RN Nursing · Pathophysiology · Practice question
Which statement about blood pH is correct?
-
Always exactly 7.4
-
More acidic than water
-
Must be below 7.0
-
✓
Ranges 7.35–7.45
Answer & explanation
Correct: Ranges 7.35–7.45
The normal physiological pH of arterial blood is maintained within a narrow range of 7.35 to 7.45. This tight regulation is critical because even small deviations can significantly impair enzyme function, cellular metabolism, and organ function. The pH is maintained by buffer systems including the bicarbonate-carbonic acid system, the phosphate buffer system, and proteins such as hemoglobin, working in concert with respiratory and renal compensation. The statement that blood pH is always exactly 7.4 is imprecise; while 7.4 is often cited as the mean or ideal value, the accepted normal range spans from 7.35 to 7.45, and values within this range are considered normal. The statement that blood is more acidic than water is incorrect; pure water has a neutral pH of 7.0, and blood with a pH of 7.35–7.45 is actually slightly alkaline relative to neutral. The statement that pH must be below 7.0 is clinically dangerous — a pH below 7.35 constitutes acidosis, and a pH below 7.0 is incompatible with life. Students should remember that pH values below 7.35 indicate acidosis and values above 7.45 indicate alkalosis, both of which require clinical intervention.
Practise Pathophysiology questions
Work through full question sets with instant rationales, timed exams, and progress tracking.
Start practising freeRelated practice questions
- The client has hearing loss, and upon examination, a large amount of earwax is found in the client's ear. What type of hearing loss is the client likely experiencing?
- A male construction worker, age 42, asks the nurse if a new mole on his scalp could be cancer. Based on the nurse's understanding of melanoma, the nurse should ask the patient which of the following? Select all that apply.
- A client presents to the clinic complaining of flaking dry skin of the elbows. Upon the nurse's assessment she notices red plaques with a scaly silvery appearance. These findings are consistent with which condition?
- Which arterial blood gas (ABG) values leads the nurse to suspect a client has developed respiratory acidosis? Select all that apply.