Respiratory Physiology Flashcards
What is external respiration?
The exchange of O2 and CO2 between the external environment and the cells of the body
What is internal respiration?
Intracellular metabolic processes carried out within the mitochondria which use O2 and nutrients to produce energy (and CO2)
What are the 2 functions of the respiratory system
Gas exchange and metabolic activity
T or F: Lungs are housed in the thoracic cavity?
True
T or F: Plueral membranes secrete a small amount of intrapleural fluid which lubricates the pleural surfaces
True
What is the conducting zone?
Brings air in and out of the lungs
What is the respiratory zone?
Gas exchange takes place
Trachea divides into….
primary bronchi, secondary bronchi, and tertiary bronchi
What structure is primary bronchi?
c-shaped cartilage AND smooth muscle
What structure is secondary bronchi?
cartilage plates AND smooth muscle
What structure is tertiary bronchi?
LESS cartilage MORE smooth muscle
T or F: Smooth muscle is innervated by the autonomic nervous system
True
T or F: Changes in diameter of the conducting airways means changes in their resistance changes in airflow
True
T or F: Sympathetic stimulation will relax and dilate airways
True
T or F: Parasympathetic stimulation will contract and constrict airways
True
T or F: an alveloar sac is a group of two or more alveloi with a common opening into a duct
True
T or F: gas exchange takes in an alveloi
True
Alveoli are lined by…
Type I and II pneumocytes
Alveoli include….
Red blood cells, type I and II pneumocytes, capillary endothelium, basement membrane, alveolar macrophage, surfactant
What is the kinetic theory of gases?
Pressure of a gas is the force per unit area exerted by the impact of gas molecules colliding with the walls of the container
What value is atmospheric pressure set to?
760 mmHg
What is Dalton’s Law
Total pressure of a mixture of gases is equal to the sum of the separate pressures of each gas
How do you calculate partial pressure (P) for dry air
P(total) x FO2(given)
for example oxygen:
760mmHg x 0.21= 159.6 mmHg
How do you calculate partial pressure (P) in the lungs
(PB-47) x FO2 same as equation above just -47
If pressure increases what will happen to gas in solution?
More in solution
If pressure increases what will happen to the volume of gas?
Decrease
What is Boyle’s Law?
At a constant temperature, the volume of a gas varies inversely with the pressure to which it is subjected
P inversely proportional to 1/V
If temperature increases what will happen to the volume of gas?
Increase
Charles Law
The volume of a gas is directly proportional to temperature
V is proportional to T
What is the general gas equation?
(P1V1/T1)=(P2V2/T2)
What happens to atmospheric or barometric pressure with increasing altitude?
Decreases (value is 250mmHg)
What does PAo2 mean?
partial pressure in the alveloi
What does Pao2 mean?
partial pressure in the arteries
T or F: changes in alveolar pressure determine direction of air flow
True
What happens to the diaphragm during inspiration? What does it due to volume? Is this an active or passive phase?
Flattens, and increases volume of the throacic cavity, active phase
What happens to the diaphragm during expiration? What does it due to volume? is it an active or passive phase?
Comes up, decrease volume of the thoracic cavity, passive phase
T or F: forceful expiration causes a rapid decrease in lung volume?
true
What is transmural pressure?
difference between atmospheric and intra-alveloar pressure
What are the opposing forces within the chest and lungs?
outward recoil of chest, inward recoil of “elastic” lung
What is the membrane directly next to the lungs called?
Visceral pluera
T or F: The intrapleural space is filled with air
False, FLUID
What is lung collapse and chest expansion called?
Pneumothorax
What are two types of pneumothorax?
Traumatic and spontaneous (hole in lung)
What happens during inspiration?
diaphragm and inspiratory intercostals contract, thoraic cage expands, increase in pressure, lungs expand, air flows into alveloi
What happens during expiration?
diaphragm and intercostals stop contracting, chest wall moves inward, air in lungs become compressed, air flows out of lungs
T or F: Intrapleural pressure is negative compared to atmospheric pressure
True
T or F: intrapleural pressure will be more negative at the end of inspiration
True
What is compliance ?
dispensability, strecth
What is elasticity?
behavior of lungs to recoil back
Disease that affect elastic recoil
Fibrosis and Emphysema
T or F: Gas exchange begins at the respiratory zone
True
What is anatomical dead space?
Air that stays in the conducting zone and does not reach the respiratory zone
What is tidal volume?
typical inhalation volume about 10-20 ml/kg
Are alveolar ducts included in anatomical dead space?
No
T or F: any alveloi that do not contribute to gas exchange are dead space
True
What is physiological dead space?
anatomical + alveolar dead space
What is a restrictive lung disease?
pulmonary fibrosis that restricts elasticity of alveloi
What is obstructive lung disease?
resistance to air movement is increased
What is functional residual capacity (FRC)?
elastic properties of lung and chest wall, forceful expiration
T or F: lungs resist distension because of high content of elastin
True
T or F: if elastic forces increase, compliance will decrease
True
What is Emphysema?
loss of tissue, easier to stretch, increased compliance
T or F: breathing must overcome surface tension of fluid lining alveloi?
True
T or F: pressure is greater in smaller avelous
True
T or F: in alveloi, pressure automatically wants to recoil inward
True
What is surfactant?
phospholipid that decreases the tendency of the lungs to recoil and increases compliance, as alveolus shrinks, the surfactant area increases, offsetting surface tension
What happens if you do not have enough surfactant?
stiff lungs and areas of collapse
What produces surfactant?
Type II pneumocytes
What does the PSNS do on airway resistance?
neurons release acetycholine and activate muscaric receptors, causes brochoconstriction
What does the SNS do on airway resistance?
neurons release adrenaline and activates B2 receptors , causes bronchodilation
T or F: Airway resistance depends on lung volume?
True
T or F: ventilation increases down the lung
True
What is ventilation rate for respiratory minute volume?
volume of air moved/ time
for example:
tidal volume=50ml, respiratory rate= 25 b/m
minute volume=(50 x25) = 1250 ml/min
What is ventilation rate for alveolar ventilation?
air that takes part in gas exchange
for example:
tidal volume=50ml, respiratory rate= 25b/m, dead space= 15ml
minute volume: (50-15) x 25= 875 ml/min
What is diffusion capacity?
the measure of how well oxygen and carbon dixoide are transferred between the lungs and the blood
In anemia what happens to diffusion capacity?
decreases
What is the PO2 gradient?
as blood flows, O2 decreases
What is PO2 in airway?
150 mmHg
What is PO2 in alvelous?
100 mmHg
What is PO2 in mean tissue capillary?
50 mmHg
What is PO2 in mitochondria?
1 mmHg
What is an anatomical R-L shunt?
when deoxygated blood that has not been oxygenated in the lungs, returns into the left atrium
T or F: a R-L will make a A-a difference gradient
true
What is the value of a A-a difference gradient
15 mmHg
What is a physiological shunt?
occurs when perfusion continues but alveolus is not ventilated
T or F: pulmonary blood flow in the lungs can be increased on demand
True
Why would a high capillary pressure in the lungs be undesirable?
Rupture and Odema
What is pulmonary vascular resistance?
resistance that can be affected by hypoxia
What is hypoxic pulmonary vasoconstriction?
Do not want to waste blood and effort sending blood to hypoxic areas, so vessels constrict
T or F: PVR increases when lung regions become hypoxic
true
What is V/Q mismatch?
When perfusion through capillaries and ventilation into alveoli differs
What are consequences of V/Q mismatch?
Hypoxia- low blood O2
Hypercapnia -high blood CO2
T or F: areas with low V/Q are poor ventilation from blocked airways
True
T or F: areas with high V/Q are poor perfusion and arise from loss of capillaries
True
What are the states of gases?
Dissolved state, bound state, chemically altered state
T or F: Gas content depends on pressure & solubility
True
T or F: O2 bound to hemoglobin does not contribute to partial pressure in blood
True
What is P50?
The PO2 at which Hb is 50% saturated
How many molecules of O2 can one Hb bind?
4
T or F: PO2 leaving the tissue capillaries of sketeal muscle is about 40 mmHg and Hb is 75% saturated
True
What is co-operative binding?
As one molecule of O2 binds to hemoglobin another will follow
What is the concentration of normal Hb in the arteries?
150 g/l
T or F: in pulmonary capillaries high PO2 causes binding to Hb
True
T or F: at tissues, low PO2 causes unloading from Hb
True
What is a right shift in O2 affinity curve mean?
favors release of O2, acidosis, low pH, increased CO2, increased temp
What is a left shift in O2 affinity curve mean?
favors association of O2, alkalosis, high pH, decreased PCO2, decreased temperature
What is 2,3-DPG?
a product of glycolysis in RBC’s, production increased under hypoxic conditions
Causes right shift of O2 affinity curve, reduced affinity, more unloading, higher P50
Increased 2,3-DPG
Causes left shift of O2 affinity curve, increased affinity, lower P50
Decreased 2,3-DPG
What gas has an increased affinity for haemoglobin compared to oxygen?
Carbon monoxide
Does myoglobin have co-operative binding?
No
When does myoglobin release O2?
Only when tissue PO2 becomes very low
T or F: fetal haemoglobin has a higher affinity for O2 and is less likely to give it up
True
How is CO2 transported?
By bicarbonate and bound to globin portion of hemoglobin
T or F: as bicarbonate leaves RBC, chorlide comes in
True
What is the haldane effect?
CO2 content of deoxygenated blood is higher than oxygenated blood
Why does the haldane effect happen?
When Hb becomes deoxygenated, H+ binds more readily to it, so equilibrium favors blood taking up more C02
What is acidtotic?
more CO2
What is alkalosis?
less CO2
What is hyperventilation? What is its value?
increased ventalation, <40 mmHg
What is hypoventaliation? What is its value?
decreased ventalation, > 45mmHg
What does hyperventilation lead to?
Hypocapnia, or low CO2, muscle cramps
What does hypoventaliation lead to?
Hypercapnia, or high CO2, coma, confusion, drowsiness
What will respiratory acidoisis cause?
Hyperventilation
Which way will the oxygen dissociation curve shift in exercising muscle?
Right
How does the body regulate breathing?
central and peripheral chemoreceptors
What are the three factors that drive breathing?
decrease in arterial PO2
increase in arterial PCO2
increase in H+ concentration
Where are peripheral chemoreceptors located? What do they signal? What is their pathway?
carotid and aortic bodies
PO2 decrese, PCO2 increase
Aortic-vagus, Carotid-glossopharungeal nerve
What do peripheral chemoreceptors stimulate?
ventaliation
Where are central chemoreceptors located? What do they signal? What is their pathway?
Suface of medulla
PCO2 increase
Direct connection to respiratory centers
T or F: central chemoreceptors deal with signaling O2?
False
T or F: regulation of both blood CO2 and blood O2 is possible?
False
Pulmonary stretch receptors located in____. They signal____. Their pathway is____which is slow adapting. Their action is to _____.
airway smooth muscle
lung over-inflation
vagus
stop inspiration
Irritant receptors are located in____. They signal____. Their pathway is___which is rapidly adapting. Their action is to_____.
epithiel surface of airways
respond to inhaled irrtants
vagus
cough
T or F: lung inflation will induce tachycardia in the heart
True
T or F: CNS sends signals to effectors ?
True
What are the three respiratory centers?
Medullary, Apneustic, Pneumotaxic
What are the two groups of neurons in the medullary respiratory center?
Dorsal respiratory group and ventral respiratory group
What is the inspiratory center of the medullary respiratory center?
dorsal respiratory group
What does the inspiratory center of the medullary respiratory center control? Where does it receive input from?
basic rhythm for breathing
peripheral chemoreceptors via vagus and glossopharyngeal nerves
Where does the inspiratory center output to?
via the phrenic nerve to the diaphragm
T or F: the pneumotaxic center is dominant over the apneustic center
True
