VO 2 max

1. Metabolic rate • VO2 max • Surface area:Volume • Atria • Ventricles • Single • double • Double incomplete • Double complete • Parabronchi • Alveoli

2. Key Area 2.4 Conformers and regulators • Effects of abiotic factors • Responses of conformers • Responses of regulators • Negative feedback control

3. Conformers and regulators Learning Intentions • How are conformers and regulators are affected by their immediate surroundings? • How do conformers and regulators maintain their metabolism?

4. Abiotic factors • Abiotic factors, in an organisms external environment can affect their metabolic rate • Conformers adapt and ‘conform’ to the external environment • Regulators can maintain their metabolic state

5. Conformers • The state of a conformers internal environment is dependent on the abiotic factors in its environment • Conformers usually live in stable environments

8. Behavioural response • Few animals are complete conformers • They employ behavioural responses to maintain their optimum metabolic rate • E.g. Lizards basking in the sun to maintain their internal temperature

9. Impact on conformers • Low metabolic cost • Does not use energy to maintain internal state • Less adaptable • Restricted to a narrow ecological niche • Less adaptable to environmental change

10. Regulators • The internal environment of a regulator is not dependent on the external environment. • Regulators employ physiological means to control their internal environment. • E.g. Fish

13. Salmon • Salmon are migratory fish and go between salt and fresh water, they must alter their internal metabolism to cope with the different osmotic pressures.

14. Impact on regulators • Advantage • Able to exploit a wide range of ecological niches. • e.g. Human • Disadvantage • Animal has to expend • energy to maintain • inner environment.

15. Task • Use the textbook and your notes to complete the notes pages given.

16. Homeostasis Learning Intentions • How is negative feedback control important to organisms? • How is temperature controlled by negative feedback control? • What are endotherms and ectotherms?

17. Homeostasis • Homeostasis is the maintenance of the body's internal environment within limits despite the external environment • Regulation requires energy and is under negative feedback control

18. Negative feedback control • When a body’s internal environment deviates from ‘normal’ it is detected by receptors • Receptors send hormonal or nervous impulses • Effectors act to return the environment back to ‘normal’

19. Conditions in the body change from set point Change detected (by receptors) Corrective mechanism(s) activated (by nerves or hormones) Conditions returned to set point (by effectors) Corrective mechanism(s) switched off

20. Thermoregulation • Thermoregulation is the control of temperature in an organism.

21. Ectotherm • An ectotherm cannot maintain its body temperature by physiological means. • Absorb heat from environment • E.g. Fish and reptiles

22. Endotherm • An endotherm maintains its body temperature at a relatively constant level regardless of environment. • E.g. All birds and mammals

23. Comparing thermoregulation • Using the graphs, describe the effect of temperature on endotherms and ectotherms.

24. Y is a ectotherm/conformer because • Internal has varied with external • Z is a endotherm/regulator because • Internal has remained the same

25. Role of the hypothalamus • The hypothalamus contains thermoreceptors and receives impulses from receptors in the skin • It also senses the temperature of blood • The hypothalamus sends appropriate impulses to effectors to trigger corrective feedback

27. Body core and shell • The shell or periphery is more susceptible to cool temperature. • The core is maintained at 37°C. • Why?

28. Correcting overheating • Vasodilation • Arterioles in the skin dilate • This allows blood flow to surface • Heat loss by radiation • Sweating • Evaporation of vapour from the skin has a cooling effect

29. hair Sweat gland Hair erector pili muscle Correcting overcooling • Vasoconstriction • Arterioles in the skin constrict • This shifts blood flow from surface • Heat loss by radiation reduced • Sweating • decreased • Erector muscle • Muscles attached to • hair erect and • an insulating layer of air is trapped.

30. Detected in hypothalamus Nerve impulses sent skin Sweating increases Messages to other effectors Rise in body temp. vasodilation Hairs lowered Decrease in metabolic rate Body temp. normal Body temp. normal Increase in metabolic rate Drop in body temp. Messages to other effectors Sweating decreases vasoconstriction Hairs raised Detected in hypothalamus Nerve impulses sent skin

31. Quick questions Q1: Complete the table with the temperature responses listed. Temperature responses: active sweat glands, decrease in metabolic rate, hair erector muscles contracted, hair erector muscles relaxed, inactive sweat glands, increase in metabolic rate, vasoconstriction, vasodilation. Q2: Which part of the brain is responsible for regulating body temperature in mammals? Q3: In which of the following ways does the body respond when its temperature falls? a) Vasoconstriction and sweating b) Contraction of hair erector muscles and vasodilation c) Vasodilation and decreased rate of metabolism d) Shivering and vasoconstriction Q4: Why do you sweat and your skin become flushed during exercise?