human body system

• Skeletal System


  • Provides shape & support
  • Helps you move
  • Protects organs
  • Produces blood cells
  • Stores certain materials
• Organs of the Skeletal System

  • Bones
  • Cartilage
  • Ligaments
• Cartilage is connective tissue that is more flexible than bone. Examples include nose, tops of ears, ends of bones
• Ligaments hold bones together to form joints
• Bone Marrow is soft connective tissue found in spaces in bone. Red marrow produces the body’s blood cells, while yellow marrow stores fat (energy reserve)
• Muscular System


  • Helps the body move
  • Moves food through the digestive system
  • Keeps the heart beating
• Involuntary muscles are not under conscious control, like muscles used for breathing & digesting food. Voluntary muscles are under conscious control, like smiling, turning pages, walking
• 3 Types of Muscle Tissue


  • Skeletal
  • Smooth
  • Cardiac
• Muscles move by contracting, or becoming shorter. They must work in pairs, one contracts while the other returns to its original length
• Integumentary System functions include covering and protecting the body, regulating body temperature, and getting rid of wastes
• Layers of the Skin

  • Epidermis
  • Dermis
• Nervous System


  • Receives information about what is happening inside & outside of the body
  • Directs the way your body responds to this information
  • Helps maintain homeostasis
• Organs of the Nervous System

  • Brain
  • Nerves (neurons – nerve cells)
  • Spinal Cord
• Central Nervous System

  • Brain controls most functions in the body, including the cerebrum which interprets input from the senses, controls movement of skeletal muscles, and complex mental processes
• Homeostasis


  Maintenance of stable internal conditions within the body
• Central Nervous System

  • Brain - controls most functions in the body
  • Cerebrum - Interprets input from the senses, Controls movement of skeletal muscles, Complex mental processes (learning)
  • Cerebellum - Coordinates muscle actions & balance
  • Brainstem (medulla) - Controls involuntary actions (ex: breathing)
  • Spinal cord - link between brain & the rest of the body
• Peripheral Nervous System

  • Neurons - nerve cell that is specialized to transfer messages in the form of fast-moving electrical energy, Electrical messages are called impulses
• Path of nerve impulse

  Sensory neuron, Spinal cord, Brain, Spinal cord, Motor neuron
• Respiratory System


  • Function: Moves oxygen from the outside environment into the body, Removes carbon dioxide and water from the body
• Path of Air into the Body

  Nose, Pharynx, Trachea, Bronchi, Alveoli
• How you breathe: Diaphragm – large dome-shaped muscle used in breathing
• Circulatory System (aka Cardiovascular System)


  • Function: Carries needed substances to cells and carries wastes away from cells
• Organs of the Circulatory System

  • Heart - Hollow, muscular organ that pumps blood throughout the body
• Organs – Blood Vessels

  • Arteries - Blood vessel that carries oxygen-rich blood away from the heart and to the body parts, Capillaries - Small blood vessels where materials are exchanged between the blood and the body’s cells (oxygen & carbon dioxide), Veins - Carries oxygen-poor blood (w/carbon dioxide) back to the heart (to be pumped out to the lungs)
• Blood

  • Plasma – liquid part of blood, Red blood cells – take up oxygen in the lungs and deliver it to cells, White blood cells – the body’s disease fighters (part of immune system), Platelets – cell fragments used in forming blood clots (that make scabs)
• Digestive System


  • Functions: Breaks down food into molecules the body can use, Molecules are absorbed into the blood & carried throughout the body (by the circulatory system), Wastes are eliminated from the body (by the excretory system)
• Roles of Organs in the Digestive System

  • Mouth – mechanical & chemical digestion starts here, Esophagus – muscular tube connecting the mouth to the stomach, Stomach – Most mechanical digestion takes place, Some chemical with the help of digestive juices (enzymes & acids), Small Intestine – Most of the chemical digestion takes place, Absorption of nutrients from digested food into the bloodstream, Large Intestine – Water is absorbed into the bloodstream, Remaining material is readied for elimination from the body, Rectum
• Small Intestine


  1. Most of the chemical digestion takes place

  2. Absorption of nutrients from digested food into the bloodstream
• Path of food through Digestive System

  1. mouth

  2. esophagus

  3. stomach

  4. small intestine

  5. large intestine

  6. rectum

  7. eliminated from body
• Active immunity occurs when a person’s own immune system produces antibodies in response to a pathogen; remembers how to “fight” the pathogen. Two ways to gain active immunity: Infection with pathogen, Vaccine – weakened or killed pathogen (Ex: chicken pox vaccine)
• Passive immunity: Antibodies are given to the person to fight a disease; their own body did not make them (Ex: rabies)