Practice BS Zoology Semester Exam questions with answers and explanations.
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Mechanosensory systems such as the lateral line detect environmental changes at a distance, improving survival in aquatic habitats.
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Adrenaline from the adrenal medulla prepares the body for emergency action by increasing heart rate, airway dilation, and energy mobilization.
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Action potentials involve voltage-gated ion channels that change sodium and potassium movement across the axon membrane. This produces a traveling electrical signal.
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Sensory receptors are specialized for particular stimulus types. Photoreceptors respond to light because their molecules and membranes are adapted for that energy form.
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All sensory receptors detect specific internal or external stimuli and begin signaling pathways that inform the nervous system.
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Glucocorticoids such as cortisol support prolonged stress responses by mobilizing energy and modifying immune activity. They act more slowly than adrenaline.
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At many neuromuscular junctions, acetylcholine transmits the signal from motor neuron to muscle. Blocking its receptors prevents normal contraction.
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Nociceptors detect potentially damaging stimuli and generate pain signals. They protect the body by prompting avoidance of injury.
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The neuron cell body contains the nucleus and organelles needed for protein synthesis and cell maintenance. It integrates many incoming signals.
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Negative feedback reduces the original change. When blood glucose falls, insulin secretion declines, preventing excessive lowering of glucose.
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Cnidarians have diffuse nerve nets rather than highly centralized brains. This arrangement coordinates simple movements and responses in radially symmetrical bodies.
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Echolocation uses sound production and hearing. Reflected sound waves are detected by auditory mechanoreceptors and interpreted by the nervous system.
