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370707510 body parts

370707510 body parts

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PARTS OF THE EAR

The human ear functions in such a way that sound

waves travel from the outer ear to the middle ear,

which are then transmitted to the inner ear in the

form of compressional waves. In the inner ear, the

compressional waves are converted into electric

impulses that are perceived by the brain. This way,

we can hear and differentiate various sound types.

Outer Ear

The outer ear or external ear is the visible portion of

the ear, which serves as a protective organ for the

eardrum. It collects and guides sound waves into

the middle ear. The outer ear consists of the Ear

Flap and the Ear Canal.

Ear Flap (Pinna) - The sound waves enter the ear

via the ear flap or pinna.

Ear Canal (Meatus) - The ear canal is about 2 cm

in length. It amplifies the sound waves and

channelizes them to the middle ear. Sweat glands

are present in this canal, which secrete earwax.

Middle Ear

The middle ear, located between the outer ear and

the inner ear, perceives sound waves from the

outer ear in the form of pressure waves. The middle

ear is an air-filled cavity and consists of the

Eardrum, Hammer, Anvil, and Stirrup.

Eardrum (Tympanic membrane) - The eardrum is a

thin membrane that acts as a partition between the

outer ear and the middle ear. It vibrates as soon as

it receives sound waves, and transforms the sound

energy into mechanical energy.

Hammer (Malleus) - It is a tiny bone, located next to

the eardrum. Since it lies adjacent to the eardrum,

the vibrations from the eardrum cause the hammer

to vibrate.

Anvil (Incus) - Anvil is another tiny bone next to

hammer; it vibrates in response to the vibration of

hammer.

Stirrup (Stapes) - Similar to hammer and anvil,

stirrup is a tiny bone in the middle ear. Eventually, it

also vibrates and passes the compressional waves

to the inner ear.

Inner Ear

The inner ear or Labyrinth, as the name suggests,

is the innermost portion of the ear. It is filled with a

water-like substance and comprises both hearing

and balancing organs. The inner ear comprises the

Cochlea, Semicircular Canals, and the Auditory

Nerve.

Cochlea - The cochlea or the spiral tube is a rolled

structure that can stretch to about 3 cm. The

membrane lining of cochlea consists of numerous

nerve cells. These hairlike nerve cells respond

differently to various frequencies of vibrations,

which ultimately lead to generation of electrical

impulses.

Semicircular Canals - These are fluid-filled loops,

attached to the cochlea and help in maintaining the

balance.

Auditory Nerve - The electrical impulses, generated

by the nerve cells, are then passed to the brain.

This way, the different parts of the human ear

perform specific functions that contribute to the

overall functioning of the ear. Any damage and/or

disorder in the ear parts may lead to ear problems

and hearing loss (deafness).

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PARTS OF THE EYE

Sclera: The sclera is the white part of the eye that

surrounds the cornea. It is made up of fibrous

tissues, and provides protection to the inner parts

of the eye. This is the tissue that is commonly

called the white of the eye.

Cornea: The cornea is the transparent tissue at the

front of the eyes through which light coming from

an object enters the eye. It also helps in focusing

the light on the retina.

Aqueous Humor: It is a clear transparent fluid that

fills the space between the cornea and the eye

lens. It also supplies nutrients and oxygen to these

parts.

Iris: The iris is a ring of muscles in the central part

of the eye, that is helpful in regulating the amount

of light entering the eye by controlling the size of

the pupil.

Pupil: This is an opening in the center of the iris

through which light passes and falls on the eye

lens. Its size is controlled by the iris.

Eye Lens: The lens of the eye is situated directly

behind the pupil. It helps in focusing the light on the

retina. The eye lens is capable of changing its

shape so as to enable us to see objects near and

far.

Ciliary Muscles: This is a ring-shaped tissue that

holds and controls the movement of the eye lens,

and therefore, helps in controlling the shape of the

lens.

Vitreous Humor: It acts as a filler and covers the

space between the eye lens and retina. It also

provides protection to the lens. It makes up for

about two-thirds of the total volume of the eye, and

is composed mainly of water.

Retina: It is a membrane responsible for converting

the light falling on it into electrical impulses that can

be sent to the brain. The retina contains light-

sensitive photoreceptor cells called rods and cones.

The rods help in black and white vision and for

seeing in dim light, while the cones help in daytime

and color vision.

Optic Nerve: It is a bundle of nerve fibers that serve

as a cable that connects the eye to the brain. This

optic nerve helps in transmitting signals from the

retina to the visual center of the brain.

Yellow Spot or Macula: Situated at the center of the

retina, this yellow spot helps in absorbing excess

light that enters the eye. The macula is responsible

for our reading vision, and helping us to see objects

right in front of us.

Eyelids: The eyelids help in the protection and

lubrication of our eyes. They also help in controlling

the amount of light falling onto our eyes.

Muscles of the Eye: The eyeball is held in its place

by the help of several eye muscles. The eye

muscles are responsible for the up and down, as

well as the left and right movement of the eye.

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PARTS OF THE EAR The human ear functions in such a way that sound waves travel from the outer ear to the middle ear, which are then transmitted to the inner ear in the form of compressional waves. In the inner ear, the compressional waves are converted into electric impulses that are perceived by the brain. This way, we can hear and differentiate various sound types. Outer Ear The outer ear or external ear is the visible portion of the ear, which serves as a protective organ for the eardrum. It collects and guides sound waves into the middle ear. The outer ear consists of the Ear Flap and the Ear Canal. Ear Flap (Pinna) - The sound waves enter the ear via the ear flap or pinna. Ear Canal (Meatus) - The ear canal is about 2 cm in length. It amplifies the sound waves and channelizes them to the middle ear. Sweat glands are present in this canal, which secrete earwax. Middle Ear The middle ear, located between the outer ear and the inner ear, perceives sound waves from the outer ear in the form of pressure waves. The middle ear is an air-filled cavity and consists of the Eardrum, Hammer, Anvil, and Stirrup. Eardrum (Tympanic membrane) - The eardrum is a thin membrane that acts as a partition between the outer ear and the middle ear. It vibrates as soon as it receives sound waves, and transforms the sound energy into mechanical energy. Hammer (Malleus) - It is a tiny bone, located next to the eardrum. Since it lies adjacent to the eardrum, the vibrations from the eardrum caus ...
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