Anatomy and physiology of the thyroid and parathyroid glands Flashcards
Where is the thyroid gland located?
Located in the neck in front of the larynx and trachea
What hormones does the thyroid gland produce?
Triiodothyronine (T3) and thyroxine (T4). Both hormones need iodine in order to be formed properly
What are thyroid hormones involved in?
Involved in skeletal growth and nervous system regulation, increase metabolic rate and production of heat and may regulate metabolism of carbs, proteins and fats. Also secretes calcitonin which lowers calcium levels in blood.
Negative feedback mechanism of thyroid hormones
When levels of thyroid hormone in blood are low, triggers hypothalamus to secrete thyroid releasing hormone which triggers pituitary gland to secrete thyroid stimulating hormone, which triggers thyroid gland to secrete thyroid hormones T3 and T4. after increased levels, causes inhibition of hypothalamus which reduces stimulation of thyroid gland so doesn’t produce anymore thyroid hormones. These raised blood levels of thyroid hormone than taken up and metabolised by cells, reducing levels in the blood.
Where are the parathyroid glands located?
located in the back surface of the thyroid gland
What is the parathyroid gland involved in?
Produces parathyroid hormone which is involved in control of calcium levels in the blood
What is the link between thyroid gland and parathyroid gland?
thyroid gland released calcitonin which stimulates osteoblasts in the bones. Osteoblasts absorb calcium from blood in bones, reducing calcium levels in blood. If calcium levels fall below threshold, parathyroid glands release parathyroid hormone. Triggers osetoclasts to digest bone and release calcium into bloodstream.
