Chapter 22: Respiratory System Flashcards
Larynx (voicebox)
- vocal folds macy act as a sphincter to prevent air passage
- example: Valsalva’s Maneuver
- glottis closes to prevent exhalation
- abdominal muscles contract
- intra-abdominal pressure rises
- helps to empty the rectum or stabilizes the trunk during heavy lifting
trachea
- windpipe: from the larynx to primary bronchioles
- wall composed of 3 layers:
1. mucosa
2. submucosa
3. adventitia: outermost layer
*tracheostomy
Conducting zone structures
Trachea-> right and left main (primary) bronchi
- main bronchus enters the hilum of one lung
- each main bronchus branches into lobar (secondary) bronchi (three right, 2 left)
- each lobar bronchus supplies one lobe
Conducting zone structures
Trachea-> right and left main (primary) bronchi
- main bronchus enters the hilum of one lung
- each main bronchus branches into lobar (secondary) bronchi (three right, 2 left)
- each lobar bronchus supplies one lobe
** Lobar (secondary) branchus-> segmental (tertiary) bronchus-> bronchioles-> terminal bronchioles are the smallest
respiratory zone
respiratory bronchioles, alveolar ducts, alveolar sacs (clusters of alveoli)
alveoli features
- surrounded by fine elastic fibers
- open alveolar pores-equalizes air pressure throughout the lung
- house alveolar macrophages-keep surfaces sterile
smoking
- tobacco
- nicotine: stimulates increased HR
- carbon monoxide: blocks oxygen transport in HB
- Tar: cancer causing
- > smoking paralyzes cilia
- > without cilia inhaled particles cling to wall or enter lung
- cilia helps move mucus
lungs
2 lungs
- left has 2 lobes
- right has 3 lobes
- > Apex-> superior tip just under clavicle
- > Base: concave inferior portion above diaphragm
- > hilum: vessels
Occasionally food or liquids will “go down the wrong pipe,” initiating a cough reflex. Which structural barrier has been breached if this happens?
epiglottis
The respiratory membrane is composed of ________.
the alveolar membrane, the capillary wall, and their fused basement membrane
Men tend to have deeper voices than women because their vocal cords …
are longer and thicker
Blood supply
- > pulmonary circulation (low pressure, high volume):
- pulmonary AA- blood from heart to be oxygenated
*pulmonary vv: freshly oxygenated blood
- > Bronchial circulation:
- oxygenated blood to lung tissue
Pleurae
- > thin, double-layered serosa
- parietal pleura: thoracic wall
- visceral pleura: on lung tissue
- pleural space: pleural fluid for lubrication
- > allows friction free movement during breathing
pressure relationships in the thoracic cavity
- Atmospheric pressure:
- pressure exerted by the air surrounding body
- 760 mm Hg at sea level
- > respiratory pressures:
- negative respiratory pressure is less than Patm :(
- positive respiratory pressure is greater than Patm
- zero respiratory pressure= Patm
intrapulmonary pressure
Intrapulmonary (intra-alveolar) pressure (Ppul)
- Pressure in the alveoli
- Always eventually equalizes with Patm
Intrapleural pressure (Pip):
- Pressure in the pleural cavity
- Always a negative pressure (
pressure relationships
- if Pip (intrapleural pressure)= Ppul (intrapulmonary pressure) the lung collapse
- > (Ppul-Pip)= transpulmonary pressure
- keeps the airways open
- the greater the transpulmonary pressure, the larger the lungs
pulmonary ventilation
- inspiration and expiration
- mechanical processes that depend on volume changes in the thoracic cavity
- volume changes -> pressure changes
*pressure changes -> gases flow to equalize pressure
Boyle’s law
- the relationship between the pressure and volume of a gas
- pressure (p) varies inversely with volume… P1V1=P2V2
Inspiration
an active process:
-inspiratory muscles contract
- thoracic volume increases
- lungs are stretched and intrapulmonary volume increases
- intrapulmonary pressure drops (to -1 mm Hg)
- air flows into the lungs, down its pressure gradient, until Ppul (intrapulmonary pressure)=Patm
sequence of events: Inspiration
- Inspiratory muscles
contract (diaphragm
descends; rib cage rises). - thoracic cavity volume increases
- lungs are stretched; intrapulmonary volume increases
- intrapulmonary pressure drops (to -1 mm Hg)
5. Air (gases) flows into lungs down its pressure gradient until intrapulmonary pressure is 0 (equal to atmospheric pressure).
expiration
Quiet expiration is normally a passive process:
- Inspiratory muscles relax
- Thoracic cavity volume decreases
- Elastic lungs recoil and intrapulmonary volume decreases
- Ppul rises (to +1 mm Hg)
- Air flows out of the lungs down its pressure gradient until Ppul = 0
Note: forced expiration is an active process: it uses abdominal and internal intercostal muscles
sequence of events: expiration
- Inspiratory muscles
relax (diaphragm rises; rib
cage descends due to
recoil of costal cartilages). - thoracic cavity volume decreases
- elastic lungs recoil passively; intrapulmonary volume decreases
- intrapulmonary pressure rises (to +1 mm Hg)
- Air (gases) flows out of
lungs down its pressure
gradient until intra-
pulmonary pressure is 0.
physical factors influencing pulmonary ventiliation
-inspiratory muscles work to overcome 3 factors that hinder air passage and pulmonary ventilation
- airway resistance
- alveolar surface tension
- lung compliance
- airway resistance
- Friction = resistance to gas flow
- The relationship between flow (F), pressure (P), and resistance (R) is:F = (P2-P1)/ R
- > delta P is the pressure gradient between the atmosphere and the alveoli (2 mm Hg or less during normal quiet breathing)
- > Gas flow changes inversely with resistance (straw)