Respiratory Notes

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The Respiratory System
2
Respiratory Notes

• The main function of the respiratory system is to
  transport gases.
• between the environment and the cardiovascular
  system.

3
There are 2 main components of the respiratory
system

• External Respiration Exchange of gases between
  atmosphere and the blood
• Internal Respiration Exchange of gases between
  blood and cells of the body

4
Passage of Air ?

• The site of gas exchange between the atmosphere
  and the blood is the lungs.

• So, how does air get from the atmosphere to our
  lungs?

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Mouth or Nose

• Hairs filter out particles

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Nasal Cavity

• Warms and moistens air
• Cilia trap particles, swept into throat (w/
  mucus)

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Pharynx

• Tube with passageways for both food (esophagus)
  and air (trachea)
• When food is swallowed, epiglottis (flap of
  cartilage) presses down and covers trachea
• When air is taken in, epiglottis is up and allows
  entry into trachea

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Trachea

• Cartilaginous tube
• Cilia-lined, sweep particles into throat
• Larynx at upper end--voice box

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Bronchi

• Two main branches off of the trachea
• Each lead to a lung (right or left)

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Bronchioles

• Smallest branches
• Each branch into sacs of alveoli

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Alveoli

• Clusters of tiny air sacs
• Alveoli are surrounded by a network of
  capillaries
• Gas exchange occurs here
• Each lung contains 3 million alveoli750 sq. feet
  total surface area!

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II. Gas Exchange
Once air is inside of the lungs, gases are
exchanged between the alveoli and the blood in
the capillaries
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Gas Exchange
14
Oxygen

• In the lungs,O2 diffuses from alveoli into the
  bloodstream (due to concentration gradient)
• 97 binds to hemoglobin
• One molecule can carry 4 O2s
• In the body, O2 diffuses from capillaries into
  nearby tissues

15
Carbon Dioxide

• In the body,CO2 diffuses from tissues into
  capillaries
• 25 binds to hemoglobin
• The rest travels in the plasma in some form
• In the lungs, CO2 diffuses from capillaries into
  alveoli

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Breathing Mechanism ?

• Inspiration
• Air enters the lungs
• Rib muscles contract, rib cage expands
• Diaphragm moves down
• Increased volume in thoracic cavity draws air in

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Breathing Mechanism ?

• Expiration
• Air exits the lungs
• Rib muscles relax, rib cage relaxes
• Diaphragm moves up
• Decreased volume in thoracic cavity forces air out

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Breathing Mechanism ?

• Regulation
• Brain and brain stem monitor CO2 levels in the
  blood
• While conscious, we can override control (holding
  breath, swimming)

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Inhalation Exhalation..