SCT II - Respiration Flashcards
How do you calculate the physiologic dead-space?
Anatomical dead space + non-perfused alveoli
Name the function, receptor, mediator and agonist of sympathetic innervation in respiratory physiology
Function: bronchodilation
Receptor: β2-Receptor
Mediator: Adrenaline (Epinephrine)
Agonist/Initiator: Isoproterenol
Name the function, receptor, mediator, and antagonist of parasympathetic innervation in respiratory physiology
Function: bronchoconstriction
Receptor: mAChR (muscarinic acetylcholine receptor)
Mediator: Acetylcholine
Antagonist: Atropin
How can you treat asthma bronchiale?
Administration of isoproterenol - agonist of sympathetic bronchodilation
What is the relationship of volume and pressure
Volume ~ 1/Pressure
How are the somatomotor fibers of the respiratory muscles controlled?
Receptor: nAChR (nicotinic acetylcholine receptor)
Antagonist: curare (muscle relaxants)
What is TV in respiratory physiology?
Tidal Volume
Volume of air breathed during relaxed breathing pattern
What is IRV in respiratory physiology?
Inspiratory Reserve Volume
Maximum volume of air you can inhale with a deep breathe
What is ERV in respiratory physiology?
Expiratory Reserve Volume
Maximum volume of air you can exhale with a deep sigh
What is IC in respiratory physiology and how can you calculate it?
Inspiratory Capacity
Total volume of air inhaled with a deep breathe and normal breathing
IC = TV + IRV
What is RV in respiratory physiology?
Residual Volume
Volume of air that will always be in the lungs despite exhalation
What is FRC in respiratory physiology and how can you calculate it?
Functional Residual Capacity
Volume of air left in the lung after normal breathing pattern’s exhalation
FRC = ERV + RV
What is VC in respiratory physiology?
Vital Capacity
Maximum volume of air that can be exhaled after a deep inhalation
What is TLC in respiratory physiology?
Total Lung Capacity
Total volume of air in the lung entirely
What happens in the case of dead space?
Ventilation is present
Perfusion is absent
What type of pressure is intrapleural pressure?
Negative, drawing air in - acting as a vaccum
What is intrapleural pressure?
Pressure in the intrapleural space
What is intrapulmonary pressure?
Pressure in the lung
What is transmural pressure?
Intrapulmonary - intrapleural
How does the surfactant function?
Separates the water molecules
LaPlace Law
Pressure = Tension/Radius
What happens at FRC+1L?
Inspiration
What happens at RV?
Exhalation
What happens exactly at FRC?
Transition point between inspiration & expiration - equilibrium between chest and lungs
What happens to the pressure during inspiration?
Volume increases
Pressure decreases, later increasing
What happens to the pressure during exhalation?
Volume decreases
Pressure increases, later decreasing
What is PEF in respiratory physiology?
Peak Expiratory Flow
Fastest the air moves during expiration
What is PIF in respiratory physiology?
Peak Inspiratory Flow
Fastest the air moves during inspiration
What is FEV in respiratory physiology?
Forced Expiratory Volume (1-2-3)
Volume of air exhaled every second for three seconds, used to measure respiratory rate
How do you calculate the Tiffenau index?
FEV1/VC
> 80% = Healthy
< 80% = Obstruction
How do you calculate pulmonary/minute ventillation?
Respiratory Rate * TV
Respiratory Rate is the amount of breaths you’re taking
It is the rate at which air enters/leaves the lungs
How do you calculate compliance?
Compliance = ΔVolume/ΔPressure
Equation of Laminar Flow
Resistance = 8Ln/πr^4
L - Length
ƞ - Viscosity
r - Radius
What is Reynolds Number and how do you calculate it?
Re = Density x Velocity x Diameter / Viscosity
Determines whether flow is turbulent or laminar
- Reducing diameter, increase velocity two-folds
- Low Re = Laminar
- High Re = Turbulent
Where can you find the highest resistance in the respiratory system?
Main bronchi
What happens in bronchoconstriction?
Low Radius, high resistance
What is the relationship between velocity and surface area?
Velocity ~ 1/Surface Area
What happens in bronchodilation?
High radius, low resistance
What happens when respiratory rate is increased when it comes to lung elasticity?
Respiratory rate increases (+)
Tidal volume decreases (-), as lung is unable to catch up with rate
Lung stretch decreases (-)
Less work is done (-)
What happens when respiratory rate is increases when it comes to air flow?
Respiratory rate increases (+)
Velocity of air increases (+)
Resistance increases (+)
What stimulates ventillation?
Low O2 levels
High CO2 levels
Equation of diffusion in the lungs
Diffusion = Diffusion Constant x Area x ΔPressure / ΔThickness (Length) of Barrier
Explain the two types of gas transport
Perfusion Limited: depends on the blood flow (N2O, CO2, O2)
Diffusion Limited: rate of diffusion is constant (O2)
How is CO2 transported around in the body?
As Bicarbonate (HCO3-)
Name the factors that may make hemoglobin want to hog O2 (high affinity for O2)
- Fetal hemoglobin
- Myoglobin
- Alkalosis
- Low CO2
- Low Temp
Name the factors that may make hemoglobin want to give O2 to tissue (low affinity for O2)
- Acidosis
- High CO2
- High Temp
- 2,3-BPG
What is the Hamburger effect?
Replacing bicarbonate with chloride in hemoglobin
What is the Bohr effect?
CO2 displaces O2 in the hemoglobin of tissues
What is the Haldane effect?
O2 displaces CO2 in the hemoglobin in the lungs
What happens to solubility when pressure is increased?
Pressure increases, solubility increases
What are peripheral chemoreceptors sensitive to?
- Hypoxia (low O2)
- Hypercapnia (high CO2)
- Acidosis (low pH)
What are central chemoreceptors sensitive to?
- Hypercapnia
- Acidosis
Not hypoxia due to blood-brain barrier
What happens when central and peripheral chemoreceptors are activated?
- Activates cardiovascular reflexes, increase MAP (mean arterial pressure) - Pressor reflex
- Stimulates ventilation
What happens to the neurons during forced breathing?
INSPIRATION
Inspiratory neurons are active
Expiratory neurons are INHIBITED
EXPIRATION
Inspiratory neurons are INHIBITED
Expiratory neurons are active
How is heart rate related to respiration?
HR increases during inspiration
HR decreases during expiration
Which receptors are responsible for controlling heart rate during respiration?
Slow Adapting Stretch Receptors (SARs)
What is the pathway of increasing heart rate during inspiration?
Inspiration → Stretch → Afferent Vagal Discharge INCREASE → Medullary Cardiovascular Center → Parasympathetic Activity DECREASES + Sympathetic Activity INCREASES → Heart rate INCREASES
- Afferent Vagal Discharge
- Medullary CV
- Parasym. DOWN
- Sym. UP
- HR UP
Which receptor is responsible for respiratory sinus arrhythmia?
SARs - Slowly Adapting Stretch Receptors
What does the Hering-Breuer reflex do?
Prevents the over-inflation of the lungs
Write the pathway of the Hering-Breuer reflex
Over-inflated lungs → Stimulates SARs → Afferent Vagal Activity INCREASES → Respiratory Centers → Terminate inspiration, Bronchodilation
- Lung full
- SARs
- Afferent Vagal Activity UP
- Terminate inspiration, bronchodilation
Which receptors are responsible for coughing and sneezing?
Rapidly Adapting Stretch Receptors (RARs)
Write the pathway of the RARs
Irritant substance → stimulation of RAR → CN X (Bronchi), CN IX (Larynx), CN V (Nose) → Respiratory Center → Coughing/Sneezing + Bronchoconstriction
What is the function of Pulmonary & Bronchial C-Fibers?
Products of inflammation, respond via increasing mucus & bronchoconstriction
How is temperature related to respiratory rate?
Temperature increases respiratory rate
