Effects of Blood PCO2 and pH on Ventilation

Chemoreceptor input to the brain stem modifies the rate and depth of breathing so that, under normal conditions, arterial PCo2, pH, and Po2 remain relatively constant. If hypoventilation (inadequate ventilation) occurs, PCO2 quickly rises and pH falls. The fall in pH is due to the fact that carbon dioxide can combine

Carotid sinus

Common carotid artery

Carotid sinus

Common carotid artery

Physiology Heart Vagus Carotid Sinus

—Sensory nerve fibers

(in glossopharyngeal nerve)

Carotid body

Sensory nerve fibers (in vagus nerve)

Aortic bodies

Heart

Aorta

—Sensory nerve fibers

(in glossopharyngeal nerve)

Carotid body

Sensory nerve fibers (in vagus nerve)

Aortic bodies

Aorta

Heart

■ Figure 16.26 Sensory input from the aortic and carotid bodies.

The peripheral chemoreceptors (aortic and carotid bodies) regulate the brain stem respiratory centers by means of sensory nerve stimulation.

with water to form carbonic acid, which, as a weak acid, can release H+ into the solution. This is shown in these equations:

The oxygen content of the blood decreases much more slowly because of the large "reservoir" of oxygen attached to hemoglobin. During hyperventilation, conversely, blood PCO2 quickly falls and pH rises because of the excessive elimination of carbonic acid. The oxygen content of blood, on the other hand, is not significantly increased by hyperventilation (hemoglobin in arterial blood is 97% saturated with oxygen during normal ventilation).

Hyperventilation Blood

Chemoreceptors

Aortic and carotid bodies

Chemoreceptors

Medulla oblongata

Chemoreceptors

Aortic and carotid bodies

Chemoreceptors

Medulla oblongata

-Spinal cord

Motoneurons to respiratory muscles

■ Figure 16.27 The regulation of ventilation by the central nervous system. The feedback effects of pulmonary stretch receptors and "irritant" receptors on the control of breathing are not shown in this flowchart.

For the reasons just stated, the blood PCo2 and pH are more immediately affected by changes in ventilation than is the oxygen content. Indeed, changes in PCo2 provide a sensitive index of ventilation, as shown in figure 16.28. In view of these facts, it is not surprising that changes in PCo2 provide the most potent stimulus for the reflex control of ventilation. Ventilation, in other words, is adjusted to maintain a constant Pœ2; proper oxygenation of the blood occurs naturally as a side product of this reflex control.

The rate and depth of ventilation are normally adjusted to maintain an arterial PCO2 of 40 mmHg. Hypoventilation causes a rise in PCO2—a condition called hypercapnia. Hyperventilation, conversely, results in hypocapnia. Chemoreceptor regulation of breath figure 16.29.

tion of breathing in response to changes in PCO2 is illustrated in

Getting to Know Anxiety

Getting to Know Anxiety

Stop Letting Anxiety Rule Your Life And Take Back The Control You Desire Right Now! You don't have to keep letting your anxiety disorder run your life. You can take back your inner power and change your life for the better starting today! In order to have control of a thing, you first must understand it. And that is what this handy little guide will help you do. Understand this illness for what it is. And, what it isn't.

Get My Free Ebook


Responses

  • Magnus
    What is blood ph with pco2 78?
    8 years ago
  • john jones
    How is ventilation linked to blood ph via carbonic acid ventilation depth?
    8 years ago
  • pansy
    HOw PACO2 affect body?
    7 years ago
  • Folco Took-Brandybuck
    What reflex regulates normal ventilation?
    7 years ago
  • Gorbadoc Gammidge
    What effects does hyperventalation have on pco2 and blood ph?
    7 years ago
  • teuvo
    How regulation of respiration in response to changes blood pco2?
    7 years ago
  • giselda
    What are the physiological effects in PCO2, PO2 and PH levels?
    7 years ago
  • jessika
    How do PCO2 and PO2 effect PH?
    7 years ago
  • Priscilla
    How ventilation affects blood pH.?
    6 years ago
  • georgia
    What effect on ventilation po2?
    6 years ago
  • polo zaragamba
    How is ventilation regulated by arterial Pco2 Po2 and pH?
    6 years ago
  • Pasqualina
    What is the EFFECT OF VENTILATION RATE ON pCO2?
    6 years ago
  • Jessika
    How would acidic pH of blood effect ventilation?
    6 years ago
  • Dorothy
    How does the level of PCO2 in the blood affect the blood pH level?
    6 years ago
  • Preston
    How is ventilation controlled by arterial PCO2 and pH?
    5 years ago
  • zak
    Which are chemoreceptors affect the oxigen and Pco2?
    4 years ago
  • KIROS SEMHAR
    How to control PCO2 level in ventulator patients?
    4 years ago
  • giacinto
    How is homeostasis of pco2 ,po2 and ph maintained?
    4 years ago
  • sm headstrong
    How to changes in ph affect rate and depth of ventilation?
    4 years ago
  • thelma
    How does ventiallation change with PCO2?
    4 years ago
  • QUINN
    What is normal Pco2 on ventilator?
    3 years ago
  • ulrike m
    What is effect of pco2 on human body?
    3 years ago
  • HARRIET
    How we can control pco2 in human body?
    3 years ago
  • dinodas
    How does high pCO2 affect ventilation?
    3 years ago
  • allie
    What would be the effect on ventilatory response of changing pH?
    3 years ago
  • lucas muller
    How does hypoventilation affect blood gasses pco2 and po2 and ph?
    3 years ago
  • Bowman
    What affect does hyperventilating have on blood pO2 levels?
    3 years ago
  • faye mckenzie
    What is the effect of exercise on pH BLOod levls and PO2 &PCO2?
    3 years ago
  • tove
    How ventilation is regulated and how blood ph and pCO2 affect it?
    3 years ago
  • afwerki
    What affects ph levels more po2 or pco2?
    3 years ago
  • Johan
    How blood adjust ph during ventilation?
    3 years ago
  • mia mitchell
    What is the nomenclature of pco2 and po2?
    3 years ago
  • richard
    Does Po2 or Pco2 have a greater effect on ventilation?
    3 years ago
  • Facondo
    How does muscle rigidity increase breath pco2?
    3 years ago
  • Mike
    What effect of arterial pco2 has on ventilation?
    3 years ago
  • mungo
    How hypercapnia affects arterial PO2?
    3 years ago
  • veli-pekka
    How to adgjust pco2 levels?
    3 years ago
  • Julia
    How does high pco2 affect breathing?
    3 years ago
  • Mario
    What changes in PaO2, PaCO2 and pH increase ventilation rate?
    3 years ago
  • myrtle
    How much increase of respiratory rate affects on pco2?
    3 years ago
  • dominik
    How does PCO2 regulate the respiratory rate and blood ph?
    2 years ago
  • merimas
    How does increased ventilation effect ph?
    2 years ago
  • topi
    How does increases in PaCO2 affect PH?
    2 years ago
  • Barbara
    How to normalize PH on ventilator?
    2 years ago
  • Fausta
    What is the effect of increased PCO2?
    2 years ago
  • Ute
    How can a ventilator decrease ph?
    2 years ago
  • macaria fanucci
    Does a PCo2 of 5560 require ventillation?
    2 years ago
  • mary
    How blood gases and pH influence ventilation?
    2 years ago
  • michaela
    What does a eise in blood PCO2 result in?
    2 years ago
  • Marina
    What happens it pco2 level increase in human body?
    2 years ago
  • bernd
    What is the side effect if pco2 is 16.2?
    2 years ago
  • timba greenhand
    What are the effects of exercise on po2, pco2 and ph blood values?
    2 years ago
  • ileana
    What will happen if pco2 level increases?
    1 year ago
  • theodoric oldbuck
    What is the impact of hyperventilation on alveolar and blood pO2 and pCO2?
    1 year ago
  • immacolata zito
    How to increse pco2level?
    1 year ago
  • cassio
    What can i do for rising Pco2 in human body?
    1 year ago
  • Frodo
    Why does Arterial PO2 and PCO2 remains constant during exercise?
    1 year ago
  • Lanfranco
    How is pH affected by PCO2?
    10 months ago
  • alida
    What is the effect of increased plasma PCO2 on pH?
    9 months ago
  • keeva
    How can hyper and hypoventilation affect the regulation of blood?
    9 months ago
  • angela
    Does ventilation affect CO2 levels tion?
    9 months ago
  • mentha
    What we can do in pressure support ventilation PaCO2 is lower PH also is lower?
    8 months ago
  • romola
    How to ventilate with elevated pco2?
    8 months ago
  • haiduc bunce
    How does high pco2 affect ph bin the blood?
    8 months ago
  • Gorhendad
    How does mechinical venting affect ph?
    8 months ago
  • EINOJUHANI
    How does blood gases infulence ventilation?
    7 months ago
  • Stephanie
    How do chemoreceptors affect ph, pco2and po2 how do they modify the rate anddepth of breathing?
    7 months ago
  • PHILIP
    HOW PCO2 AFFECTS BLOOD PH?
    7 months ago
  • Faramir Lightfoot
    How to lower pH on ventilator?
    7 months ago
  • tilly
    How does hypoventilation effect blood gases?
    5 months ago
  • priscilla
    What is po2 vent temp?
    5 months ago
  • WILLIAM
    How does pc02 impact on blood ph?
    4 months ago
  • Brigida
    How po2 pco2 and ph affects respiratory movements?
    4 months ago
  • elisa
    Why does increased ph not increase ventilation?
    4 months ago
  • Miia
    How does a ventilator change the pco2 levels?
    4 months ago
  • Gustavo
    Does rebreathing increase blood ph?
    4 months ago
  • luigia
    What happens when your hyperventilation paco2?
    4 months ago
  • Katariina
    How does he hugh pCO2 affect the breathing?
    4 months ago
  • magnus
    Does arterial CO affect rate and deepth of breathing?
    3 months ago
  • jan
    How does changes in HCO3 effect PH?
    3 months ago
  • marko hirsch
    What happends to vasculature during hyperventilation?
    3 months ago
  • Kyle
    How oes overexercising affect ph of blood?
    3 months ago
  • ernest
    What happens to arterial PCO2 as a result of hyperventilation?
    3 months ago
  • debora
    How are po2 and pco2 in arterial blood affected by hyperventilation?
    3 months ago
  • Ronnie
    What is the effect of elevated PCO2 on respiratory function and on pH?
    3 months ago
  • abraham aziz
    How does ph influence the rate and depth of respiration?
    3 months ago
  • billye crossman
    What effects in blood ph and ventilation rate are expected with hypoventilation?
    3 months ago
  • russom
    How does elevated hco3 affect ph?
    3 months ago
  • liliana
    What happens when the PaCO2 of the arterial blood increases petaining to respirations and ph levels?
    2 months ago
  • kacper
    How does o and co2 affect pulmonaty ventilation?
    2 months ago
  • Naomi
    How does alveolar ventilation rate affect blood ph?
    2 months ago
  • jessica
    How hyperventilation affects pco2 and plasma ph, and?
    2 months ago
  • raymond
    How hypoventilation affects h in blood?
    2 months ago
  • Theodoric Baggins
    How does hypoventillating affect the body?
    2 months ago
  • p
    How are PACO2 and ph affected by anemia?
    29 days ago
  • iris
    How does pH affect pulmonary vasculature?
    15 days ago

Post a comment