Thermoregulation & Water Balance Study Notes

Thermoregulation & Water Balance Study Notes

Key Terms

• Solute: A substance that is dissolved in a solution (e.g., salt in water).

• Solvent: The substance that dissolves the solute (e.g., water).

• Solution: A homogeneous mixture of solute and solvent.

• Isotonic Solution: A solution with the same concentration of solutes as another solution.

• Hypertonic Solution: A solution with a higher concentration of solutes compared to another.

• Hypotonic Solution: A solution with a lower concentration of solutes compared to another.

Human Thermoregulation

• Homeostasis: The process by which the human body maintains a stable internal environment despite changes in external conditions.

• Maintaining Temperature Increases:

  • Mechanism: Sweating, increased blood flow to the skin, and behavioral changes (e.g., seeking shade).

  • Example: Sweating cools the body through evaporation.

• Maintaining Temperature Decreases:

  • Mechanism: Shivering, vasoconstriction (narrowing of blood vessels), and behavioral adjustments (e.g., wearing warmer clothes).

  • Example: Shivering generates heat through muscle activity.

Cellular Structure and Function

• Plasma Membrane: A bi-layer that regulates what enters and exits the cell, essential for maintaining the homeostasis of both the cell and organism.

• Role in Homeostasis: Controls ion concentrations and prevents harmful substances from entering.

Importance of Stable Internal Temperature

• Critical for enzymatic reactions, cellular processes, and overall metabolic functions.

• Prevents heat-related illnesses or hypothermia, ensuring survival and proper physiological functions.

Feedback Mechanisms

• Negative Feedback: Reduces output or activity to return to a set point (e.g., thermoregulation: body temperature rises → body sweats → temperature decreases).

• Positive Feedback: Enhances or increases a process or output (e.g., during childbirth, oxytocin increases contractions).

Body Temperature Regulation

• Regulating body temperature involves negative feedback mechanisms where deviations from the norm trigger responses to restore balance.

Osmoregulation: Water and Salt Balance

• Osmoregulation: The process by which the body regulates water and solute concentrations, primarily through the kidneys.

• Kidney Function: Filters blood, retains essential substances (like water), and eliminates waste, maintaining fluid balance and osmolarity of blood.

Osmosis

• Definition: The movement of water across a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration.

• Cell Behavior in Different Solutions:

• Hypotonic Solution: Cell swells as water enters (could lead to bursting).

• Hypertonic Solution: Cell shrinks as water exits.

• Isotonic Solution: No net movement of water, cell maintains size.

Hydration Importance

• Maintaining Hydration: Essential for physiological functions, nutrient transport, temperature regulation, and metabolic processes.

Helpful Videos for Review

• Cell Transport - Amoeba Sisters

• Temperature Regulation of the Human Body

• Osmosis - Amoeba Sisters

• Hypertonic, Hypotonic, and Isotonic Solutions

• Homeostasis and Feedback Mechanisms

• How do your kidneys work? TedEd