Practice BS Zoology Semester Exam questions with answers and explanations.
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Steroid hormone-receptor complexes often bind DNA or influence transcription. This can lead to slower but longer-lasting physiological changes.
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Exocrine glands release secretions through ducts to surfaces or cavities. Endocrine glands release hormones directly into internal fluids without ducts.
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Amphibians have two atria and one ventricle, allowing partial separation of blood streams. It is an intermediate condition between fish and birds/mammals.
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The hypothalamus links nervous and endocrine systems. It releases factors that regulate the pituitary and receives feedback from circulating hormones.
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Exocrine glands use ducts to deliver secretions to body surfaces or cavities. Endocrine glands are ductless and release hormones internally.
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High thyroid hormone feeds back to reduce hypothalamic and pituitary stimulation, including TSH. This prevents excessive thyroid activity.
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Four-chambered hearts fully separate oxygenated and deoxygenated blood. This supports efficient oxygen delivery and high metabolism.
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Thyroid-stimulating hormone from the anterior pituitary stimulates thyroid hormone production. It is part of the hypothalamic-pituitary-thyroid axis.
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Low insulin reduces glucose uptake and storage, causing blood glucose to rise. Long-term imbalance affects metabolism and tissues.
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Steroid and thyroid hormone receptors often function inside cells and regulate gene expression. Many peptide hormone receptors are on the membrane.
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Most reptiles have two atria and a partially divided ventricle. Crocodilians are exceptions with four-chambered hearts.
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Oxytocin stimulates uterine contractions and milk ejection in mammals. It is released from the posterior pituitary.
