1. (a) (i) Define the term ‘homeosasis’
The nervous system and hormones enable us to respond to external changes in the environment and monitor and change our internal environment to adapt to those needs, so that our bodies can carry on functioning properly.
Functions controlled by homeostatic mechanisms are heartbeat, blood pressure, body temperature, respiration, and glandular secretion. (1)
(ii) Giving one example, explain why homeostasis is important in mammals.
Example of importance homeostasis in mammals.
1; metabolic reactions are controlled by enzymes.
2; enzymes work best in a narrow range of temperature and pH only.
3; it’s important to keep internal environment as steady as possible.
4; without homeostasis our bodies would not work properly, we would die. (2)
(b) (i) cross-channel swimmers experience a large decrease in external temperature when they enter the water. Describe the process involved in thermoregulation in response to this large decrease in external temperature.
Thermoregulation is maintenance of consistent internal body temperature, even when there is a significant change in external environmental temperature. Thermoregulation works generally in two ways. 1. Hypothermia, where the body becomes so cold that its systems can no longer function properly. 2. Hyper-thermia, this is the opposite effect, the body becomes over heated.
Thermoregulation is achieved through physiological process, as a function of the nervous and endocrine system. These are two organ systems that act as co- directors of all the activities that occur in the body. They continuously monitor the well-being of all the billions of cells in the body, taking action through messenger systems to keep all the cells as healthy as possible....