Final Part 3 Flashcards
Main function of Pulmonary System
gas exchange
4 Processes of Pulmonary System
Pulmonary Ventilation (Breathing): movement of air in and out of lungs Pulmonary Diffusion: exchange of O2 and CO2 between lungs and blood Transport of O2 and CO2 via blood stream Capillary Gas Exchange: exchange of O2 and CO2
Internal vs External Respiration
Internal= Pulmonary Ventilation and Pulmonary Diffusion
External: Transport and Capillary Gas Exchange
Nasal and Oral Cavities
- Mainly nose, but mouth used when demand exceeds Nasal Capacity
- Air entering nasal cavities swirls through the irregular surfaces (nasal conchae) lined with mucus and cilia. As it does so, air is brought to 37 degrees C, 100% RH, and filtered of particles
- All air particles lined with cilia and mucus. Cilia beat toward larynx
Pharynx
throat.
free passage of air and food
Larynx
voice box
9 cartilages
Vocal Folds
Speech sounds
folds on larynx surface. air vibrates through folds to produce songs. muscle contraction moves cartilages to change tension on folds
Epiglottis
lid on larynx
- normally, larynx open for air to reach lungs
- swallowing causes epiglottis to close off larynx and any particles called are directed down esophagus
- if particles get past epiglottis, cough reflex initiated to expel object
Trachea
windpipe.
4” non-collapsible tube
c-shaped rings of cartilage reinforce walls, keep trachea open despite pressure changes of breathing
Primary Bronchi
- trachea splits and plunges into lungs
- R and L primary bronchus
primary bronchi split into secondary bronchi, which split into tertiary, which then split into bronchioles
bronchioles
branches off bronchi
terminal bronchioles
smallest bronchioles
respiratory bronchioles
terminal bronchioles that have alveoli leading directly off them
alveolar ducts
smal ducts leading from terminal bronchioles which have clusters of alveoli extending off them
alveoli
small, elastic, thin-walled membranous sacs, allow for gas diffusion
-alveolus lined with thin layer of fluid
Epiglottis function
routing of food and air
of alveoli and SA provided
> 600 million
SA= 85 m2 (about 35x body external SA or about 1/2 tennis court)
Visceral Pleura
outer membrane of lungs
Parietal Pleura
lines thoracic wall (rib cage)
Functions of Serous Fluid in Pleural Cavity
- eliminates friction when membranes slide over each other
- indirect connector: when one pleura moves, other pleura moves
Low Volume in Breathing Mechanics
low P, Pi < Pb air flows in until equal
High Volume in Breathing Mechanics
high P, Pi > Pb air flows out until equal
Muscles involved in rest and during exercise for inhalation
contraction of diaphragm and external intercostals doesn’t provide enough expansion to support exercise, so more muscles are recruited to help
-Sternocleiodmastoid
-Scalenes
-Pectorals
-Serratus Anterior
-Trapezius
Pull rib cage up and back
Muscles involved in rest and during exercise for exhalation
also needs more help than just recoil from relaxation of diaphragm and external intercostals
Internal intercostals: collapse rib cage
Abdominals: push diaphragm up durther
Breathing frequency
Rest: f=12 br/min
Exercise: f= up to 70r/min
Pulmonary Diffusion
Law of Leplace—-> P=2ST/r
Surfactant reduces ST
Hydrostatic Pressure
pressure exerted outwards from blood on capillary wall (15 mmHg)
Colloid Osmotic Pressure
pressure caused by proteins in blood shot creates a force that pulls fluid from interstitial into capillary (25 mmHg)
HP and COP
- as long as COP > HP, interstitium dry and diffusion occurs
- if HP > COP, interstitial wet and diffusion hampered
Laws of Diffusion
Diffusion a SA
Diffusion a 1/thickness of alveolar membrane
Diffusion is dependent on a partial pressure gradient
Goal of Diffusion
Equilibrium
Dalton’s Law
total pressure of a gas mixture is equal to the sum of the partial pressures of each gas in the mixture
Pt= P1 + P2 + P3 +……..+ Pn
Partial Pressures
- pressure that a gas exerts independently in a gas mixture
- –Px = Pt (fraction of x in total mixture)
% of gases in dry air
20.93% O2
0.03% CO2
79.04 N2
0% H2O
Why are partial pressures in body different from what’s calculated
because air entering lungs mixes with residual lung voumes
strongest stimulus to breath
high CO2
Pulmonary response to exercise
- At onset of exercise, immediate marked rise in ventilation due to body movement followed by a gradual rise due to changes in temperature and chemical concentrations
- Post-exercise, breathing takes a few minutes to return to normal, EPOC
- active recovery returns lactate and pH to normal faster than passive recovery, mainly due to keeping blood flow and ventilation elevated
pulmonary adaptations to training
few pulmonary adaptations to training because CV system is primary limiter of performance, not respiratory
O2 transport
- 2% in plasma establishes PO2
- 98% bound to hemoglobin
- –dependent on PO2
- –cooperative binding
- ——hemoglobin changes formation with unloading/loading of O2
Hemoglobin changed formation with unloading/loading of O2
- as Hb binds 1 O2, Hb more readily binds more O2
- as Hb offloads O2, O2 more easily offloads from Hb
CO2 transport
- 7% in plasma establishes PCO2
- 23% bound to Hb-carbaminoHb
- –Haldane Effect
- 70% as bicarbonate ion
- -Carbonic Anhydrase Reaction
- -Chloride Shift
Chloride Shift
exchange of Cl- and HCOS- between blood and RBC to maintain ionic equilibrium
normal blood pH
7.4
ph of 7.0
nausea, headache, dizziness, pain, in active muscles
3 Mechanisms of pH regulation
- chemical buffers
- rapid, first line defense
- Sodium Bicarbonate and Lactic Acid Reaction
2 Ventilatory Regulation
- CO2 produced from chemical buffers can be blown off at lungs
- Slower but more powerful than chemical buffers
renal buffers
slowest but most powerful buffering capability
accomplished through complex reactions that secrete H+ in urine
