Railway Science (Biology – Sensory Organs)

Gustatory receptor is the sensory system that is partially responsible for the perception of taste. Thermoreceptors are parts of neurons, or nerve cell endings, that give the body the ability to detect changes in temperature. Phonoreceptors are the organ of the sense of hearing and are present in the inner ear.

Parts of human eye: Pupil - The black hole seen at the centre of the iris of the eye which permits light towards the retina. Iris - The coloured tissue at the front of the eye that contains the pupil in the center.
Retina - sensitive layer that contains nerve cells. Its function is to convert the images formed by the lens into electrical impulses. Sclera - Outermost coat of the eyeball.
Cornea - It is the clear, transparent, anterior portion of the external coat of the eyeball. The rays of light enter this layer. The Cornea accounts for two-thirds of the total optical power of the eye.

The tongue works on its own and has specific functions attached to it like tasting with the help of taste buds, gulping, and providing enzymes for digestion. In the human body, the gluteus maximus is the largest muscle and stapedius muscle is the smallest muscle.

After passing through the ear canal, the sound waves travel toward a flexible, oval membrane at the end of the ear canal called the eardrum, or tympanic membrane. It separates the outer ear from the middle ear.
The outer ear consists of the pinna (auricle), external auditory meatus (canal). The middle ear is comprised of some of the small bones in the human body including the malleus, incus, and stapes. The inner ear is comprised of the cochlea, semicircular canals and vestibule.

Olfactory receptors are found in the nose. It is a protein capable of binding odour molecules that plays a central role in the sense of smell (olfaction).
The auditory system is the sensory system for the sense of hearing. The visual sensory system enables you to be aware of color, light level, contrast, motion and other visual stimuli.

It is a sensory organ that picks up sound waves, allowing us to hear. It is also essential to our sense of balance: the organ of balance (the vestibular system) is found inside the inner ear.
It is made up of three semicircular canals and two otolith organs, known as the utricle and the saccule. The semicircular canals and the otolith organs are filled with fluid.
Each of the three semicircular canals is responsible for a specific direction of head movement.

It consists of three ossicles called the malleus, incus, and stapes. They are commonly referred to as Hammer, Anvil, and stirrup. The hammer is connected to the eardrum. When the hammer vibrates, it transmits the sound to the other two bones, i.e. to the anvil and stirrup. These sound waves are amplified up to 20 times of original waves.

Cone cells are of three colors in the eyes mainly blue, green, and red. The function of Iris is to control the diameter and size of the pupil. The eye gets its color by pigment present in Iris. Rods are used for low light vision. The optic disc is the location where ganglion cell axons exit the eye to form the optic nerve.

Anaesthetic - It temporarily blocks sensory signals from your nerves at the site of the procedure to the centers of your brain. Uses: They are used during tests and surgical operations to numb sensations in certain areas of the body or induce sleep. This prevents pain and discomfort and enables a wide range of medical procedures to be carried out. Examples: Desflurane, Isoflurane, Nitrous oxide, Sevoflurane, Xenon.

The primary function of the organ of the Corti is transduction of auditory signals. Sound waves enter the ear via the auditory canal and cause vibration of the tympanic membrane. The Organ of Corti includes three rows of outer hair cells and one row of inner hair cells. Vibrations caused by sound waves bend the stereocilia on these hair cells via an electromechanical force.