The Respiratory System

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The Respiratory System
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Respiratory System

• Living cells need energy for maintenance, growth,
  defense, and replication
• Aerobic respiration
• Body requires O2 and produces CO2
• Our bodies can achieve this by our respiratory
  exchange surfaces inside the lungs

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Functions of the Respiratory System

• 1. moves air to and from the gas- exchange
  surfaces
• 2. provides defense against pathogenic invasion
• 3. permits vocal communication
• 4. helps control body fluid pH

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Respiratory Tract

• Conducting portion and Respiratory portion
• Conducting airways carry air to and from the
  exchange surfaces on the lungs
• these airways filter, warm and humidify the air
• This protects the alveoli from debris, pathogens
  and environmental extremes
• Respiratory Portion includes the smallest and
  most delicate bronchioles and alveoli that are
  the site for gas exchange

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The Nose

• Air enters the respiratory system via the
  external nares (nostrils)
• Coarse hairs guard the nasal cavity from large
  airborne particles such as sand, dust and insects

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The Pharynx

• Chamber shared by the digestive and respiratory
  systems
• Extends between the internal nares and the
  entrance to the larynx and esophagus

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• Hyoid bone is a bone in the neck, that sits on
  top of the larynx
• It is the only bone in the human skeleton not
  articulated to any other bone.
• It is supported by the muscles of the neck and in
  turn supports the root of the tongue.

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The Larynx

• Incoming air leaves the pharynx, passes through
  the glottis, which is surrounded and protected by
  the larynx
• Prevents food from going down the trachea
• Filters air, voice box
• Vocal cords vibrate when air passes through the
  glottis generating sound waves
• At puberty, the larynx of a male enlarges more
  than that of a female. Their vocal cords are
  thick and longer with lower tones compared to a
  female.

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The Trachea

• windpipe
• Tough, flexible tube
• 11 cm long and 2.5 cm in diameter
• The cartilage bands of the trachea support it and
  keep it from collapsing (20 of them)
• C-shape of the cartilages face towards the
  esophagus and do not continue around the trachea

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Tracheal Blockage

• Foreign objects can become lodged in larynx or
  trachea
• Coughing can expel the object if the airway isnt
  completely blocked.
• If a person cannot breathe or speak, immediate
  action must be taken
• Heimlich Maneuver or abdominal thrust
• This elevates the diaphragm forcefully and can
  generate enough pressure to remove the object.

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Thyroid Gland

• Regulates metabolism by secreting Thyroxine
• Maintains hormone levels 
• common thyroid problems involve abnormal
  production of thyroid hormones. 
• Hyperthyroidism- due to an overproduction of
  thyroid hormones
• Hypothyroidism- due to an underproduction of
  thyroid hormones.

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Bronchi

• Left Bronchus- takes air to the left lung
• Right Bronchus- takes air to the right lung
• C-Shaped rings that resemble the tracheas

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Bronchial Tree

• Think of a tree having a trunk (trachea), two
  large branches (L. Bronchi R. Bronchi)
• Each of the large branches give rise to secondary
  bronchi that enter the lobes of that lung.
• The bronchi divide into 9-10 smaller tertiary and
  the bronchi become smaller and smaller.
• When the passageways diameter is lt1 mm, the
  narrow passage is a bronchiole

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Bronchioles

• Control the amount of resistance to air flow
• Control the distribution of air in the lungs
• Sympathetic activation leads to a relaxation of
  smooth muscles in the walls causing dilation of
  the respiratory passageways
• Constriction can block the passageways
• Ex. Asthma or allergic reactions- inflammation of
  the bronchioles

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Alveolar Ducts and Alveoli

• Bronchioles open into chambers called alveolar
  ducts
• The passageways end at the alveolar sacs
• Alveolar sacs- supply air to alveoli
• Alveoli- pockets at the end of the respiratory
  tree
• Gas exchange with the blood occurs here across
  the respiratory membrane

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Gas exchange by diffusion in the lungs The
alveoli have a capillary network CO2 leaves the
veins and Oxygen enters the alveoli
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Pneumonia

• Infection of the lobules of the lung causing
  inflammation
• Respiratory function deteriorates
• Swelling and constricting of the respiratory
  bronchioles
• More likely when respiratory defenses are
  compromised by other factors
• For ex. Smoking, AIDS

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The Lungs

• Area of gas exchange
• Left and Right Lobes
• Paired organs of respiration
• Left- area of gas exchange on L. side
• Anterior Lobe of Right Lung
• Median Lobe of Right Lung
• Posterior Lobe of Right Lung
• Postcaval Lobe of Right Lung

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Lungs

• Most of the actual volume of each lung consists
  of air-filled passageways and alveoli
• The lung is light and spongy
• Elastic fibers give the lungs the ability to
  tolerate large changes in volume

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Lung Capacity

• The total volume of the lungs can be divided into
  volumes and capacities
• Expiration reserve vol.- amt. of air that could
  be voluntarily expelled
• Inspiratory reserve volume- amt. of air that can
  be taken in
• Vital capacity- sum of the inspiratory reserve
  vol. expiratory reserve vol. the tidal vol.
  vital capacity

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Lung Capacity Cont.

• Residual Volume- air that remains after
  exhausting the expiratory reserve vol.
• Minimal Volume- when the lungs collapse and the
  amt. of air in the respiratory system is reduced
  to the minimal vol.

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Pleural Cavities

• The thoracic cavity has a broad cone shape
• The walls are the rib cage and its floor is the
  muscular diaphragm
• Diaphragm separates the thoracic cavity from the
  abdominal cavity
• Each lung occupies a single pleural cavity, lined
  by a pleura membrane

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Pleural Cavity
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Respiration Process

• 1. Pulmonary ventilation or breathing
• Movement of air in and out of lungs
• 2. Gas diffusions across respiratory membrane
• 3. Storage and transport of oxygen and carbon
  dioxide
• 4. Exchange of oxygen and carbon dioxide between
  the blood and intestinal fluids

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Tuberculosis

• TB results from a bacterial infection of the
  lungs
• Bacteria colonize in the respiratory passageways
  or alveoli
• Symptoms vary- usually coughing and chest pain,
  fever, night sweats, fatigue, wt. loss
• Major health problem throughout the world
• Transmitted through casual contact
• Basically anyone alive and breathing is at risk
• 2 billion are infected at this time and 8 mill.
  Cases are diagnosed each year

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Bacteria have colonized in the respiratory
passageways or alveoli Can target almost any part
of your body
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Pulmonary Ventilation

• Physical movement of air into and out of the
  respiratory tract
• A single breath or respiratory cycle consists of
  an inhalation (inspiration) and an exhalation
  (expiration)
• In other words, breathing in and out one time is
  a respiratory cycle

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Emphysema

• Chronic, progressive condition
• Shortness of breath and inability to tolerate
  physical exertion
• Destruction of the alveolar surfaces and
  inadequate surface area for oxygen and carbon
  dioxide exchange
• Linked to inhalation of air containing fine
  matter or toxic vapors Ex) cigarette smoke

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Gas Pickup and Delivery

• Oxygen is retained by hemoglobin
• If a tissue has a low oxygen content, oxygen will
  be released by hemoglobin
• Carbon Dioxide all transports are reverseable
• after entering the bloodstream can CO2 may be
• 1. dissolved in the plasma
• 2. bound to the hemoglobin in RBC
• 3. converted to a molecule of carbonic acid

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• Carbonic acid breaks down into a hydrogen ion and
  a bicarbonate ion
• Most hydrogen ions get bound up by hemoglobin
  molecules
• Bicarbonate ions diffuse in to the surrounding
  plasma
• Here they associate with sodium ions to form
  sodium bicarbonate (NaHCO3)

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Carbon Monoxide Poisoning

• Each year entire families can be killed by leaky
  furnaces or space heaters
• Found in the exhaust of automobiles, oil lamps,
  space heaters
• Carbon monoxide competes with oxygen for the
  binding sites on heme units and usually wins
  because it has a much stronger affinity for
  hemoglobin

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Anemia

• a deficiency of red blood cells or the hemoglobin
  molecules within them
• Oxygen has trouble getting where to it needs to
  go because hemoglobin is not accessible
• Therefore, the blood struggles to bring oxygen
  molecules to tissues for energy in the body
• This can be very serious because the human body
  depends on oxygen to survive. Ex.)
  holding your breath under water 
• Weakness, fatigue

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SIDS

• Sudden Infant Death Syndrome
• crib death
• Kills 10,000 infants each year in the United
  States alone
• Usually in infants 2-4 months old and usually
  between midnight and 9 am in the late fall and
  winter months
• Eyewitness accounts- infant suddenly stops
  breathing, turns blue and relaxes
• Causes-many ideas- genetic, respiratory
  infections, sleeping position, environment

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Lung Cancer

• Originates in the bronchial passageways or
  alveoli
• 85-90 of all lung cancers are the direct result
  of cigarette smoking
• Symptoms usually dont appear until the point
  when the tumor masses are restricting airflow.
• Common symptoms- cough, wheeze, chest pain,
  shortness of breath, wt. loss
• Treatments vary- surgery, radiation or
  chemotherapy may be involved

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Lung Cancer

• Incidence of lung cancer for
• Nonsmokers- is 3.4 per 100,000
• Smokers (half a pack and a pack a day) 59.3 per
  100,000
• Smokers (one to two packs a day) 217.3 per
  100,000
• This isnt surprising with all the toxic
  chemicals contained in the smoke