Introduction to Organ Systems & Homeostasis. Packet #2

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1 Introduction to Organ Systems & Homeostasis Packet #2

2 Properties of Life

3 Order All living things maintain a high degree of order and complexity Even the smallest living thing a cell

4 Regulate Use of Energy All life depends on chemical reactions that take place within cells Chemical reactions are regulated by enzymes.

5 Respond to Environment {Stimuli} All living things must be able to respond to environmental changes in order to survive.

6 Animation Movement The utilization of energy allows organisms to have the capacity to move. Internal Movement of substances around body External Movement within a particular environment

7 Growth & Development As living things adapt to the environment, this allows them to grow and develop. Grow Divide Develop Differentiate

8 Leading to an organism s ability to reproduce. Reproduction

9 Properties of Life How do organisms, including humans, keep everything in balance? with the help, and use, of organ systems.

10 Introduction to Organ Systems

11 Organ System Overview I Integumentary Forms the external body covering Protects deeper tissue from injury Helps regulate body temperature Location of cutaneous nerve receptors Figure 1.2a

12 Organ System Overview II Skeletal Protects and supports body organs Provides muscle attachment for movement Site of blood cell formation Stores minerals Figure 1.2b

13 Organ System Overview III Muscular Produces movement Maintains posture Produces heat Figure 1.2c

14 Organ System Overview IV Nervous Fast-acting control system Responds to internal and external change Activates muscles and glands Figure 1.2d

15 Organ System OverviewV Endocrine Secretes regulatory hormones Growth Reproduction Metabolism Figure 1.2e

16 Organ System Overview VI Cardiovascular Transports materials in body via blood pumped by heart Oxygen Carbon dioxide Nutrients Wastes Figure 1.2f

17 Organ System Overview VII Lymphatic Returns fluids to blood vessels Cleanses the blood Involved in immunity Figure 1.2g

18 Organ System Overview VIII Respiratory Keeps blood supplied with oxygen Removes carbon dioxide Figure 1.2h

19 Organ System Overview IX Digestive Breaks down food Allows for nutrient absorption into blood Eliminates indigestible material Figure 1.2i

20 Organ System Overview X Urinary Eliminates nitrogenous wastes Maintains acid-base balance Regulates water and electrolytes Figure 1.2j

21 Organ System Overview XI Reproductive Produces offspring Figure 1.2k l

22 Homeostasis

23 Homeostasis The tendency of the body to maintain a stable, balanced, internal environment. The maintenance of a relatively constant internal environment that is essential to life. Homeostasis requires the use coordinated efforts of multiple organ systems Human body integrated to support life

Homeostasis II Intrinsic Regulation Activities of cells, tissue, organs or organ systems to automatically adjust to an environmental change Extrinsic Regulation Intrinsic Regulation Cells Tissue

24 Homeostasis II Intrinsic Regulation Activities of cells, tissue, organs or organ systems to automatically adjust to an environmental change Extrinsic Regulation Intrinsic Regulation Cells Tissue Organs Results from activities within the nervous or endocrine system. Nervous System Rapid, short and specific responses Endocrine System Hormonal and slow response that has long lasting effects. Homeostasis Extrinsic Regulation Organ Systems Nervous System Endocrine System

25 Homeostasis III Feedback Inhibition An end product, of a metabolic pathway, inhibits an initial (pathway) enzyme by altering efficiency of enzyme action. The enzyme is prevented from operating. 25 Tuesday, August 23, 2016

26 Homeostasis IV Receptor Sensor that detects stimulus (change) Control Center Receives and processes information from receptor Effector Cell/organ that responds to direction from control center to oppose or enhance the stimulus.

28 Negative Feedback Mechanisms Negative feedback occurs when the body attempts to keep a particular variable at a set point. The body senses a change and activates a mechanism to reverse it. Dynamic equilibrium.

29 Negative Feedback Loop Body senses a change and activates mechanisms to reverse it - dynamic equilibrium Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1 Room temperature falls to 66 F (19 C) 6 Room cools down C F C Thermostat activates furnace F Thermostat shuts off furnace 4 Room temperature rises to 70 F (21 C) (a) 3 Heat output 1-29

30 Room temperature ( F) Negative Feedback, Set Point Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display Furnace turned off at 70 F Set point 68 F Furnace turned on at 66 F (b) 60 Time Room temperature does not stay at set point of 68 degrees -- it only averages 68 degrees 1-30 Figure 1.9b

31 Negative Feedback Thermoregulation in Humans Brain senses change in blood temperature If too warm, vessels dilate (vasodilation) in the skin and sweating begins (heat losing mechanisms) If too cold, vessels in the skin constrict (vasoconstriction) and shivering begins (heat gaining mechanism)

32 Negative Feedback Control of Blood Pressure Sitting up in bed causes a drop in blood pressure in the head and upper thorax Baroreceptors in the arteries near the heart alert the cardiac center in the brainstem Cardiac center sends nerve signals that increase the heart rate and return the blood pressure to normal Failure of this to feedback loop may produce dizziness in the elderly 1-32

33 Control of Blood Pressure Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Person rises from bed Blood pressure rises to normal; homeostasis is restored Blood drains from upper body, creating homeostatic imbalance Cardiac center accelerates heartbeat Baroreceptors above heart respond to drop in blood pressure Figure 1.11 Baroreceptors send signals to cardiac center of brainstem 1-33

34 Negative Feedback Control of Blood Pressure II 1-34

35 Positive Feedback Mechanisms Self amplifying cycle Effectors respond by exaggerating or enhancing stimulus Typically used to deal with a threat or stress Blood clotting: clotting causes more clotting until wound is plugged

Positive Feedback Mechanisms Birth Contractions promote more contractions until delivery 2 Nerve impulses from cervix Transmitted to brain 3 Brain

36 Positive Feedback Mechanisms Birth Contractions promote more contractions until delivery 2 Nerve impulses from cervix Transmitted to brain 3 Brain stimulates pituitary gland to secrete oxytocin 4 Oxytocin stimulates uterine contractions and pushes fetus toward cervix 1 Head of fetus pushes against cervix 1-36

37 Harmful Positive Feedback Mechanism Fever > 104 F Metabolic rate increases Body produces heat even faster Body temperature continues to rise Further increasing metabolic rate Cycle continues to reinforce itself Becomes fatal at 113 F 1-37

38 Review

The Human Body: An Orientation

1 The Human Body: An Orientation Yong Jeong, MD, PhD Department of Bio and Brain Engineering The Human Body An Orientation Anatomy Study of the structure and shape of the body and its parts Physiology