Question

Sodium is an incredibly important substance in our body. You may remember from Module 1 that sodium ions play a crucial role in conducting nerve impulses during depolarization. You may also remember from Biology 20 that sodium is involved in muscle contractions. Hyponatremia is a condition where there is too little sodium in the body. This can result in difficulty processing thoughts, nausea, decreased ability to balance, seizures and coma. On the other hand, an excessive amount of sodium or hypernatremia, in the body can also lead to many different neurological problems including seizures and coma. Katrina has an excessive amount of sodium ions in her blood plasma. This is occurring despite the fact that she had been watching her salt intake and ensuring that she's drinking enough fluid throughout the day. From what you have learned in this module, which hormone imbalance is causing this problem for Katrina? Explain your reasoning

Answer 1

Hypernatremia generally results from dehydration, people lose body fluid and become dehydrated due to vomiting, diarrhea, sweating excessively, excessive loss of urine, etc.

Excessive loss of urine takes place in the body under the condition such as Diabetes Mellitus(DM) and Diabetes Insipidous(DI).

In DM, there may be inadequate insulin production or decreases in the sensitivity of insulin which results in excretion of glucose from the urine. Glucose is osmotically active and its removal draws a lot of water from the urinary tract which results in dehydration of the body and eventually causing Hypernatremia.

In DI, there is inadequate production of ADH/Vasopressin or decrease the sensitivity of ADH action on the kidney. ADH is secreted from the posterior pituitary and acts on receptors present on collecting duct of the nephron and increases the permeability of water in DCT and collecting duct which is normally impermeable to water and helps in water reabsorption from the collecting duct. In the absence of ADH water are not reabsorbed and secreted from the kidney which leads to dehydration and it will eventually lead to Hypernatremia.