Final answer:
Ms. Palmeri's skin felt dry after swimming in the Mediterranean Sea due to osmosis, where the salty, hypertonic seawater drew moisture out of her skin cells, leading to dryness. The high salt concentration in the Mediterranean created an osmotic pressure that caused water to move out of the skin to balance the solute concentration difference.
Step-by-step explanation:
Ms. Palmeri's experience of dry skin after swimming in the Mediterranean Sea can be explained using the concept of osmosis. Osmosis is the movement of water through a semipermeable membrane from an area of high water concentration to an area of low water concentration, driven by differences in solute concentration. The Mediterranean Sea is a hypertonic solution compared to the cells of the human body because it has a higher salt concentration. When Ms. Palmeri went swimming, the salt water drew out moisture from her skin cells due to osmotic pressure, leading to dry skin.
This dehydration of the skin cells is similar to how the body becomes thirstier after drinking seawater due to its high osmolarity. The skin, specifically the epidermis, is protected by layers that normally retain moisture, but prolonged exposure to hypertonic solutions like seawater can overwhelm these defenses, leading to dryness. This is in contrast to the body's better ability to handle hypotonic solutions, where excess water can be excreted through the kidneys.
The feeling of dry skin is a signal of the body's need to rehydrate and balance the osmotic pressure difference created by the salty sea water. Essentially, Ms. Palmeri's skin lost moisture as water was drawn out to dilute the salt from the sea, leading to dryness.