Body systems

body systems

Excretory System

  • Function: Removes waste products from the body and regulates water and electrolyte balance.

  • Main Organs:

    • Kidneys: Filter blood, remove waste, and produce urine.

    • Ureters: Tubes that carry urine from the kidneys to the bladder.

    • Bladder: Stores urine until it is expelled.

    • Urethra: Channel through which urine is expelled from the body.

  • Key Processes:

    • Filtration: Blood is filtered in the kidneys to remove waste.

    • Reabsorption: Essential nutrients and water are reabsorbed into the bloodstream.

    • Secretion: Additional wastes are secreted into the urine.



Digestive System

  • Function: Breaks down food into nutrients that can be absorbed and utilized by the body.

  • Main Organs:

    • Mouth: Begins the digestive process through chewing and saliva.

    • Oesophagus: Transports food to the stomach.

    • Stomach: Breaks down food with acids and enzymes.

    • Small Intestine: Primary site for digestion and nutrient absorption.

    • Large Intestine: Absorbs water and forms waste (feces).

    • Liver: Produces bile, which helps digest fats; processes nutrients.

    • Pancreas: Produces enzymes and hormones (like insulin).

  • Key Processes:

    • Ingestion: Taking in food.

    • Digestion: Mechanical and chemical breakdown of food.

    • Absorption: Nutrients pass into the bloodstream.

    • Excretion: Elimination of indigestible food as feces.

Circulatory System

  • Function: Transports blood, nutrients, gases, hormones, and waste products throughout the body.

  • Main Components:

    • Heart: Pumps blood through the circulatory system.

    • Blood Vessels:

      • Arteries: Carry oxygenated blood away from the heart.

      • Veins: Return deoxygenated blood to the heart.

      • Capillaries: Tiny vessels where gas and nutrient exchange occurs.

    • Blood: Composed of red blood cells (carry oxygen), white blood cells (immune response), platelets (clotting), and plasma (liquid component).

  • Key Processes:

    • Circulation: Blood circulates in two main loops:

      • Pulmonary Circulation: Carries blood to the lungs for oxygenation.

      • Systemic Circulation: Distributes oxygenated blood to the rest of the body.

    • Homeostasis: Helps regulate body temperature, pH, and fluid balance.

Summary

  • The excretory system focuses on waste removal and balance.

  • The digestive system is essential for nutrient absorption.

  • The circulatory system is crucial for transporting substances throughout the body.