Transcript Respiratory A & P

Respiratory A & P
Aaron J. Katz, AEMT-P, CIC
www.PrehospitalTraining.com/emt
Respiratory system -- purpose
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Bring O2 into the body
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Produce sufficient ATP
Eliminate CO2 from the body
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Prevent acidosis
Respiratory system -- divisions
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Upper respiratory tract
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Parts found outside chest cavity
Lower respiratory tract
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Parts found inside chest cavity
Upper respiratory tract
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Air passages of nose
Nasal cavities
Pharynx
Larynx
Upper trachea
Lower respiratory tract
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Lower trachea
Lungs:
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Bronchi
Bronchioles
Alveoli
Other divisions
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Pleural membranes
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Visceral
Parietal
Diaphragm
Intercostal muscles
Nose and Nasal cavities
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Nose – bones & cartilage
Nasal cavities
Nasal septum
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Nasal mucosa
Ciliated epithelium
Conchae/turbinates
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Increases surface area of mucosa
Warms and moistens inspired air
Nose and Nasal cavities
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Olfactory receptors
Paranasal sinuses
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Lighten the skull
Provides resonance for voice
Pharynx
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Nasopharynx
Oropharynx
Laryngopharynx
Nasopharynx
Behind nose
 Soft palate
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Elevates while eating to prevent food from
going up
Uvula
Adenoid – lymph tissue
Pharyngeal tonsils – lymph tissue
Eustachean tubes
Oropharynx
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Behind mouth
Palatine tonsils
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On lateral wall – lymph tissue
?? Question ??
What is the main function of
tonsils/adenoids?
Larygopharynx
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Most inferior portion of pharynx
Opens anteriorly into larynx
Opens posteriorly into esophagus
Swallowing reflex causes contraction of
oro/laryngopharynx muscles
Why is this important?
Larynx – “Voice Box”
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Voice production
Conducts air to/from pharynx to/from trachea
Composed of 9 pieces of cartilage
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Connected by ligaments
Prevents collapse of larynx
Tony Kubek
Ciliated epithelium – except for vocal cords
Larynx – “Voice Box”
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Thyroid cartilage – “Adams Apple”
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Epiglottis – on top of glottis
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largest cartilage of larynx
Uppermost cartilage of larynx
Leaf shaped covering of trachea
Prevents food from entering trachea
Hyoid bone supports epiglottis
Larynx – “Voice Box”
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Vocal cords
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Glottis
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Opening on either side of vocal cords
Breathing
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On either side of glottis
Vocal cords move to side
Talking
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Vocal cords pulled to center
Exhaled air causes vibration  speech
Larynx – “Voice Box”
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Controlled by vagus/accessory cranial nerves
arytenoid cartilage
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Attach to vocal cords
Pivoting arytenoids move cords
Arthritis of arytenoids?
Corniculate
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“Corn kernel”
Covers arytenoids
?? Questions ??
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What does “bearing down” accomplish?
When would one want to do this?
Why are the positions of the arytenoids
important?
Trachea
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4 – 5”
Made up of 16-20 C-shaped cartilages
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Keeps trachea open
Opening is posterior – allows for expansion of
esophagus with food
Ciliated epithelium
Top cartilage is cricoid cartilage
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Completely encloses the trachea
Implications?
Trachea vs. Esophagus
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Trachea
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Esophagus
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Opening maintained by cartilage
Antertior to esophagus
Smaller than “open” esophagus
Usually closed unless food is inside
Posterior to trachea
“Open” esophagus larger than trachea
Very easy to intubate the esophagus –
with disasterous results
Bronchial Tree
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Right/Left “primary bronchi
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Bronchioles
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Right – 3 branches  3 lobes
Left – 2 branches  2 lobes
No cartilage to maintain lumen
Implications for asthmatics
Alveoli
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“where the action takes place”
Alveoli
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Clusters of elastic tissue
One cell thick
Surrounded by pulmonary capillaries
Tissue fluid on internal surface
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Pulmonary surfactant
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Potential problem: surface may stick to itself –
collapsed alveoli
Coats tissue fluid
Reduces surface tension – preventing collapsed alveoli
Hyaline Membrane Disease – Respiratory Distress
Syndrome (“RDS”)
Lung Tissue
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Base rests on diaphragm
Apex is at the level of clavicle
Hilus
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Indentation on medial surface of lungs
Bronchus & pulmonary artery/vein enter lung at the
Hilus
Visceral pleura
Parietal pleura
Serous fluid
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Prevents friction
Keeps pleura from separating
Ventilation
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Movement of air to/from alveoli
Inhalation
Exhilation
Under control of medulla and pons
Muscles of ventilation
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Diaphragm
External intercostals
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Pulls ribs upward/outward
Inhalation
Internal intercostals
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Pulls ribs downward/inward
Exhalation
Air pressures
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Atmospheric pressure: 760mm Hg
Intrapleural pressure
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756mm Hg
“negative pressure”
Intrapulmonic pressure
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Pressure within bronchial tree and alveoli
Pressure depends on point within the
breathing cycle
Inhalation/inspiration
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An active process
Brain detects high levels of CO2 in
the blood and sends an “impulse”
Medulla  phrenic nerves  intercostal
muscles
Diaphragm contracts  moves
downward
Inhalation/inspiration
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External intercostals pull ribs outward
and upward
Intrapulmonic pressure decreases below
760mm Hg
Air rushes in – until intrapulmonic
pressure equals atmospheric pressure
Intrapleural pressure becomes more
negative
?? Question ??
What’s different about a COPD patient?
Exhalation/expiration
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Passive process in “normal” people
Impulses from medulla decrease
Diaphragm and external intercostals relax –
internal intercostals contract
Intrapulmonic pressure rises above 760mm
Hg
Air rushes out until intrapulmonic pressure
equals atmospheric pressure
Lung and healthy alveoli recoil to initial
shape
Respiration
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Two types
External respiration
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Gas exchange at alveoli/pulmonary
capillaries
Internal respiration
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Gas exchange at body tissue/systemic
capillaries
Diffusion
Within the body a gas will diffuse from
an area of greater concentration to an
area of lower concentration
Partial Pressure of Gases
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The partial pressure (measured in
mm Hg) of a particular gas within a
mixture of gases is the pressure that
the gas exerts
Gas may be in gas form or dissolved in
a liquid (e.g. blood)
“P” – e.g. PO2 means the partial
pressure of oxygen a mixture of gasses
Typical partial pressures
PO2
PCO2
Atmosphere
160
0.30
Alveoli
104
40
Pulmonary
blood (venous)
Systemic blood
(arterial)
Tissue fluid
40
45
100
40
40
50
Calculation of partial pressures
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Pgas = % of gas in the mixture X total
pressure
For example:
PO2 = 21% X 760 = 160mm Hg in the
atmosphere
Why is this important?
What does this have to do with
diffusion?
Movement of gasses
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Inspired air in alveoli: High PO2; low PCO2
Blood in pulmonary capillaries: Low PO2; high
PCO2
What happens?
O2 diffuses from alveoli to pulmonary
capillaries
CO2 diffuses from pulmonary capillaries to
alveoli
Life continues nicely!
Internal respiration
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Arterial blood reaching systemic
capillaries: High PO2; low PCO2
Body tissues (after production of
energy): low PO2; high PCO2
What happens?
O2 diffuses from blood to tissues
CO2 diffuses from tissues to blood
Life continues nicely!
Some definitions
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Tidal Volume (TV): volume inspired in
one quiet breath
Minute Volume (MV): volume inspired in
one minute of quiet breathing
MV = RR X TV
MV approximately 5 – 6 liters
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See book for other similar definitions
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Respiratory Disease Processes
Arise from problems with one or more of:
 Brain’s sensing O2 needs
 Chest wall movement
 Blood flow to lungs
 Air exchange
 Amount of lung surface area
 Quality of lung surface area
Problems with brain’s sensing O2 needs
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CO2 retention
Head trauma
Depressant drugs (e.g. narcotics)
Hypo/hyperthermia
Stroke
Problems with chest wall movement
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Trauma
Rib fractures
Flail chest
Ruptured diaphragm
MAST usage
Pregnancy
Gastric distention
Airway constriction
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FBAO
Asthma, croup, epiglottitis
Problems with blood flow to lungs
Pulmonary emboli caused by:
 Blood clots (e.g. DVT)
 Air
 Amniotic fluid (explosive delivery)
 Fat/marrow (long bone fracture)
Problems with air exchange
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Thick alveolar walls (lung diseases)
“Water” (A.P.E.)
Loss of elasticity (COPD – emphysema)
Mucus/pus (pneumonia)
Mucus/pus (COPD – chronic bronchitis)
Insufficient perfusion (shock)
Problems with amount of lung surfaces
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“Water” (A.P.E., aspiration)
Pneumothorax (“atelectasis” –
“collapsed lung”)
Obstruction
Emphysema
Gastric distention
Problems with quality of lung surfaces
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A.P.E.
Emphysema
Pulmonary burns
Pulmonary contusions
In summary…
Items needed for quality respiration:
 O2 usage
 Sufficient lung surface area
 Quality lung surface area
 Brain function
 Functioning chest wall
  Known as the “Fick Principle”