Reference no: EM133096265

Question 1

Critical Thinking

In many species, not just humans, melanin concentration is highest at the equator, and is reduced in the population as one moves further away in latitude. What is the relationship between melanin concentration and vitamin D production? What mechanisms explain the loss of melanin as one moves closer to the poles?

One notable exception in this trend is Australia. However, there is a hole in the ozone layer that sometimes fluctuates over the continent. How might this explain the prevalence of skin cancer in European immigrants to Australia?

Question 2.

Chief Complaint: A young boy was admitted for severe second- and third-degree burns after spilling boiling water on his entire body.

History: Johnny Williams, a 10-year-old white male, was transported by ambulance to the emergency room after being burned from spilling a large pot of boiling water on his body. His mother had been cooking dinner for a large group of people at their church and turned her back just long enough for Johnny to pull the pot over on himself.

In the emergency room, Johnny was unconscious. He had second-degree burns over 8% of his body and third-degree burns over 17% of his body -- both covering his thoracic and abdominal regions and his left elbow. His vital signs were quite unstable: blood pressure = 54 / 34; heart rate = 212 beats / min.; and respiratory rate = 39 breaths / min. He was struggling from circulatory failure. Two IVs were inserted and fluids were administered through each. His vital signs stabilized and he was transported to the pediatric intensive care unit (ICU).

Johnny regained consciousness later that evening, complaining of only minor pain over his trunk. Following debridement of his burns and application of a broad-spectrum, topical antibiotic, a plastic epidermal graft was applied over the burned areas. Despite treatment with a broad-spectrum antibiotic, he developed a systemic staphylococcal infection, necessitating a switch to a different antibiotic.

Johnny began a long, slow recovery. His position in bed had to be changed every 2 hours to prevent the formation of decubitus ulcers (i.e. bedsores). He lost nearly 10 pounds over the next several weeks, despite nasogastric tube feeding of 5500 calories ("Kcals") per day. After 9 weeks, sheets of cultured epidermal cells were grafted to his regenerating dermal layer. By the 14th week of his hospitalization, his epidermal graft was complete, and he was back on solid foods, his antibiotics were discontinued, and he was discharged from the hospital with a rehabilitation plan for both physical and occupational therapy at home, as well as twice-weekly visits by a nurse.

1. Describe the three major layers that make up normal, healthy skin. Include their location, their primary functions, the tissues that they are made up of, and any additional important information.

2. Major burn injuries need to be taken seriously not only for the cosmetic reasons, but also because this type of injury can lead to shock and even death. How does a burn injury affect the capillaries, in turn leading to shock?

3. What was the purpose of immediately administering the IV fluids to Johnny? How could this have saved his life?

4. Why do you think Johnny lost 10 pounds of weight so quickly, even though he was on a 5500 calorie/day diet?