Answers to Part 4:
Q: Draw and describe the negative feedback loop between TSH-RH, TSH, and thyroxine
A: The hypothalamus detects low levels of thyroxine in the body à the hypothalamus secretes TSH-releasing hormone to the anterior pituitary gland à the anterior pituitary gland is stimulated to release TSH to the thyroid à the thyroid is stimulated to release thyroxine into the body à increases levels of thyroxine in the body à increased levels of thyroxine in the body cause the hypothalamus to release TSH inhibiting hormone, which stops the release of TSH by the anterior pituitary gland which stops the release of thyroxine by the thyroid.
Q: What could be the cause of too little thyroxine production in Janet’s body?
A: too little iodine could be the cause of low thyroxine levels or her thyroid could be damaged, causing it to not function properly
Q: In Janet’s case would the hypothyroidism be referred to as cretinism or myxedema?
A: Myxedema because cretinism is hypothyroidism in a child where as myxedema is hypothyroidism as an adult
Q. What is the common name for the enlargement of the thyroid gland? What is it caused by?
A. Simple Goiter, it can be caused by a lack of iodine in the diet, which results in thyroid gland being unable to produce thyroxin. If thyroxin is not being produced there will be nothing to stop the secretion of TSH resulting in the constant stimulation of the thyroid gland.