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The Human Body

Year 9 The Human Body - For additional resources visit:

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The Human Body

  1. 1. The Human Body Sarah Jones
  2. 2. Body Systems
  3. 3. A body system is a collection of parts able to work together to serve a common purpose – growth, reproduction and survival. Each part of a system depends on the other parts to perform tasks that can’t be achieved by single parts acting alone.
  4. 4. Each individual system works in conjunction with other systems to improve our chances of survival by maintaining a stable internal body environment. This stable environment is known as homeostasis.
  5. 5. Respiratory System • Your body uses the glucose from the food you digest as a source of energy. • Glucose reacts with oxygen to produce energy – this process is called respiration. Glucose + Oxygen Carbon Dioxide + Water + Energy
  6. 6. The dissolved food and oxygen required for respiration are carried around the body by the circulatory system.
  7. 7. • When you inhale your body is taking in the oxygen required for respiration. • When you exhale your body is removing the waste product of respiration – carbon dioxide.
  8. 8. Circulatory System • Heart • Blood Vessels • Blood
  9. 9. • Oxygen that is required for respiration is transported to the body's cells. • Carbon dioxide is carried away from the body's cells.
  10. 10. The Heart
  11. 11. Double Circulation • Left side of the heart pumps oxygen rich blood to the body. • Oxygen poor blood travels from the body to the rights side of the heart. • The right side pumps the oxygen poor blood to the lungs. • Oxygen rich blood returns to the left side of the heart. • Called double circulation because during a single circuit of the body blood passes through the heart twice.
  12. 12.
  13. 13. Digestive System
  14. 14.
  15. 15. Physical Digestion Teeth – Premolars grind soft food – Molars grind hard food – Canines bite and tear – Incisors cut food
  16. 16. Chemical Digestion • Saliva is an enzyme. • Enzymes speed up reactions. • Different enzymes – Carbohydrases digest carbohydrate – Proteases digest protein – Lipases digest fats (lipids)
  17. 17. • Mouth – teeth, tongue and saliva • Swallow – food moves to the pharynx (back of the mouth) • The epiglottis covers the trachea (to the lungs) • Food travels to stomach – containing hydrochloric acid (mucus protects stomach lining) • Large molecules are digested to produce small soluble molecules that can be absorbed by the blood.
  18. 18. • Particles travel from the stomach to the small intestine. • Gastric juices are very acidic – mucus and bile stop the acid from damaging the lining of the small intestine. • Bile is produced in the liver. • The liver, gall bladder, pancreas and small intestine are all important for fat digestion.
  19. 19. • The small intestine is where to absorption of useful molecules occurs. • The molecule pass across the lining of the small intestine and enter the blood stream.
  20. 20. • The food that enters the large intestine (colon) is waste material and water. • The blood reabsorbs the excess water. • The waste material passes to the rectum. • From here the faeces passes out through the anus.
  21. 21. Nervous System • The human body is made up of trillions of cells. • Cells of the nervous system, called nerve cells or neurons, are specialised to carry "messages" through an electrochemical process. The human brain has approximately 100 billion neurons.
  22. 22. • Neurons have specialised projections called dendrites and axons. Dendrites bring information to the cell body and axons take information away from the cell body. • Information from one neuron flows to another neuron across a synapse.
  23. 23.
  24. 24. • Communication of information between neurons is accomplished by the movement of chemicals across a small gap called the synapse. • Chemicals, called neurotransmitters, are produced at the end of a neuron’s axon. They carry the impulse across the synapse to the next neuron.
  25. 25. Central Nervous System Brain and Spinal Cord
  26. 26. Peripheral Nervous System From Spinal cord to the rest of your body.
  27. 27. Neuron Types • Sensory Neurons - Relay messages from receptor to the brain or spinal cord. • Motor Neurons - Relay messages from the brain or spinal cord to muscles and organs. • Interneuron - Connects the various neurons within the brain and spinal cord.
  28. 28. Excretory System • The kidney plays a central role in homeostasis, forming and excreting urine while regulating water and salt concentration in the blood. • It maintains the precise balance between waste disposal and an animal's needs for water and salt.
  29. 29. Ammonia, the nitrogenous waste product from protein metabolism in cells, is highly toxic and needs to be removed as quickly as possible or converted to a less harmful form.
  30. 30. Aquatic animals, fish and invertebrates mostly excrete ammonia. Ammonia is toxic, but can be released continuously (out of respiratory structures such as gills) and directly into the water.
  31. 31. On land, however, animals need to conserve water. By converting ammonia into less toxic forms, they can hold it for longer in the body and excrete it periodically.
  32. 32. Internal structure of the kidney • Mammals have two kidneys. • Each kidney is made up of about one million small filtering units called nephrons. It is in these structures that urine is produced.
  33. 33. The formation of urine - the kidneys continuously process an enormous volume of blood to form a small volume of urine. There are three processes in the formation of urine: filtration, reabsorption and secretion.
  34. 34. Endocrine System • Coordinates the body's organs so they are working together. • This system is based on the production of hormones – chemical messengers. • Hormones are produced by glands that are located in different parts of the body.
  35. 35. • Hormones are responsible for coordinating long-term processes such as growth and sexual development. • Diabetes results from blood sugar levels being unregulated. • Blood sugar is regulated by the hormone insulin that is produced in the pancreas.