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Nervous System

📆 November 5, 2024

Total Questions: 39

1. Which of the following plays an important role in regulating the amount of light entering into the eye? [S.S.C. JE Electrical Exam 28.01.2020 (Shift-I)]

Correct Answer: (b) Pupil
Solution:The pupil is the opening in the center of the iris that allows light to enter the retina. Its size is controlled by the iris muscles. In bright light, the pupil constricts (gets smaller) to reduce the amount of light entering, and in dim light, it dilates (gets larger) to allow more light in.

Cornea: The transparent outer layer that covers the front of the eye and helps focus light, but doesn't regulate the amount of light.
Crystalline lens: Focuses light onto the retina, but doesn't regulate the amount of light entering.
Sclera: The white outer layer of the eyeball; provides structural support.

2. The transparent front part of the eye is called: [S.S.C. JE Mechanical Exam 27.01.2020 (Shift-I)]

Correct Answer: (d) Cornea
Solution: The cornea is the clear, outermost layer of the eye that covers the iris, pupil, and anterior chamber. It plays a crucial role in focusing light onto the retina.

Retina: The light-sensitive layer at the back of the eye.
Iris: The colored part of the eye that surrounds the pupil.
Pupil: The opening in the center of the iris.

3. Which of the following birds has a large number of rods and fewer cones on its retina? [S.S.C. JE Mechanical Exam 27.01.2020 (Shift-II)]

Correct Answer: (d) Owl
Solution:Rods are photoreceptor cells in the retina responsible for vision at low light levels (scotopic vision). They are more sensitive to light but do not perceive color.

Cones are photoreceptor cells responsible for color vision and high spatial acuity (detail) in brighter light (photopic vision).

Owls are nocturnal birds, meaning they are active at night. To see effectively in low light conditions, their retinas are highly adapted with a very large number of rods and relatively fewer cones, allowing them superior night vision. Birds like sparrows, eagles, and kites are diurnal (active during the day) and therefore have a higher proportion of cones for color vision and sharp daytime sight.

4. Which of the following is an example of unstriated muscles? [S.S.C. JE Mechanical Exam 22.03.2021 (Shift-I)]

Correct Answer: (a) Muscles of the iris in the eye
Solution: Unstriated muscles are also known as smooth muscles. They are involuntary, meaning their contractions are not under conscious control, and they lack the striped (striated) appearance characteristic of skeletal and cardiac muscles.

Muscles of the iris in the eye control pupil size (dilation and constriction), which is an involuntary action. These are smooth muscles.

Muscles of the arms: These are skeletal muscles, which are striated and voluntary.

 Cardiac muscles: Found only in the heart, these are also striated but involuntary

5. Which of the following minerals helps in maintaining a healthy retina, cell membrane, and protein structure of the eye? [S.S.C. JE Mechanical Exam 27.01.2020 (Shift-II)]

Correct Answer: (b) Zinc
Solution:Zinc is an essential trace mineral that plays a vital role in eye health. It is highly concentrated in the retina and is crucial for the proper function of enzymes involved in vision. It helps transport vitamin A from the liver to the retina to produce melanin (a protective pigment) and plays a role in maintaining the structure of cell membranes and proteins.

Iron: Important for red blood cell formation and oxygen transport.

Iodine: Essential for thyroid hormone production.

Sodium: Important for fluid balance and nerve function.

6. Which part of the brain plays an important role in motor control? [S.S.C. Online Graduate Level (T-1) 3.09.2016 (Shift-III)]

Correct Answer: (a) Cerebellum
Solution: The cerebellum (Latin for "little brain") is located at the back of the brain, underneath the cerebrum. It plays a crucial role in coordinating voluntary movements, balance, posture, and motor learning. It refines movements, making them smooth and precise.

 Cerebrum: The largest part of the brain, responsible for higher-level functions like thought, language, memory, and voluntary action.

Medulla (oblongata): Part of the brainstem, controls vital involuntary functions like breathing, heart rate, and blood pressure.

Pons: Part of the brainstem, relays signals from the forebrain to the cerebellum and deals primarily with sleep, respiration, swallowing, bladder control, hearing, equilibrium, taste, eye movement, facial expressions, facial sensation, and posture.

7. Which organ is responsible for movement and hand-eye coordination in the human body? [S.S.C. Online MTS (T-I) 16.08.2019 (Shift-II)]

Correct Answer: (b) Brain
Solution: The brain is the central processing unit of the human body. It integrates sensory information, coordinates all voluntary and involuntary actions, and controls complex processes like thought, memory, and emotions. Movement, including fine motor skills and complex coordinated actions like hand-eye coordination, is centrally controlled and orchestrated by various parts of the brain, especially the cerebellum and motor cortex of the cerebrum.

Liver: Involved in metabolism, detoxification, and digestion.
Kidney: Filters blood and produces urine.
Heart: Pumps blood throughout the body.

8. Which part of the brain maintains posture and balance of the human body? [S.S.C. Online MTS (T-I) 8.08.2019 (Shift-I)]

Correct Answer: (b) Cerebellum
Solution:The part of the brain responsible for maintaining posture and equilibrium of the body is the Cerebellum. This part of the brain appears to be a separate structure, distinct from the rest of the brain. It is located right below the cerebrum, which is made of two hemispheres. It is called a "little brain." The cerebellum is also responsible for receiving information from the sensory organs, the spinal cord, and other parts of the brain. It also regulates motor learning and movement.

9. Identify the part of the brain that controls the maintenance of posture, balance, and equilibrium. [S.S.C. Online Graduate Level (T-I) 13.06.2019 (Shift-II)]

Correct Answer: (d) Cerebellum
Solution:The part of the brain responsible for maintaining posture and equilibrium of the body is the Cerebellum. This part of the brain appears to be a separate structure, distinct from the rest of the brain. It is located right below the cerebrum, which is made of two hemispheres. It is called a "little brain." The cerebellum is also responsible for receiving information from the sensory organs, the spinal cord, and other parts of the brain. It also regulates motor learning and movement.

10. Which part of the brain is responsible for triggering actions like thinking, intelligence, memory, and ability to learn? [S.S.C. Online CHSL (T-I) 21.01.2017 (Shift-III)]

Correct Answer: (c) Cerebrum
Solution:The cerebrum is the largest and most superior part of the brain, divided into two hemispheres. It is responsible for all conscious thoughts, voluntary actions, perception, language, memory, learning, and intelligence. The cerebral cortex, the outer layer of the cerebrum, is where these higher cognitive functions occur.

Diencephalon: Involved in sensory relay and autonomic functions, but not the primary seat of complex thinking and memory.

Hypothalamus: A small but vital part of the diencephalon, involved in regulating basic drives like hunger, thirst, and body temperature, and links the nervous system to the endocrine system.

Control: Not a specific part of the brain; refers to a function.
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