hypotonic response

Definition

Target type: biologicalprocess

Any process that results in a change in state or activity of a cell or an organism (in terms of movement, secretion, enzyme production, gene expression, etc.) as a result of detection of, or exposure to, a hypotonic environment, i.e. an environment with a lower concentration of solutes than the organism or cell. [GOC:jl, PMID:12598593]

Hypotonic response is a cellular process that occurs when a cell is placed in a solution with a lower solute concentration than the cell's cytoplasm. This results in a net movement of water into the cell, causing it to swell and potentially burst. The process can be broken down into several stages:

1. **Water Movement:** The difference in solute concentration creates an osmotic gradient, driving water from the hypotonic solution across the cell membrane into the cell's cytoplasm. This influx of water increases the cell's volume.

2. **Mechanical Stress:** As the cell swells, its internal pressure increases, placing stress on the cell membrane and internal structures. This stress can activate various signaling pathways.

3. **Regulatory Mechanisms:** The cell responds to the increased pressure and volume by activating various regulatory mechanisms. These mechanisms aim to maintain cell homeostasis and prevent lysis.

4. **Ion Transport:** The cell may activate specific ion channels and pumps to regulate ion concentrations and maintain osmotic balance. This can involve transporting solutes out of the cell, decreasing the osmotic gradient and reducing water influx.

5. **Water Transport:** In addition to ion transport, the cell may also activate water channels (aquaporins) to increase water permeability across the membrane. This can facilitate water movement out of the cell, counteracting the influx caused by the osmotic gradient.

6. **Structural Adaptations:** Some cells may possess specialized structures or adaptations that allow them to withstand significant volume changes. For example, red blood cells have a flexible membrane that can accommodate volume fluctuations without rupturing.

7. **Cell Lysis:** If the influx of water overwhelms the cell's regulatory mechanisms, the cell can eventually burst (lyse) due to the excessive internal pressure. This is a critical point at which the cell's viability is compromised.

Overall, the hypotonic response is a complex process that involves a delicate balance of water movement, ion transport, and regulatory mechanisms. Cells must effectively adapt to these osmotic challenges to maintain their integrity and function properly.'
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Proteins (2)

Compounds (2)