RESPIRATORY SYSTEM

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RESPIRATORY SYSTEM
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FUNCTION

• Responsible for supplying oxygen (GAS) and
  disposing carbon dioxide(GAS).
• It includes the nose, pharynx, larynx, trachea,
  bronchi and lungs.

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NOSE-

• FUNCTION- warms, cleans and humidifies air
• NOSTRILS (EXTERNAL NARES)-
• NASAL CAVITY- interior of the nose
• NASAL SEPTUM- midline that separates the nasal
  cavity

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3 ways nasal cavity protects the lungs

• 1. RESPIRATORY MUCOSA- lines the nasal cavity
  and warms and moistens the air as it flows past
• 2. CILIA- (pseudostratified columnar epithelial)
  filter bacteria and other contaminants to the
  throat- (except on cold days when the cilia
  become slow and allow mucus to drip- runny nose

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3 ways nasal cavity protects the lungs

• 3. CONCHAE- 3 levels of projections or lobes that
  greatly increase the surface area to allow mucosa
  to take affect SUPERIOR CONCHAE, MIDDLE CONCHAE,
  and INFERIOR CONCHAE

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PARANASAL SINUSES-

• cavities in the skull which lighten the skull and
  used for speech resonance (sound different with
  plugged nose)

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PHARYNX-(THROAT)

• muscular passageway that carries food and air
• NASOPHARYNX- top near the nostrils
• OROPHARYNX- back of the mouth
• LARYNGOPHARYNX- bottom where esophagus and
  trachea meet

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LYMPHATIC TISSUE IN THE PHARYNX

• FIGHTS OF INFECTIONS
• PHARYNGEAL TONSILS (ADENOIDS)- located high in
  the nasopharynx
• PALATINE TONSILS-located at the end of the soft
  palate
• LINGUAL TONSILS- located under the tongue

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• LARYNX- (VOICE BOX)- Eight rigid hyaline
  cartilages and EPIGLOTTIS (elastic cartilage flap
  over) routes air and food into the proper
  channel.
• THYROID CARTILAGE- Adams Apple- largest of the
  cartilage and does the most protection
• TRUE VOCAL CORDS- (VOCAL FOLDS) vibrate with
  airflow movement

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Pitch control

• Intrinsic muscles control tension of the vocal
  cords
• High tension high pitch
• Low tension low pitch

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TRACHEA- (WINDPIPE)- travels from larynx to
bronchi

• - 10-12 cm (4 inches)
• - walls are reinforced with C-shaped rings of
  hyaline cartilage
• -open parts of the ring are against the esophagus
  and allow us to swallow large portions of food

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TRACHEA

• -lined with mucosa and cilia which sweep upwards
  away from the lungs
• In smokers the cilia becomes damaged and the
  mucus can only be removed by coughing (smokers
  cough)

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Choking occurs in the trachea due to its rigidity

• HEIMLICH MANEUVER- make a fist and press inward
  and upward just below the xiphoid process of the
  sternum
• TRACHEOSTOMY- a surgical procedure used when the
  airway is obstructed - cut a hole through the
  trachea just below the larynx and insert a solid
  tube to allow breathing

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BRONCHI

• PRIMARY BRONCHI- formed by a division of the
  trachea.
• Right primary bronchus- is wider, shorter and
  straighter than the left
• -Bronchi enter the lungs at the center of the
  lobes called the HILUS.

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BRONCHIAL TREES (respiratory tree)

• -Once the bronchi come in contact with the lungs
  then it divide into smaller and smaller branches
  called secondary bronchi, tertiary bronchi etc
• -The smallest are called bronchioles

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Lungs
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LUNGS

• LUNGS - 5 lobes total- 3 on the right and 2 on
  the left
• -MEDIASTENUM- gap between the lungs that houses
  the heart
• APEX- is the top the lungs located just under
  the clavicle
• BASE- is the bottom of the lungs and rests on
  the diaphragm
• - lungs are covered in Visceral Pleura and the
• -thoracic cavity is lined with Parietal Pleura-
  (these reduce friction)

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ALVEOLI- air sacs

• - 300 to 500 million in the average adult
• -provide the only site of gas exchange between
  the external environment and the bloodstream

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RESPIRATORY PHYSIOLOGY

• How does oxygen (gas) from the environment get to
  the cells and how does carbon dioxide (gas) exit
  the cells and get placed back into the
  environment?
• RESPIRATION- 4 step process
• 1. PRIMARY VENTILATION- (BREATHING) moving air
  into and out of the lungs to continually supply
  alveoli with fresh air
• 2. EXTERNAL RESPIRATION- Diffusion (gas exchange)
  between the pulmonary blood and alveoli

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RESPIRATION CONT.

• 3. RESPIRATORY GAS TRANSPORT- Oxygen and carbon
  dioxide must be carried to and from the various
  cells of the body via the bloodstream
• 4. INTERNAL RESPIRATION- Diffusion (gas exchange)
  between the blood and individual cells (CELLULAR
  RESPIRATION)

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MECHANICS OF BREATHING- increasing and
decreasing lung volume

• VOLUME CHANGES LEAD TO PRESSURE CHANGES, WHICH
  LEAD TO THE FLOW OF GASES TO EQUALIZE THE
  PRESSURE.

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INSPIRATION - air moving into the lungs

• - DIAPHRAGM - contracts and moves inferiorly and
  flattens out from its dome shape
• -EXTERNAL INTERCOSTALS- contract and lift the rib
  cage and thrust the sternum forward
• - lungs which adhere tightly to the thoracic
  cavity walls expand increasing the volume
• - as volume increases the gas spreads out causing
  a partial vacuum which sucks air into the lungs
  to equalize the pressure with the atmospheric
  pressure

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EXPIRATION air moving out of the lungs

• DIAPHRAGM- relaxes back to its bell shape
• EXTERNAL INTERCOSTALS- relax lowering the rib
  cage
• - lungs are forced more closely together and
  pressure rises causing air to be expelled
• In a FORCED EXPIRATION- Internal intercostals
  muscles are activated to help depress the ribcage
  and abdominal muscles contract to help force air
  out.

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RESPIRATORY VOLUMES

• TIDAL VOLUME- (VT) -During normal breathing
  approximately 500 mL of air move in and out of
  the lungs.
• INSPIRATORY RESERVE VOLUME- the amount of air a
  person can inhale more than the tidal volume-
  typically between 2100 and 3200 mL

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RESPIRATORY VOLUMES

• EXPIRATORY RESERVE VOLUME- the amount of air
  that can be expelled after tidal expiration-
  typically 1200mL
• RESIDUAL VOLUME- even after the most strenuous
  expiration you have about 1200mL of air
• Residual volume is important because it allows
  gas exchange to go on even between breaths and
  keeps alveoli inflated

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RESPIRATORY VOLUMES

• VITAL CAPACITY-(VC) the volume of air that can
  be expelled after the deepest inhalation and the
  greatest exhalation- (everything but the residual
  volume)
• -found by the sum of the tidal volume ,
  inspiratory reserve volume, and expiratory
  reserve volume
• - typically about 4800 mL in healthy adult males

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Lung Capacity
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LUNG CAPACITY

• SPIROMETER- measures respiratory capacities by
  measuring air volume
• RESPIRATORY SOUNDS-
• BRONCHIAL SOUNDS- occur as air rushes through
  the trachea and bronchi (high pitch and louder)
• VESICULAR SOUNDS- occurs as air fills the
  alveoli (lower pitch, softer and resemble a
  muffled breeze)

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BREATHING RATES AND BREATHING PROBLEMS

• EUPNEA- normal respiration rate
• HYPERPNEA- breathe more vigorously and deeply
• HYPOXIA- lack of oxygen getting to the cells

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BREATHING RATES AND BREATHING PROBLEMS

• APNEA- brief periods where breathing is stopped
  (causes can be anxiety attacks, sleep disorders)
• CYANOSIS- can occur with extended lack of oxygen-
  (bluish coloration of the skin)

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FACTORS INFLUENCING RESPIRATORY RATES

• 1. PHYSICAL FACTORS- increased body temperatures,
  talking, coughing, and sneezing
• 2. CONSCIOUS CONTROL- (during singing,
  swallowing, and holding of breath) voluntary
  control is limited because when oxygen supply is
  getting low or blood pH falls medulla will take
  over)
• 3. EMOTIONAL FACTORS- stress, upset, or scared
  are some of the examples
• 4. CHEMICAL FACTORS- levels of carbon dioxide and
  oxygen in the blood (there is an oxygen sensor in
  the aortic arch and carotid artery)

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FACTORS INFLUENCING RESPIRATORY RATES

• Having high levels of carbon dioxide is more of
  a signal to the brain than low levels of oxygen
  
• As CO2 levels rise and pH levels drop in the
  blood you begin to breathe more deeply and more
  rapidly this is called --- HYPERVENTILATION

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FACTORS INFLUENCING RESPIRATORY RATES

• EXCEPTION- People who retain high levels of
  carbon dioxide due to emphysema and chronic
  bronchitis. Their brain no longer reads the high
  levels of CO2 as important as the low levels of
  oxygen. This is why patients who require
  oxygen are given low levels of oxygen because if
  they were given high levels they would stop
  breathing.

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DISORDERS

• CARBON MONOXIDE POISONING- hypoxia that
  occurs because carbon monoxide gas binds more
  readily to hemoglobin than oxygen does. So this
  crowds out (low amounts of CO) or even totally
  displaces the oxygen (high amounts of CO)

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DISORDERS

• CHRONIC BRONCHITIS- mucosa of the lower
  respiratory passages becomes severely inflamed
  and produces excessive amounts of mucus. The
  excess mucus impairs ventilation and increases
  the risk of lung infections. Hypoxia and carbon
  dioxide retention occurs.

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DISORDERS

• ASTHMA hypersensitive bronchial passages that
  quickly inflame due to irritants (dust mite, dog
  dander, fungi)

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DISORDERS

• EMPHYSEMA- the alveoli enlarge and become less
  elastic (fibrosis) and cause the airways to
  collapse during exhale- (patients give incredible
  amounts of energy to exhale)

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DISORDERS

• CYSTIC FIBROSIS- (genetic) 1 out of 2400-
  oversecretion of a thick mucus that clogs the
  respiratory system.

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CARBON DIOXIDE- is transported in plasma as a
bicarbonate ion (HCO3-)

• CO2 leaves the individual cells and bonds with
  water in the plasma to form carbonic acid which
  quickly separates into H ions and bicarbonate
  ions HCO3 This is what causes the pH levels to
  drop and become more acidic in blood
• CO2 H2O ? HCO3- H
• For carbon dioxide to be released for diffusion
  from its bicarbonate ion form it must first bond
  with a hydrogen atom to form carbonic acid
  (H2CO3 ). Then the carbonic acid breaks down to
  form CO2 and H2O and can be released into the
  lungs
• HCO3- H ? CO2 H2O

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GAS TRANSPORT

• SURFACTANT- covers the alveoli reducing the
  surface tension which prevents the alveoli from
  collapsing during expiration
• OXYGEN is carried through the bloodstream
  attached to hemoglobin to form OXYHEMOGLOBIN
  (HbO2) - (small amount of oxygen is dissolved in
  the plasma)

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GAS TRANSPORT

• RESPIRATORY MEMBRANE- where gases flow on one
  side and blood flows on the other side.
• -Walls of alveoli are composed largely of a
  single, thin layer of squamous epithelial cells.
  (Much thinner than a piece of paper)
• -Pulmonary capillaries (one cell thick) cover
  the external surfaces of the alveoli for gas
  exchange
• -Oxygen and carbon dioxide pass through the one
  celled membranes by diffusion.

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DISORDERS

• CHRONIC OBSTRUCTIVE PULMONARY DISEASE-
  chronic bronchitis and emphysema
• major cause of death and disability
• 4 features in common with COPD
• 1. patients almost always have a history of
  SMOKING
• 2. DYSPNEA- labored breathing occurs and
  becomes progressively worse
• 3. coughing and frequent pulmonary infections
• 4. retain carbon dioxide (HYPOXIC ) and have
  respiratory acidosis