Define homeostasis as maintaining a stable internal environment within narrow limits and identify blood pH, water balance and glucose as controlled variables.
The dimensions of four structures were measured in the hearts of eleven patients with anorexia and in the same number of control subjects.
(a) Discuss the support provided by the data for the claim that anorexia leads to the breakdown of heart tissue.
(b) In control subjects, blood potassium levels are maintained, through homeostasis, between 3.5 and 4.5 mmol litre . In patients with anorexia, blood potassium can fall below this level. This is known as hypokalemia. In patients with kidney failure, levels can rise above this range, causing hyperkalemia. The traces show the electrocardiograms (ECGs) of a patient with hypokalemia, a normal subject and a patient with hyperkalemia.
Sometimes hyperkalemia occurs as a body tries to respond to low blood pH . State the normal range of blood pH in the human body.