Amanda is an 18-year-old with anorexia nervosa. She was recently ...

[Themember4]

Amanda is an 18-year-old with anorexia nervosa. She was recently admitted to an eating disorders clinic with a BMI of 13.9, and although she was a voluntary patient, she was reluctant about the treatment.
 
  She was convinced she was overweight because her clothes felt tight on her. She complained that even her hands and feet were fat. One of her nurses explained that a protein in her blood was low. The nurse further explained that, as difficult as it may be to believe, eating a normal healthy diet would make the fat hands and feet go away.
 
  What protein do you suspect the nurse was referring to? How would a deficiency in this protein contribute to edema?
 
  What is the difference between the physiology of pitting and nonpitting edema?
 
  Because of her weakened condition, Amanda was moved around the ward in a wheelchair when she was not on bed rest. How does this affect her edematous tissues?

Question 2

Shauna is a healthy, fit 28-year-old who decided to go on a 2-week tour of Mexico for young singles. One hot afternoon in a small market community, she grabbed some fruit juice from a street vendor.
 
  Several hours later, she developed abdominal cramping and diarrhea. The diarrhea became so severe that she missed 3 days of the tour and stayed in her hotel room. By the end of her illness, she felt weak and tired. Her head ached, but the mild fever had disappeared, and she was able to join her new friends for the rest of the tour.
 
  What is the acid-base imbalance Shauna might have experienced and its etiology?
 
  What are the functions and importance of the bicarbonate buffer system in the body?

[emilymalinowski12]

Answer to Question 1

Amanda was presenting with low serum albumin. Albumin has a low molecular weight and high concentration in the plasma, allowing it to create a strong colloidal osmotic pressure. When albumin levels are decreased, the serum osmotic gradient declines. Fluid therefore leaves the capillaries to the surrounding interstitial space.

Pitting edema is a result of an increased level of interstitial fluid that exceeds the absorptive capacity of the tissue gel. The edema is mobile and can shift with pressure. Nonpitting edema involves the migration of capillary fluid and plasma proteins into the tissue space. The protein coagulates and creates a firm edema that does not move with pressure.

Edema increases the distance between tissue cells and circulation. The diffusion of gases, nutrients, and wastes between tissue cells and capillaries is consequently decreased. Edema can also mechanically compress tissue capillaries. Both situations leave tissues prone to ischemic damage and, when the patient is immobile, pressure ulcers.

Answer to Question 2

Severe diarrhea predisposes an individual to metabolic acidosis. Intestinal secretions are high in bicarbonate, so the loss of these fluids through prolonged or severe diarrhea reduces pH levels. In cases of microbial infection, intestinal secretions of bicarbonate are particularly abundant in an attempt to neutralize the metabolic acids of the pathogen. This situation further contributes to a loss of base and development of metabolic acidosis.

The bicarbonate buffer system uses carbonic acid (H2CO3) to substitute a strong acid and a bicarbonate salt to substitute a strong base in the maintenance of serum pH levels. The bicarbonate/carbon dioxide (HCO3/CO2) system is particularly efficient in buffering pH levels because of the ability to quickly form these components in the body and eliminate them as needed.