Respiratory Physiology One Flashcards
What is Fractual
A repeated geomertic shaoe repated at different magnitudes
The repetitive sape of the airway and blood vessel branches
What is the portions as a consequence of the fractal geometry of lung tubular structures
Generations of airway branchig is 23 from the trachea to the last avolei
this creates a airway length of 8km
what is the branch generation 1 - 16
conductive zone and is dead spcae as it does not participate in gas exchange
conduction gas to and from the avolei
what is the branch generation of 17 - 23
The repsiraotry zone
gas exhngae occurs and the unit of the repsiaotry zone
How does gas movement occur in teh lungs
gas abdudance in the lung in terms of partial pressure
Room air presses down on the body 70+ % nitrogen 21% oxygen
21 x 760 - 160 partil pressure of oxygen in the atmosphere
equilibrates with true water with room air partial pressure remains the same but the concentration of oxygen changes
Blood partial pressure remains the same concentration of oxygen that dissolves that dissolves in water and all the other oxygen that binds to hameglobin
so different
Why do we use partial pressure
Parital pressure tells you the direction of movement of gas conc does not
gas moves from high pp to low pp both within phases and between phases
concentration can be as a gas or a solvent
I dont know
gas phase in the avolei into the liquid that lines the avolei
Partial pressure falls from 156 to 100 ml of mercy
oxygen dissolves into liquid (blue part of the avoleoius) per unit of partial pressure
blood contains that is dissolved in liquid and what is bound to hameglobin
what is the mmHg of PO2
Mixed venous blood arrives at the lung at 40 mmHg PO2
Whats the relationship
alveolar ASL has lower O2 concentration but higher partial pressure than venous blood
oxygen would move out of your blood leave your body and not be able to breath
partial pressure graident of oxygen from the avolei into the blood
oxygen moved from the avolei into the blood
does not move because of concentration graident
What are the partial pressure rules
Gas moves down its partial pressure graident
O2 would move from aveolar ECF to blood
we would be dead otherwise
Follow the O2 partial pressure around the body
But be aware of corrections for water vapours
What happens to Oxygen in the repsiraotry system
dissolves the ogygen then the oxygen turn to water vapor process of oxidative phosphorylation to generate ATP and heat across the oxidase
Two consequences for lung function
- increases surface area for gas exchange
- Disspiates resistance to air flow as airway diamtere narrows towards the
Two consequences for lung function
- increases surface area for gas exchange
- Disspiates resistance to air flow as airway diamtere narrows towards the
what is posieullie’s Law
narrow tubes conduct well gas going down the lungs
a doubling of total airway diameter at each branch generation reduces 16 fold
Where n = viscosity (nreliabible in air)I total tube length at each branch generation
What is net pressure
The bulk of flow of gas into the conductive zone is driven by difference in net pressure caused by expansion and relaxation of the chest cavity
How is gas movement
Gas movement in the airways arises by convection not diffusion
Gas moves into alveoli if
Alveolar pressure less than atmopheric
Airways are open
Gas moves out of aloveoli if
alveolar pressure greater than atmpopheric
airway are open
Alvolar pressure is the sum of
elastic recoil pressure (always collasping)
plueural pressure variable by muscular effort
What is the external intercostal
External intercostal muscle slope obzliquely betyween ribs forward and downward
because the attachment to the lower rib is father forward from the axis rotation contraction raises the lower rib more than it depresses the upper
what are the muscle of inspriatory
Diaphragm, dome shaped, sits above liver– phrenic nerves, C3-5– flattens on contraction– moves 1cm in quiet breathing, up to 10cm– major insp muscle* External intercostals– intercostal nerves at “rib level”* Accessory muscles– sternocleidomastoid, scalenes, plus someothers* Chest expands, intrapleural pressure falls
What expiration
Internal Intercostal msucles slop oblquiely between ribs backward and downward depressing the upper rib more than raising the lower rib
what main expiratory muscles
Expiration is mainly passive during quietbreathing (elastic recoil pressure is sufficient )* Forced expiration (exercise, voluntary (cough,sneeze, defaecation)– abdominal wall - push guts up againstdiaphragm– internal intercostals
