Full Answer Section

1. • Importance:
     • Enzyme that breaks down bacterial cell walls.
     • Provides chemical defense against bacterial infections.

2. Keratin:

   • Common Locations: Skin, hair, nails.
   • Importance:
     • Tough, fibrous protein that forms a protective barrier.
     • Resists abrasion, water loss, and microbial invasion.

3. Acid pH:

   • Common Locations: Stomach, vagina.
   • Importance:
     • Inhibits the growth of many microorganisms.
     • Provides a hostile environment for pathogens.

4. Cilia:

   • Common Locations: Respiratory tract.
   • Importance:
     • Tiny hair-like structures that sweep mucus and trapped particles away from the lungs.
     • Helps to clear the airways and prevent infection.

Part B: Decompression Sickness

Mary Ann’s symptoms are consistent with decompression sickness, also known as “the bends.” This condition occurs when dissolved gases, primarily nitrogen, come out of solution and form bubbles in the bloodstream and tissues as pressure decreases rapidly.

During scuba diving, the increased pressure at depth causes more nitrogen to dissolve in the body’s tissues. As Mary Ann ascended too quickly, the nitrogen gas came out of solution too rapidly, forming bubbles that can obstruct blood flow and damage tissues.

The symptoms she experienced, including joint pain, nausea, and shortness of breath, are common manifestations of decompression sickness. The condition typically resolves as the body reabsorbs the gas bubbles.

To prevent decompression sickness, divers should ascend slowly and adhere to specific decompression schedules. Additionally, it’s important to avoid flying immediately after diving, as the reduced cabin pressure can exacerbate the risk of bubble formation.