packet 15 Flashcards
covers lungs — parietal pleura lines ribcage & covers upper surface of diaphragm
visceral pluera
potential space between ribs & lungs
pleural cavity
Base, apex (cupula), costal surface, cardiac notch
Oblique & horizontal fissure in right lung results in 3 lobes
Oblique fissure only in left lung produces 2 lobes
lungs (anatomy)
Blood vessels & airways enter lungs at hilus
Forms root of lungs
Covered with pleura (parietal becomes visceral
Mediastinal Surface of Lungs
Branchings of single arteriole, venule & bronchiole are wrapped by elastic CT
Respiratory bronchiole
simple squamous
Alveolar ducts surrounded by alveolar sacs & alveoli
sac is 2 or more alveoli sharing a common opening
lobule of lung
cell types of alveoli
type I alveolar
type II alveloar
alveolar dust cells
simple squamous cells where gas exchange occurs
type I alveolar
free surface has microvilli
secrete alveolar fluid containing surfactant
type II alveolar
wandering macrophages remove debris
alveolar dust
Respiratory membrane = 1/2 micron thick Exchange of gas from alveoli to blood 4 Layers of membrane to cross alveolar epithelial wall of type I cells alveolar epithelial basement membrane capillary basement membrane endothelial cells of capillary Vast surface area = handball court
Alveolar-Capillary Membrane
Air moves into lungs when pressure inside lungs is less than atmospheric pressure
How is this accomplished?
Air moves out of the lungs when pressure inside lungs is greater than atmospheric pressure
How is this accomplished?
Atmospheric pressure = 1 atm or 760mm Hg
Breathing or Pulmonary Ventilation
As the size of closed container decreases, pressure inside is increased
The molecules have less wall area to strike so the pressure on each inch of area increases.
boyle’s law
Diaphragm moves 1 cm & ribs lifted by muscles
Intrathoracic pressure falls and 2-3 liters inhaled
quiet inspiration
Passive process with no muscle action
Elastic recoil & surface tension in alveoli pulls inward
Alveolar pressure increases & air is pushed out
quiet expiration
abdominal mm force diaphragm up
internal intercostals depress ribs
forced expiration
sternocleidomastoid, scalenes & pectoralis minor lift chest upwards as you gasp for air
forced inspiration
labored breathing
forced expiration and forced inspiration
Alveolar pressure decreases & air rushes in
Alveolar pressure increases & air rushes out
breathing
Thin layer of fluid in alveoli causes inwardly directed force = surface tension
water molecules strongly attracted to each other
Causes alveoli to remain as small as possible
However, there is an ‘optimum’ for surface tension
Detergent-like substance called surfactant produced by Type II alveolar cells
lowers alveolar surface tension
insufficient in premature babies so that alveoli collapse at end of each exhalation
alveolar surface tension
Pleural cavities are sealed cavities not open to the outside
Injuries to the chest wall that let air enter the intrapleural space
causes a pneumothorax
collapsed lung on same side as injury
surface tension and recoil of elastic fibers causes the lung to collapse
pneumothorax
Ease with which lungs & chest wall expand depends upon elasticity of lungs & surface tension
Some diseases reduce compliance
tuberculosis forms scar tissue
pulmonary edema — fluid in lungs & reduced surfactant
paralysis
compliance of the lungs
Resistance to airflow depends upon airway size increase size of chest airways increase in diameter contract smooth muscles in airways decreases in diameter
airway resistance
connective tissue that hold arteries, veins, bronchi, that enter
provide roots and passageway for movement of vessels
hilus
exchange gas into respiratory system
alveolar sucts
remove things from surface of alveolai
surfactant
happens by diaphram movement
low pressure to high pressure
atmoshperic pressure
ON TEST
basic role of pressure in breathing
- breath in to creat a pressure gradient to increase atmosphere, decrease in lungs
- breath out opposite, constrict to increase pressure in chest and force air out
can’t breath because air coming in is the same pressure as air going out
–no pressure gradient
pneumothorax
