Endocrine System 2 (MD203)

The thyroid gland is located in the neck, below the larynx and in front of the trachea.

The thyroid gland produces two key hormones: thyroxine (T4) and triiodothyronine (T3). These hormones are essential for growth, development, and the reproductive system.

A condition characterized by an overactive thyroid gland, resulting in excessive thyroid hormone production.

Calcitonin is released by the thyroid gland in response to high blood calcium levels. Its role is to decrease calcium levels in the blood.

A common cause of hyperthyroidism, characterized by an enlarged thyroid, bulging eyes (exophthalmos), weight loss, increased heart rate (tachycardia), and nervous system excitability.

Iodine is a vital component in the synthesis of thyroid hormones. Thyroxine (T4) has four iodine atoms, while triiodothyronine (T3) has three.

A hormone produced by the thyroid gland, regulating calcium levels in the blood. It lowers calcium levels by promoting calcium excretion in the urine, reducing intestinal absorption, and stimulating osteoblasts to deposit calcium.

Thyroxine (T4) is produced by the thyroid gland, has a longer duration of action, and is less potent compared to triiodothyronine (T3).

A condition where blood calcium levels are abnormally high.

The production and release of T4 and T3 are regulated by TSH (thyroid-stimulating hormone) from the pituitary gland. TSH itself is stimulated by TRH (thyrotropin-releasing hormone).

The levels of T3 and T4 are regulated through a negative feedback loop. High levels of T3 and T4 suppress the production of TSH and TRH.

A hormone produced by the parathyroid glands, regulating calcium levels in the blood. It increases calcium levels by stimulating calcium reabsorption from kidneys, promoting calcium absorption in the intestines, and activating osteoclasts to release calcium from bones.

A condition caused by low PTH levels, leading to abnormally low blood calcium levels, and symptoms like muscle cramps and convulsions.

Hypothyroidism refers to a condition where the thyroid gland doesn't produce enough thyroid hormones. Myxedema is a severe form of hypothyroidism occurring in adults, characterized by swelling, weight gain, and slowed heart rate. Cretinism is a severe form of hypothyroidism in infants, resulting in physical and mental retardation.

A condition caused by excessive PTH secretion, leading to weak and brittle bones due to increased bone breakdown.

A condition characterized by low blood calcium levels.

The process of calcium depositing within body tissues and organs, hindering their proper functioning.

Special groups of cells found in the pancreas responsible for producing hormones like insulin and glucagon.

A hormone produced in the pancreas that helps to increase blood glucose levels by breaking down stored sugars, converting proteins, and utilizing fats.

The process by which the body converts glycogen (stored sugar) into glucose to raise blood sugar levels.

The process of producing glucose from non-carbohydrate sources like amino acids or fats to raise blood sugar levels.

The process of breaking down fats into glycerol and fatty acids, which can be converted into glucose.

A hormone produced by the pancreas that lowers blood glucose levels by promoting glucose uptake by cells and converting excess glucose into glycogen.

The process of converting glucose into glycogen (stored sugar) to lower blood glucose levels.

Melatonin is a hormone produced by the pineal gland and helps regulate sleep-wake cycles. When light levels are low, the pineal gland releases more melatonin, making you feel sleepy.

Testosterone is a male sex hormone responsible for the development of male characteristics like increased muscle mass, deeper voice, and body hair growth.

Estrogen is a female sex hormone that plays a crucial role in the development of female reproductive organs and secondary sexual characteristics, including breast growth and increased fat deposition.

Atrial natriuretic peptide (ANP) is a hormone secreted by the heart. It helps regulate blood pressure by reducing sodium reabsorption and inhibiting the Renin-Angiotensin-Aldosterone System (RAAS).

The kidneys produce erythropoietin (EPO), a hormone that regulates red blood cell production. EPO ensures the body has enough red blood cells to carry oxygen.

The thymus gland, located in the chest, produces the hormone thymosin. Thymosin plays a vital role in developing and strengthening the immune system.

Insulin-like growth factor (IGF-1), secreted by the liver, promotes growth and development throughout the body. It's crucial for muscle and bone growth.

Gastrin is a hormone produced by the stomach lining that helps stimulate the production of gastric juices, which are essential for digestion.

Aldosterone is a hormone produced by the adrenal cortex. When blood pressure is low, aldosterone is released, causing the body to retain sodium and water. This increases blood volume, ultimately raising blood pressure.

Cortisol is a hormone secreted by the adrenal cortex that has various effects on the body. It promotes the use of fats and amino acids for energy, reducing glucose use. It also has anti-inflammatory properties, suppressing the actions of inflammatory substances.

Addison's disease occurs when the adrenal cortex is damaged, leading to low levels of cortisol and aldosterone. This causes symptoms such as low blood sugar, low blood pressure, weight loss, and a craving for salty foods.

Cushing syndrome is caused by high levels of cortisol due to a tumor in the pituitary gland that overproduces ACTH. This leads to physical changes like a moon-shaped face, a fat deposit on the upper back, weight gain, and hair loss.

Melatonin, secreted by the pineal gland, is often called the 'sleep hormone'. Its production is sensitive to light levels. In the morning, bright light reduces melatonin secretion, making you feel awake.

The adrenal gland is a pair of small glands located on top of the kidneys. The outer part, called the adrenal cortex, produces hormones such as aldosterone and cortisol. The inner part, called the adrenal medulla, secretes epinephrine and norepinephrine.

When the pancreas cannot produce enough insulin, or the body becomes resistant to its effects, individuals develop diabetes. This disrupts blood sugar regulation, leading to high blood sugar levels.

Epinephrine and norepinephrine, released from the adrenal medulla, are key in the 'fight-or-flight' response. They prepare the body to deal with stressful situations by increasing heart rate, blood pressure, and energy.