50 pts!!compare the two theories regarding the extinction of dinosaurs. they have all but one point in common. that is
1 answer:
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Explanation:
When calcium levels in the blood become too low, parathyroid hormone leads to an increase in calcium by degrading bone. In response, calcitonin from the thyroid is released when the levels are high again, to decrease calcium levels in the blood.
Further Explanation:
During homeostasis the body maintains a constant internal balance in pH, temperature, blood pressure etc. Cells in a multicellular organism become specialized for particular tasks and communicate with one another in order to maintain homeostasis. Within the human body these are known as hormone cascades, where several complex steps occur- the tissues signal to one another with the use of hormones released by the endocrine system. The regulation (increase and decrease) of these secretions is achieved by negative feedback loops, where the release of certain substances during a cascade in turn halts the secretion of hormones at earlier stages.
In the body calcium homeostasis, which is generally defined as the maintenance of specific internal conditions, is mediated by the endocrine system through hormonal control. This regulates the calcium flux between the bloodstream and the bone; and the hormones responsible, change the ratio of osteoclast activity to osteoblast activity -osteoblasts build bone while osteoclasts breakdown or degrade bone.
Hormones responsible include calcitonin (from special parafollicular cells in the thyroid gland), calcitriol (activated vitamin D) and the parathyroid hormone (from the parathyroid glands). These affect the absorption of calcium from the gut, or kidney reabsorption; both parathyroid hormone and calcitriol act by causing the increase of calcium ions into the bloodstream as the bone is degraded by osteoclasts.
Learn more about tissue types at brainly.com/question/8487952
Learn more about homeostasis at brainly.com/question/1601808
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