SISTEMA ENDÓCRINO: O que são Glândulas e como elas funcionam
How Does the Endocrine System Work?
Overview of the Endocrine System
- The endocrine system coordinates all body functions through a network of glands that produce hormones.
- Hormones are chemical substances that regulate biological functions such as metabolism, growth, and sexuality. They are produced by specialized glands, tissues, and neurons.
Understanding Glands in the Endocrine System
- Glands are structures made of epithelial tissue capable of producing secretions either inside or outside the body. The endocrine glands include:
- Hypophysis (pituitary gland)
- Thyroid and parathyroid glands
- Thymus
- Adrenal glands
- Pancreas
- Sexual glands (ovaries and testes)
Key Glands and Their Functions
Hypophysis (Pituitary Gland)
- Located at the base of the brain; known as the "master gland" because it regulates other glands like the thyroid and sexual glands.
- Produces growth hormone; excess leads to gigantism while deficiency causes dwarfism. Also produces antidiuretic hormone (ADH), which helps conserve water during urine excretion.
Thyroid Gland
- Found in the neck; produces T3 and T4 hormones that control cellular metabolism speed, weight maintenance, heat regulation, growth, and heart rate.
- Hyperthyroidism accelerates metabolism leading to weight loss; hypothyroidism slows metabolism causing various complications.
Parathyroid Glands
- Four small glands located behind the thyroid; they produce parathyroid hormone which regulates calcium and phosphorus levels in blood.
Thymus
- Situated between the lungs; produces hormones crucial for newborn immune defense against infections.
Adrenal Glands
- Located above each kidney; they produce adrenaline which prepares the body for action during stress situations.
Pancreas
- A mixed gland that produces insulin (regulates glucose entry into cells) and glucagon (stimulates glycogen breakdown when blood sugar is low). Insufficient insulin production can lead to diabetes characterized by high blood sugar levels.
Sexual Glands: Ovaries and Testes
- Ovaries produce estrogen and progesterone responsible for female secondary sexual characteristics.
- Testes produce testosterone responsible for male secondary sexual characteristics such as beard growth and deeper voice.
These hormones are stimulated by signals from the pituitary gland.
Summary of Endocrine Glands Locations
- Hypophysis: located in head
- Thyroid & Parathyroids: found in throat
- Thymus: situated between lungs
- Adrenals: positioned above kidneys
- Pancreas: located near stomach