Human Biology
This course reviews “foundation” concepts in biology to prepare you for further courses in human biology
Human biology is the study of human life . . . it’s structures, functions, and interelationships with other organisms

• Human biology is the starting point for understanding human medicine and health professions, athletics and exercise science, and other applied sciences

What is Life?
If this review centers on the study of human life, we must be clear on what we mean by “life” in a biological sense
The approach offered in most textbooks lists “characteristics of life”

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

Life is self-organizing

• Seems to resist entropy (nature’s tendency toward disorder)
  • 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 stated that life is less a “thing” and more a “process”
  • Vernadsky said that living organisms are simply special forms of water

Logical approach to studying “the nature of nature”
Hypothesis -> Experiment -> Theory

• Hypothesis is the preliminary idea to be tested
  • Theory is what we call an idea that has been thoroughly tested and found to be true

• We try to achieve higher levels of confidence in our ideas
  • A theory has the highest level of confidence in a scientific statement or fact

• Control experiments – “control” for factors that could influence experimental results in unwanted ways (to make sure you are testing what you want to test)

• Many variations of the scientific process
  • Thus, MANY scientific methods—not just one template
  • Templates are meant to illustrate a process and give a general approach—not to be a rigid must-do set of steps

Template of the Scientific method

The general idea of how scientists (in any discipline, not just human biology) develop theories. It is an oversimplification of how scientists really work—but it does illustrate the process simply. See also the template in the A&P textbook.

• Latin, the language of the ancient Roman Empire, became the primary language of scholars in the west until the 20th century, because everyone who could read learned to read Latin before their own language

• Most terminology in science, but especially in human biology, is therefore Latin in origin and usage

• Latin borrows much from the ancient Greek language, and therefore so does scientific terminology

Word parts

• root – main part of the word
• prefix – word part added to the front of a root
• suffix – word part added to the end of a root
• Example
  • postsynaptic (root is “-synapt-” prefix is “post-” suffix is “-ic”)

Eponym

• Term that use a person’s name (usually whomever first identified it) or a place (usually the location of its discovery)
  • Useful to learn history, but not as useful as a descriptive term for day-to-day use
  • Eponyms are now being replaced with Latin-based descriptive terms
    • It is now preferable to use the descriptive form rather than the eponym form
      —but it’s a good idea to know both 
• If you want to know more about a person in an eponym click here

• When eponyms are used, it is preferable to avoid the possessive form
  • For example, Henle loop is better than Henle’s loop or loop of Henle
  • For medical conditions, the AMA (American Medical Association) style does not use the possessive form (‘s)
    • Parkinson disease is proper whereas Parkinson’s disease is improper (in the AMA style)
    • The AMA style is used in this course (and in our textbook)

This video summarizes some of the key principles needed in understanding scientific terminology

Background
Metric System

• “Metric” is literally “pertaining to length”

• Developed in France in 1791 to standardize units of measurement throughout the world (there were MANY local systems in use back then)

International System of Units

• Modern version of metric system formed in 1960

• Abbreviated SI from the French le Système international d’unités

Metric system is used for everyday measurements in most contries of the world

• In the U.S. (as in the rest of world) the metric system is the preferred system of measurement in the sciences

Basic Units
The SI system uses standard, basic units for measurement

• The table below lists the units that will be useful in your A&P course (it’s not a complete list)

• We will (of course) use the American spellings in our course

U.S. = United States    U.K. = United Kingdom

Prefixes
In the SI system when you need to use smaller or larger units, prefixes are used with the basic unit name to form the name of larger or smaller units.

Prefixes change the size of a basic unit by some factor of ten (making the SI system a decimal system)

µ = lower case mu (from Greek alphabet) often used to signify “micro”
Prefixes shown in boldface are those that you should memorize

Examples of using prefixes

• A kilogram (kg) is 1,000 times the size of a gram

• A microgram (µg) is one million times smaller than a gram (g)—one-millionth of a gram

• A millimeter (mm) is !,000 times smaller than a meter (m)

Additional units

• Time – the second is the basic unit
  • Minutes, hours, days, are also used
  • Anything smaller than a second uses SI prefix with “second”
    • Example—a millisecond (ms or msec) is a thousandth of a second

• Temperature
  • Celsius scale
  • Eponym for Swedish astronomer Anders Celsius
    • Also known as centigrade scale (because it is based on 100 degrees between the freezing and boiling points of water)
  • Degree Celsius (°C) is basic unit
    • Prefixes are not used with this unit
  • Examples
    • 0 °C is the freezing point of water
    • 100 °C is the boiling point of water
    • 37 °C is used as a ballpark average for human oral temperature at rest
  • Other scales may also be used, such as Kelvin (K) scale (we won’t use these in our course

Levels of Organisation

Atoms

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

Molecules

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

Organelles

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

Cells

• 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

Tissues

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

Organs

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

Systems

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

Organism

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

Population

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

Community

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

Ecosystem

• Group of interacting biotic (living) community and abiotic (nonliving) features
• Biotic features include plants, animals, bacteria, etc.
• Abiotic features include geology, climate, etc.
• Examples: forest ecosystem, desert ecosystem

Biome

• All similar ecosystems on earth together

• Examples: the forest biome (all forests on earth), the desert biome (all deserts on earth)

Biosphere

• The whole living layer around the globe (includes even abiotic features)
  • Examples: the forest biome (all forests on earth), the desert biome (all deserts on earth)