Urinary System Overview

• The urinary system's primary functions include filtering waste from the blood and maintaining electrolyte and fluid balance.
• Erythropoietin production is a key function of the urinary system, stimulating red blood cell production.

Organs of the Urinary System

• Kidneys filter blood and produce urine.
• Ureters transport urine from the kidneys to the bladder.
• The bladder stores urine.
• The urethra excretes urine from the body.

Kidney Anatomy

• Renal cortex is the outer region of the kidney.
• Renal medulla is the inner region of the kidney.
• Renal pelvis collects urine before it passes to the ureters.
• Renal artery delivers blood to the kidney.
• Renal vein carries blood away from the kidney.
• Segmental arteries branch from the renal artery.
• Interlobar arteries pass through the renal columns.
• Arcuate arteries arch over the base of the renal pyramids.
• Cortical radiate arteries supply the cortex.

Nephron

• Bowman's capsule (glomerular capsule) is the initial filtering component of the nephron.
• Proximal convoluted tubule is responsible for most reabsorption in the nephron.
• Loop of Henle (nephron loop) establishes a concentration gradient in the medulla.
• Distal convoluted tubule is involved in further reabsorption and secretion.
• Collecting duct receives urine from several nephrons.

Filtrate and Reabsorption

• Filtrate contains urea, uric acid, and creatinine as waste products.
• Water, glucose, amino acids, and ions are reabsorbed into the blood.
• Water intake and balance regulates blood volume and concentration.

Hormonal Control

• Aldosterone increases sodium and water reabsorption.
• ADH (antidiuretic hormone) increases water reabsorption.
• Atrial natriuretic hormone (ANH) decreases sodium reabsorption.

Urinary System Pathologies

• Kidney stones are mineral deposits that can obstruct urine flow.
• Urinary tract infections (UTIs) are infections of the urinary system.

Components of Blood

• Erythrocytes (red blood cells) transport oxygen.
• Leukocytes (white blood cells) are involved in immune defense:
  • Neutrophils are phagocytic cells.
  • Basophils release histamine and heparin.
  • Eosinophils combat parasitic infections and mediate allergic reactions.
• Platelets are involved in blood clotting.
• Plasma is the fluid component of blood.
• Albumin maintains osmotic pressure.

Clot Formation

• Clot formation involves a cascade of steps to stop bleeding.

Blood Pathologies

• Thrombus is a blood clot that forms in a vessel.
• Hemophilia impairs the blood's ability to clot.
• Anemia is a deficiency of red blood cells or hemoglobin:
  • Pernicious anemia is caused by vitamin B12 deficiency.
  • Sickle cell anemia is a genetic disorder affecting hemoglobin.
• Polycythemia is an excess of red blood cells.

Blood Types

• Blood types (A, B, AB, O) are determined by antigens on red blood cells.

Immune Defense

• Primary immune defense includes physical barriers like skin and mucous membranes.
• Secondary immune response is triggered by pathogens that bypass the primary defense:
  • Monocytes differentiate into macrophages and dendritic cells.
  • Dendritic cells present antigens to T cells.
  • Mast cells release histamine during inflammation.
  • Cytokines and complement proteins enhance the immune response.
• Tertiary immune response involves specific immune cells:
  • Plasma B cells produce antibodies.
  • Antibodies target specific antigens.
  • Helper T cells coordinate the immune response.
  • Cytotoxic T cells kill infected cells.
  • Memory B and T cells provide long-term immunity.

Lymphatic Organs

• Lymph nodes filter lymph and mount immune responses.
• GALT (gut-associated lymphoid tissue) is found in the digestive system.
• MALT (mucosa-associated lymphoid tissue) is found in mucous membranes.
• BALT (bronchus-associated lymphoid tissue) is found in the respiratory system.
• Spleen filters blood and removes damaged blood cells.

Immune Pathologies

• Allergies are hypersensitive immune responses.
• Autoimmune diseases occur when the immune system attacks the body's own tissues.
• Lymphoma is cancer of the lymphatic system.
• Vaccines induce immunity by exposing the body to weakened or inactive pathogens.