Athabasca University, Athabasca BIO 235 Assignment 1 70.5 Georgette Gibas – Bio 235

Each question is worth 10 marks. 1. Maintenance of calcium ion homeostasis is critical to neurological, cardiac and skeletal muscle function. Consider the roles of two hormones involved in the regulation of the concentration of calcium ions in the blood. Parathyroid hormone increases the concentration of calcium ions in the blood, while calcitonin decreases the concentration. Based on this information predict the body’s response to restore calcium balance if a person swallowed 100 antacid tablets made of a calcium compound in 10 minutes. Include in your answer the definition of homeostasis, the type of feedback loop involved and all of the components of a feedback loop. 1. Homeostasis – the balance or equilibrium in the body’s internal environment produced by the body’s regulatory processes.FYI homeostasis: as maintenance of body conditions within acceptable limits as ‘equilibrium’ for a cell is death 2. the body might also send signals to block the action of parathyroid hormone because the calcium levels are already too high. 3. there must be a way for the body to get rid of the extra calcium in the blood. 4. two possibilities are putting more calcium into the bones or excreted more calcium out of the body through the urine or feces..  the cells that put calcium into the bone or release it into the urine or feces would be the effectors in the case described here