Sensory Organs MCQ Quiz - Objective Question with Answer for Sensory Organs - Download Free PDF

The correct answer is middle ear.

Key Points

• The human ears help in sensory functions like hearing and maintenance of body balance.
• The human ears can be anatomically divided into three major sections called the outer ear, the middle ear, and the inner ear.
• The middle ear contains three ossicles namely malleus, incus, and stapes.
• The malleus, incus, and stapes attached to one another in a chain-like fashion.
• The middle ear is an air-filled chamber.
• The smallest bone called stapes (or stirrup) found in the human body is located in the middle ear.
• Stapes is the smallest bone in the human body.
• The stapes is attached to the oval window of the cochlea.
• The malleus is attached to the tympanic membrane.

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Additional Information

• The eustachian tube is the narrow tube that leads to the pharynx in the middle ear.
  • It helps in equalizing the pressures on either side of the eardrum.
• The outer ear consists of the pinna and external auditory canal.
• Helix is a prominent outer rim of the ear pinna.

Answer:
B) An eye disorder caused by prolonged Vitamin A deficiency

Key Points

• Caused by Vitamin A deficiency 
• Leads to dryness of eyes
• Cornea becomes opaque
• Can cause night blindness
• Common in malnourished children

Important Points

• Preventable with Vitamin A supplementation
• Promoted by WHO in deficiency-prone areas
• If untreated, leads to permanent blindness

Additional Information

• Vitamin A sources: carrots, spinach, liver, dairy
• Also affects immunity and growth
• Major public health concern in developing countries

The correct answer is Gustatory receptors.

Key Points

• Gustatory receptors are specialized sensory receptors responsible for detecting taste.
• These receptors are located on the taste buds found on the tongue, soft palate, and epiglottis.
• Taste buds contain gustatory cells that respond to different taste stimuli such as sweet, sour, salty, bitter, and umami.
• When gustatory cells are stimulated by tastants, they send signals to the brain via the gustatory pathway to interpret different tastes.
• The detection and differentiation of tastes play a crucial role in dietary choices, nutrition, and overall health.

Additional Information

• Olfactory receptors
  • These receptors are responsible for the detection of smell.
  • Located in the olfactory epithelium within the nasal cavity, they respond to odor molecules.
• Photoreceptors
  • These are specialized cells in the retina that respond to light.
  • Photoreceptors include rods and cones, which are essential for vision.
• Phonoreceptors
  • These receptors are involved in detecting sound.
  • They are primarily found in the cochlea of the inner ear and are crucial for hearing.

Key Points

• Nerve cells or neurons are the structural and functional units of the brain.
• Nerve cells are of two types sensory and motor nerve cells.
• Sensory nerve cells detect the signal from the environment.
• Sensory nerve cells called rods and cones are present in the retina.
• The retina is the innermost layer of the eye.
• Rods and cones help in vision.
• Rods cells are involved in night vision, and cone cells in daylight vision.
• It is due to these cells that we are to see the images, scenes or texts

 Additional InformationCochlea:

•  The cochlea is part of the inner ear.
• It is a coiled structure.
• It helps in hearing.

Skin:​​

• Skin is the largest organ and consists of the epidermis, hypodermis and dermis.
• It protects the body from pathogens.

Epidermis:

• It is the outermost layer.
• It provides coloration to the body.
• It depends on the inner layer dermis for nutrients.

Dermis or corium:

• It is the inner part of the skin.
• It is present in between the epidermis and subcutaneous tissue.
• It is rich in blood vessels.
• It supports the inner layer and controls the body temperature.

The correct answer is Gustatory.

Key Points

• The receptors responsible for detecting taste are called gustatory receptors, located on the tongue and other parts of the oral cavity.
• Gustatory receptors are housed within specialized structures known as taste buds, which are primarily found on the papillae of the tongue.
• These receptors can detect five basic taste sensations: sweet, sour, salty, bitter, and umami (savory).
• The activation of gustatory receptors is triggered by the interaction of specific chemical compounds in food with the receptor cells.
• These signals are then transmitted to the brain via cranial nerves such as the facial nerve (cranial nerve VII), glossopharyngeal nerve (cranial nerve IX), and vagus nerve (cranial nerve X).

Additional Information

• Olfactory Receptors: These are responsible for detecting smells and are located in the olfactory epithelium in the nasal cavity. They are unrelated to taste detection.
• Auditory Receptors: Found in the cochlea of the inner ear, these receptors detect sound vibrations and contribute to the sense of hearing.
• Taste Buds: Each taste bud contains 50–100 gustatory receptor cells. They are distributed across different types of papillae, such as fungiform, foliate, and circumvallate papillae.
• Umami Taste: Discovered relatively recently, umami is associated with the taste of amino acids such as glutamate, commonly found in protein-rich foods and flavor enhancers like monosodium glutamate (MSG).
• Neurotransmission in Taste: Once activated, gustatory receptors release neurotransmitters that generate action potentials in the associated cranial nerves, relaying the taste information to the brain's gustatory cortex for perception.

• Vibrations inside the ear are amplified by the three bones, namely the hammer, anvil and stirrup in the middle ear.
• Ear in the human body performs two functions, namely: Hearing and maintaining the balance of the body.
• An Ear consists of three major sections namely: Outer Ear, middle ear and Inner Ear.

The correct answer is Blindspot.

Key Points

• Blindspot: It is that part of the vertebrate eye, where the optic nerve connects to the retina.
  • It does not have receptors that respond to light.
  • It is composed of nerve fibres that do not have the ability to reconstruct on their own. 

Additional Information 

• Fovea: It is a tiny pit located in the retina that provides the clearest vision.
  • Here, the light falls directly on the cones because of which the cone cells give the sharpest image. 
• Iris: It regulates the size of the eye and controls the amount of light entering the eye.
  •  Pigments in the iris help in creating the colour of the eye.
• Optic chiasm: It is a region in the eye where photoreceptors are absent.

Concept:

• Receptors are the organs or cells which respond to light, heat, or external stimulus and transmit the signal to the sensory nerve.

Explanation:

• Olfactory receptors are located in our nose.
• The olfactory system allows the human body to detect and process smell.
• These are also known as smell receptors and are capable of binding odour molecules.
• They belong to the G-protein-coupled receptor family.
• Most of the olfactory receptors are found on the superior or external surface of the nasal cavity.

Additional Information

Gustatory receptors

• These are is present on the tongue are spread evenly across the taste buds.
• Their main function is to provide a sense of taste.

Somatosensory receptors:

• These receptors in human beings detect touch and temperature.

The correct answer is Pinna.

Important Points 

• Ear is the sense organ for hearing.
• Ear also maintains the balance of the human body.
• The three parts of the ear are the external ear, middle ear, and inner ear.
• The human external ear consists of the pinna and external auditory canal.
  • The pinna collects sound from the surroundings.
    • The pinna is also called auricle.
  • The external auditory canal leads inwards and extends up to the tympanic membrane.

Additional Information 

• The tympanic membrane separates the external ear from the middle ear.
  • The malleus is attached to the tympanic membrane.
• The part of the inner ear which helps for hearing is called the cochlea.
  • The stapes bone is attached to the oval window of the cochlea.
• The nerve impulses are transmitted via auditory nerves to the auditory cortex of the brain.

Image of Ear Diagram:

Iris.Key Points

• Iris part of eye controls size of a pupil.
• Iris is a dark muscular diaphragm that controls the size of the pupil.
  • The pupil is a small empty space surrounded by the iris.
  • The pupil regulates and controls the amount of light entering the eye. 
  • The iris contracts and relaxes to regulate the size of the pupil.
  • When it is dark, the pupil expands to allow more light to enter the eye.
  • Iris controls the pupil which in turn controls the amount of light entering the eye. 

Additional Information

The correct answer is Gustatory receptors

Explanation:

• Receptors are the organs or cells which respond to light, heat or external stimulus and transmit the signal to the sensory nerve.
• Gustatory receptors are the receptors for detecting taste.
• Sensory receptors - These are broad categories of receptors responsible for converting external stimuli from the environment into internal electrical impulses that can be interpreted by the nervous system. Sensory receptors can be classified based on the type of stimulus they detect, such as mechanoreceptors for touch, thermoreceptors for temperature, and photoreceptors for light. 
• Chemical receptors - This term usually refers to receptors that detect chemical substances. It can encompass a wider range of receptor types, including those involved in taste (gustatory receptors), smell (olfactory receptors), and even some internal bodily functions (such as chemoreceptors that monitor carbon dioxide levels in the blood). 
• Olfactory receptors - These are specific to the sense of smell. Olfactory receptors are located in the olfactory epithelium, part of the nasal cavity, and are responsible for detecting odorous compounds in the air.

The correct answer is Tongue.

Key Points

• The gustatory receptors which detect taste are present in the tongue.
• Gustatory receptors
  • It is present on the tongue and is spread evenly across the taste buds.
  • Their main function is to provide a sense of taste.
  • Gustatory receptors are found in the tongue.
  • The gustatory system is much easier than the olfactory system.
  • Four primary taste varieties are generally recognized as sweet, sour, salty, and bitter.
  • In different regions on the tongue are present different sensitivities to the four taste varieties.
  • The tip of the tongue is the most sensitive to sweetness and saltiness.

Additional Information

• Receptors are the organs or cells which respond to light, heat, or external stimulus and transmit the signal to the sensory nerve. 
• Olfactory receptors
  • It is present on the surface of the olfactory neurons.
  • Their main function is to sense smell.
  • These receptors equip sperm cells for finding the egg through a sense of smell.
• Sensory receptors occur in specialized organs such as the eyes, ears, nose, and mouth, as well as internal organs.

The correct answer is middle ear.

Key Points

• The human ears help in sensory functions like hearing and maintenance of body balance.
• The human ears can be anatomically divided into three major sections called the outer ear, the middle ear, and the inner ear.
• The middle ear contains three ossicles namely malleus, incus, and stapes.
• The malleus, incus, and stapes attached to one another in a chain-like fashion.
• The middle ear is an air-filled chamber.
• The smallest bone called stapes (or stirrup) found in the human body is located in the middle ear.
• Stapes is the smallest bone in the human body.
• The stapes is attached to the oval window of the cochlea.
• The malleus is attached to the tympanic membrane.

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Additional Information

• The eustachian tube is the narrow tube that leads to the pharynx in the middle ear.
  • It helps in equalizing the pressures on either side of the eardrum.
• The outer ear consists of the pinna and external auditory canal.
• Helix is a prominent outer rim of the ear pinna.

The correct answer is Pupil.Key Points

• The amount of light entering the eye is controlled by the pupil.
• The pupil is a small empty space surrounded by the iris.
• The iris contracts and relaxes to regulate the size of the pupil.
• When it is dark, the pupil expands to allows more light to enter the eye.
• Iris controls the pupil which inturn controls the amount of light entering the eye.The pupil is just an adjustable opening, the iris is a membrane.
• When it is bright, the pupil contracts to prevent more light from entering the eye.
• 

Concept:

• The brain is the central information processing organ of our body, and acts as the ‘command and control system’.
• It controls the voluntary movements, the balance of the body, the functioning of vital involuntary organs (e.g., lungs, heart, kidneys, etc.), thermoregulation, hunger and thirst, circadian (24-hour) rhythms of our body, activities of several endocrine glands and human behaviour.
• It is also the site for the processing of vision, hearing, speech, memory, intelligence, emotions, and thoughts.
• The brain can be divided into three major parts: (i) forebrain, (ii) midbrain, and (iii) hindbrain

1. The forebrain consists of the cerebrum, thalamus, and hypothalamus
2. The midbrain is located between the thalamus/hypothalamus of the forebrain and the pons of the hindbrain. A canal called the cerebral aqueduct passes through the midbrain. The dorsal portion of the midbrain consists mainly of four round swellings (lobes) called corpora quadrigemina
3. The hindbrain comprises pons, cerebellum, and medulla (also called the medulla oblongata)

Explanation:

• The cerebrum is a part of the forebrain.
• It has two parts called cerebral hemispheres.
• It forms the front, superior, and lateral sides of the brain.
• It is the largest part constituting 80% of the brain.
• The cerebrum in the human brain is the center of intelligence, memory, and emotions. It is the main thinking part of the brain.
• All our thoughts, sensations, actions, and movements are controlled by the cerebrum.
• It coordinates voluntary muscle movements and helps in maintaining posture and balance.
• Thus, if the memory of the person weakens it can be due to an injury of the cerebrum

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Additional Information

• The medulla contains centers that control respiration, cardiovascular reflexes, and gastric secretions.
• Cerebellum has a very convoluted surface in order to provide the additional space for many more neurons
• The hypothalamus lies at the base of the thalamus. The hypothalamus contains a number of centers that control body temperature, urge for eating and drink.
• It also contains several groups of neurosecretory cells, which secrete hormones called hypothalamic hormones.