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Intro AP

Learning Outline

Introduction to Anatomy & Physiology

Defining the subject

Human Biology – biological study of humans

  • Biology is study of the nature of living organisms

Anatomy (“to cut apart”) – study of structure of organisms

  • Dissection also means “to cut apart” and is the primary method of the anatomist

  • Gross anatomy – structure of visible structures

  • Microscopic anatomy – structure of invisible (too small to see) structures

Physiology (“words about nature”) – study of function of organisms

Medieval dissection

Medieval dissection. Note that the professor is in a chair while the dissector receives instruction.

Defining life

The approach offered in the textbook lists “characteristics of life”

  • Responsiveness, conductivity, growth, respiration, digestion, absorption, secretion, excretion, circulation, reproduction (please do NOT memorize this list!)
  • Unsatisfactory because it fails to define (it merely describes) and the list does not apply to all living beings


  • Seems to resist entropy (nature’s tendency toward disorder)
    • This is the view taken by Lynn Margulis and Dorion Sagan in their book What Is Life?
    • Autopoiesis (“self making”) refers to life’s continual making of itself by means of metabolism
  • Metabolism — the inter-linked and ongoing chemical reactions of life; body chemistry
    • Anabolism— metabolic reactions that make larger molecules out of smaller ones
    • Catabolism — metabolic reactions that make smaller molecules out of larger ones
  • Vladimir Vernadsky says that life is less a thing and more a process
    • Vernadsky said that living organisms are simply special forms of water

Dorion Sagan (coauthor of What Is Life? ) jots a few notes on the meaning of life
for Kevin Patton (right).

Here is an interesting perspective on what it means to be alive:

“. . . living organisms, including people, are merely tubes which put things in at one end and let them out at the other, which both keeps them doing it and in the long run wears them out. So to keep the farce going, the tubes find out ways of making new tubes, which also put things in at one end and let them out at the other. At the input end they even develop ganglia of nerves called brains, with eyes and ears, so that they can more easily scrounge around for things to swallow. As and when they get enough to eat, they use up their surplus energy by wiggling in complicated patterns, making all sorts of noises by blowing air in and out the input hole, and gathering together in groups to fight with other groups. In time, the tubes grow such an abundance of attached appliances that they are hardly recognizable as mere tubes, and they manage to do this in a staggering variety of forms. There is a vague rule not to eat tubes of your own form, but in general there is serious competition as to who is going to be the top type of tube. All this seems marvelously futile, and yet, when you begin to think about it, it begins to be more marvelous than futile.” —Alan Watts from The Book: On the Taboo Against Knowing Who You Are

liontrack Required Superseded Scientific Theories

Analogies and models slide_icon

  • Used frequently to explain or illustrate concepts
  • Are simplified and are therefore incomplete

“The most exciting phrase to hear in science, the one that heralds new discoveries, is not ‘Eureka!’ (I found it!) but ‘That’s funny …’ “

—Isaac Asimov

History and culture

  • Western and Eastern traditions
  • Western tradition still uses Latin (also with Greek word parts) in terminology  slide_icon   slide_icon   slide_icon


Homeostasis = relative constancy of the internal (fluid) environment  slide_icon   slide_icon

  • Examples: constancy of body temp (around 37°C), of blood pressure, blood glucose


  • Negative feedback – reverses the direction of change

  • Positive feedback – amplifies the change (same direction)


  • Aquarium model, Engineering model, Wallenda model

liontrack Please review the required Mini Lesson: Homeostasis

Levels of homeostatic control

  • Intracellular – regulation within a cell
  • Intrinsic – regulation within a tissue or organ
  • Extrinsic – regulation across systems and the whole body

Take note! Human body temperature varies!

Carl Wunderlich studied body temperatures of thousands of people way back in 1868 and pronounced the average human body temperature (oral) to be 98.6 °F (37.0 °C). However, in 1992, P.A. Mackowiak’s research team used modern equipment and techniques and found that the human body temperature (oral) averages about 98.2 °F (36.8 °C). Here are their overall results:
Oral body temp
Average temp
Upper limit of normal temp
Daily variability of temp


What does this tell us? That body temperature, and other physiological variables, are not the same for everyone and even vary within an individual. This variability is NORMAL.
NOTE: Even though Wunderlich’s average body temperature has been revised to a slightly different number by Mackowiak’s more recent work, we usually still use the older numbers for the sake of discussion—a “ball park” number—neither average applies to any particular individual.


Chaos (as science concept) is “constrained randomness”

Human structure:

  • Self-similarity (fractal geometry) and anatomy slide slide_icon

Human function:

  • Periodic body functions
    • “periodic” means rhythmic (not chaotic)
    • Example: heart voltage (EKG)
  • Aperiodic body functions
    • “aperiodic” means nonrhythmic (chaotic)
    • Example: heart rate (HR; beats/min)

Change from chaotic to rhythmic OR change from rhythmic to chaotic

  • May be associated with aging, disease, injury

liontrack Please review the required Mini Lesson: Chaos

Levels of Organization


  • Smallest unit of a pure substance (element) that still has properties of the substance
  • Examples: H (hydrogen), O (oxygen), C (carbon)


  • Groups of atoms linked together
  • Examples: H2O (water), CO2 (carbon dioxide), C6H12O6 (glucose)


  • “Tiny organs” made up of molecules that have certain functions; parts of a cell
  • Examples: nucleus, mitochondrion, plasma membrane of cell


  • Smallest unit of a living organism; made up of organelles
    • The cell theory states that all living organisms are made of one or more cells
    • Proposed by Schleiden & Schwann
    • Also called the “cell doctrine”
  • Examples: muscle cell, nerve cell, skin cell, blood cell


  • Group of similar cells together
    • “Fabric” of the body
  • Four groups of tissues in the human body:
    • Epithelial
    • Connective
    • Nerve
    • Muscular


  • Discrete structures made up of more than one kind of tissue
  • Examples: stomach, heart, lung, bone, skin


  • Group of organs that function together
  • Typical list of human body systems:
    • Integumentary
    • Skeletal
    • Muscular
    • Nervous
    • Endocrine
    • Digestive
    • Respiratory
    • Circulatory
    • Lymphatic
    • Urinary
    • Reproductive


  • Group of systems functioning together as a separate individual body
  • Examples: human individual, tree, squirrel


  • Group of similar organisms living together
  • Examples: human population, tree population, squirrel population


  • Group of interacting populations
  • Examples: forest community (trees, squirrels, foxes), desert community (cacti, rattlesnakes, armadillos)


  • biotic (living) community and abiotic (nonliving) features
    • Abiotic features include geology, climate, etc.
    • Biotic features are the living organisms themselves (or their parts or activities)
  • Examples: forest ecosystem, desert ecosystem


  • All similar ecosystems on earth together
  • Examples: the forest biome (all forests on earth), the desert biome (all deserts on earth)

Biosphere (Gaia)

  • The whole living layer around the globe (includes even abiotic features)
    • Biosphere concept developed by the Russian, V. Vernadsky
  • Gaia hypothesis
    • Originated with James Lovelock; further developed by Lynn Margulis
    • Looks at the earth as a giant living organism (Gaia, named for the ancient Greek goddess of the earth)
    • Characterized by feedback mechanisms, as in an organism
    • In their book What Is Life?, Margulis and Sagan (see above) stipulate that the whole biosphere is really one giant organism and each of us is really a collection of organs of the whole organism. What do YOU think?
    • In his book (and film) An Inconvenient Truth Al Gore discusses global warming from the biosphere perspective. If you are familiar with the content, do you think he uses the concept in a scientifically appropriate sense?
Gaia (click to enlarge)

Body cavities, planes, and directions

These topics are covered in the Pre-A&P review outline Human Body

lion track icon   If you are using one of Kevin Patton’s A&P textbooks or manuals:

Hint #1: the inside front cover of your textbook has a handy reference

Hint #2: use the anatomical rosette (compass rose) to check directions on diagrams throughout the book

compass rose
Patton's Anatomical Rosette

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Last updated: October 22, 2019 at 12:32 pm