human ear structure and function | class 10

Aslam o alikum
I am Hassam ur Rahman and I am teaching Fsc biology since 2014 .I am always trying to improve myself and provide best lecture to students.i am taking content for the lecture from authentic and relevant sources but human errors are possible . you are requested to please highlight the mistakes.My lectures are equally reliable for Fsc and mdcat students
#visiblescience
This lecture is about
Ear
Hearing is as important as vision. Our ear helps
us in hearing and also to maintain the balance
or equilibrium of our body. Ear has three main
parts i.e. external ear, middle ear, and internal
ear.
A- External Ear
External ear consists of pinna, auditory canal
and ear drum (tympanum). Pinna is the broad
external part, made of cartilage and covered
with skin. It helps to direct sound waves into
auditory canal. There are special glands in the
walls of auditory canal, which produce wax. The
wax and the hairs in auditory canal protect ear
from small insects, germs and dust. In additions
to this, they help to maintain the temperature
and dampness of auditory canal. Auditory
canal ends in ear drum. This thin membrane
B- Middle Ear
Middle ear is a chamber after external ear. Three small bones, called middle ear ossicles, are
present in a chain in middle ear. These movable bones include malleus, incus and stapes.
Malleus is attached with ear drum, then comes incus and finally stapes that is connected with a
membrane called oval window. Oval window separates middle ear from inner ear. Middle ear also
communicates with the nasal cavity through Eustachian tube. This tube regulates the air pressure
on both sides of ear drum
C- Inner Ear
Inner ear consists of three parts i.e. vestibule,
semicircular canals and cochlea. Vestibule is
present in the centre of inner ear. Three canals
called semicircular canals are posterior to the
vestibule. The cochlea is made of three ducts
and wraps itself into a coiled tube. Sound
receptor cells are present within the middle duct
of cochlea.The Process of Hearing
The pinna of the external ear focuses and directs sound
waves into auditory canal. The sound waves strike ear
drum and produce vibrations in it. From ear drum,
the vibrations strike middle ear and produce further
vibrations in malleus, incus and then stapes. From
stapes, the vibrations strike the oval window and then
reach the fluid-filled middle duct of cochlea. The fluid
of cochlea is moved and receptor cells are stimulated.
The receptor cells generate a nerve impulse, which
travels to brain and is interpreted as sound.
Ears maintain the Balance of Body
Semicircular canals and vestibule help to maintain the
balance of body. Semicircular canals contain sensory
nerves which can detect any movement of head.
Vestibule can detect any changes in the posture of
body. The neurons coming from these two receptors
reach cerebellum through the auditory nerve