Unit 1-Essentials of Human Anatomy and Physiology.docx

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Essentials of Human Anatomy and Physiology
Unit 1
Chapter 1: 12-13
Chapter 2: 39-42,45,47-54,56-57
Chapter 3: 63-82
Chapter 7: 230-238
Homeostasis
Bodies ability to maintain relatively stable internal conditions even though
the outside world is constantly changing
Dynamic system of equilibrium, vary within narrow limits
Every organ system plays a role in maintaining constancy of internal enviro.
Homeostatic Controls
Communication within body is essential for homeostasis; accomplished by
nervous and endocrine system, electric signals by nerves or blood borne
hormones as information carriers
Receptor: type of sensor that monitors and responds to changes, stimuli, by
sending information to control center
o Information flows from receptor to control center long afferent
pathway
Control Center (CC): determine level at which variable is to be maintained,
analyzes info it receives and determines appropriate response
Effector: Provides means for control center response to stimulus
o Info flows from CC to effector along efferent pathway
o Influence stimulus by negative (most common) or positive feedback
o Positive feedback is rare because it pushes original disturbance
farther away from original state
Biochemistry: Chemical Composition of living matter
Inorganic compounds: lack carbon and tend to be small i.e. water, salt,
acids, bases
Organic Compounds: carbon containing compounds, fairly large covalently
bonded molecules i.e. carbohydrates, lipids, proteins, nucleic acids
Inorganic Compounds
Water
1. High heat capacity
Absorbs and releases large amounts of heath before temp changes
Prevents sudden changes in body temp
2. Polarity/Solvent properties
Excellent solvent
Small reactive chemicals (salts, acids, bases) dissolve easily
Act as transport and exchange medium for nutrients, respiratory gases,
and wastes
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3. Chemical Reactivity
Hydrolysis reaction: water molecules added to bonds of large molecules
Salts
Ionic compound containing cations, other than H+, and anions other than
OH-
Most contain Ca and P i.e. bones and teeth
When dissolved easily separate into ions i.e. dissociation
Na and K essential for nerve impulses
Electrolytes: conduct electricity current in solution
Salt imbalance = BAD
Acids
Sour taste, can dissolve metals
Proton donor- H+
Dissolved in H20 releases H+ and anions
i.e. acetic acid, carbonic acid
Strong acids- ionize completely
Weak acids- ionize incompletely
Bases
Bitter taste, slippery
Proton acceptor- OH-
Acid + Base = Neutralization Reaction
pH
Relative concentration of OH- and H+ in various body fluids is measured in
concentration units
Above 7 = basic, Below 7 = acidic
Regulated by kidneys, lungs, buffers
Blood 7.35-7.45
Lipids
i.e. meat, egg yolks, milk, oil
Most abundant are triglycerides, phospholipids, steroids
All have C, H2, O2
Insoluble in water but dissolve in other lipids and other organic solvents
Triglycerides (neutral fats)
Synthesized by dehydration synthesis
3 fatty acid chains attached to single glycerol molecules, water is lost at each
bond site
Short fatty acid i.e. olive oil, soybean
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Body’s most abundant and source of useable energy when oxidized
Stored in fat deposits beneath skin and around body organs, insulate
Phospholipid molecule
2 fatty acid chains and a phosphorous containing group attached to glycerol
backbone
1 fatty acid chain is unsaturated
Special chemical properties and polarity
o Attracts and interacts with water and ions
o Allows cell boundaries to be selective about what enters and leaves
Trans-fats
i.e. margarines, baked products
Oils that have been solidified by addition of H2 atoms at sites of double C
bonds
Increase heath risk
Steroids
Flat molecules formed of 4 interlocking rings, H2, C, fat soluble
Cholesterol: found in cell membranes, raw material of vitamin D, steroid
hormones and bile salts
Proteins
50% of organic matter, most varied functions of organic molecules
Some construction materials, vital cell function
C, O2, H2, N2, S
Amino acids: 20 different kinds which all have NH2 which gives them basic
properties and a acid group (COOH)
o Different R group, make amino acids different
o Sequence varies structure and function
Primary
o Polypeptide chain: backbone
Secondary
o Twist and bend on themselves
o Common alpha helix- coiling of primary chain and is stabilized by H2
bonds, link different parts of chain
o Beta-pleated sheet: linked side by side by H2 bonds to form pleated,
ribbon structure
o H2 bond may link together different polypeptide chains as well as
different parts of same chain folded back on itself
Tertiary
o When alpha and beta region fold on one another to make a globular
structure
o Maintained by covalent and H2 bonds between amino acids
o 2+ polypeptide chain = quaternary structure
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