Homeostasis: Temperature Control | Biology for GCSE/IGCSE - Year 11 PDF Download

The Skin & Homeostasis

• Regulating body temperature is a fundamental homeostatic process.
• Homeostasis entails sustaining a stable internal environment.
• This involves maintaining internal conditions, like temperature, blood pressure, and glucose concentration, within specific boundaries to support cellular functions and overall organism survival.
• Human body temperature is typically maintained at approximately 37°C, optimal for enzyme activity.
• Exceeding this temperature threshold can lead to enzyme denaturation, compromising their efficiency in catalyzing vital reactions such as respiration.

The Structure of the Skin

Temperature Regulation by the Skin

• Temperature regulation is overseen by the brain, which houses receptors that monitor blood temperature.
• Additionally, the skin possesses temperature receptors, relaying sensory signals to the brain through sensory neurons.
• The brain reacts to these inputs by dispatching nerve impulses to skin effectors, aiming to sustain the temperature close to the optimal 37°C.
• Fatty tissue beneath the dermis serves as an insulating layer, minimizing excessive heat loss from the body through the skin.

Responses to changes in temperature

Vasoconstriction & Vasodilation

• In response to cold, vasoconstriction occurs, wherein arterioles leading to skin capillaries constrict, diminishing blood flow.
• This constriction minimizes heat loss from blood via radiation by reducing blood exposure to the skin surface.
• Conversely, during heat exposure, vasodilation takes place, wherein blood vessels leading to skin capillaries dilate.
• Vasodilation facilitates heat dissipation as blood circulates more rapidly through the skin, augmenting heat loss through radiation.