Other glands Flashcards
What are the parathyroid glands and what do they do?
There are four parathyroid glands which are embedded, two each side, in the posterior lobes of the thyroid gland.
Parathyroid hormone (sometimes called parathormone) helps regulate blood calcium levels mainly to increase calcium levels when it is low.
Parathormone and Calcitonin from the thyroid gland complement each other to maintain blood calcium levels in a normal range and this is essential for muscle contraction, blood clotting and the transmission of nerve impulses.
What do the kidneys do?
The kidneys produce erythropoietin (EPO). This hormone regulates red blood cell production by stimulating bone marrow cells.
Red blood cells are essential for transporting oxygen to the tissues and removing carbon dioxide. It has been shown that part of the adaptation when training at high altitude is an increased release of EPO, which in turn stimulates more red blood cell production to help the body work efficiently in the thinner air.
Erythropoietin is therefore important in the body’s adaptation to training at altitude.
What does the pancreas do?
The pancreas is located behind and slightly below the stomach. The two major hormones that it secretes are insulin and glucagon.
The principal action of glucagon is to increase blood glucose level when it falls below normal. The role of insulin, on the other hand, is to lower blood glucose level when it is too high. The level of blood glucose controls the secretion of glucagon and insulin via negative feedback.
In effect, glucagon stimulates the release of insulin because it increases blood glucose levels, whereas insulin inhibits the release of glucagon in order to lower blood glucose levels.
Blood levels of glucagon gradually rise while exercising. This is to meet the increased metabolic demands of the working muscles.
What do the ovaries do?
The ovaries secrete oestrogens and progesterone.
These female sex hormones regulate the menstrual cycle, maintain pregnancy, and prepare the mammary glands for lactation.
They also help to establish and maintain feminine secondary sex characteristics such as breasts and wide hips.
What do the testes do?
The testes secrete testosterone.
Testosterone performs a variety of important functions, for example, the formation and development of sperm, normal growth and development, skeletal muscle growth, muscle protein retention and resistance training induced muscle hypertrophy.
