endocrine system

Endocrine System

The endocrine system consists of ductless glands that secrete hormones, which act as chemical messengers regulating various bodily functions, including metabolism, growth, fluid balance, and sexual processes.

Major Endocrine Glands

• Pineal

• Pituitary Gland

• Thyroid

• Thymus

• Adrenal

• Pancreas

• Ovaries

• Testes

Pituitary Gland

• Characteristics: Master gland located at the base of the brain, producing many hormones that affect other glands. Has 2 lobes:

  • Anterior

  • Posterior

Diseases and Abnormalities

• Acromegaly: Overproduction of growth hormone due to a pituitary tumor.

• Gigantism: Similar overproduction before puberty.

• Diabetes Insipidus: Low vasopressin causes excessive urination.

• Dwarfism: Insufficient growth hormone due to various factors.

Thyroid Gland

• Characteristics: Synthesizes hormones that regulate metabolism and calcium levels, located in front of the upper part of the trachea. Requires iodine (53) obtained from certain foods and salt. Has 2 lobes.

Thyroid Disorders

• Goiter: Enlargement of the thyroid gland due to hyperactivity, iodine deficiency, or over secretion of TSH. Symptoms include thyroid enlargement, dysphagia, dyspnea, and cough.

  • Treatment: Iodine, eliminate cause, surgery, radioiodine therapy.

• Hyperthyroidism: Increased production of thyroid hormone, increased basal metabolic rate (BMR) leading to symptoms such as extreme nervousness, tremors, irritability, rapid pulse, diarrhea, excessive sweating, heat intolerance, weight loss, and goiter formation.

  • Treatment: Radiation, thyroidectomy, antithyroid medications, beta blockers.

• Grave's Disease: Severe form of hyperthyroidism, more common in women with symptoms of tense facial expression, exophthalmia, nervous irritability, and tachycardia.

  • Treatment: Medications, radioactive iodine, thyroidectomy.

• Hypothyroidism: Underactivity of the thyroid gland leading to deficiency of hormones. Symptoms include fatigue, weight gain, cold intolerance, and dry skin.

  • Treatment: Thyroid hormones.

Additional Conditions

• Cretinism: Infancy condition causing lack of mental and physical growth.

• Myxedema: Conditions in later childhood or adulthood leading to similar symptoms.

Parathyroid Glands

• Characteristics: 4 small glands located behind and attached to the thyroid, regulating calcium level in blood.

• Hyperparathyroidism: Overactivity resulting in elevated calcium levels.

Adrenal Glands

• Located above each kidney. Cortex secretes steroids; medulla secretes epinephrine and norepinephrine, affecting blood pressure.

Conditions

• Addison's Disease: Decrease in aldosterone secretion, interfering with sodium and water reabsorption.

• Cushing's Syndrome: Over secretion of glucocorticoids from adrenal cortex.

Pancreas

• Functions as both an endocrine and exocrine gland.

  • Exocrine: Secretes pancreatic juices into small intestine via pancreatic duct.

  • Endocrine: Islets of Langerhans produce insulin.

Diabetes Mellitus

• Chronic disease caused by a decrease in insulin secretion, affecting metabolism of carbohydrates, proteins, and fats. Classifications:

  • Type 1: Usually occurs in early life, requires insulin.

  • Type 2: Controlled with diet and oral hypoglycemic medications.

Symptoms include hyperglycemia, polyuria, polydipsia, polyphagia, and can lead to coma or death if untreated. Treatment options include diet, exercise, oral hypoglycemics, or insulin.

Ovaries and Testes

• Ovaries: Regulate menstruation and secondary sex characteristics through estrogen and progesterone.

• Testes: Produce testosterone, regulating secondary sex characteristics.

Thymus

• Aids with immunity during prepuberty (thymosin).

Pineal Body

• Located on the roof of the third ventricle, secreting melatonin, adrenoglomerulotropin, serotonin.

Placenta

• Temporary structure promoting lactation, secreting hormones including estrogen, progesterone, chorionic gonadotropin.

The endocrine system consists of ductless glands that secrete hormones, which act as chemical messengers regulating various bodily functions, including metabolism, growth, fluid balance, and sexual processes. Major glands include the pineal, pituitary, thyroid, thymus, adrenal, pancreas, ovaries, and testes.

The pituitary gland, known as the master gland, controls other glands and has anterior and posterior lobes.

Diseases include:

• Acromegaly: Overproduction of growth hormone due to a pituitary tumor.

• Gigantism: Similar overproduction before puberty.

• Diabetes Insipidus: Low vasopressin causes excessive urination.

• Dwarfism: Insufficient growth hormone due to various factors.

The thyroid regulates metabolism and calcium levels, and can be affected by:

• Goiter: Enlargement due to various causes, treated with iodine or surgery.

• Hyperthyroidism: Increased hormone production shown by symptoms like nervousness and weight loss.

• Hypothyroidism: Deficient hormone levels leading to fatigue and weight gain.

Parathyroid glands regulate calcium levels in the blood. Hyperparathyroidism results in elevated calcium levels.

Adrenal glands produce hormones affecting blood pressure. Addison's disease results from insufficient aldosterone, while Cushing's syndrome involves excessive glucocorticoids.

The pancreas functions as both an endocrine and exocrine gland, with diabetes mellitus stemming from inadequate insulin secretion, classified as Type 1 (insulin-dependent) or Type 2 (diet-controlled).

Ovaries produce estrogen and progesterone, while testes produce testosterone. The thymus aids immunity, and the pineal gland secretes melatonin. The placenta, temporary, is involved in pregnancy hormones.

Acromegaly: Enlarged hands and feet, facial changes, joint pain.

Gigantism: Excessive growth before puberty, increased height, large hands and feet.

Diabetes Insipidus: Excessive urination, intense thirst.

Dwarfism: Short stature, delayed growth and development.

Goiter: Enlargement of the thyroid gland, difficulty swallowing, choking sensation, cough.

Hyperthyroidism: Nervousness, tremors, irritability, rapid pulse, weight loss, increased appetite, heat intolerance, excessive sweating.

Hypothyroidism: Fatigue, weight gain, cold intolerance, dry skin, slow mental function, puffiness in the face.

Hyperparathyroidism: Elevated calcium levels, weakness, fatigue, kidney stones.

Addison's Disease: Fatigue, low blood pressure, weight loss, darkening of the skin.

Cushing's Syndrome: Weight gain, particularly around the abdomen and face, thinning skin, purple stretch marks.

Diabetes Mellitus: Increased thirst, frequent urination, extreme hunger, fatigue, blurred vision, slow healing sores, unintentional weight loss.