Respiratory I & II Lectures Flashcards
what are the 4 main steps involved in respiration ? (2 physiological processes)
- pulmonary ventilation (convection)
- alveolar gas exchange (diffusion)
- gas transport (convection)
- systemic gas exchange (diffusion)
what are the major organs of the respiratory system that diffusion of alveoli?
pharynx, larynx, and trachea
what is the difference between conducting and respiratory zones in the respiratory system?
conducting zone: conducts air to respiratory zone (convection) aka “dead space”. The components include the trachea and bronchial tree (bronchi, bronchioles, and terminal bronchioles)
respiratory zone: exchange of gases between air and blood (diffusion). The components include respiratory bronchioles and alveolar sacs/ducts
what two structures are important for gas diffusion to occur in the respiratory system?
capillary wall and alveolar wall
define the surface area of the alveoli structure in the body
large surface area (~300 mil alveoli) and thin barrier (2 cells thick: alveolar and capillary walls)
what is the function of type I alveolar cells?
forms walls and structure of the cells
what is the function of type II alveolar cells?
produce lipoproteins, which facilitate diffusion
the fluid with surfactant of the alveolar cells ______ surface tension
decrease
what are the functions of alveolar macrophages and pores of Kohn?
- communicate
- assist in ventilation
- allow alveoli to remain open
In the respiratory system, lungs are enclosed by membranes called ______
pleura
what are the two types of pleura in the respiratory system? Where are they located?
- visceral pleura: located on outer surface of the lungs
- parietal pleura: lines the thoracic wall
what is the purpose of the intrapleural space in the respiratory system?
The intrapleural pressure is lower (negative) than the atmosphere, so it prevents the collapsing of alveoli
define the mechanics of breathing
- movement of air occurring via bulk flow (convection)
- the movement of molecules are due to pressure differences in the lungs
- two types: inspiration and expiration
what are the differences of inspiration and expiration?
Inspiration: The diaphragm is pushed downwards while the ribs lift outwards. The volume of lungs increases while intrapulmonary pressure is lowered
Expiration: diaphragm relaxes while rubes are pulled downward. The volume of lungs decrease while intrapulmonary pressure is raised
At rest, expiration is a ______ process (elastic recoil of chest wall and lungs)
passive
how do respiratory muscles adapt to training?
increase oxidative capacity of respiratory muscles & reduces work of breathing
what two things does airflow depend on?
- pressure difference between two ends of the airway
- resistance of airway
airway resistance depends on _____ of airway
diameter
MAP = _______ x __________
cardiac output, SVR
what does SVR stand for?
systematic vascular resistance
define pulmonary ventilation
the amount of air moved in or out of the lungs per minute (Ve)
pulmonary ventilation equation
Ve = tidal volume (Vt) x breathing frequency (f) = ___ L/min
define tidal volume
number of breaths per minute
define alveolar ventilation (Va)
volume of air/min that reaches the respiratory zone
define dead-space ventilation (Vd)
volume of air/min remaining in the conducting zone
define spirometry
measures inspired and expired gas volumes
during light-moderate-heavy exercise, tidal volume and frequency of pulmonary ventilation _________
increases
define Dalton’s law of partial pressure
the pressure exerted by a gas is proportional to the total (barometric) pressure (Pb) multiped by the fractional concentration of the gas
define Fick’s law of diffusion
the rate of gas transfer (V gas) is proportional to the tissue area, the diffusion coefficient of the gas, and the difference in the partial pressure of gas on the two sides of the tissue, and inversely proportional to the thickness
Fick’s law equation
V gas = (A/T) x D x (P1 - P2)
Dalton’s law equation
Pair - PO2 + PCO2 + PN2
when standing, most of the blood flow does to the ___ (____) of the lungs. Why?
base (bottom), due to gravity
what is the difference of pressure in systemic and pulmonary circulation?
both receive the same rate of flow (due to cardiac output), but pulmonary is lower in pressure
efficient gas exchange between blood and lungs requires ___ _____ of blood flow to ventilation, which is called ______-______ relationships/Q
proper matching, ventilation-perfusion
what is the ideal ratio of ventilation to perfusion?
1.0 or slightly greater (at rest 0.5 is adequate to meet gas exchange)
how does lung blood flow (BF) go up during exercise?
exercise increases cardiac output, which causes vasodilation in the capillaries
the amount of O2 concentration that can be transported per unit volume of blood is dependent on _______ _______
hemoglobin (Hb) concentration
each gram of Hb can transport ____ mL O2
1.34
what is the O2 carrying capacity of Hb?
1.34 mL O2/g Hb
does arterial blood change during rest or exercise?
No, arterial blood stays the same
Oxygen-Hb Equation
Deoxy-hemoglobin + O2 <-> Oxy-hemoglobin
the direction of oxygen-hemoglobin concentration depends on what two things?
- PO2 of the blood
- affinity between Hb and O2
In the lungs, PO2 is ____, forming _______ (“O2 ______”)
high, oxyhemoglobin, loading
In the tissues, PO2 is ___, releasing ____ to tissues (“O2 ___”)
low, O2, unloading
what are the two locations of O2 and CO2 transportation in the blood?
lungs and tissues (muscle)
what happens during the loading portion of the oxygen-hemoglobin dissociation curve?
- saturation stays high even with large changes in PO2
- ensures blood will be saturated
what happens during the unloading portion of the oxygen-hemoglobin dissociation curve?
- saturation changes quickly with even small changes in PO2, allowing oxygen unloading to tissues
- changes in PO2 so the muscle can grow
what happens to pH values and temperature in O2-Hb affinity?
pH: decreased values lower Hb-O2 and shifts the curve “rightward” (favoring offloading O2 to tissue)
temperature: increased temperature lowers Hb-O2 and shifts the curve “rightward” (favoring offloading O2 to tissues)
define myoglobin (Mb) and its role with O2 transport in muscle
Mb is a protein found in skeletal and cardiac muscle – shuttles O2 from the cell membrane to the mitochondria
myoglobin has a ______ affinity for O2 than hemoglobin. Why?
higher, due to Mb picking up O2 released from the Hb at low PO2’s
what are the two protocols involved in ventilatory responses to exercise?
constant and incremental
what happens at the onset of constant-load submaximal exercise?
- initial increase in ventilation, then slows down towards steady state
- PO2 and PCO2 are unchanged (slight decrease/increase)
- suggests that an increase in alveolar ventilation is slower than increase metabolism
what is the difference in ventilatory response in “untrained” and “elite” athletes during incremental exercise?
Untrained: increase H+, decrease pH, blood becomes acidic and chemoreceptors signal RS for increased ventilation efforts (VT is lower than athletes)
Elite: decrease RBC, exercise-induced arterial hypoxemia (EIAH) can occur (due to mismatch ventilation and cardiac output)
how does the body control ventilation at rest?
- inspiration and expiration (produced by contraction/relaxation of the diaphragm)
- controlled by somatic motor neurons in the spinal cord (pons and medulla oblongata)
stimulus for inspiration comes from what four respiratory rhythm centers?
- medulla: preBotzinger complex and retrotrapeziodal nucleus
- pons: pneumotaxic center and caudal pons
what are the two inputs for the stimulation of inspiration?
humoral and neural
