Q30. Which structure in the eye provides its oxygen and nutrients?
a) Cornea
b) Lens
c) Retina
d) Choroid
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Correct Answer: d) Choroid
Explanation: The choroid, a layer of the eye between the retina and the sclera, provides oxygen and nutrients to the eye, particularly the outer part of the retina. It contains a network of blood vessels that supply essential nutrients and oxygen to the eye tissues. The choroid also helps to cool the eye and absorb excess light, preventing light reflection within the eye.
Q31. What is the primary function of the frontal lobe in the human brain?
a) Vision processing
b) Hearing and language comprehension
c) Movement control and decision making
d) Balance and coordination
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Correct Answer: c) Movement control and decision making
Explanation: The frontal lobe of the human brain is primarily responsible for movement control and decision making. It’s involved in executive functions such as planning, organizing, problem-solving, attention, and behavior regulation. The motor cortex, located in the frontal lobe, controls voluntary movements.
Q32. Which hormone is critical for the regulation of the body’s water balance?
a) Aldosterone
b) Vasopressin (antidiuretic hormone, ADH)
c) Cortisol
d) Insulin
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Correct Answer: b) Vasopressin (antidiuretic hormone, ADH)
Explanation: Vasopressin, also known as antidiuretic hormone (ADH), is critical for regulating the body’s water balance. It’s produced in the hypothalamus and stored and released by the pituitary gland. ADH acts on the kidneys to reduce the amount of water excreted, thus controlling water retention and influencing hydration status.
Q33. What are the chemicals that act as messengers in the endocrine system called?
a) Enzymes
b) Hormones
c) Antibodies
d) Neurotransmitters
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Correct Answer: b) Hormones
Explanation: Hormones are the chemicals that act as messengers in the endocrine system. They are secreted directly into the bloodstream by endocrine glands and are transported to various organs and tissues, where they regulate a wide range of biological processes including growth, metabolism, and reproduction.
Q34. Which part of the human brain is involved in the regulation of hunger and satiety?
a) Amygdala
b) Cerebellum
c) Hypothalamus
d) Hippocampus
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Correct Answer: c) Hypothalamus
Explanation: The hypothalamus plays a crucial role in the regulation of hunger and satiety. It contains several nuclei and networks that detect and respond to levels of nutrients and hormones related to energy balance. The hypothalamus integrates signals from the body and influences eating behavior, thereby regulating hunger and feelings of fullness.
Q35. What is the role of dopamine in the human body?
a) Regulating blood pressure
b) Controlling the sleep cycle
c) Acting as a neurotransmitter influencing mood, movement, and reward
d) Facilitating muscle contractions
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Correct Answer: c) Acting as a neurotransmitter influencing mood, movement, and reward
Explanation: Dopamine is a neurotransmitter that plays several important roles in the human brain and body. It is particularly known for its influence on mood, movement, and the brain’s reward and pleasure centers. Abnormalities in dopamine levels and receptors are linked to disorders such as Parkinson’s disease, schizophrenia, and depression.
Q36. What structure connects the left and right hemispheres of the brain?
a) Brainstem
b) Cerebellum
c) Corpus callosum
d) Thalamus
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Correct Answer: c) Corpus callosum
Explanation: The corpus callosum is a broad band of nerve fibers that connects the left and right hemispheres of the brain. It enables communication between the two hemispheres, allowing them to function in a coordinated and integrated manner. This structure plays a crucial role in integrating motor, sensory, and cognitive performances.
Q37. Which part of the human nervous system controls the “fight or flight” response?
a) Central nervous system
b) Somatic nervous system
c) Sympathetic nervous system
d) Parasympathetic nervous system
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Correct Answer: c) Sympathetic nervous system
Explanation: The sympathetic nervous system, a part of the autonomic nervous system, controls the “fight or flight” response. It prepares the body to respond to perceived threats or emergencies by increasing heart rate, redirecting blood flow to essential organs and muscles, and releasing stored energy. These physiological changes enable quick reactions in stressful situations.
Q38. What is the primary function of the cones in the human retina?
a) Night vision
b) Peripheral vision
c) Color vision
d) Motion detection
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Correct Answer: c) Color vision
Explanation: The primary function of the cones in the human retina is color vision. Cones are photoreceptor cells sensitive to different wavelengths of light, which enables the perception of color. They function best in bright light and provide sharpness and detail to images.
Q39. Which gland produces melatonin, the hormone that regulates sleep-wake cycles?
a) Pineal gland
b) Pituitary gland
c) Thyroid gland
d) Adrenal gland
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Correct Answer: a) Pineal gland
Explanation: The pineal gland produces melatonin, a hormone that plays a role in regulating sleep-wake cycles, commonly known as the circadian rhythm. Melatonin production is influenced by light exposure; it is typically increased in the dark and decreased in light, thus helping regulate the timing of sleep.
Q40. What is the main role of the limbic system in the human brain?
a) Controlling voluntary muscle movements
b) Regulating balance and posture
c) Processing emotions and memories
d) Managing visual and auditory functions
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Correct Answer: c) Processing emotions and memories
Explanation: The limbic system, a complex system of nerves and networks in the brain, is primarily involved in processing emotions and memories. It includes structures such as the amygdala, hippocampus, and parts of the thalamus and hypothalamus. The limbic system plays a key role in emotional responses, formation of memories, and various aspects of motivation and pleasure.