The other hormones produced by the anterior pituitary regulate the production of hormones by other endocrine tissues Table The posterior pituitary is significantly different in structure from the anterior pituitary. It is a part of the brain, extending down from the hypothalamus, and contains mostly nerve fibers that extend from the hypothalamus to the posterior pituitary. The thyroid gland is located in the neck, just below the larynx and in front of the trachea Figure It is a butterfly-shaped gland with two lobes that are connected.
The thyroid follicle cells synthesize the hormone thyroxine, which is also known as T 4 because it contains four atoms of iodine, and triiodothyronine, also known as T 3 because it contains three atoms of iodine.
T 3 and T 4 are released by the thyroid in response to thyroid-stimulating hormone produced by the anterior pituitary, and both T3 and T4 have the effect of stimulating metabolic activity in the body and increasing energy use.
A third hormone, calcitonin, is also produced by the thyroid. Calcitonin is released in response to rising calcium ion concentrations in the blood and has the effect of reducing those levels.
Most people have four parathyroid glands; however, the number can vary from two to six. These glands are located on the posterior surface of the thyroid gland Figure The parathyroid glands produce parathyroid hormone.
Parathyroid hormone increases blood calcium concentrations when calcium ion levels fall below normal. The adrenal glands are located on top of each kidney Figure The adrenal glands consist of an outer adrenal cortex and an inner adrenal medulla. These regions secrete different hormones.
The adrenal cortex produces mineralocorticoids, glucocorticoids, and androgens. The main mineralocorticoid is aldosterone, which regulates the concentration of ions in urine, sweat, and saliva.
Aldosterone release from the adrenal cortex is stimulated by a decrease in blood concentrations of sodium ions, blood volume, or blood pressure, or by an increase in blood potassium levels. The glucocorticoids maintain proper blood-glucose levels between meals. They also control a response to stress by increasing glucose synthesis from fats and proteins and interact with epinephrine to cause vasoconstriction. Androgens are sex hormones that are produced in small amounts by the adrenal cortex.
They do not normally affect sexual characteristics and may supplement sex hormones released from the gonads. The adrenal medulla contains two types of secretory cells: one that produces epinephrine adrenaline and another that produces norepinephrine noradrenaline.
Epinephrine and norepinephrine cause immediate, short-term changes in response to stressors, inducing the so-called fight-or-flight response. The responses include increased heart rate, breathing rate, cardiac muscle contractions, and blood-glucose levels. They also accelerate the breakdown of glucose in skeletal muscles and stored fats in adipose tissue, and redirect blood flow toward skeletal muscles and away from skin and viscera. The release of epinephrine and norepinephrine is stimulated by neural impulses from the sympathetic nervous system that originate from the hypothalamus.
The pancreas is an elongate organ located between the stomach and the proximal portion of the small intestine Figure It contains both exocrine cells that excrete digestive enzymes and endocrine cells that release hormones. The endocrine cells of the pancreas form clusters called pancreatic islets or the islets of Langerhans.
Among the cell types in each pancreatic islet are the alpha cells, which produce the hormone glucagon, and the beta cells, which produce the hormone insulin. These hormones regulate blood-glucose levels. Alpha cells release glucagon as blood-glucose levels decline. This hormone is involved in the response to illness and also helps to regulate body metabolism. Cortisol stimulates glucose production helping the body to free up the necessary ingredients from storage fat and muscle to make glucose.
Cortisol also has significant anti-inflammatory effects. Adrenal androgens : male sex hormones mainly dehydroepiandrosterone DHEA and testosterone. The adrenal medulla produces catecholamines: Catecholamines include adrenaline , noradrenaline and small amounts of dopamine — these hormones are responsible for all the physiological characteristics of the stress response, the so called 'fight or flight' response. What could go wrong with my adrenal glands?
Last reviewed: Jan Prev. Related Glands. Pituitary gland Kidneys Thyroid gland View all Glands. Related Endocrine Conditions. Cushing's disease Addison's disease Hyperthyroidism Hypothyroidism Diabetes mellitus Obesity Osteoporosis Multiple endocrine neoplasia type 1 Phaeochromocytoma Congenital adrenal hyperplasia Primary hyperaldosteronism Eating disorders Multiple endocrine neoplasia type 2A Multiple endocrine neoplasia type 2B Cushing's syndrome Female infertility View all Endocrine conditions.
Related Hormones. Related Glossary Supplements. Topical issues What is HRT? Find out more Thyroid dysfunction in pregnancy has consequences for mother and baby. Potential problems include pre-eclampsia, prematurity and congenital abnormality.
Read more on Australian Prescriber website. Authors' conclusions: This review found that orbital radiotherapy is more effective than sham radiotherapy for the treatment of mild-to-moderate thyroid eye disease. Read more on Cochrane Australasian Centre website. The diagnosis of acute pancreatitis requires the presence of at least two of the three diagnostic criteria characteristic abdominal pain, elevated serum Neuropathic pain is caused by damage to the somatosensory nervous system.
Find out more about diagnosis and management of this challenging condition. Read more on Diagnostic Imaging Pathways website. This pathway provides guidance on the imaging of adult patients with suspected chronic pancreatitis. This pathway provides guidance on imaging patients with suspected pancreatic cancer to confirm the diagnosis and to aid in determining the subsequent course of treatment. This pathway provides guidance on the investigation of adult patients with suspected acute pancreatitis and its complications.
Hyperglycaemia is the medical condition in which a patient presents with abnormally high levels of glucose circulating in their bloodstream Better Health Channel It is common for people not to experience the symptoms of hyperglycaemia until their blood sugar levels reach this high level.
Hormones produced by other glands in the body In total more than hormones or hormone-like substances have been discovered. It promotes normal metabolism, maintains blood sugar levels and blood pressure, provides resistance to stress and acts as an anti-inflammatory agent. It also plays a part in regulation of fluid balance in the body. Thyroxine Thyroid Thyroxine controls many body functions, including heart rate, temperature and metabolism.
It also plays a role in the metabolism of calcium in the body. Oestrogen Ovaries Oestrogen facilitates growth of the tissues of the sex organs and other tissues related to reproduction. Oestrogen also acts to strengthen bones and has a protective effect on the heart. Progesterone Ovaries Progesterone promotes the changes in the uterus that occur in preparation for the implantation of a fertilised ovum and prepares the breasts for milk production. Testosterone Testes Testosterone is responsible for the characteristics of the masculine body, including hair growth on the face and body and muscle development.
Testosterone is essential for the production of sperm and also acts to strengthen bones. For more information about glands and hormones, as well as educational resources, visit the Society for Endocrinology's 'You and Your Hormones' website Also in this section What is the pituitary gland?
Pituitary conditions Symptoms, diagnosis and tests Treatments for pituitary conditions Living with a pituitary condition Adrenal insufficiency and adrenal crisis Publications Related links Research Endocrine glands Hormones Webinars Membership. Stimulates the adrenal gland to produce a hormone called cortisol.
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