Human Respiratory System

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Human Respiratory System

• By D. Reis

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The Respiratory System

• Air enters the respiratory system through both
  the nasal cavity and mouth.
• The nasal cavity is lined with tiny hairs and
  mucus to trap foreign particles.
• The air is warmed and moistened.

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Respiration and Gas Exchange
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The Respiratory System

• Pharynx where the nasal cavity and oral cavity
  meet
• Epiglottis flap that closes over the top of the
  trachea(glottis) due to reflexive action while
  eating
• Trachea the windpipe through which air passes
• Supported by cartilage rings

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The Respiratory System

• Larynx voicebox located in the trachea
  containing vocal cords. The vocal cords vibrate
  producing sounds.
• Adams Apple thick band of cartilage protecting
  larynx.

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The Respiratory System

• Bronchi extend from the trachea also contains
  cartilage
• Bronchioles the smallest passageways of the
  respiratory tract
• Alveoli tiny air sacs where gas exchange occurs
  between the air and the blood

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Alveoli

• Each lung is made up of 150 million alveoli.
• Capillaries surround each cluster of alveoli and
  ensure
• gas diffusion between the air and blood occurs.
• Oxygen moves from the air inside the lungs to the
  alveoli while carbon dioxide moves from the
  alveoli into the air inside the lungs.
• Lipoprotein prevents alveoli from sticking
  together

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Goblet cells

• Goblet cells mucus secreting cells lining the
  trachea, bronchi and bronchioles to trap foreign
  particles.
• Cilia - hair like structures that sweep the
  foreign particles up towards the mouth

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Thoracic Cavity

• External intercostal muscles muscles between
  the ribs that raise the rib cage, increasing
  volume and reducing air pressure in chest.
• Diaphragm muscle that separates organs of the
  chest from abdominal cavity.

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• Pleural membrane thin fluid-filled membrane
  surrounding lungs and inner wall of chest cavity
  that reduces friction during inhalation.

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The Movement of Air

• Air moves from an area of high pressure to an
  area of low pressure.
• Air will move into the lungs when the air
  pressure inside the lungs is less than the air
  pressure outside the body.
• Air will move out of the lungs when the air
  pressure inside the lungs is______ than the air
  pressure outside the body.

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Inspiration (Inhaling)

• The diaphragm contracts and moves down
• External intercostal muscles expand rib cage
  upward and outward
• Volume of thoracic cavity increases therefore air
  pressure decreases.
• Movement of air into the lungs.

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Expiration (Exhaling)

• The diaphragm relaxes and moves up
• External intercostal muscles move rib cage inward
  and downward.
• Volume of thoracic cavity decreases therefore air
  pressure increases.
• Movement of air out of the lungs.

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