Question

Which set of characters will be more helpful to an animal, when outside temperature is considerably higher than body temperature?

• A. Skin smooth, covered with oil
• B. Skin dark, covered with feathers
• C. Skin soft with scales
• D. Skin soft with abundant sweat glands

Answer 1

The correct option is D Skin soft with abundant sweat glands

Temperature receptors in the skin detect changes in the external temperature. They pass this information to the processing centre in the brain, called the hypothalamus. The processing centre automatically triggers changes to the effectors to ensure our body temperature remains constant, at ${37}^0$C. The effectors are sweat glands and muscles. If we are too hot or too cold, the processing centre sends nerve impulses to the skin, which has two ways to either increase or decrease heat loss from the body's surface. Tiny muscles in the skin can quickly pull the hairs upright to reduce heat loss, or lay them down flat to increase heat loss. If the body is too hot, glands in the skin secrete sweat onto the surface to increase heat loss by evaporation. This cools the body. Sweat secretion slows, when the body temperature returns to normal.