Anatomy and Phisiology 1 Ch.2 Dr. Sam Yacoub TCC southeast

Matter

Has mass and occupies space and exists in three forms: solid liquid and gas

Atom

The smallest particle exhibiting the chemical properties of an element

Chemical element

A substance that cannot be broken down to other substances by ordinary chemical means

Oxygen (O)

Major element composing 65.0% of body weight

Carbon (C)

Major element composing 18.0% of body weight

Hydrogen (H)

Major element composing 10.0% of body weight

Nitrogen (N)

Major element composing 3.0% of body weight

Calcium (Ca)

Major element composing 1.5% of body weight

Phosphorus (P)

Major element composing 1.0% of body weight

Sulfur (S)

Minor element composing 0.25% of body weight

Potassium (K)

Minor element composing 0.20% of body weight

Sodium (Na)

Minor element composing 0.15% of body weight

Chlorine (Cl)

Minor element composing 0.15% of body weight

Magnesium (Mg)

Minor element composing 0.05% of body weight

Iron (Fe)

Minor element composing 0.006% of body weight

96.3% of body wet weight

The percentage made up by the first four elements (oxygen carbon hydrogen and nitrogen) plus water

Neutron

Subatomic particle with a mass of one atomic mass unit (amu) and no charge

Proton

Subatomic particle with a mass of one amu and a positive charge of one (+1)

Electron

Subatomic particle with a negative charge of one (-1) located at varying distances from the nucleus in regions called orbitals

Electron shell

A region surrounding the nucleus of an atom that holds electrons; the innermost shell holds two electrons and the second shell holds up to eight

Chemical symbol

Unique identifier for each element usually the first letter or first letter plus an additional letter such as C for carbon

Atomic number

The number of protons in an atom of an element located above the symbol on the periodic table

Average atomic mass

The mass of both protons and neutrons shown below the element's symbol on the periodic table

Isotopes

Different atoms of the same element with the same number of protons and electrons but a different number of neutrons

Carbon-12

The most prevalent isotope of carbon with 6 neutrons

Carbon-13

An isotope of carbon with 7 neutrons

Carbon-14

An isotope of carbon with 8 neutrons

Radioisotope

An isotope that contains excess neutrons making it unstable

Octet rule

The tendency of elements to lose gain or share electrons to obtain complete outer shells with eight electrons

Ion

A charged atom created when atoms gain or lose electrons

Ionic bond

An electrical attraction between ions with opposite charges

Anion

An ion with a negative charge

Cation

An ion with a positive charge

Chloride ion (Cl-)

Common anion that alters nerve cell responsiveness to stimulation is a component of stomach acid (HCl) and is involved in chloride shift in erythrocytes

Sodium ion (Na+)

Common cation that is the most common extracellular cation participates in conducting electrical signals in nerves and muscle is most important in osmotic movement of water and its gradient is involved in cotransport of other substances across a plasma membrane

Salt (chemistry)

A compound formed by ionic bonds such as table salt (NaCl)

Molecule

A chemical structure consisting of atoms held together by covalent bonds such as O2

Compound

A chemical substance composed of atoms of two or more different elements such as CO2

Types of chemical bonds

Ionic covalent and hydrogen bonds

Molecular formula

Indicates the number and type of atoms in a molecule such as carbonic acid H2CO3

Structural formula

Indicates the number and type of atoms as well as their arrangement within a molecule allowing differentiation of isomers

Isomers

Molecules with the same number and type of elements but arranged differently in space

Glucose galactose and fructose

Isomers that share the same molecular formula of 6 carbon 12 hydrogen and 6 oxygen but have their atoms arranged differently

Single covalent bond

A bond formed when two atoms share one pair of electrons such as in hydrogen gas H2

Double covalent bond

A bond formed when two atoms share two pairs of electrons such as in oxygen gas O2

Triple covalent bond

A bond formed when two atoms share three pairs of electrons such as in nitrogen gas N2

Nonpolar covalent bond

A bond in which electrons are shared equally between atoms because both nuclei have the same charge

Polar covalent bond

A bond in which electrons are shared unequally and spend more time near the larger positive charge nucleus resulting in partial charges such as in water

Amphipathic molecules

Large molecules with both polar and nonpolar regions such as phospholipids

Hydrogen bond

Forms between polar molecules as an attraction between a partially positive hydrogen atom and a partially negative atom; individually weak but collectively strong and influences how water molecules behave

Water

A polar molecule composing two-thirds of the human body by weight with one oxygen atom bonded to two hydrogen atoms that can form four hydrogen bonds with adjacent molecules

Gas (water vapor)

A phase of water consisting of substances with low molecular mass

Liquid water

The phase that makes up almost all water in the body and is liquid at room temperature due to hydrogen bonding

Transport (function of water)

Substances dissolved in water move easily throughout the body

Lubrication (function of water)

Decreases friction between body structures

Cushioning (function of water)

Absorbs sudden force of body movements

Excretion of wastes (function of water)

Unwanted substances dissolved in water are easily eliminated

Cohesion

Attraction between water molecules due to hydrogen bonding

Surface tension

Inward pulling of cohesive forces at the surface of water which can cause moist sacs of air in the lungs to collapse

Surfactant

A lipoprotein that prevents the collapse of moist air sacs in the lungs caused by surface tension

Adhesion

Attraction between water molecules and a substance other than water

Specific heat

The amount of energy required to increase the temperature of 1 gram of a substance by 1 degree Celsius

Heat of vaporization

The heat required for the release of molecules from a liquid phase into a gaseous phase for 1 gram of a substance

Solute

A substance that dissolves in water

Universal solvent

A term for water because most substances dissolve in it

Hydrophilic

Meaning water-loving; describes polar molecules and ions that water surrounds forming a hydration shell

Hydration shell

The shell water forms around a dissolved substance

Dissociation (chemistry)

When a substance dissolves and separates into ions such as NaCl dissociating into Na+ and Cl- ions

Hydrophobic

Meaning water-fearing; describes nonpolar molecules that do not dissolve in water and require carrier proteins for transport in the blood

Hydrophobic exclusion

When cohesive water molecules force out nonpolar molecules

Hydrophobic interaction

The excluded molecules resulting from hydrophobic exclusion

Micelle

A structure formed by amphipathic molecules with their polar heads facing outward

Phospholipid bilayer

The structure resulting from phospholipid polar heads contacting water while nonpolar tails group together such as in cell membranes

Acid

A substance that dissociates in water to produce H+ and an anion; acts as a proton donor and increases the concentration of free H+

Base

A substance that accepts H+ when added to a solution; acts as a proton acceptor and decreases the concentration of free H+

pH

A measure of the relative amount of H+ in a solution ranging between 0 and 14; inversely related to H+ concentration

Neutral solution

A solution with equal concentrations of H+ and OH- and a pH of 7

Acidic solution

A solution with greater H+ than OH- and a pH less than 7

Basic (alkaline) solution

A solution with greater OH- than H+ and a pH greater than 7

Hydrochloric acid (HCl)

Has a pH of 1

Lemon juice and stomach acid

Have a pH of 2 to 3

Wine

Has a pH of 2.4 to 3.5

Grapefruit juice

Has a pH of 3

Tomato juice

Has a pH of 4.7

Urine

Has a pH of 6

Milk and saliva

Have a pH of 6.3 to 6.6

Pure water

Has a neutral pH of 7

Human blood

Has a pH of 7.4

Seawater

Has a pH of 8

Antacid

Has a pH of 10.5

Household ammonia

Has a pH of 10.5 to 11

Household bleach

Has a pH of 12

Sodium hydroxide (NaOH)

Has a pH of 14

Neutralization

When an acidic or basic solution is returned to a neutral pH of 7

Buffer

A substance that helps prevent pH changes by accepting H+ from excess acid or donating H+ to neutralize a base such as carbonic acid and bicarbonate buffering blood pH between 7.35 and 7.45

Suspension

A mixture containing material larger in size than 100 nanometers

Colloid

A mixture containing protein of a size from 1 to 100 nanometers

Solution (mixture type)

A homogeneous mixture of material smaller than 1 nanometer

Emulsion

A mixture of water and a nonpolar liquid substance

Organic molecule

A molecule that contains carbon and is usually a component of living organisms