Human Excretory and Endocrine Systems: Health and Diseases
Excretory System
The excretory system eliminates waste substances produced by the activity of the cells in our body.
Urinary Tract
The urinary tract is composed of the kidneys, ureters, bladder, and urethra.
Kidneys
Kidneys are approximately 12cm in length and are located in the back of the abdominal cavity.
Features:
- Eliminate waste substances.
- Control the concentration of mineral ions and salts.
Each kidney is bean-shaped, covered by a layer of fat, and consists of a million nephrons.
Three zones can be distinguished: the cortex, renal medulla, and renal pelvis (an area in the hilum).
Structure of the Nephron
- Bowman’s Capsule: A cup-shaped structure surrounding the glomerulus.
- Proximal Tubule: Located further than Bowman’s capsule, in the cortex.
- Loop of Henle: It has two branches, one ascending and one descending.
- Distal Tubule: Further than the ramus, and is located in the renal cortex.
- Collecting Tubules: Formed by the union of several distal tubules.
Physiology of the Nephron and Urine Formation
The nephron cleans the plasma of waste. Blood carrying waste reaches the glomeruli in Bowman’s capsule, where it is filtered. The filtrate moves through the proximal tubule, loop of Henle, and distal tubule. During this period, waste remains in the nephron.
Some filtered substances are reabsorbed, preventing the loss of beneficial substances. At the end of the route, the nephron produces urine.
Urinary Tract Components
- Ureters: Two tubes that start from the kidneys and transport urine from the renal pelvis to the bladder.
- Urinary Bladder: A sac-like organ where urine collects. The contraction of the bladder causes urine output.
- Urethra: A tube that leaves the bladder and ends at the meatus.
Diseases of the Excretory System
- Renal Failure: Decreased ability of the kidney to remove waste, causing it to accumulate in the blood.
- Kidney Stones: Small, solid particles that block the urinary tract, causing severe abdominal pain.
- Cystitis: An infection of the urinary tract, often caused by fecal bacteria.
- Gout: Excess accumulation of uric acid that has not been eliminated and accumulates in areas such as limbs and joints.
Healthy Habits for the Excretory System
- Liberal intake of water (2-3 liters/day).
- Avoid foods with too much salt.
- Maintain a healthy diet.
- Avoid consumption of toxic substances or drugs that are eliminated by the renal system.
Mental Health and Drugs
Precautions:
- Sleep an adequate number of hours.
- Have an orderly life.
- Eat a balanced diet.
- Engage in physical exercise and avoid drugs.
Addictive Substances
A drug is a substance that alters the nervous system and can produce harmful central nervous system and physical effects, including psychological dependence. It can also lead to tolerance (addiction).
Endocrine System
The endocrine system is formed by a set of glands that produce hormones, which regulate and coordinate activities in our body.
- Pituitary Gland: Controls the activity of other glands and is regulated by the hypothalamus.
- Endocrine Glands: Organs that synthesize hormones, which are sent to the blood.
- Hormones: Chemical substances, often protein-based, that act as messengers.
Endocrine System Disorders
- Diabetes Mellitus: Accumulation of blood sugar because the pancreas does not produce enough insulin.
- Hyperthyroidism: Increased cellular activity due to the thyroid producing too much thyroxine. Symptoms include weight loss, insomnia, and sweating.
- Osteoporosis: Calcitonin deficiency causes a reduction in bone calcium, making bones fragile.
- Pituitary Gigantism: Excess growth hormone during the growth period.
- Pituitary Dwarfism: Low production of growth hormone.
- Hirsutism: Excess of male hormones in women.