. Advanced biology. Biology; Physiology; Reproduction. 196 DUCTLESS GLANDS The parathyroid. There are four small structures attached to the thyroid glands, and weighing in all about two grains. They are the parathyroids (para means "near"). These, also, produce an internal secretion which is related to the calcium metabolism. Their removal, or atrophy, gives rise to tetany, a sudden convul- sive contraction of the muscles, which may result in death. The injection of small doses of parathyroid extract usually results in temporary relief. The effects of too great activity of the parath
. Advanced biology. Biology; Physiology; Reproduction. 196 DUCTLESS GLANDS The parathyroid. There are four small structures attached to the thyroid glands, and weighing in all about two grains. They are the parathyroids (para means "near"). These, also, produce an internal secretion which is related to the calcium metabolism. Their removal, or atrophy, gives rise to tetany, a sudden convul- sive contraction of the muscles, which may result in death. The injection of small doses of parathyroid extract usually results in temporary relief. The effects of too great activity of the parathyroids have not been fully ascertained, al- though it has been shown by Collip that the injection of parathyroid extract into the blood of an animal will increase the calcium con- tent of the blood while the removal of a part of the parathyroid tissue will give rise to a calcium deficiencv. Pituitary gland. The pituitar}^ gland weighs about one sixteenth of an ounce and is located at the base of the skull. Galen and Vesalius knew that there w^as a pituitary gland. They thought it had some- thing to do with the secretion of the nose. (Pituitary is from the Latin word jntuita, meaning phlegm.) Modern experimentation has proved that there is no such connection or relationship. There seems to be sufficient evidence to justify the acceptance of. Juunial of Heredity Giantism and dwarfism are probably due to defective pituitary Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Wheat, Frank Merrill; Fitzpatrick, Elizabeth T. New York ; Boston [etc. ] : American Book Company
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