Sense Organs

(a) Give the collective term for the structure located in the internal ear.
The collective term for the structure located in the internal ear is the labyrinth. It consists of the cochlea, vestibule, and semicircular canals, all of which contribute to hearing and balance.
(b) Name the sensory organ in the Cochlea which was damaged for Rajat Singh.
The sensory organ in the cochlea that was damaged for Rajat Singh is the organ of Corti. It contains hair cells that are responsible for converting sound vibrations into electrical signals for the brain to interpret as sound.
(c) What kind of pollution do the workers face in the stone quarry?
The workers in the stone quarry are primarily exposed to noise pollution. The high decibel levels from the drilling and blasting operations can lead to hearing damage and other health issues related to prolonged exposure to loud noises.

(a) Name the eye disorder she is suffering from.
The eye disorder Tara's grandmother is suffering from is known as Presbyopia. This is an age-related disorder where the ability to focus on nearby objects decreases due to the hardening of the lens and weakening of the eye's ciliary muscles.
(b) How can the above defect be corrected?
Presbyopia can be corrected using bifocal or reading glasses, or in some cases, contact lenses. These help to focus on nearby objects by compensating for the loss of accommodation.
(c) Where is the image formed in the above disorder?
In presbyopia, the image is formed behind the retina due to the inability of the eye lens to change its shape adequately to focus on close objects.

The loss of the ability to constrict pupils in bright light suggests a disruption in the autonomic regulation of the eye. The autonomic nervous system, which controls pupil constriction and dilation, is governed by structures in the brainstem, particularly the midbrain and the medulla oblongata.

- (A) Suspensory ligaments: These are ligaments that hold the eye lens in place. They don't have a direct role in controlling pupil constriction, so this is not the correct answer.
- (B) Medulla oblongata: The medulla oblongata, part of the brainstem, is responsible for regulating autonomic functions like heart rate, breathing, and pupil constriction. Damage to the medulla could impair the pupillary reflex.
- (C) Eye lens: The eye lens is responsible for focusing light onto the retina but does not control pupil constriction. This is not the correct answer.
- (D) Eye lid: The eyelid protects the eye and plays a role in blinking but does not regulate pupil constriction. This is not the correct answer.
The inability to constrict the pupils in bright light is indicative of damage to the medulla oblongata, which controls the autonomic functions of the pupils. Therefore, the correct answer is (B).

Final Answer: (B) Medulla oblongata.

The sympathetic nervous system is activated during stressful or exciting situations, such as when someone wakes up late and experiences urgency. This leads to the "fight or flight" response, which prepares the body for quick action.

- Constriction of Coronary arteries (A): This is not a typical response of the sympathetic nervous system. It generally causes dilation of blood vessels to increase blood flow to muscles.

- Muscle relaxation (B): This is not a typical sympathetic response. Sympathetic stimulation generally causes muscle contraction and alertness, not relaxation.

- Decrease in Respiration rate (C): Sympathetic activation leads to an increase in respiration rate, not a decrease, to supply more oxygen to the muscles.

- Bronchodilation (D): This is the correct answer. Sympathetic activation causes bronchodilation, allowing more air to reach the lungs to increase oxygen supply during stressful situations.
Based on the "fight or flight" response, the sympathetic nervous system causes bronchodilation to increase airflow and prepare the body for quick physical action.

Final Answer: (D) Bronchodilation.

(a) Name the structure.
The structure shown in the diagram is the Cross-section of the Spinal Cord. The spinal cord is a crucial part of the central nervous system that transmits neural signals between the brain and the rest of the body.

(b) Label Gray matter and White matter.
In the diagram, the Gray matter is located in the central region of the spinal cord, resembling a butterfly shape. It consists of neuron cell bodies, dendrites, and unmyelinated axons.
The White matter surrounds the gray matter and contains myelinated axons that transmit signals along the spinal cord.