Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Organ System Overview

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Figure 1.2a Organ System Overview  Integumentary  Forms the external body covering  Protects deeper tissue from injury  Helps regulate body temperature  Location of cutaneous nerve receptors

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Figure 1.2b Organ System Overview  Skeletal  Protects and supports body organs  Provides muscle attachment for movement  Site of blood cell formation  Stores minerals

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Figure 1.2c Organ System Overview  Muscular  Produces movement  Maintains posture  Produces heat

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Organ System Overview  Nervous  Fast-acting control system  Responds to internal and external change  Activates muscles and glands Figure 1.2d

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Organ System Overview  Endocrine  Secretes regulatory hormones  Growth  Reproduction  Metabolism Figure 1.2e

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Figure 1.2f Organ System Overview  Cardiovascular  Transports materials in body via blood pumped by heart  Oxygen  Carbon dioxide  Nutrients  Wastes

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Organ System Overview  Lymphatic  Returns fluids to blood vessels  Cleanses the blood  Involved in immunity Figure 1.2g

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Organ System Overview  Respiratory  Keeps blood supplied with oxygen  Removes carbon dioxide Figure 1.2h

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Organ System Overview  Digestive  Breaks down food  Allows for nutrient absorption into blood  Eliminates indigestible material Figure 1.2i

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Organ System Overview  Urinary  Eliminates nitrogenous wastes  Maintains acid-base balance  Regulates water and electrolytes Figure 1.2j

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Organ System Overview  Reproductive  Produces offspring Figure 1.2k–l

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Homeostasis

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Homeostasis  Homeostasis—maintenance of a stable internal environment  A dynamic state of equilibrium  Homeostasis is necessary for normal body functioning and to sustain life  Homeostatic imbalance  A disturbance in homeostasis resulting in disease

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Maintaining Homeostasis  The body communicates through neural and hormonal control systems 1.Receptor 2.Control center 3.Effector

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Maintaining Homeostasis  Receptor  Responds to changes in the environment (stimuli)  Sends information to control center  Information flows from the receptor to the control center along a path called the afferent pathway.

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Maintaining Homeostasis  Control center  Determines set point to maintain  Analyzes information  Determines appropriate response  Effector  Provides a means for response to the stimulus  Information flows from the control center to the effector along the efferent pathway.

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Feedback Mechanisms  Negative feedback  Includes most homeostatic control mechanisms  Shuts off the original stimulus, or reduces its intensity  Works like a household thermostat  Ex. Mechanisms that regulate heart rate, blood pressure, breathing rate, and blood levels of glucose, oxygen, carbon dioxide, and minerals.

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Household Thermostat  Thermostat set at 70°F  Stimulus – temperature of house drops to 68°F  Receptor – the thermometer detects a cool temp. o Tells the heater thermostat the change through the afferent pathway  Control Center – thermostat turns on the heater.  Once the house temperature rises to 70° the thermostat turns the heater off

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Feedback Mechanisms  Positive feedback  Increases the original stimulus to push the variable farther  Typically control explosive events and do not require continuous adjustments.  In the body this only occurs in blood clotting and during the birth of a baby

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Figure 1.4 Change detected by receptor Stimulus: Produces change in variable Input: Information sent along afferent pathway to Receptor (sensor) Effector Variable (in homeostasis) Response of effector feeds back to influence magnitude of stimulus and returns variable to homeostasis Control center Imbalance Output: Information sent along efferent pathway to activate

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Figure 1.4, step 1a Variable (in homeostasis)

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Figure 1.4, step 1b Stimulus: Produces change in variable Variable (in homeostasis) Imbalance

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Figure 1.4, step 2 Change detected by receptor Stimulus: Produces change in variable Receptor (sensor) Variable (in homeostasis) Imbalance

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Figure 1.4, step 3 Change detected by receptor Stimulus: Produces change in variable Input: Information sent along afferent pathway to Receptor (sensor) Variable (in homeostasis) Control center Imbalance

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Figure 1.4, step 4 Change detected by receptor Stimulus: Produces change in variable Input: Information sent along afferent pathway to Receptor (sensor) Effector Variable (in homeostasis) Output: Information sent along efferent pathway to activate Control center Imbalance

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Figure 1.4, step 5 Change detected by receptor Stimulus: Produces change in variable Input: Information sent along afferent pathway to Receptor (sensor) Effector Variable (in homeostasis) Response of effector feeds back to influence magnitude of stimulus and returns variable to homeostasis Output: Information sent along efferent pathway to activate Control center Imbalance