taste
substance
which are
not soluble
in water

5. The
receptors
which are
sensitive to
taste and
smell are
called as
CHEMO
RECEPT
ORS

6.  In air breathing vertebrates, receptors for
smell and taste are physically separated.
 Smell receptors are present in nose and
taste receptors in mouth

7. Smell is
detected
by two
patches of
receptor
cells
present in
the nose

8.  Nose has a long narrow cavity
1. Upper nasal cavity
2.Lower vestibular cavities
 Nasal cavity is lined with Mucous
membrane.
 Supplied with large no. of blood
vessels

10.  Mucous membrane secretes
mucous and keeps the membrane
moist.
 Also have several types of
chemoreceptor cells(Olfactory
receptors)

11.  They have cilia which project into
nasal cavity and responsible for
smelling.
 When air enters nose, chemicals
present in the air dissolve in the
moisture.

12. These
chemical
s are
detected
by the
olfactory
receptors
.

13.  Nerve fibres present at the base of
each receptor passes through the
holes present on the plate.
 The plate separates the cavity from
the rest of the skull.

15.  Nerve fibres join to form a large
nerve called as Olfactory nerve.
 Whenever a chemical substance is
detected, receptors give a
electrical signal which is carried to
the brain by the Olfactory nerve.

16.  Brain has a separate centre to
analyse information about sense of
smelling