Browse exam-wise, subject-wise, and country-wise MCQs with explanations.
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Sensory organs detect stimuli, but the nervous system transmits and processes those signals to produce perception or response.
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Insulin promotes glucose uptake and storage, reducing blood glucose after meals. It is secreted by pancreatic beta cells and acts through target-cell receptors.
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Some crustaceans use neuroendocrine hormones to move pigments within chromatophores, changing body coloration for camouflage or signaling.
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Sensory cells generally require a minimum stimulus intensity before producing a receptor potential strong enough to signal the nervous system.
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Dendrites increase the receptive surface of a neuron. Multiple dendrites allow integration of inputs from several neurons or receptors.
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Glucagon is secreted by pancreatic alpha cells and stimulates glycogen breakdown and glucose release, helping maintain blood glucose during fasting.
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Invertebrates often use neurosecretory cells and endocrine-like messengers to regulate reproduction, growth, and behavior, even without vertebrate-type glands.
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Hearing depends on mechanical vibrations that stimulate hair cells or related mechanoreceptors. These receptors convert sound waves into neural signals.
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Sensory adaptation is reduced responsiveness during continuous stimulation. It allows animals to remain sensitive to new or changing stimuli.
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Nodes of Ranvier are gaps in myelin where ion exchange occurs. Saltatory conduction between nodes increases impulse speed.
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Endocrine glands release hormones into blood or body fluids. These chemical messengers reach target cells with specific receptors.
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Nematodes use signaling pathways to regulate development, molting, reproduction, and stress responses. Chemical communication is not limited to vertebrates.
