Exercise 10: Acid Base Balance

Student instructions:
Follow the step-by-step instructions for this exercise found in your lab manual and record your answers in the spaces below. Submit this completed document by the assignment due date found in the Syllabus. Rename this document to include your first and last name prior to submitting, e. g.
Exercise 10_JohnSmith. oc. Please make sure that your answers are typed in RED. (You may delete these instructions before submission. ) Grading: True/False, Multiple-Choice, and Fill-in-the-blank type questions will be worth 1 point each whereas Short-answer type questions will be worth 2 points each. This lab will be worth a total of 45 points but will be converted to a percentage grade when registered in your “Gradebook”.

ACTIVITY
1: Hyperventilation and Answers
A substance that dissolves in water to release hydrogen (H+) ions is a(n) _______. (Acid)
Which of the following is not a regulatory mechanism for acid/base balance in the body? D – Digestive System

the kidneys
the respiratory system
protein buffers
the digestive system

The maximum pH measured during hyperventilation was _______. (7. 58 )
The tidal volume (TV) when breathing at rest was about _____ ml. The TV with hyperventilation was (3 ) about _____ ml.
Describe the normal ranges for pH and PCO2 in the blood.

Min Pco2 – 40 Max Pco2 – 40
Min pH – 7. 41 Max pH – 7. 41

Describe what happened to the pH and the carbon dioxide in the blood with hyperventilation.

Min Pco2 lowered to 25. 94 (well below normal)
Min pH stayed around normal at 7.

Explain how returning to normal breathing after hyperventilation differed from hyperventilation

With straight hyperventilation, the pH stayed within average.
without returning to normal breathing.
the carbon dioxide lowered tremendously.

With the

Hyperventilation then back to normal breathing the carbon
dioxide levels did not lower as much and the pH stayed around
the normal zone as well.

Describe some possible causes of respiratory alkalosis. serious cardiac disorder (ACTIVITY)
2. RebreathingIn cases of acidosis, the pH of the blood is

C – Less than
Between and 7. 55
Between 7. 35 and 7. 45
Less than 7. 35
Greater than 7. 5

In this lab simulation, the minimum pH during rebreathing was _______.

If a person is “treated” in a hospital emergency department by breathing in and out of a paper

Rebreathing

sack, this is a classic example of _________ to lower the blood pH.
Hypoventilation results in
C – An accumulation of CO2 in the blood
lightheadedness.
numbness around the lips.

Answer: _________

accumulation of CO2 in the blood.
a good treatment for respiratory acidosis.
Describe what happened to the pH and the PCO2 levels in the blood during rebreathing. |Min pH lowered
to  Max pH raised
to Min Pco2 stayed the same at 40 Max Pco2 raised
to Describe several possible causes of respiratory acidosis. airway obstructions or inadequate ventilation, also possible
from an overproduction of Pco2
Explain how the renal system can compensate for respiratory acidosis.
the renal system compensates by retaining hco3 and excreting
hydrogen ions

ACTIVITY
3. Renal Responses to Respiratory Acidosis and Respiratory Alkalosis
When carbon dioxide (CO2) mixes with water in the bloodstream, carbonic acid is formed. This

Hydrogen
carbonic acid can then dissociate into the _______ ion and the _______ ion.
Bicarbonate

When more CO2 is produced by the body than can be expired from the lungs, the pH of the blood might

C – Decrease
increase
stay normal
decrease
either stay in the normal range or decrease.

True or False:
The renal system is able to fully compensate for acidosis or alkalosis.

True
Describe what happened to the concentration of ions in the urine when the blood PCO2 was lowered. H Decreased
HCO3 Increased

What condition was simulated when the blood PCO2 was lowered?

Alkalosis

Describe what happened to the concentration of ions in the urine when the blood PCO2 was raised.

H Increased
HCO3 Decreased

What condition was stimulated when the blood PCO2 was raised?

Acidosis

ACTIVITY
4. Respiratory Responses to Metabolic Acidosis and Metabolic Alkalosis
The cellular gaseous waste product than can accumulate in the bloodstream is ____________.

Carbon Dioxide

In this lab simulation, when the metabolic rate was increased to 80 kcal/hour, the pH of the blood
C – 7. 25; 63 lowered to ______ because of an accumulation of _______ [H+] in the blood.
When the metabolism was decreased, the number of breaths/minute _________

increased, decreased
decreased
remained the same

True or False:
In a hospital, the treatments for respiratory acidosis and metabolic acidosis are

False
Usually the same because these conditions are so similar.
Describe what happened to the blood pH when the metabolic rate was increased to 80 kcal/hr.

The blood pH decreased to 7. 26, BPM increased tremendously, PCo2 body system was compensating?

Also, H increased as well. The HCO3 decreased.
List and describe some possible causes of metabolic acidosis, i. e. how the acidosis is caused. Keto Acidosis – A buildup of keto acids that result from
Diabetes Mellitus

Salicylate Poisoning – a toxic condition resulting from

the ingestion of too much aspirin or oil of wintergreen, alcohol
strenuous exercise
Describe what happened to the blood pH when the metabolic rate was decreased to 20 kcal/hr.

What body system was compensating?

List and describe some possible causes of metabolic alkalosis, i. e. how the alkalosis is caused.
Ingestion of alkali, vomiting, constipation.