5.1.1 Pulmonary Flashcards
why do we breath?
we need oxygen for last step of ETC (for ATP synthesis)
how do we breath?
- negative pressure ventilation is how a typical healthy person draws air into lungs
- relax and elastic recoil drives air back out of lungs
what is the primary driver for why we breath?
CO2 (not oxygen)
what cells in our stomach make hydrochloric acid?
parietal cells make HCL- and intrinsic factor
1) what do mucous cells makes?
2) parietal?
3) cheif?
4) G cells?
1) mucus
2) HCl- and intrinsic factor
3) pepsinogen
4) Gastrin
carbonic anhydrase equation?
CO2 + H2O = H2CO3 =HCO3- + H+
why is carbonic anhydrase important?
- HCO3- exchanged for Cl- in blood creating alkaline tide
- H+ exchanged for K+
- Need 20 bicarbs for every proton
define ventilation
air into and out of lungs
define perfusion
blood to and from lungs
define gas exchange
1) O2 from alveoli into blood
2) CO2 from pulmonary capillaries into alveoli
define contol of respiration
how O2 is carried thru bloodstream (major-idly by oxyhemoglobin)
explain normal breathing with diaphragm?
- contracts and goes down to help with generation of negative pressure
- assisted by EXternal intercostals with deeper breath; causingrib cage to go upward and out
accessory inspiration muscles?
1) sternocleidomastoid
2) scalene
3) pec minor
4) external intercostals
* *they all decrease pressure
normal expiration
normal tidal expiration, do NOT need to contract any muscles
forced expiration
we activate expiratory adominal muscles and INternal intercostals to increase intrapleural pressure
what happens to diaphragm during expiration?
whether passive or forced, it will move upwards to push air out
define conducting airway
- no alvioli associated with it
* NO gas exchange
define alveolar space
- site of gas exchange CO2 and O2
* extremely vascular
how many alveolar per lung?
500,00 alveolar per lung, and 1000 capillaries per alveolar
for ventilatory mechanics, the pressure of gas in the atmosphere is?
O cm of water pressure
what is alveolar pressure and intrapleural pressure at rest?
- alveolar= O
* intrapleural= -5
what is functional residual capacity (FRC)?
when you are relaxed and alveolar and atmospheric pressure in lung is O = amount of air that is IN your lungs when relaxed
*equilibirum point
what does a relaxed lung mean?
no flow or gradient of air between atmospheric or alveolar pressure
What has elastic recoil? means? what stops it?
alveoli. means they want to snap down to a small shape. ribs are like a bow and want to snap the other way
inward vs outward elastic recoil?
- In= alveoli
- out= ribs
- **equal and opposite when at FRC
what yeilds the FRC equilibrium point?
intrapleural pressure
simplest way to think of the negative intrapleural pressure?
Negative pressure SUCKS
** meaning -5 pressure is pulling chest wall AND alveoli wall towards it. So in equilibrium (relaxation) everything stays in place
what is normal breathing called?
normal tidal inspiration
how do you get air into lungs during NTI?
contraction of diaphragm down increases thoracic cavity volume which causes the pressure to go DOWN
**the negative (-8) intrapleural pressure is going to pull the alveolar walls open. So if alveolar volume increases, then the pressure decreases
what is the relationship between pressure and volume?
inverse!
during normal quiet breathing, which requires more muscles… to contract, inspire or expire?
normal expiration is PASSIVE
*it does not require muscle contraction
why is normal expiration passive?
pressure gradient provides energy for air flow (expiration)
when you make a deep forced inspiration, you cause?
greater muscle contraction
- greater increase in thor cavity volume
- greater decrease in interpleural pressure
- *air will flow into a greater rate and volume (exception is restrictive lung disease)
do you need muscles for forced expiration?
you MUST have muscle contraction for forced expiration
define forced expiration?
exhaling beyound functional residual capacity (FRC)
negative vs positive pressure and its affect on air?
- negative= draws air in, pulls
* positive= driving air in, pushes
steps of positive pressure inspiration?
1) ventilator generates + pressure by the nose and mouth
2) pressurizes air by nose/mouth
3) forces air in
4) fills alveoli
5) once alveoli reaches same pressure as nose/mouth the flow expansion stops
steps of positive pressure expiration?
1) ventilator switches back to 0
2) alveoli recoil back down, pressurizing the gas to force it out of lung
“smart ventilators will sigh” means?
deep breaths help ventilate poorly ventilated areas in lung
*we do this naturally, ventilators do this for patients
when is + pressure ventilation used?
in a “save you NOW” situation. not long term
consequences of + pressure long term ventilation?
changes profusion of blood to the lungs if used too long
real world example in history of + pressure ventilation?
Polio and the iron lung
** used to manipulate pressure outside chest wall to pull chest outward and therefore pull alveoli walls out to allow air in
Heimlich maneuver
increases the alveolar pressure by supplementing the upward movement of the diaphragm, this compressing the thoracic cavity to dislodge foreign objects in the airways
what happens if chest wall is breached?
air will flow into thoracic cavity (bc goes from high to low pressure) causing a sucking chest wound
what happens to intrapleural pressure in sucking chest wound?
it goes to 0
(remember it was the - pressure keeping the alveolar open
what happens to the lung with a sucking chest wound
collapses
pneumothorax
lung collapse bc of air in lung due to lung or chest wall damage
hemothorax
build-up squishes airways, driving air out, leading to collapse
atelectases
-caused by sucking chest wound
asis
ec
tel
a
asis= condition of ec= out tel= distance a= not
emphysema blebs can spontaneously rupture leading to?
pneumothorax
what is emphysema?
weakened area on lung
what happens if lung wall itself is compromised?
air goes from lung in intrapleural space and causes a collapsed lung once it reaches equilibrium
