Chapter 10 - exam 2 Flashcards
What is pulmonary respiration vs cellular respiration
PULMONARY RESPIRATION:
- ventilation (breathing)
- exchange of O2 and CO2 in the lungs
** ventilation, alveolar gas exchange, circulatory transport, systemic O2 diffusion
CELLULAR RESPIRATION:
- O2 utilization and CO2 production by the tissues
What are the two purposes of the respiratory system during exercise
- gas exchange between the environment and the body
- regulation of acid-base balance during exercise – pH is chaining
What is ventilation
movement of air that occurs via bulk flow
- movement of molecules due to pressure difference
What is inspiration and what happens during this
when the intrapulmonary pressure is less than the atomospheric pressure
- diaphragm pushes downward, ribs lift outwards
- volume of lungs increase == decrease pressure inside of lungs and O2 enters
What is expiration and what happens during this
when the intrapulmonary pressure is greater than the atmospheric pressure
- diaphragm relaxes, ribs pulled downwards
- volume of lungs decreases = at high intensities move out air faster
Explain what pulmonary ventilation is (what is the other name for it)
also called minute ventilation (VeV, MV)
- amount of air moved in or out of the lungs per minute (L/min)
— tidal volume (Vt) = amount of air moved per breath (amplitude) in L/breath
— breathing frequency (f) = number of breaths per minute
what is the equation for minute ventilation
Ve = Vt * f
What happens to tidal volume and breathing frequency during graded exercise
both increase as intensity increases
How do breath patterns change from rest to exercise
rest = relatively constant breaths and only inspiratory reserve volume
moderate exercise (50% VO2max) = increase tidal volume and frequency – both inspiratory and expiratory reserve volume
heavy exercise (70% VO2max) = increase frequency and increase tidal volume
very heavy exercise (100% VO2max)= no change in tidal volume (b/c cant get more O2 b/c capped by anatomical size of lungs) but frequency increases
Inspiration and expiration is produced by what
contraction and relaxation of the diaphragm
How is ventilation controlled at rest
controlled by somatic motor neurons in the spinal chord and respiratory control center in medulla oblongata
– somatic NS = release ACh onto target organ
What are the two types of input to the respiratory control center
1) Neural imput
2) Humoral chemoreceptors
Explain the neural imput that goes to the respiratory control center
from motor cortex and skeletal muscle mechanoreceptors
- muscle spindles, Golgi tendon organs, joint pressure receptors == if stimulated you will breathe more
All neural imput causing contraction of muscles sends signal to respiratory center to do what
increase respiration
explain the humoral chemoreceptors (two)
** humoral = components found in blood
- Central chemoreceptors: CNS
— located in the medulla = CSF protecting the area
— PCO2 and H+ (cause change in pH) concentration in CSF — sense partial pressure change by the CNS - Peripheral chemoreceptors: PNS
— aortic and carotid bodies
— PO2, PCO2, H+ (effect pH), and K+ in blood === change in partial pressure of any of these – w/ PCO2 and PO2 altitude changes preference for chemoreceptors
Explain the 4 steps of how the central and peripheral chemoreceptors are activated and effect inspiration and expiration
1) stimulus: Central and peripheral chemoreceptors and signals from active muscles (neural imput) stimulate inspiratory center
2) response: external intercostal muscle and diaphragm contract
3) stimulus: stretching of the lungs triggers expiratory center
4) Response: intercostal and abdominal muscles contract == thoracic volume decrease and force air out of lungs
Ventilatory control during submax exercise is primarily mediated by what type of input
neural input
- greatest input in ventialtion at beginning due to neural input — maintained with humoral and level off
What are the 4 factors that effect the ventilatory control during submax exercise
1) higher brain centers
2) peripheral chemoreceptors
3) respiratory muscles
4) skeletal muscle — chemoreceptors and mechanoreceptors
Explain the ventilatory control stimulus and where it comes from during exercise and recovery
EXERCISE:
-neural then humoral activation
RECOVERY:
- decline of neural then humoral deactivation
what does the subscript mean with the partial pressure
location
PeCO2 = expired oxigenation
PaO2 = arteries
explain the flow of blood through the pulmonary system
1) pulmonary artery receives mixed venous blood from the right ventricles
2) oxygenated blood is returned to the left atrium via the pulmonary vein
3) low pressure system with a rate of blood flow equal to the systemic circut
What happens if the pressure is too high in the lungs
push fluid into the lungs = hard to breathe b/c less availablity of o2 exchange in alveoli
Explain the blood flow to the lung (specifically where in the lung)
- at REST (standing): blood flow is to the base of the lung (gravity)
- EXERCISE (standing): blood flow increases to top of lung
=== increases O2 consumption availability
lowest blood flow to top of lungs and most at middle-bottom — w/ exercise just increase blood flow
Explain the gas exchange at each step:
- alveolar gas exchange
- gas transport
- systemic gas exchange
- alveolar gas exchange: O2 loading and CO2 unloading
- gas transport: O2 carried from alveoli to systemic tissues, CO2 carried from systemic tissues to alveoli
- systemic gas exchange: O2 unloading, CO2 loading
What is the function of pulmonary capillaries with the flow of blood
= slows down blood flow for gas exchange === HIGHLY VASCULARIZED
what is the ventilation-perfusion ratio
(V/Q) – you want V/Q to be about 1
– Va = rate of ventilation (at the alveoli)
– Q - rate of perfusion (blood going past alveoli)
- indicate matching of blood flow to ventilation (> 0.5 is good)
What is the difference between being underperfused vs overperfused relative to ventilation
Underperfused: ventilation > blood flow (usually at the top of the lungs)
Overperfused: ventilation < blood flow (usually at the bottom of the lungs
— perfusion usually around 0.4
Explain exercise-induced asthma
contraction of smooth muscle around airway (bronchospasm) and mucus in airways during or post-exercise
Symptoms:
- labored breathing (dyspena)
- wheezing
what are the effects of ventilation and perfusion rate of someone with asthma or airway obstruction
- decrease in ventilation
- perfusion rate below 1 (ventilation < blood flow)
With asthma explain what happens at the alveoli
- reduced alveolar ventilation with excessive perfusion — V/Q <1
- low PO2 and high PCO2 in alveoli
- pulmonary arterioles constrict in order to match decrease in ventilation
—– B/C MUST BE CLOSE TO 1 FOR CORRECT BLOOD FLOW
– reduced alveolar ventilation, reduced perfusion
With asthma explain what happens at the alveoli
- enhanced alveolar ventilation with low perfusion — V/Q > 1
- high PO2 and low PCO2 in alveoli
- pulmonary arterioles dilate to allow more perfusion
- enhanced alveolar ventilation and enhanced perfusion
What is pulmonary capillary transit time
amount of time it takes for RBC to move through alveoli
What type of exercise improves ventilatory-perfusion ratio?
low to moderate intensity exercise
What is the result of high intentisty exercise on ventilatory perfusion ratio
slight V/Q inequlaity
- issues w/ V/Q relationship because dont have time to change partial pressure of O2 in alveoli
- RBC move too fast to absorb complete amount of O2 to saturate – decrease O2 perfusion
how is oxygen transported through the body
99% of O2 transported is bound to hemoglobin
What are the two types of hemoglobin
- oxyhemoglobin: Hb bound to O2
- deoxyhemoglobin: Hb not bound to O2
the amount of O2 that can be transported per until volume of blood is dependent on what
dependent on concentration of Hemoglobin
- hemoglobin concentration
- arterial O2 saturation
- amount dissolved in plasma
What is the equation for oxyhemoglobin dissociation curve
deoxyhemoglobin + O2 <-> oxyhemoglobin
The direction that the oxyhemoglobin dissociation curve depends on what two factors
- PO2 of the blood
- affinity between Hb and O2
- if you decrease partial pressure == drive equation to the left
at the lung a high PO2 causes the formation of what in the oxyhemoglobin dissociation curve
formation of oxyhemoglobin (loading O2)
at the tissues (skeletal muscles) a low PO2 causes the formation of what in the oxyhemoglobin dissociation curve
Low PO2 = release of O2 to tissues (unloading)
On an oxygen-hemoglobin dissociation curve explain what is happening on the steep and flat portions at what PO2 and how do you find the (a-v) O2 difference
On the steep portion oxygen is being dropped off and at the flat portion O2 is being uptaken by the hemoglobin
- find (a-v) o2 difference by finding difference between the arterial PO2 and the tissue VO2
why do you want small changes in the partial pressure
becasue it causes large changes in the saturation
What is the effect of Ph on the O2-Hb dissociation curve
- decreased pH lowers Hb-O2 affinity == more hemoglobin dissociation – cause confirmational change and lower affinity for O2
- “righward” shift of the curve (Bohr effect) === favor offloading of O2 to the tissues
How does H+ directly interact with hemoglobin
witih high H+ due to exercise, H+ bind to hemoglobin == reduce its O2 transport capacity
How does the O2-Hb graph shift with high and low pH changes
low pH = shift rightward
high pH = shift leftward
How does temperature effect the O2-Hb dissociation curve
allow O2 to be delivered more easily
- increased blood temperature owers Hb-O2 affinity
- restults in “righward” shift o fthe curve
Physiologically how does temperature cause faster deliverance of O2 to tissues
at an increased temperature = weakens bond b/t O2 and hemoglobin == assist unleading of O2 to working muscle
How does 2-3 DPG effect the O2-Hb dissociation curve
- DPG is the byproduct of RBC glycolysis
- may result in “righward” shift of the curve
- – during altitude exposure
- – not major cause of righward shift during exercise
how does the oxygen-hemoglobin dissociation shift with exercise
shift right with exercise
* more (a-v) O2 difference – lower saturation = more O2 to the muscles
a rightward shift in O2 hemoblobin dissociaton curve during exercise causes what
- unloading becomes easier at the muscles
Explane how the (a-v) O2 conent during exercise changes
- with more oxygen uptake the O2 content decreases == greater (a-v) O2 difference
ex. artery with 20mL O2 per 100mL blood -(goes to)-> vein now with 15 mL O2 per 100 mL blood
vs.
artery with 20mL O2 per 100mL blood -(goes to)-> vein now with 5 mL O2 per 100 mL blood
at exercise you will have greater uptake of O2 into muscles
What does myoglobin do
shuttle O2 from the cell membrane (from the blood) to the mitochondria of skeletal and cardiac muscle
What is the myoglobin content in different types of muscle fibers: type I vs type IIx
myoglobin higher in type I than type IIx because type I is for endurance training == less fatigue —> less myoglobin in type IIx
Does myoglobin or hemoglobin have a higher affinity for O2
Myoglobin has higher affinity for O2 than hemoglobin
- binds O2 and very low PO2
Explain the dissociation curves for myoglobin and hemoglobin
- myoglobin curve has steep slope upwards and reaches plateau fast == during steep curve myoglobin is unloading – during plateau myoglobin is loading
- hemoglobin curve == less steep slope that begins ot plateau around 50% PO2 == during steep slope hemoglobin is unloading – during plateau myoglobin is loading
the venous blood at around 40% PO2 on the hemoglobin vs myoglobin graph shows what
lower oxygenation == lower PO2 because comsuming more O2 at the tissue - O2 is leaving blood vessels and going inside tissues
(O2 leaving blood = lower PO2)
Explain how myoglobin effects the oxygen deficit and EPOC graph
- myoglobin serves as a reserve for O2 == during transition period from rest to exercise
- at end of exercise (beginning of EPOC) - myoglobin stores are replenished – fill up myoglobin quickly with O2 to “store” == this O2 consumption above rest contributes to O2 debt (EPOC)
explain how CO2 is transported in the blood in 3 warys
- 10% dissolved in plasma
- 20% boud to hemoglobin (
- 70% as bicarb (HCO3-) == becasue you want to get rid of bicarb faster
What is the equation for bicarbonate buffering
CO2 + H2O <–> H2CO3 (carbonic acid) <–> HCO3- + H+ (bicarbonate + hydrogen ion)
where is CO2 the highest
in the tissues == b/c of metabolism
How does CO2 transport from the blood to the lung
- CO2 dissolved in plasma diffuses to alveoli
- Hemoglobin + CO2 delivers CO2 into the alveoli
- bicarb and H+ convert to H2CO3 convert to CO2 and H2O using bicarb buffering
EXHALATION
What is given a biproduct of CO2 with ventilation and acid-base balance
high H2CO3 from the muscles
increased ventilation results in what regarding CO2
restults in CO2 exhalation
- reduces PCO2 (increase pH as hyperventilate – exhale more CO2) and H+ concentration
Decreased ventilation results in what regarding CO2
results in buildup of CO2
- high CO2 = high H+ which means low pH
What two things happen to ventialtion and arterial gases during the transition from rest to moderate submax steady state exercise
- Po2 and PCO2 are relatively unchanged – slight decrease due to offload of O2 from myoglobin
- initially, ventilaiton increases rapidly then slower, steady rise to steady state
What changes in ventilation and blood glases during prolonged exercise in heat
- little change in PCO2 == higher ventilation not due to high PCO2 – drivt in ventilaiton - moving anatomical deadspace (short shallow breaths w/ little gas exchange
- ventilation tends to drift upwards = increased blood temperature affects respiratory control center
** drift in O2 = high ventilation for thermoregulation
explain the change in pulmonary ventilation during graded exercise and why does this effect happen
Ventilatory threshold Tvent = inflection point where Ve increases exponentially
- increase in ventilation b/c body needs to exhale more CO2 to decrease H+ ion concentration
explain the effects of graded exercise in untrained individual on: Ventilation, Arterial PO2, Arterial PCO2, Venout PO2, and arterial pH
- ventilation gradually increases w/ increase intensity
- arterial PO2 stays constant @ 100
- arterial PCO2 stays constant and then at highest intensity it decreases b/c of high exhalation (hyperventilation) increase CO2 exhale
- Venous PO2 decreases b/c w/ more exercise muscle is uptaking more O2 for ATP
- arterial pH remains constant and then decreases == because of bicarb buffering
Explain what is effected by graded exercise in a trained subject
- mechanical limitations of the lung == high ventilation during max exercise = high risk for respiratory fatigue – too much blood to the lungs and not enough for the legs
- respiratory muscle fatigue during prolonged high intensity exercise
- exercise induced arterial hypoexemia (EIAH)
Explain exercise induced arterial hypoxemia (EIAH)
- at high intensity there is a high desaturation of O2 in the arteries
- for elite athletes they have continuous high SV that causes exhaustion
- at VO2 max = PO2 significantly dropped
