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The Endocrine System - Coggle Diagram
The Endocrine System
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The endocrine system:
Is slow-acting
Is based on chemicals (hormones)
Produces long-lasting, widespread effects.
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A hormone is:
A protein or steroid
Produced by endocrine glands
Carried in the blood to other parts, where it has a special effect.
The pituitary gland:
Is located in the middle of the head, just below the brain Makes growth hormone, which controls body growth.
The hypothalamus:
Is located at the base of the brain
Makes anti-diuretic hormone, which controls osmoregulation.
The pineal gland:
Is located in the brain
Makes melatonin, which controls body rhythms.
The thyroid gland:
Is located on the trachea in the neck
Makes thyroxine, which controls metabolism.
Deficiency of thyroxine:
Causes cretinism in young children (mental and physical retardation) Causes goitre, swelling and reduced rates of metabolism in adults
Is controlled by taking thyroxine or iodine.
Excess thyroxine:
Causes increased rates of metabolism, weight loss, large appetite, nervousness (Graves' disease)
Is controlled by removing part of the thyroid or killing it with radioactive iodine.
The parathyroids (4):
Are located in the thyroid
Make parathormone, which controls the release of calcium from bones.
The thymus gland:
Is located in the chest
Makes thymosin, which matures white blood cells.
The adrenal glands (2):
Are located on top of the kidneys Make adrenaline, which causes us to respond to stress.
The pancreas (islets of Langerhans):
Is located in the abdomen just below the stomach
Make insulin, which reduces blood sugar levels.
The pancreas is:
An exocrine gland (releases enzymes into ducts)
An endocrine gland (releases insulin into bloodstream).
Inability of the islets of Langerhans to make sufficient insulin is called diabetes. Diabetes can be controlled by regular iniections of insulin (and by controlling the intake of carbohydrates).
Anabolic steroids are sometimes used in sport to enhance muscle growth.
Abuse of anabolic steroids can result in liver and adrenal disorders and a number of sexual disorders.
Hormone levels are often controlled by negative feedback mechanisms. Normal concentrations of thyroxine inhibit TSH production.
This means no more thyroxine is made.
Reduced concentrations of thyroxine allow TSH to be made.
New thyroxine is then produced until its concentration returns to normal.
Goitre is a swelling of the thyroid gland in the neck. It is normally caused by:
A lack of iodine, which results in an underproduction of thyroxine.
In this case the thyroid swells due to storing large amounts of TSH.