biology - homeostasis incorrect exam questions

In humans, when body temperature drops below 35°C, positive feedback causes a continued decrease in body temperature. This process is referred to as hypothermia. Explain how positive feedback accelerates the process of hypothermia.

-positive feedback is when an initial change is amplified further

-lower temp reduces the kinetic energy of a molecule

-so enzyme activity is reduced causing less frequent successful collisions

-rate of respiration is then slowed

-less metabolic heat is generated

-body temp drops even further

Explain how vasoconstriction helps to return body temperature to its optimum.

-arterioles in the skin become narrower

-less blood flows through the capillaries

-less heat is lost to surroundings

explain how shivering helps the body to increase temp

muscle contraction releases heat

explain how the secretion of adrenaline helps return the body temp to its optimum

-increases rate of respiration

-so more heat is released

Animals have both physiological and behavioral adaptations to help them maintain their core body temperature. Elephants have large, thin ears which move forwards and backwards in hot conditions. Suggest and explain how this adaptation allows elephants to control their body temperature.

-large ears provide large surface area to lose heat

-thin ears so blood vessels are close to surface of skin to lose heat

-movement of ears increase air movement over the skin surface to lose heat