Which structure regulates the transport of substances in and out of a cell?

The cell membrane, also known as the plasma membrane, regulates the transport of substances in and out of a cell. It acts as a selective barrier, controlling the passage of molecules and ions based on their size, charge, and lipid solubility. This regulation is essential for maintaining cellular homeostasis and ensuring that the cell's internal environment remains stable.

When antidiuretic hormone (ADH) is secreted, cells in the collecting tubules of the nephrons respond by increasing water reabsorption from the urinary filtrate. This action helps to concentrate urine and conserve water in the body, ultimately reducing urine output.

In the anatomical position, a person stands erect with their feet together and pointing forward, while their palms face forward (anteriorly) as well. This position serves as a reference point for describing the orientation and location of body structures.

The muscle of the quadriceps femoris group that lies on the side surface of the lower extremity is the vastus lateralis. It is one of the four muscles that make up the quadriceps group and is located on the lateral, or outer, aspect of the thigh. The vastus lateralis is