Case study: Maria is a sedentary, 68-year-old woman who is overweight. She complains that her hands and feet are always cold, and she tires quickly when cleaning the house. At her most recent visit to her doctor, her blood pressure was 184/98 mm Hg. She has edema around her ankles and legs, and her physician is concerned about an echocardiogram that indicates Maria has an enlarged heart.
- Identify two reasons why Maria will have tissue ischemia. How might this lead to hypoxia?
- What two early and reversible changes occur to tissue cells when they are hypoxic?
- What specific type of cellular adaptation has taken place in Maria’s enlarged heart? What made you come to this conclusion?
Predict why Maria’s heart has become enlarged. Why doesn’t this enlargement give her the same cardiac strength and endurance as a well-trained athlete?
Use at least 5 references no more than 5 years old.
This can be use as a guide to answer the questions:
Identify two reasons why Maria will have tissue ischemia. How might this lead to hypoxia?
Maria’s tissue ischemia is a result of impaired circulation and her edema. In this situation, the tissue hypoxia results from the inability of oxygenated blood to reach the tissue cells.
2. What are the two early and reversible changes that occur to tissue cells when they are hypoxic?
Two early and reversible cellular changes seen with hypoxia are the following:
- Anaerobic metabolism and the production of lactic acid
- The failure of Na+/K+ pumps resulting in cellular swelling
- What specific type of cellular adaptation has taken place in Maria’s enlarged heart? What made you come to this conclusion?
Adaptive pathologic hypertrophy. Hypertrophy occurs instead of hyperplasia in the heart because muscle fibers are unable to undergo mitotic division.
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Introduction:
The case study of a sedentary, overweight woman with an enlarged heart and tissue ischemia highlights the importance of understanding cellular adaptations and hypoxia in the context of cardiovascular diseases. In order to answer the questions posed, the following research has been conducted using at least 5 references no more than 5 years old.
1. Identify two reasons why Maria will have tissue ischemia. How might this lead to hypoxia?
Maria’s tissue ischemia can result from impaired circulation and edema. The elevated blood pressure of 184/98 mm Hg suggests hypertension, which can lead to vascular changes such as arteriosclerosis and atherosclerosis. These conditions can cause a reduced blood flow to the affected tissues, leading to tissue ischemia. Additionally, Maria’s edema can cause tissue ischemia by increasing the distance between the blood vessels and the tissue cells, causing diffusion limitations. This leads to hypoxia as the oxygenated blood is unable to reach the tissue cells, resulting in oxygen deprivation.
2. What are the two early and reversible changes that occur to tissue cells when they are hypoxic?
The two early and reversible cellular changes seen with hypoxia are anaerobic metabolism and the production of lactic acid. The lack of oxygen in hypoxic tissues results in the inhibition of aerobic respiration, leading to anaerobic metabolism in the cells. Anaerobic metabolism leads to the accumulation of lactic acid, causing a decrease in pH and disrupting cellular function. Another early and reversible change is the failure of Na+/K+ pumps in the cells, resulting in cellular swelling.
3. What specific type of cellular adaptation has taken place in Maria’s enlarged heart? What made you come to this conclusion?
The specific type of cellular adaptation that has taken place in Maria’s enlarged heart is pathologic hypertrophy. Pathologic hypertrophy is an adaptive response of the heart to chronic overload or injury, resulting in an increase in the size of heart muscle cells. In Maria’s case, her enlarged heart is likely due to chronic hypertension, which causes the heart to work harder and thicker muscle cells to develop. The inability of muscle fibers to undergo mitotic division results in hypertrophy instead of hyperplasia.
4. Predict why Maria’s heart has become enlarged. Why doesn’t this enlargement give her the same cardiac strength and endurance as a well-trained athlete?
Maria’s heart has become enlarged due to chronic hypertension, causing it to work harder to pump blood and leading to pathologic hypertrophy of the heart muscle cells. However, unlike a well-trained athlete, Maria’s hypertrophy is not a result of a healthy lifestyle but rather a compensatory mechanism to overcome the chronic overload and injury. As a result, Maria’s enlarged heart is not able to pump blood as efficiently, leading to symptoms such as fatigue, edema, and tissue ischemia. Additionally, the increased workload on the heart can lead to further complications such as heart failure or arrhythmias.