Respiratory Anatomy

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Respiratory Anatomy
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Interesting Facts

• The surface area of the lungs is about the same
  size as a tennis court
• You lose about ½ L of water a day through
  breathing
• Tuberculosis (TB) is caused by bacteria that
  destroy the air sacs in the lungs
• 2 million people die of TB each year

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• Lizards cant breathe when they are running . . .
  their breathing depends on the muscles between
  their ribs which MUST be used during running
• The vapour that comes out of your mouth when you
  cough travels at about 160 km/h
• Some animals (some frogs) can breathe through
  their skin

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• One acre of trees produces enough oxygen to keep
  18 people alive for one year
• Cigarettes and cigarette smoke contain over 4000
  chemicals, including 43 known to cause cancer
• Every cigarette shortens your life by 14 minutes

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The need for oxygen

• Humans need oxygen to survive (250 mL/min). We
  can live several days without water, weeks
  without food, but only minutes without oxygen
• Composition of atmosphere 78 nitrogen, 21
  oxygen, 0.03 carbon dioxide
• Cells obtain energy by breaking down sugars
  oxygen is needed for this to happen

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• The process of breaking down sugars into energy
  is called cellular respiration
• C6H12O6 6O2 ? 6H2O 6CO2 energy
• The opposite is photosynthesis

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Nasal/oral cavity -gt pharynx -gt epiglottis -gt
larynx -gt trachea -gt bronchi -gt bronchioles -gt
alveoli

• Air enters through the nasal cavities or the
  mouth. Three important things happen
• Foreign particles are prevented from entering
  because of tiny hairs.
• Air is warmed and moistened as it enters the
  body.

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Nasal/oral cavity -gt pharynx -gt epiglottis -gt
larynx -gt trachea -gt bronchi -gt bronchioles -gt
alveoli

• From the nasal cavity, air travels through the
  pharynx (air filled channel in the mouth) into
  the larynx through the epiglottis.
• Your tonsils are located in the pharynx

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Nasal/oral cavity -gt pharynx -gt epiglottis -gt
larynx -gt trachea -gt bronchi -gt bronchioles -gt
alveoli

• The pharynx also opens into the esophagus where
  food travels to the stomach.
• When food is chewed, it is forced to the top of
  the mouth, and pushed backwards. This forces the
  epiglottis to close, allowing food to enter the
  esophagus, not the trachea.
• If you swallow too fast, cilia (hair-like protein
  structures) push particles out of respiratory
  tract and force a violent cough.

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Nasal/oral cavity -gt pharynx -gt epiglottis -gt
larynx -gt trachea -gt bronchi -gt bronchioles -gt
alveoli

• Air travels through the larynx, commonly called
  the voice box.
• Elastic ligaments create sound when air from the
  lungs is forced towards the pharynx.
• The larynx is protected by a thick band of
  cartilage, commonly called the Adams Apple. The
  growth of this cartilage and larynx during
  puberty cause the deep voices of males.

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Nasal/oral cavity -gt pharynx -gt epiglottis -gt
larynx -gt trachea -gt bronchi -gt bronchioles -gt
alveoli

• Air travels through the trachea (12 cm longs) and
  through right and left bronchi. These structures
  contain cartilaginous rings for support.
• The bronchi lead to the right and left lung,
  leading air into the bronchioles.

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Nasal/oral cavity -gt pharynx -gt epiglottis -gt
larynx -gt trachea -gt bronchi -gt bronchioles -gt
alveoli

• The bronchioles lead to the alveoli.
• The alveoli are surrounded by capillaries. It is
  here where oxygen and carbon dioxide exchange
  takes place.

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The Lungs

• Well protected by the ribs, sternum and spine
• Contained within the pleura, 2 membranous sacs
  which surround the lungs
• The pleura help to isolate each lung

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• For air to enter the lungs, 2 basic actions must
  occur
• 1. The diaphragm a thin, dome shaped sheet of
  muscle (level with the bottom of the ribs), is
  curved upward in the middle, like an upside down
  saucer as we breathe in, the sheet is pulled
  downward (flattens it out)

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• 2. The second action causes the rib cage to move
  upward and outward this results in contraction
  of the intercostals muscles which lie between the
  ribs

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Inspiration (breathing in)

• The volume of the lungs increases as the chest
  wall moves upward and outward, and the diaphragm
  moves downward
• As the volume increases, pressure decreases as
  the pressure decreases, air rushes in to equalize
  the pressure inside the lungs

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• The process of inspiration requires that muscles
  actively contract

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Expiration (breathing out)

• As the diaphragm relaxes, it pushes up to regain
  its shape
• The intercostals muscles in the chest wall relax
  and the ribs move down and inward

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• These movements decrease the volume of the lungs,
  the pressure inside increases which pushes air
  out of the lungs until the internal and external
  pressure are equal once more
• Breathing out requires no muscle contraction it
  is just the result of muscle relaxation

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Lung Capacity

• Healthy adult average 14-20 breathes per minute
• The amount of air moved by a normal individual
  breathing while at rest is called the tidal
  volume this is only a portion of the potential
  lung capacity

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• If you forcibly push out as much air as you can,
  the air you remove is called the expiratory
  reserve volume
• Similarly the amount of extra air you can
  forcibly pull in is the inspiratory reserve volume

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• These three volumes together make up the vital
  capacity of the lungs
• No matter how hard you try to push air out of the
  lungs, there will always be a small amount left
  in the spaces and tubes called residual air
  capacity

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Structure and Function

• The structure and function of the respiration
  tract is to maximize air exchange, and minimize
  foreign particles from entering the lungs.

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Repiratory system with the Circulatory System

• Respiratory system brings oxygen into the body
• Oxygen will cross the membranes, enter the
  bloodstream, and be transported to the cells
  which require oxygen for their activities