Master the Basics of Physiology

Homeostasis

• Homeostasis is the ability of the body to maintain a constant internal environment despite changes in the external environment.
• The main physiological variables for which the body attempts to maintain homeostasis are temperature, pH, blood sugar levels, and blood pressure.

Anticipatory Responses

• Anticipatory responses are neural responses that occur before a change in the internal environment, helping to maintain homeostasis by anticipating and preparing for changes.

Mechanisms of Homeostasis

• The most common mechanism used to maintain homeostasis is negative feedback loops, which counteract changes in the internal environment.

Cell Membrane Proteins

• Cell membrane proteins have various functions, including transport, signaling, and cell-cell recognition, but NOT generating energy for the cell.

Osmosis

• Osmosis is the movement of water molecules from an area of high concentration to an area of low concentration through a selectively permeable membrane.
• Osmosis helps to equalize solute concentrations on both sides of the membrane.

Osmotic Pressure

• Osmotic pressure is the pressure required to prevent water from flowing into a solution that is hypertonic to the surrounding fluid.

Tonicity

• Tonicity refers to the ability of a solution to change the volume of a cell by altering the osmotic pressure.
• Solutions can be classified as isotonic (equal solute concentration), hypotonic (lower solute concentration), or hypertonic (higher solute concentration).

Effects of Hypertonic Solutions

• Hypertonic solutions cause cells to shrink due to water leaving the cell to equalize the osmotic pressure.