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The Human Respiratory System

The Human Respiratory System. Thursday May 19, 2011. Inhalation – breathing in, then where? Upper Respiratory Tract. Why does it usually take place through the nose? Nose – opening at the base of the nose (nostrils) Lined with: Nose hairs = filters dust from air

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The Human Respiratory System

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  1. The Human Respiratory System Thursday May 19, 2011

  2. Inhalation – breathing in, then where?Upper Respiratory Tract • Why does it usually take place through the nose? • Nose – opening at the base of the nose (nostrils) Lined with: • Nose hairs = filters dust from air • Conducts air into hollow nasal passages • The mouth is also an entry point for air

  3. In the nostrils… • Turbinates– thin bones, covered with thin membrane that secretes mucus • Turbinates help increase surface area of nasal chambers • Mucus moistens air • Nasal Chambers – epithelial linings supplied with blood capillaries, WHY? • Warms incoming air, increases humidity • Turbinate bones also warm and humidify air • Filters air

  4. After the nostrils, where to now? • Pharynx – part of the alimentary canal (digestive system) • Connects the mouth and the nasal cavity to the larynx and oesophagus • Intersection between trachea and esophagus • Opens to TRACHEA (gas exchange system!) • Glottis – opening of trachea, space of folds • Main apparatus of lungs • Epiglottis – flap-like structure, prevents food from entering trachea

  5. I'm clean, now where? • Larynx (also called voice box) • Contains 2 folded structures of vocal cords • When you breathe, there is a large gap between the cords • When speaking, muscles around larynx contract bringing the cords close together • As air passes through the narrower space, the cords vibrate to produce a sound PITCH = length of cords (Did I swallow Adam's apple?)

  6. Trachea • Also called windpipe • Supported by semi-circular cartilage rings (prevent from collapsing) • Like nasal passages, epithelial cells are ciliated and secrete mucus (yum!) It… • Conducts air to lungs (mucus traps foreign materials) • Cilia propels material back to nose and through throat Expelled by coughing or sneezing

  7. Lower Respiratory Tract • Bronchi – two smaller passageways that branch from trachea; lined with ciliated mucus membrane • Enters the lungs • Subdivides to produce a network of bronchioles • Carries air from trachea to the bronchioles • Bronchioles - branches from bronchi • ends in clusters of alveoli (air sacs) • Carries air from bronchi to alveoli

  8. Alveoli – Structure (approx. 300,000,000 sacs)FUNCTIONAL UNIT OF RESPIRATORY SYSTEM • Air sacs in grapelike clusters • Always moist, wall is 1 cell thick • Wall is next to a network of tiny capillaries • Elastic connective tissue fills spaces between alveoli and bronchioles • A lipoprotein based lubricating film to keep from collapsing

  9. Alveoli - FunctionFUNCTIONAL UNIT OF RESPIRATORY SYSTEM • Site of gas exchange • Oxygen diffuses into the capillaries from the alveoli • Carbon dioxide (CO2) diffuses out • Facilitated diffusion by a protein-based molecule in the alveolar allows more oxygen transfer

  10. All together makes the…LUNGS • Right lung has 3 lobes • Left lung has 2 lobes • Each lobe is made of a number of lobules, each with its own bronchiole

  11. Pleural Membrane • Made up of 2 layers of flexible membrane separated by a thin film of lubricating fluid (chicken breast?) • In the thoracic cavity (chest) Why lubricating fluid? • Contains lungs while allowing them to expand and contract without any friction (*sigh)

  12. Diaphragm • Bone or muscle?!?!??! • Thin sheet of __________ under lungs • Shaped like an inverted bowl when relaxed • Separates thoracic Cavity from abdominal Cavity - EJECT and breathing

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