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Chapter 1 Characteristics and Maintenance of Life.

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Presentation on theme: "Chapter 1 Characteristics and Maintenance of Life."— Presentation transcript:

1 Chapter 1 Characteristics and Maintenance of Life

2 Characteristics of Life 1.Ability to respond and adapt to the environment.

3 Characteristics of Life 2.Growth – Increase in mass.

4 Characteristics of Life 3.Growth and Development – Growth is increase in size. – Development is the formation of new structures.

5 Characteristics of Life 4.Reproduction – Ability to produce new organisms.

6 Characteristics of Life 5.Metabolism – Physical and chemical changes that occur through the digestion of a food source that allows an organism to obtain, release, and utilize energy.

7 Table 01.03

8 Maintenance of Life Except for the reproductive system, and body structures and functions work in ways that maintain life.

9 Maintenance of Life Environmental factors needed for life: 1.Water Transports substances Important for regulating body temperature Required for many metabolic processes Most abundant substance in the body

10 Maintenance of Life Environmental factors needed for life: 2.Food Provides energy and raw materials for building new living matter.

11 Maintenance of Life Environmental factors needed for life: 3.Oxygen Used in the process of releasing energy from food.

12 Maintenance of Life Environmental factors needed for life: 4.Heat Partly controls the rate at which metabolic reactions take place. Heat is a form of energy. Temperature is a measurement of the amount of heat present.

13 Maintenance of Life Environmental factors needed for life: 5.Pressure Application of force on an object or substance. Examples: – Atmospheric pressure » Caused by air particles – Hydrostatic pressure » Caused by particles of a liquid such as water » Blood pressure is a type of hydrostatic pressure

14 Table 01.04

15 Maintenance of Life Homeostasis – The maintenance of a stable internal environment. – Requires most of a humans metabolic energy. – Homeostasis is maintained through self-regulating control systems called homeostatic mechanisms.

16 Maintenance of Life Homeostatic Mechanisms – Have 3 components: Receptors – Provide info about specific conditions (stimuli) in the internal environment. Control Center – Tells what a particular value should be (set point). Effectors – Elicit responses that alter conditions in the internal environment.

17 Maintenance of Life Homeostatic Mechanisms – Have 3 components: Receptors – Provide info about specific conditions (stimuli) in the internal environment. Control Center – Tells what a particular value should be (set point). Effectors – Elicit responses that alter conditions in the internal environment.

18 Maintenance of Life Homeostatic Mechanisms

19 Maintenance of Life Homeostatic Mechanisms – Work through negative feedback. If a change from the set point is detected by the receptors, the effectors are triggered to bring the conditions back (negative) to the set point. As conditions get closer to the set point, the receptors begin to shut down so that conditions do not move past the set point.

20 Maintenance of Life Homeostatic Mechanisms – Although homeostasis is usually maintained through negative feedback, there are some positive feedback systems (which move conditions away from the normal) such as blood clotting that also contribute to homeostasis.

21 Homeostatic mechanism regulates body temperature Slide number: 2 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Stimulus Body temperature rises above normal. too high Normal body Temperature 37 o C (98.6 o F)

22 Homeostatic mechanism regulates body temperature Slide number: 3 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Receptors Thermoreceptors send signals to the control center. Stimulus Body temperature rises above normal. too high Normal body Temperature 37 o C (98.6 o F)

23 Homeostatic mechanism regulates body temperature Slide number: 4 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Control center The brain detects the deviation from the set point and signals effector organs. Receptors Thermoreceptors send signals to the control center. Stimulus Body temperature rises above normal. too high Normal body Temperature 37 o C (98.6 o F)

24 Homeostatic mechanism regulates body temperature Slide number: 5 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Control center The brain detects the deviation from the set point and signals effector organs. Receptors Thermoreceptors send signals to the control center. Effectors Skin blood vessels dilate and sweat glands secrete. Stimulus Body temperature rises above normal. too high Normal body Temperature 37 o C (98.6 o F)

25 Homeostatic mechanism regulates body temperature Slide number: 2 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Stimulus Body temperature rises above normal. too high Normal body Temperature 37 o C (98.6 o F)

26 Homeostatic mechanism regulates body temperature Slide number: 3 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Receptors Thermoreceptors send signals to the control center. Stimulus Body temperature rises above normal. too high Normal body Temperature 37 o C (98.6 o F)

27 Homeostatic mechanism regulates body temperature Slide number: 4 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Control center The brain detects the deviation from the set point and signals effector organs. Receptors Thermoreceptors send signals to the control center. Stimulus Body temperature rises above normal. too high Normal body Temperature 37 o C (98.6 o F)

28 Homeostatic mechanism regulates body temperature Slide number: 5 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Control center The brain detects the deviation from the set point and signals effector organs. Receptors Thermoreceptors send signals to the control center. Effectors Skin blood vessels dilate and sweat glands secrete. Stimulus Body temperature rises above normal. too high Normal body Temperature 37 o C (98.6 o F)

29 Homeostatic mechanism regulates body temperature Slide number: 6 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Control center The brain detects the deviation from the set point and signals effector organs. Receptors Thermoreceptors send signals to the control center. Effectors Skin blood vessels dilate and sweat glands secrete. Stimulus Body temperature rises above normal. Response Body heat is lost to surroundings, temperature drops toward normal. too high Normal body Temperature 37 o C (98.6 o F)

30 too low Normal body Temperature 37 o C (98.6 o F) Homeostatic mechanism regulates body temperature Slide number: 7 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Stimulus Body temperature drops below normal.

31 Receptors Thermoreceptors send signals to the control center. too low Normal body Temperature 37 o C (98.6 o F) Homeostatic mechanism regulates body temperature Slide number: 8 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Stimulus Body temperature drops below normal.

32 Receptors Thermoreceptors send signals to the control center. too low Normal body Temperature 37 o C (98.6 o F) Homeostatic mechanism regulates body temperature Slide number: 9 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Stimulus Body temperature drops below normal. Control center The brain detects the deviation from the set point and signals effector organs.

33 Receptors Thermoreceptors send signals to the control center. too low Normal body Temperature 37 o C (98.6 o F) Homeostatic mechanism regulates body temperature Slide number: 10 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Stimulus Body temperature drops below normal. Control center The brain detects the deviation from the set point and signals effector organs. If body temperature continues to drop, control center signals muscles to contract involuntarily.

34 Effectors Skin blood vessels constrict and sweat glands remain inactive. Receptors Thermoreceptors send signals to the control center. too low Normal body Temperature 37 o C (98.6 o F) Homeostatic mechanism regulates body temperature Slide number: 11 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Stimulus Body temperature drops below normal. Effectors Muscle activity generates body heat. Control center The brain detects the deviation from the set point and signals effector organs. If body temperature continues to drop, control center signals muscles to contract involuntarily.

35 Effectors Skin blood vessels constrict and sweat glands remain inactive. Receptors Thermoreceptors send signals to the control center. too low Normal body Temperature 37 o C (98.6 o F) Homeostatic mechanism regulates body temperature Slide number: 12 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Stimulus Body temperature drops below normal. Response Body heat is conserved, temperature rises toward normal. Effectors Muscle activity generates body heat. Control center The brain detects the deviation from the set point and signals effector organs. If body temperature continues to drop, control center signals muscles to contract involuntarily.

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