Respiratory Flashcards
What are the four major functions of the respiratory system?
- gas exchange such as oxygen and carbon dioxide between the blood and the atmosphere
- regulation of body pH - H+ + HCO3- —-> H2CO3 —->CO2 + H20 - works with blood buffers and kidneys
- Protection from inhaled pathogens and irritants - this can be viruses and bacteria and other pathogens
- Vocalization - through vibration of vocal cords in the larynx
How is pH regulated by the kidneys, lungs, and blood buffers and on what time scales do they work?
kidneys - all the time - get rid of bicarbonate and H+
lungs - blow off CO2 - minutes
blood buffers - seconds and sequester charged species
We have two lungs one on each side which lung is bigger?
right is bigger than left cause left needs to make space for heart
What are the three lobes of the lungs?
superior, middle, and inferior lobes
What are the total number of orders of brinchi branching?
23 orders of branching into bronchioles which terminate in alveoli
What causes bronchodilation and constriction?
smooth muscle surrounding the bronchioles
What are the bronchioles reinforced by?
c shaped cartilaginous rings
What does a type i alveolar cell do?
gas exchange is only one epithelial cell thick
What does a type ii alveolar cell do?
make surfactant and mucus
What happens to the chest wall when you inhale versus exhale?
chest wall moves outward when you inhale and moves inward when you exhale
Where do the lungs sit?
inside the pleural cavity
What is the distance between an alveoli and red blood cell?
one micron or 0.5 micron and this is due to interstitial fluid
What is around the alveoli?
alot of blood vessels and capillaries for gas exchange
What are the three types of fluids in nature?
gases liquid or plasma
How does fluid move pressure gradient wise?
from high to low pressure
What characterizes flow or Q?
Q is directly proportional to the delta P and inversely to R
What can cause resistance?
the friction of the fluid moving against the wall of the capillaries and turbulence which dissipates energy
What is Dalton’s Law?
the total pressure of a gas mixture is the sum of the partial pressures
What is Boyle’s law?
P1V1=P2V2 - pressure and volume are inversely related
What is the tidal volume?
the air going in and out during quiet breathing and tends to be 500-750mL
What is the inspiratory reserve volume?
the maximum inspiration not counting the tidal volume inspiration - 2L
What is the expiratory reserve volume?
the maximum expiration not counting the tidal volume expiration - 1L
What is the residual volume?
The volume remaining in the lungs post maximum expiration due to the elastin proteins and surface tension in alveoli keeping the lung from completely compressing
What is the vital capacity?
the IRV + ERV + TV
What is the inspiratory capacity?
IRV + TV - max amount of air you can stuff in the lungs
What is the functional residual capacity?
ERV + RV - air left in the lung during quiet breathing
What is the total lung capacity?
IC + FRC or the total of everything
What is the FEV1?
force expiratory volume in one second - how much air is moved out in first second
What is the FVC?
forced vital capacity is the total amount of air you exhaled
What does the FEV1/FVC ratio show?
-if it is greater meaning the FEV1 is bigger than the FVC - restrictive disease because lungs are not as compliant
-if it is smaller meaning that the FEV1 is smaller than the FVC then obstructive disease cause airways are blocked
What happens in a pneumothorax?
Puncture in intrapleural space so the lungs collapse air gets trapped there and the chest expands and IP pressure decreases more
Understand this graph
Inspiration Occurs when Alveolar Pressue Decreases cause Lung Volume Increases
-when the diaphragm contracts it drops towards the abdomen the ribs and pulled upwards and outwards during inhalation
-negative numbers are sub atmospheric pressure and positive numbers are above atm
-in brief pause between breaths teh alveolar pressure is 0mmHg like the air causing not net flow of air
-during inspiration the increase in thoracic volume leads to a drop in alveolar pressure which is now -1mmHg and air flow into the alveoli - because thoracic volume changes faster than air can flow the alveolar pressure reaches its lowest volume about halfway through inspiration
-as air continues to flow into the alveoli pressure increases until the thoracic cage stops expanding just before the end of inspiration - air flow will continue intil pressure inside the lungs equals the atm —– at the end of inspiration the air volume in the lings is at the max and the pressure in alveoli equals taht of the outside environment
Expiration occurs when alevolar pressure increases because lung volume decreases
-at end of inspiration somatic MNs stop impulses in inspiratory muscles and air pressure increases and reaches a max of about 1mmHg and since the alveolar pressure is higher than the outside the air flows out until 0mmHg is reaches again and the outside equals the inside
Intrapleural Pressure Changes during Ventilation
-the intraplerual pressure between the pleural membranes is subatmospheric
-the combination of the outward pull os the thoracic cavity and inward pull of the elastic recoil of the lungs creates an IP of -3mmHG
Pneumothorax -collapses lung due to air flowing into IP when punctured causing thorax to inflate and lung to collapse
Intrapleual pressure during respiratory cycle
-as the inhalation is occurring the lungs move with expsanding thoraci cavity but the cinnectuve elastic recoil of the kings increases causing the IP to become more negative -6mmmHG and then during expiration it returns ti -3mmHG
-IP pressure never equilibriate with the atm because it is closed off
What is compliance?
distensibility how likely is the lung to expand and it can be the delta V/delta P aka change in volume in response to an applied pressure
-how much force does it take to distend an object
What is elasticity?
the tendency of a structure to return to its initial size after being distended
What causes elasticity?
elastin proteins and collagen in the lung and surface tension in alveolar fluid
What is the law of laplace?
P = 2(Tension)/r
this means the pressure is greater in smaller alveoli because they can H bond better but this is usually mitigated against in the lung because the smaller alveoli have a greater number of surfactant molecule made by type ii alveolar cells which are proteins which can disrupt the H bonding making it equal size wise
What is infantile respiratory distress syndrome?
the fact that alveolar type ii cells do not make surfactant in premature babies cause it happens later on in development so breathing is difficult
What is Fick’s law of diffusion?
Diffusion rate = the concentration gradient * area * permeability of the membrane/ membrane thickness^2
What depends on pressure solubility and temperature?
the amount of gas present in a solution
What is more solubility in water O2 or CO2?
CO2
Is the PO2 in water equal to the [O2]?
know the PO2 in water will equal the PO2 in the air but the concentration will be less because O2 is not that soluble in water
What is the PO2 and PCO2 in the dry air?
PO2 = 160 mmHG
PCO2 = 0.25 mmHG
What is the PO2 and PCO2 in the alveoli?
PO2 = 100 mmHG
PCO2 = 40 mmHG
What is the PO2 and PCO2 in the systemic arteries?
PO2 = 100 mmHG
PCO2 = 40 mmHG
What is the PO2 and PCO2 in the post gas exchange with cells in the body and the veins?
PO2 = 40 mmHG
PCO2 = 46 mmHG
What is the PO2 and PCO2 in the pulmonary artery?
PO2 = 40 mmHG
PCO2 = 46 mmHG
What is the PO2 and PCO2 in the pulmonary vein?
PO2 = 100 mmHG
PCO2 = 40 mmHG
What is the safety margin built into the alveolus for gas exchange?
there is a mesh of capillaries around the alevolus which the pulmonary artery wraps around and it does not take the whole distance to cause gas exchange at resting levels so if a person is exercising then it may take the whole distance instead
What is an obstructive lung disease and how many cases does it constitute?
-80% of cases
-resistance of airays increased
What is an restrictive lung disease and how many cases does it constitute?
-20% of cases
-reduced compliance of the lung and reduced lung volume
What do all lung diseases involve and but do must involve?
all involve hypoxia and some involve hypercapnia
What happens in the obstructive lung disease known as asthma?
- constriction of the bronchioles due to the smooth muscle contraction or even due to excess secretion of mucus causing the lumen of bronchioles to be smaller increasing airway resistance and making it an obstructive lung disease
What happens in the obstructive lung disease known as emphysema?
due to smoking and loss of tissue and elastin proteins leading to the lung and alveoli to overinflate and reduce in number due to apoptosis which causes hypoxia - have a barrel chest - can’t exhale cause lung will not compress due to loss of elastin
What happens in the obstructive lung disease known as bronchiectasis?
widening of the bronchi which causes thickened walls ane excess mucus secretion causing obstruction
What happens in the obstructive lung disease known as bronchiolitis?
infection and inflammation of bronchioles causing excess mucus secretion in them causing the airways to be narrowed
What is a common complication in obstructive lung diseases?
Pulmonary edema - this causes a buildup of interstitial fluid between alveoli and capillary preventing diffusion which causes chronic pulmonary hypertension
What happens in the restrictive lung disease known as pulmonary fibrosis?
excess scar tissue prevents the lung from compliance or expanding
What happens in the restrictive lung disease known as asbestosis?
crystals embedded in the lung prevent expansion
What happens in the restrictive lung disease known as sarcoidosis?
there are clumps of inflammatory granuloma cells in the lungs preventing expansion
What happens in the restrictive lung disease known as hyaline membrane disease?
premature infants cannot produce surfactant causing a loss of compliance via their type ii alveolar cells
If you have pulmonary edema will you have hypoxia and hypercapnia?
yes to hypoxia no to hypercapnia because co2 is more diffusable in fluid so it might not be affected
What increases the affinity of Hb for oxygen?
lower temperature cause cells are not working as hard so do not need oxygen
-lower PCO2
-higher pH
What decreases the affinity of Hb for oxygen?
-higher temp so cells are working hard so need o2 so need to dump O2
-high PCO2
-low pH
What does the glycolysis intermediate do to the affinity of Hb for oxygen?
decreases the affinity because if it is produced then the cell is working and needs oxygen so need to decrease affinity and dump oxygen
-in hypoxic tissues there is less aerobic metabolism so will have excess 2,3BPG indicating oxygen is needed
What does oxyHb do in regards to 2,3BPG?
inhibits the enzyme that converts 1,3BPG to 2,3BPG increasing the affinity of Hb to oxygen
What is the difference between fetal Hb and maternal Hb?
fetal has two gamma chains instead of beta chains and does not bind BPG so it has greater Hb affinity for O2
How do systemic tissues make CO2?
through aerobic metabolism
What percent of carbon dioxide enters the plasma?
7%
Where does the remaining 93% of CO2 go?
in the red blood cell
What percent of CO2 in the red blood cell binds to Hb?
23% and binds to a free amine group
What percent of CO2 in the red blood cell combines with water and via carbonic anhydrase becomes bicarbonate and H+?
70%
What happens to the H+ and bicarbonate made from CO2 in the red blood cells?
H+ binds to Hb, making HbH
bicarbonate is removed via a Cl- antiporter
To exchange CO2 with the alveoli in the lung what does the rbc do?
uses the Cl- bicarbonate antiporter to bring bicarbonate in and Cl- out so bicarbonate via H+ from HbH can combine and make CO2 which can be expelled by the alveoli and free dissolved co2 in the plasma goes directly into the alveoli
What is the resting membrane potential of an rbc?
it is positive
What two groups of neurons in the medulla of the brainstem regulate rhythmic breathing patterns and what are they influenced by?
the dorsal respiratory group and the ventral respiratory group and they are controlled by peripheral and central chemoreceptors
Where are peripheral chemoreceptors located?
in the carotid and aortic bodies which are systemic arteries and there are glomus cells which release dopamine in response to low PO2 concentration to sensory neurons which then increase ventilation in the medulla control centers
What do the central chemoreceptors detect?
co2 in the csf cause it can cross the bbb and doe this by detecting drop in pH since CO2 will combine with H2o and make bicarbonate and H+ and will tell medulla centers to increase respiration
What does the apneustic center in the pons do?
stimulate ventilation
What does the pneumotaxic center in the pons do?
inhibits respiration
What is the hering-breur inflation reflex?
sent inhibitory signals to prevent inhalation in response to stretch receptors
What happens if you hyperventilate and blow off too much co2 and become high pH?
next breath is delayed
