Main organ systems of the body

• Vision


  • The eye is the organ of vision
  • It converts light energy into electrical nerve impulses which are then interpreted by the brain as sight
  • The lens of the eye focus light on the retina
  • The retina contain specialized nerve receptors sensitive to light intensity (rods) and wavelengths or colors of light (cones)
  • The optic nerve then carries the message to the brain where it is interpreted as sight in the visual center of the occipital lobes
  • Muscles attach to the outer surface of the eye
• The 11 Human Body Systems

  • Nervous system
  • Integumentary system
  • Respiratory system
  • Digestive system
  • Excretory system
  • Skeletal system
  • Muscular system
  • Circulatory system
  • Endocrine system
  • Reproductive system
  • Lymphatic (immune) system
• Main Organ Systems of the Body

  • Nervous System
  • Respiratory System
  • Circulatory System
  • Urinary System
• Nervous System


  • Purpose: to coordinate the body's response to changes in its internal and external environment
  • Major Organs and Their Functions: Brain - control center of the body, where all processes are relayed through (consists of cerebrum and cerebellum)
  • Spinal Cord - sends instructions from the brain to the rest of the body and vice versa
  • Nerves - conduct impulses to muscle cells throughout the body
• Circulatory System


  • Purpose: to deliver oxygenated blood to the various cells and organ systems in your body so they can undergo cellular respiration
  • Major Organs and Their Functions: Heart - the major muscle of the circulatory system (pumps blood through its four chambers)
  • Arteries - carry blood away from the heart and to the major organs of the body
  • Veins - carry blood back to the heart away from the major organs of the body
  • Capillaries - small blood vessels where gas exchange occurs
  • Blood - the cells that flow through the circulatory system (red blood cells, white blood cells, platelets)
  • Spleen - helps to filter out toxins in the blood
• Respiratory System


  • Purpose: to provide the body with oxygen and to remove carbon dioxide
  • Major Organs and Their Functions: Nose & Mouth - internal entry and exit point for air
  • Pharynx - serves as a passage way for both air and food at the back of the throat
  • Larynx - your "voicebox", as air passes over your vocal chords, you speak
  • Trachea - the "windpipe", or what connects your pharynx to your lungs
  • Lungs - Supplies oxygen to the blood and remove CO2 from blood
• Urinary System


  • Purpose: eliminate of waste products nitrogenous wastes, toxins and drugs
  • Kidney - Paired, located retroperitoneally on the posterior wall of the abdomen from T12-L3, controls the excretion of various ions
  • Nephron - Each kidney has approximately 1 million nephrons, responsible for the initial formation of urine
  • Chronological Order of Excretion of Waste in the Body Through Urine: 1. Kidneys, 2. Ureters, 3. Urinary bladder, 4. Urethra