Which statement is true regarding myocardial functioning in the normal heart, based upon the Frank Starling law?

Disseminated intravascular coagulation (DIC) is a serious condition characterized by widespread activation of coagulation throughout the body, leading to both thrombosis and hemorrhage. Here's why option C is the correct choice:

A) Glucosuria and lethargy:

Glucosuria (presence of glucose in the urine) and lethargy are not typical findings associated with DIC. Glucosuria may indicate diabetes mellitus or renal dysfunction, while lethargy can result from various causes but is not specific to DIC.

B) Frothy urine and anorexia:

Frothy urine may indicate proteinuria, which can occur in conditions such as nephrotic syndrome, but it is not a characteristic finding of DIC. Anorexia (loss of appetite) is a nonspecific symptom that can occur in many conditions but is not directly related to DIC.

C) Hematuria and hemoptysis:

Correct. Hematuria (blood in the urine) and hemoptysis (coughing up blood) are common manifestations of DIC. In DIC, widespread activation of the coagulation cascade can lead to microthrombi formation in small blood vessels, resulting in tissue ischemia and bleeding. Hematuria and hemoptysis can occur due to bleeding from the urinary tract or respiratory system, respectively, as a result of DIC-induced coagulopathy.

D) Polyuria and productive cough:

Polyuria (excessive urination) and productive cough (cough with production of sputum) are not specific findings of DIC. Polyuria may occur in conditions such as diabetes mellitus or diuretic use, while productive cough can be seen in respiratory infections or chronic lung diseases but is not directly related to DIC.

A) An increase in afterload results in decreased systolic pressure, which creates a decreased cardiac output:

This statement is not consistent with the Frank-Starling law. Afterload refers to the resistance against which the heart must pump blood during systole. An increase in afterload typically results in increased systolic pressure, not decreased, as the heart works harder to overcome the increased resistance. However, increased afterload can lead to decreased cardiac output due to the increased work of the heart.

B) A decrease in afterload causes the cardiac muscles to hypertrophy, resulting in increased diastolic volume:

This statement is not consistent with the Frank-Starling law. Afterload refers to the pressure or resistance against which the heart must pump blood during systole. A decrease in afterload typically reduces the workload on the heart, which may lead to reverse remodeling and a reduction in cardiac hypertrophy. Increased diastolic volume may occur due to reduced afterload, but it's not the direct result of hypertrophy.

C) An increase in preload results in greater shortening of myocardial fibers, thereby increasing contractility:

Correct. According to the Frank-Starling law, an increase in preload (end-diastolic volume or stretch of myocardial fibers) leads to greater overlap of actin and myosin filaments within myocardial fibers during systole. This increased overlap results in stronger myocardial contraction (increased contractility), leading to an increased stroke volume and cardiac output.

D) A decrease in preload results in increasing diastolic muscle fiber length, which impedes contractility:

This statement is not consistent with the Frank-Starling law. Preload refers to the degree of stretch of the myocardial fibers at the end of diastole. A decrease in preload would lead to decreased stretch of the myocardial fibers, not increasing diastolic muscle fiber length. Decreased preload typically results in decreased contractility rather than impediment to contractility due to reduced myocardial stretch.