Browse exam-wise, subject-wise, and country-wise MCQs with explanations.
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Lacteals are lymphatic vessels in intestinal villi that absorb dietary fats and transport them as chyle into lymphatic circulation.
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Negative feedback counteracts deviations from a normal range. It is a central principle in homeostasis, including glucose, calcium, temperature, and hormone regulation.
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Some hormones are derived from amino acids. Thyroxine derives from tyrosine with iodine, and adrenaline is a catecholamine.
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Cells can reduce receptor number or signaling after prolonged stimulation. This decreases sensitivity and helps prevent overstimulation.
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The lymphatic system returns excess tissue fluid to the bloodstream and also participates in immune defense through lymph nodes and lymphocytes.
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Endocrine disruptors can interfere with normal signaling by mimicking, blocking, or altering hormone pathways. This can affect development, reproduction, and metabolism.
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Thyroid hormones increase metabolic activity in many tissues. This can help regulate energy use, growth, and heat production.
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Paracrine signals act locally on nearby cells, unlike classical endocrine hormones that travel through circulation to distant targets.
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Blocked lymph drainage prevents interstitial fluid from returning to blood, causing edema or swelling in tissues.
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Chemical regulation is widespread across animal groups. Invertebrates use endocrine and neuroendocrine signals for molting, growth, reproduction, and metabolism.
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Negative feedback normally limits secretion when hormone levels are adequate. Failure of feedback can produce excessive hormone action.
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Autocrine signaling occurs when a cell releases a messenger that binds receptors on the same cell. It is common in growth and immune regulation.
