Chapter 1 The Human Body An Orientation Notes Anatomy-the

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					                    Chapter 1: The Human Body: An Orientation Notes
Anatomy-the study of the structure and shape of the body and its parts and their
relationships to one another (Ana-apart, -tomy-to cut Greek)
       Gross anatomy-observable to the naked eye
       Microscopic anatomy-observable only through a microscope like tissues and cells
Physiology-the study of how the body and its parts work or function (physio-nature, -ology-
study of)
How do they relate? Structure determines what functions can take place.

Levels of Structural Organization (page 4)
Atoms (smallest unit of matter) combine to make molecules -> cells (smallest unit of life)->
tissues (groups of similar cells that have a common function)-> organs (two or more tissue
types that performs a specific function for the body) -> organ system (group of organs that
work together to accomplish a common purpose) -> organism (highest level of structural
organization that makes up the living body)

Organ System Overview (page 4)
Integumentary System
Skeletal System
Muscular System
Nervous System
Endocrine System
Cardiovascular System
Lymphatic System
Respiratory System
Digestive System
Urinary System
Reproductive System

Maintaining Life (page 10-12)
Necessary Life Functions:
Movement by use of muscular, skeletal, cardiovascular (blood), digestive (foodstuffs), and
urinary (urine) systems
Responsiveness or irritability is the ability to sense changes (stimuli) in the environment
and then to react to them; mostly controlled by nervous system
Digestion is the process of breaking down ingested food into simple molecules that can then
be absorbed into the blood; digestive and cardiovascular system
Metabolism refers to all chemical reactions that occur within body cells; depends on
digestive and respiratory systems and regulated by the endocrine system
Excretion is the process of removing excreta or wastes from the body; digestive and urinary
systems
Reproduction is the production of offspring that occur at the cellular (mitosis) or organismal
level; reproductive system with regulation by the endocrine system
Growth is an increase in size by the accumulation of cells
Homeostasis (pages 12-15) is the body’s ability to maintain relatively stable internal
conditions even though the outside world is continuously changing
(homeo-the same; stasis-standing still)
        Homeostasis is controlled by the nervous and endocrine systems
        Internal conditions change and vary but always within relatively narrow limits
Virtually every organ system plays a role in maintaining the constancy of the internal
environment




http://www.mattk.com/anatomy_notes_homeostasis_negative_feedback.php


All homeostatic control mechanisms have at three components:
       Receptor-type of sensor that monitors and responds to changes in the environment
(stimuli) and sends information to the control center along the afferent pathway (information
approaches the control center)
       Control center-determines the level at which a variable is to be maintained, analyzes
the information in receives then determines the appropriate response or course of action
               Information flows from the control center to the effector through the efferent
pathway (information exits the control center)
       Effectors provides the means for the control center’s response to the stimulus
The results of the response then “feed back” to influence the stimulus, either by depressing it
(negative feedback) to shut off the whole mechanism or by enhancing it (positive feedback)
so that the reaction occurs at a faster rate.

Most homeostatic control mechanisms are negative feedback mechanisms
       The net effect of the response to the stimulus is to shut off the original stimulus or
reduce its intensity
       Ex. Panting to increase the rate of breathing in response to the lack of oxygen in
muscles during strenuous activity;
Positive feedback mechanisms are rare because they tend to increase the original
disturbance (stimulus) and to push the variable farther from its original value.
       Ex. Blood clotting and childbirth are the most familiar examples

Survival Needs (pages 11-12)
Nutrients from food
       Carbohydrates are the major energy providing fuel for body cells
       Proteins are essential for building structures
       Fats also are necessary for building structures and cushioning body organs and store
       energy
       Minerals and vitamins are required for chemical reactions that go on in cells and for
       oxygen transport in the blood
Oxygen is necessary for the release of energy in food
       20% of the air is oxygen
Water accounts for 60-80% of body weight and provides the fluid base for body secretions
and excretions
Body temperature must be maintained around 37°C (98°F)
Atmospheric pressure (the force exerted on the surface of the body by the weight of air)
       Breathing and the exchange of oxygen and carbon dioxide in the lungs depend on
appropriate atmospheric pressure

				
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