<< Chapter < Page Chapter >> Page >

Metabolic compensation

Metabolic and renal compensation for respiratory diseases that can create acidosis revolves around the conservation of bicarbonate ions. In cases of respiratory acidosis, the kidney increases the conservation of bicarbonate and secretion of H + through the exchange mechanism discussed earlier. These processes increase the concentration of bicarbonate in the blood, reestablishing the proper relative concentrations of bicarbonate and carbonic acid. In cases of respiratory alkalosis, the kidneys decrease the production of bicarbonate and reabsorb H + from the tubular fluid. These processes can be limited by the exchange of potassium by the renal cells, which use a K + -H + exchange mechanism (antiporter).

Diagnosing acidosis and alkalosis

Lab tests for pH, CO 2 partial pressure (pCO 2 ), and HCO 3 can identify acidosis and alkalosis, indicating whether the imbalance is respiratory or metabolic, and the extent to which compensatory mechanisms are working. The blood pH value, as shown in [link] , indicates whether the blood is in acidosis, the normal range, or alkalosis. The pCO 2 and total HCO 3 values aid in determining whether the condition is metabolic or respiratory, and whether the patient has been able to compensate for the problem. [link] lists the conditions and laboratory results that can be used to classify these conditions. Metabolic acid-base imbalances typically result from kidney disease, and the respiratory system usually responds to compensate.

Reference values (arterial): pH: 7.35–7.45; pCO 2 : male: 35–48 mm Hg, female: 32–45 mm Hg; total venous bicarbonate: 22–29 mM. N denotes normal; ↑ denotes a rising or increased value; and ↓ denotes a falling or decreased value.
Types of Acidosis and Alkalosis
pH pCO 2 Total HCO 3
Metabolic acidosis N, then ↓
Respiratory acidosis N, then ↑
Metabolic alkalosis N, then↑
Respiratory alkalosis N, then ↓

Metabolic acidosis is problematic, as lower-than-normal amounts of bicarbonate are present in the blood. The pCO 2 would be normal at first, but if compensation has occurred, it would decrease as the body reestablishes the proper ratio of bicarbonate and carbonic acid/CO 2 .

Respiratory acidosis is problematic, as excess CO 2 is present in the blood. Bicarbonate levels would be normal at first, but if compensation has occurred, they would increase in an attempt to reestablish the proper ratio of bicarbonate and carbonic acid/CO 2 .

Alkalosis is characterized by a higher-than-normal pH. Metabolic alkalosis is problematic, as elevated pH and excess bicarbonate are present. The pCO 2 would again be normal at first, but if compensation has occurred, it would increase as the body attempts to reestablish the proper ratios of bicarbonate and carbonic acid/CO 2 .

Respiratory alkalosis is problematic, as CO 2 deficiency is present in the bloodstream. The bicarbonate concentration would be normal at first. When renal compensation occurs, however, the bicarbonate concentration in blood decreases as the kidneys attempt to reestablish the proper ratios of bicarbonate and carbonic acid/CO 2 by eliminating more bicarbonate to bring the pH into the physiological range.

Chapter review

Acidosis and alkalosis describe conditions in which a person's blood is, respectively, too acidic (pH below 7.35) and too alkaline (pH above 7.45). Each of these conditions can be caused either by metabolic problems related to bicarbonate levels or by respiratory problems related to carbonic acid and CO 2 levels. Several compensatory mechanisms allow the body to maintain a normal pH.

Watch this video to see a demonstration of the effect altitude has on blood pH. What effect does high altitude have on blood pH, and why?

Because oxygen is reduced, the respiratory rate increases to accommodate, and hyperventilation removes CO 2 faster than normal, resulting in alkalosis.

Got questions? Get instant answers now!

Questions & Answers

what is systemic anatomy
Friday Reply
it's a study of organ structure
Amarachi
definition of anatomy and physiology
Kapil Reply
in anatomy we study about structure of human body........ in physiology we study about function
Zahid
Explain the anatomy
Junaid
structure of heart
Anusha
explain biology
saviour
biology is the science of life. biologists study the structure, function, growth, origin, evolution and distribution of living organisms.
Kadence
how is albino affected
Ujam Reply
what are the important stuff in the papillary layer
Ujam
Melanie's is responsible for the change in the color of the skin
Ujam
what happened when they are badly severed
Ujam
what happened when they are badly severed
Ujam
Examples of glial cells?
Nesh Reply
glial cell s help in the attractive foces of motion in the cellular network
Ujam
What is glial cell?
Esther
what is homeostasis
Laura Reply
homeostasis- The ability to maintain relatively stable internal conditions even though the outside world changes continuously. i,e, maintaining normal values in your body such as Adequate blood levels,blood pressure, heart activity and blood pressure.
Williams
thank you
Laura
Give atleast three reasons to study anatomy and physiology
George Reply
It helps to know about the body structure properly and administer proper care for the patient
Opeyemi
what's augmentin
Aphet Reply
augmentin is a type of combination antibiotic.
wintana
Can you explain to Heart anatomy in details please?
Handren Reply
definition of anatomy and physiology
Sardar Reply
Anatomy is the study structure of the body while physiology is the study of function of the body
Ayan
What is a dorsal cavity?
John Reply
Explain in detail mitosis and meiosis
sedeck Reply
What is Sodium Potassium Pump?
Mwamba Reply
The process of moving sodium and potassium ions across the cell membrance is an active transport process involving the hydrolysis of ATP to provide the necessary energy. It involves an enzyme referred to as Na+/K+-ATPase
USAMA
yes men.
Carlos
does it mean that there are two definitions of gross anatomy
Esther Reply
what is anatomy?
Hridy Reply
I think it's the study of the internal and external features of the body and its physical relationship between body parts
Esther
anatomy is the study of all the structure of body parts of living organisms
Kishan
to study the structure of human body parts
Sardar
anatomy is the study of human body
Meena
jaundice causes by when bilirubin blockage of bilary system
mahamed Reply
Yeah, when there is a blockage in the bilary system( bile ducts) which lead to obstruction of the bile pigments called bilirubin leading to a characteristically yellowish appearance of the eyes.
ibrahim
yes
mahamed
there are three main resons why bilirubin levels in the blood may rise: 1. pre-hepatic jaundice,2. hepatic jaundice, 3. post hepatic
mahamed

Get the best Anatomy & Physiology course in your pocket!





Source:  OpenStax, Anatomy & Physiology. OpenStax CNX. Feb 04, 2016 Download for free at http://legacy.cnx.org/content/col11496/1.8
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Anatomy & Physiology' conversation and receive update notifications?

Ask