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14.1 What is a hormone?
- A biological substance that acts on a specific target.
14.2 How do the ultrastructural components of endocrine cells indicate their function?
- The abundance of mitochondria, endoplasmic reticulum, Golgi bodies, secretory vesicles and prominent nuclei.
14.3 What are the two components of the pituitary gland?
- Glandular epithelial tissue (anterior lobe) and neural secretory tissue (posterior lobe).
14. 4 Which specialised type of blood vessel features in endocrine glands?
- Fenestrated capillaries, which are highly permeable to facilitate significant molecular exchange between endocrine glands and the blood.
14. 5 What is the primary function of the pineal gland?
- To regulate daily body rhythm.
14.6 What is the structural and functional unit of the thyroid gland?
- Thyroid follicle.
14.7 What element is essential for thyroid hormone synthesis?
- Iodine.
14.8 Which of the two cell types of the parathyroid parenchyma have a secretory function?
- Principal or chief cells, which secrete parathyroid hormone.
14.9 What are the zones into which the cells of the adrenal cortex are arranged?
- Zona glomerulosa, zone fasciculata, zona reticularis.
14.10 How do the cells of the adrenal medulla differ from the cells of the cortex?
- Cortical cells are epithelial in origin, the cells of the medulla have the same origin as the post-ganglionic cells of the nervous system. Medullary cells are neurons that have been modified to secrete.
14.11 By what name is the functional endocrine unit of the pancreas known?
- Islets of Langerhans.
14. 12 Which secretory product of the cells of the islets of Langerhans is unique to the pancreas?
- Insulin.
14.13 What feature of open enteroendocrine cells enables them to test the contents of the lumen?
- They have a thin cytoplasmic extension with microvilli which reach into the lumen, allowing the cell to function as a chemoreceptor.
14.14 Where are Kulchitsky cells found?
- These are the enteroendocrine cells of the respiratory epithelium.