Author Question: Brianna is 47 years old and has not been able to work for over a year. She finds the simplest daily ... (Read 29 times)

magmichele12 · **on:** Jun 25, 2018

Brianna is 47 years old and has not been able to work for over a year. She finds the simplest daily tasks difficult to do because of her extreme fatigue.

In spite of her fatigue, her sleep is disturbed and is never refreshing for her. She also suffers from joint pain, muscle soreness, low-grade fever, and frequent sore throats. Her doctor examined her thoroughly, and after careful consideration, concluded Brianna had chronic fatigue syndrome.

There are other functional disorders that share similar features to chronic fatigue syndrome, making a definitive diagnosis of CFS difficult. What are some examples?

Her doctor told Brianna that, in spite of how difficult it may seem, regular gentle exercise would be beneficial for her, particularly for her immune system. Why did he emphasize that the exercise should be moderate and not strenuous?

Brianna told her doctor that what she preferred to do was to go to bed and stay there until her muscle and joint discomfort went away. Why would her doctor dissuade her from this decision?

Question 2

Melissa is a 15-year-old high school student. Over the last week, she had been feeling tired and found it difficult to stay awake in class. By the time the weekend had arrived, she developed a sore throat that made it difficult to eat and even drink.

Melissa was too tired to get out of bed, and she said her head ached. On Monday morning, her mother took her to her doctor. Upon completing the physical exam, he told Melissa the lymph nodes were enlarged in her neck and she had a fever. He ordered blood tests and told Melissa he thought she had mononucleosis, a viral infection requiring much bed rest.

Innate and adaptive immune defenses work collectively in destroying invasive microorganisms. What is the interaction between macrophages and T lymphocytes during the presentation of antigen?

Melissa's illness is caused by a virus. Where are type I interferons produced, and why are they important in combating viral infections?

Humoral immunity involves the activation of B lymphocytes and production of antibodies. What are the general mechanisms of action that make antibodies a key component of an immune response?

polinasid · **Reply #1 on:** Jun 25, 2018

Answer to Question 1

Symptoms of CFS closely mimic those of fibromyalgia, multiple chemical sensitivities, depression, and irritable bowel syndrome.

Some students may note that in CFS, muscular activity can create postexertional malaise that lasts longer than 24 hours. In terms of immunity, strenuous activity can have a negative effect on immune system integrity. Moderate exercise, however, increases the number of circulating leukocytes and increases NK cell activity.

Bed rest is detrimental to the musculoskeletal system because it
promotes muscular disuse atrophy.
decreases force-generating capacity and increases fatigability in muscles.
encourages muscle shortening.
causes contractures leading to a decreased range of motion in joints.
promotes anatomical changes in articular cartilage, tendons, and ligaments.
results in altered bone metabolism and the development of osteoporosis.

Answer to Question 2

Macrophages are a component of innate immunity and are responsible for the phagocytosis of microbes and processing of antigen. When working with T lymphocytes, macrophages can act as antigen-presenting cells. After ingesting the microbe, digestive enzymes break down antigen into small peptides and combine them with class II MHC. These complexes are presented on the cell membrane surface to CD4+ helper T cells, which recognize the antigen-MHC II complex by means of a T-cell receptor.

Type I interferons are produced by macrophages and fibroblasts. They inhibit viral replication and allow a virally infected cell to be recognized by lymphocytes. IFNs are also responsible for triggering uninfected cells to produce antiviral proteins to inhibit viral synthesis and spread.

Antibodies contribute to the agglutination of microbes to prevent their spread, facilitate phagocytosis, and encourage their destruction. They have the ability to neutralize bacterial toxins and inhibit the ability of viruses to invade host cells. Antibodies also contribute to the activation of complement and assist in the adherence of antigen to immune cells.