NUR 631 Topic 3 DQ 1

Sample Answer for NUR 631 Topic 3 DQ 1 Included After Question

Select two of the following discussion questions for your discussion response. Indicate which questions you have chosen using the format displayed in the “Discussion Forum Sample.”

  1. Explain how acid-base physiology leads to the regulation of fluid balance and extra cellular pH.
  2. What is the equation for the carbonic acid/bicarbonate buffering system? How do actions at the lungs and kidneys affect this equation and thus compensate for alterations in plasma pH levels?
  3. How do changes in plasma osmolality affect the physiology of erythrocytes?

A Sample Answer For the Assignment: NUR 631 Topic 3 DQ 1

Title: NUR 631 Topic 3 DQ 1

1. Explain how acid-base physiology regulates fluid balance and extracellular ph.

The body uses a variety of physiological adjustments to keep things in homeostatic balance. Maintaining the proper acid-base balance is one of them. The normal pH of the human body is between 7.35 and 7.45, with an average of 7.40. This is the case when no pathogenic conditions are present. The oxygenation of the blood, an essential biological activity, functions best at this pH. ( Hopkins et al., 2022).

 Cellular metabolism produces acids as waste products. Metabolic acidosis, metabolic alkalosis, respiratory acidosis, and respiratory alkalosis are humans’ four most common acid-based illnesses. Compatibility of homeostatic physiological processes requires regulating fluid balance and extracellular pH, intimately connected to acid-base physiology and can be fatal if not maintained ( Hopkins et al., 2022). The pH and HCO3 values show the acid-base balance regulated by the lungs and the kidneys, respectively. Normal bodily processes require harmony between the two. Short- and long-term shifts in the acid-base balance are primarily controlled by the respiratory and renal systems, which work together to achieve this. The body stores both volatile and nonvolatile acids. Carbon dioxide (CO2) from the lungs is an example of a volatile acid, while the kidneys are responsible for excreting metabolic acids (McCance & Huether, 2019).

2. How do changes in plasma osmolality affect the physiology of erythrocytes?

The main factor affecting plasma osmolality is the plasma sodium concentration. It is limited to modest ranges under ordinary physiological conditions. Changes in plasma osmolality can cause compensatory reactions like increased water intake or increased water excretion because hypothalamic receptors in the brain are sensitive to these changes. The brain induces thirst and fluid intake when plasma volume or osmolality changes. Additionally, the kidneys are instructed to expel less water to dilute the plasma by the rise in ADH (McCance & Huether, 2019). When red blood cells are placed in plasma with higher osmolarity, fluid moves from the intracellular to the extracellular compartment and shrinks. When the plasma has a lower osmolarity, the red blood cells tend to gain water and may likely burst (McCance & Huether, 2019).

References

Hopkins E, Sanvictores T, Sharma S. (2022). Physiology, Acid-Base Balance.

Stat Pearls Publishing; Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK507807/ 

McCance, K. L., & Huether, S. E. (2019). Pathophysiology: The biologic basis for disease in adults and children (8th ed.). Elsevier.  

A Sample Answer 2 For the Assignment: NUR 631 Topic 3 DQ 1

Title: NUR 631 Topic 3 DQ 1

How do changes in plasma osmolality affect the physiology of erythrocytes?

Under normal conditions, plasma sodium concentration is held within a normal range. Under certain pathological conditions however, it can vary greatly. This change in plasma osmolality can lead to either swelling or shrinkage of red blood cells (RBCs). Hyponatremic hypoosmolality in conditions such as syndrome of inappropriate ADH secretion (SIADH) which occurs in some brain injuries or when excess free water is either ingested or infused lead to symptoms of nausea, malaise, headache, and in later stages lethargy, disorientation, seizure, coma and even death. Hyponatremic hyperosmolality which is seen in diabetes insipidus from a lack of ADH or the kidney’s inability to respond to the ADH leads to similar symptoms such as anorexia, restlessness, nausea, vomiting, and in severe cases neurological symptoms such as lethargy, stupor, or coma.

The neurological symptoms of these diseases are explained by the osmotic gradient between the intra and extracellular components of the brain cells. With hypoosmolality, water moves into the neuronal cells and causes swelling and tissue edema. In hyperosmolality, water is lost and leads to cell shrinkage. These volume shifts affect all cells exposed to the gradient. In hypoosmolality, RBCs increase their volume and reduce their cellular viscosity. In hyperosmolality, RBCs shrink and increase viscosity. These changes lead to RBC deformability, and affect microvascular blood flow (Reinhart, et al., 2015). 

What is the equation for the carbonic acid/bicarbonate buffering system? How do actions at the lungs and kidneys affect this equation and thus compensate for alterations in plasma pH levels?

The formula for the carbonic acid/bicarbonate buffering system is: 

                                    H2O + CO2 <-> H2CO3 <-> H+ + HCO3-

The lungs and kidneys are the two main modulators of pH balance. In the lungs, pH is adjusted using carbon dioxide. With expiration, carbon dioxide is released from the body, into the environment. Because carbon dioxide forms carbonic acid when combined with water in the body, the amount of expired carbon dioxide causes pH to either increase or decreased. With increased respiration, more carbon dioxide is released, therefore pH increases. With a depressed respiratory effort, less carbon dioxide is released, therefore pH decreases. Changes in pH due to the respiratory system happen rather quickly, in minutes to hours. The kidneys play a role in the pH system due to the reabsorption of bicarbonate and excretion of fixed acids. Blood flows through the kidneys for some substances to be filtered out and others to be reabsorbed and recycled. If bicarbonate is reabsorbed and/or acid is secreted, pH increases. If bicarbonate is unable to be reabsorbed or acid is not excreted, pH decreases. These metabolic changes occur over a longer period compared to the respiratory system. In the renal systems, metabolic compensation takes days versus minutes to hours (Hopkins, Sanvictores, & Sharma, 2022). 

Hopkins, E., Sanvictores, T., Sharma, S. (2022). Physiology, acid base balance. National Library of Medicine.

Retrieved on May 20, 2023, from https://www.ncbi.nlm.nih.gov/books/NBK507807/

Reinhart, W., Piety, N., Goede, J., Shevkopylas, S. (2015). Effect of osmolality on erythrocyte rheology and perfusion of an artificial microvascular network. Microvascular Reseasrch, 98,102-17. https://doi.org/10.1016/j.mvr.2015.01.010