Breath

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Chapter 28

• Breath

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Respiratory System

• 2 central functions
• Capture distribute oxygen
• Dispose of carbon dioxide
• Other functions
• Regulates pH in blood
• Speech
• Respiration exchange of gases between
  atmosphere outside body and cell within body

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Respiratory System Types of Respiration

• External respiration exchange of gases between
  atmosphere and lungs
• Internal respiration exchange of gases between
  blood and cells of body

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Respiratory System Structures

• Lungs
• Site of external respiration
• 2 sides
• Right lung larger 3 lobes
• Left lung smaller 2 lobes covers heart
• Located inside thoracic cavity bounded by rib
  cage and diaphragm
• Pleura membranes that secrete a slippery fluid
  that decreases friction from breathing
• Lines entire cavity and encases lungs

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Respiratory System Steps of Air Passage

• External respiration
• Air filters through small hairs in nose passes
  into nasal cavity
• Mucus membranes warm moisten air
• Cilia lines walls of nasal cavity traps
  particles
• Moves to pharynx
• Pharynx tube at back of nasal cavity mouth
• Passageway for food air
• When food is swallowed
• Epiglottis flap of skin that covers passageway
• When air is taken in
• Air passes to trachea
• 10-12 cm long lined with cilia

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Respiratory System Steps of Air Passage

• Larynx upper end of trachea
• Voicebox
• Trachea
• Branches off into two bronchi which lead to a
  specific lung
• Walls made of smooth muscle cartilage
• Lined with cilia
• Bronchi branch into bronchioles
• Filled with cilia mucus
• Bronchioles branch into alveoli
• Air sacs
• Where gas exchange takes place
• Network of capillaries
• http//www.wisc-online.com/objects/index_tj.asp?ob
  jIDAP15104
• http//www.smm.org/heart/lungs/breathing.htm

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Respiratory System Steps of Air Passage

• Internal respiration
• When air is in lungs
• Oxygen in air crosses alveolar membranes and
  capillary walls to enter blood
• Carbon dioxide crosses capillary walls and
  alveolar membrane to enter alveoli
• Oxygen diffuses into blood
• 3 dissolves in plasma
• 97 moves into RBCs
• Combines with hemoglobin
• 4 iron 4 oxygen
• Oxygen is released from iron and sent into
  capillaries and into cells to become oxygenated

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Respiratory System Steps of Air Passage

• Carbon dioxide diffuses out of cells and into
  blood
• 8 dissolves in plasma
• 25 binds to hemoglobin
• 67 reacts with water to form bicarbonate ions
• Bicarbonate ions travel in blood
• Reaches lungs and form carbonic acid which forms
  carbon dioxide and water
• Carbon dioxide moves into alveoli and is exhaled

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Respiratory System Breathing

• Breathing process of moving air into and out of
  lungs
• Inspiration process of taking air into lungs
• Chest expands ribs move up and out
• Diaphragm contracts
• Air moves in
• Expiration process of air leaving lungs
• Diaphragm and rib muscles relax
• Lungs deflate
• Air moves out
• Regulation of breathing
• More activity requires more oxygen
• Rate of breathing controlled by brain
  brainstem

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Common Respiratory Diseases

• Lung cancer
• http//www.bioscope.org/taste/cd1/a0255a.htm --
  normal cilia
• http//www.bioscope.org/taste/cd1/a0255b.htm --
  smokers cilia
• Emphysema loss of elasticity
• Pleurisy infection that causes loss in fluid
  that increases friction during breathing
• Painful to breath
• Laryngitis inflammation of vocal cords
• Bronchitis inflammation of bronchi

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Amazingbut true

• At rest, a person breathes about 14 to 16 times
  per minute. After exercise it could increase to
  over 60 times per minute.
• New babies at rest breathe between 40 and 50
  times per minute. By age five it decreases to
  around 25 times per minute.
• The total surface area of the alveoli (tiny air
  sacs in the lungs) is the size of a tennis court.
  
• The lungs are the only organ in the body that can
  float on water.
• The lungs produce a detergent-like substance
  which reduces the surface tension of the fluid
  lining, allowing air in.