Principles of homeostasis

Question 1

WHy does the body need a extretion system?

Answer 1

• enzyme-controoled reactions of life can only take place if the conditions are right
• the conc of chemicals such as glucose and sodium ions must be kept within a narrow range, as must pH and water balance of body fluids, and the core temperature of the body
• organsims use both chemical and electrical systems to monitor and respond to any changes from the steady state of the body, and use the information to maintain dynamic equilibrium

Question 2

What is homeostasis?

Answer 2

• the tendency towards a relatively stable equilibrium between interdependant elements
• body maintains a dynamic equilibrium, with small fluctuations over a narrow range of conditions

Question 3

How are conditions monitored?

Answer 3

• using receptors to maintain the dynamic equilibrium
• receptors detect changes in the internal and external environment, which is important in maintaining a constant internal environment

Question 4

How is information triggered?

Answer 4

• informations from the sensory receptros is transmitted to the brain and impulses are sent along the motor neurones to the effectors to bring about changes to restore the equilibrium in the body

Question 5

What are effects?

Answer 5

• muscles or glands that react tot he motor stimulus to bring about a change in response to a stimulus

Question 6

How are feedback systems used?

Answer 6

• homeostasis depends on sensory receptors detecting small change in the body, and effectors working to restore the status quo
• these precise control mechanisms in the body are based on feedback systems that enable the maintenence of a relatively steady state around a narrow range of conditions

Question 7

What is a negative feeback system?

Answer 7

• most of the feedback systems in the body involve negative feedback
• a small change in one direction is detected by sensory receptors
• as a result, effectors work to reverse the change and restrore condition to their base level
• negative feedback systems work to reverse the initial stimulus
  
  • counteract of an effect by its own influence on the process giving rise to it - e.g. high glucose causes insulin to be released, when glucose returns to normal levels, this stops more insulin from being released.

Question 8

What is a positive feedback system?

Answer 8

• a change in the internal environment of the body is detected by sensory receptors
• effectors are stimulatated to reinforce that change and increase the response
• e.g. blood clotting cascade - platelets stick to damaged region and this causes more platelets to be attracted to that region - this continues until a clot is formed