1. What’s the link????

7. Communication & homeostasis Links to G.C.S.E Endocrine system Endocrine system Negative feedback Negative feedback Homeostasis Homeostasis Circulatory system Circulatory system Adaptation Adaptation Links to AS level Cell signalling Cell signalling Cellular organisation Cellular organisation Enzymes Enzymes

8. Outline the need for communication systems within multicellular organisms (with reference to the need to respond to changes in the internal and external environment and to coordinate the activities of different organs). Outline the need for communication systems within multicellular organisms (with reference to the need to respond to changes in the internal and external environment and to coordinate the activities of different organs). State that cells need to communicate with each other by a process called cell signalling. State that cells need to communicate with each other by a process called cell signalling. State that neuronal and hormonal systems are examples of cell signalling. State that neuronal and hormonal systems are examples of cell signalling.

9. Keeping cells active What conditions need to be maintained in order to cells to function efficiently? What conditions need to be maintained in order to cells to function efficiently? Temperature Temperature pH pH Oxygen & glucose levels Oxygen & glucose levels Water potential & ion levels Water potential & ion levels Blood pressure Blood pressure Removal of wastes produced BY THE CELLS as a result of respiration Removal of wastes produced BY THE CELLS as a result of respiration

10. Key definition Homeostasis is the maintenance of the internal environment in a constant state despite external changes Homeostasis is the maintenance of the internal environment in a constant state despite external changes

11. Homeostasis is based on Homeostasis is based on STIMULUS: RESPONSE A stimulus is any change in the internal or external environment A stimulus is any change in the internal or external environment A response is a change in behaviour or physiology as a result of a change in the environment A response is a change in behaviour or physiology as a result of a change in the environment

12. Environments The external environment may consist of water, air, soil etc around the organism. The external environment may consist of water, air, soil etc around the organism. Changes may occur slowly (seasonal) or more rapidly (going from indoors to outdoors). Changes may occur slowly (seasonal) or more rapidly (going from indoors to outdoors). The internal environment of multicellular organisms is the tissue fluid that bathes the cells and tissues. The internal environment of multicellular organisms is the tissue fluid that bathes the cells and tissues. Changes occur as cells undergo their various metabolic activities. Changes occur as cells undergo their various metabolic activities. It is monitored and maintained by the hypothalamus which takes action to alter the blood composition It is monitored and maintained by the hypothalamus which takes action to alter the blood composition

14. Cell signalling

15. A good communication system: Should: Should: -cover the whole body -enable cells to communicate with one another -enable SPECIFIC communication -enable RAPID communication -enable short and long term responses

16. Describe the physiological and behavioural responses that maintain a constant core body temperature in ectotherms Describe the physiological and behavioural responses that maintain a constant core body temperature in ectotherms

17. Key definition An ectotherm is an organism that relies on external sources of heat to regulate it’s body temperature An ectotherm is an organism that relies on external sources of heat to regulate it’s body temperature DO NOT SAY COLD BLOODED!!! Some ectotherms have a body temperature of 37°C which is not cold!! DO NOT SAY COLD BLOODED!!! Some ectotherms have a body temperature of 37°C which is not cold!!

18. Assignment You will be given the name of an ‘ectotherm’ (fish, reptiles, amphibians, invertebrates) You will be given the name of an ‘ectotherm’ (fish, reptiles, amphibians, invertebrates) You need to produce a short presentation detailing You need to produce a short presentation detailing -information about the environmental conditions that the organism has to survive in -the upper and lower limits of temperature range they can function at -any behavioural or physiological adaptations that the organism employs to aid survival -advantages of being an ectotherm -disadvantages of being an ectotherm

19. Describe the physiological and behavioural responses that maintain a constant core body temperature in endotherms with reference to peripheral temperature receptors, the hypothalamus and effectors in skin and muscles. Describe the physiological and behavioural responses that maintain a constant core body temperature in endotherms with reference to peripheral temperature receptors, the hypothalamus and effectors in skin and muscles.

20. Key definition An endotherm is an organism that can use internal sources of heat, such as that generated from metabolism (an exergonic reaction) in the liver, to maintain it’s body temperature An endotherm is an organism that can use internal sources of heat, such as that generated from metabolism (an exergonic reaction) in the liver, to maintain it’s body temperature

21. Key definition Negative feedback mechanisms initiate to maintain or regulate physiological functions within a set and narrow range. Any change in a parameter results in action to reverse this change e.g. temperature or blood sugar Negative feedback mechanisms initiate to maintain or regulate physiological functions within a set and narrow range. Any change in a parameter results in action to reverse this change e.g. temperature or blood sugar The brain receives ‘negative feedback’ about the conditions that are occurring and seeks to change them back rather than allowing or encouraging it to continue (positive feedback) The brain receives ‘negative feedback’ about the conditions that are occurring and seeks to change them back rather than allowing or encouraging it to continue (positive feedback)

22. © Pearson Education Ltd 2009 This document may have been altered from the original Week 1 (a) Vasodilaton; (b) vasoconstriction

23. Responses may be behavioural as well as physiological e.g. Responses may be behavioural as well as physiological e.g.-burrowing -moving into the shade -reducing surface area of body facing the sun -staying inactive -

25. Outcomes Outline the need for communication systems within multicellular organisms (with reference to the need to respond to changes in the internal and external environment and to coordinate the activities of different organs). Outline the need for communication systems within multicellular organisms (with reference to the need to respond to changes in the internal and external environment and to coordinate the activities of different organs). State that cells need to communicate with each other by a process called cell signalling. State that cells need to communicate with each other by a process called cell signalling. State that neuronal and hormonal systems are examples of cell signalling. State that neuronal and hormonal systems are examples of cell signalling. Describe the physiological and behavioural responses that maintain a constant core body temperature in ectotherms Describe the physiological and behavioural responses that maintain a constant core body temperature in endotherms with reference to peripheral temperature receptors, the hypothalamus and effectors in skin and muscles. Describe the physiological and behavioural responses that maintain a constant core body temperature in ectotherms Describe the physiological and behavioural responses that maintain a constant core body temperature in endotherms with reference to peripheral temperature receptors, the hypothalamus and effectors in skin and muscles.