MSD Manual

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Major Organ Systems

Major Organ Systems


Organs in the System

Some Major Functions of the System

  • Heart

  • Blood vessels (arteries, capillaries, veins)

Pumps blood and circulates it throughout the body

  • Nose

  • Mouth

  • Pharynx

  • Larynx

  • Trachea

  • Bronchi

  • Lungs

Adds oxygen to the blood (and removes carbon dioxide from the blood)

  • Brain

  • Spinal cord

  • Nerves (both those that carry impulses to the brain and those that carry impulses from the brain to muscles and organs)

Directs intentional (and many automatic) actions of the body

Enables thinking, self-awareness, and emotions

  • Skin (both the surface that is generally thought of as skin and the underlying structures of connective tissue, including fat, glands, and blood vessels)

Provides barrier protection between the inside of the body and the external environment

  • Muscles

  • Tendons and ligaments

  • Bones

  • Joints

Provides structure and allows motion of the body

  • Red blood cells, white blood cells, and platelets

  • Plasma (the liquid part of blood)

  • Bone marrow (where blood cells are produced)

  • Spleen

  • Thymus

Transports oxygen and nutrients to all the cells of the body (and removes carbon dioxide and waste products)

  • Mouth

  • Esophagus

  • Stomach

  • Small intestine

  • Large intestine

  • Rectum

  • Anus

  • Liver

  • Gallbladder

  • Pancreas (the part that produces enzymes)

  • Appendix

Extracts nutrients from foods

Excretes waste products from the body

  • Thyroid gland

  • Parathyroid gland

  • Adrenal glands

  • Pituitary gland

  • Pancreas (the part that produces insulin and other hormones)

  • Stomach (the cells that produce gastrin)

  • Pineal gland

  • Ovaries

  • Testes

Produces chemical messengers carried in the blood (hormones), which direct the activities of different organ systems

  • Kidneys

  • Ureters

  • Bladder

  • Urethra

Filters waste products from the blood

  • Penis

  • Prostate gland

  • Seminal vesicles

  • Vasa deferentia

  • Testes

Enables reproduction

  • Vagina

  • Cervix

  • Uterus

  • Fallopian tubes

  • Ovaries

Enables reproduction