Nervous System — Set 4
Biology · तंत्रिका तंत्र · Questions 31–40 of 50
Which part of the brain is located between the thalamus and the pons?
Correct Answer: D. Midbrain
The midbrain is a small part of the brainstem that serves important functions in motor movement. It is particularly involved in movements of the eye and auditory processing. It acts as a bridge between the forebrain and hindbrain.
Which ions are primarily responsible for the resting membrane potential of a neuron?
Correct Answer: D. Sodium and Potassium
Sodium and Potassium ions create an electrical gradient across the cell membrane. The sodium-potassium pump maintains the high concentration of sodium outside and potassium inside. This potential energy is used to fire nerve impulses.
The specialized receptors for smell are known as?
Correct Answer: D. Olfactory receptors
Olfactory receptors are located in the nasal cavity and detect chemical molecules in the air. These signals are sent directly to the olfactory bulb in the brain. Smell is the only sense that bypasses the thalamus.
Which part of the brain is responsible for problem-solving and personality?
Correct Answer: B. Frontal lobe
The frontal lobe is the most highly developed part of the human brain. It manages executive functions, emotions, and complex motor tasks. Damage here can drastically change an individual's personality.
The white matter of the brain appears white because of the presence of?
Correct Answer: B. Myelinated axons
White matter consists of axons covered by the fatty myelin sheath. Myelin acts as an insulator and gives the tissue its characteristic white appearance. It functions primarily as the 'wiring' that connects different gray matter areas.
Which area of the brain is specifically involved in the production of speech?
Correct Answer: A. Broca's area
Broca's area is located in the frontal lobe of the dominant hemisphere. It coordinates the muscular movements required for speaking. Damage to this area results in difficulty forming words correctly.
The knee-jerk reflex is a type of?
Correct Answer: C. Spinal reflex
A spinal reflex is an automatic response that is processed entirely within the spinal cord. It allows for a very fast reaction to a stimulus without waiting for the brain. Doctors use the knee-jerk test to check the health of the nervous system.
Which cells produce the myelin sheath in the Central Nervous System?
Correct Answer: D. Oligodendrocytes
Oligodendrocytes provide the insulating layer for neurons in the brain and spinal cord. One oligodendrocyte can insulate several different axons at once. In the peripheral system, this job is done by Schwann cells.
The involuntary dilation of pupils in low light is controlled by which system?
Correct Answer: A. Autonomic system
Pupillary light reflex is an autonomic function that regulates the amount of light entering the eye. It occurs without conscious effort to protect the retina and optimize vision. Both sympathetic and parasympathetic nerves are involved in this process.
Which part of the brain helps in regulating the sleep-wake cycle?
Correct Answer: B. Pineal gland
The pineal gland secretes melatonin, which regulates circadian rhythms. It responds to light and dark signals received via the eyes. This tiny gland is often called the 'third eye' because of its location.