describes the front or direction toward the front of the body; also referred to as ventral

anterior

larger body cavity located anterior to the posterior (dorsal) body cavity; includes the serous membrane-lined pleural cavities for the lungs, pericardial cavity for the heart, and peritoneal cavity for the abdominal and pelvic organs; also referred to as ventral cavity

anterior cavity

breaking down of more complex molecules into simpler molecules

catabolism

describes a position below or lower than another part of the body proper; near or toward the tail (in humans, the coccyx, or lowest part of the spinal column); also referred to as inferior

caudal

smallest independently functioning unit of all organisms; in animals, a cell contains cytoplasm, composed of fluid and organelles

cell

medical imaging technique in which a computer-enhanced cross-sectional X-ray image is obtained

computed tomography (CT)

compares values to their normal range; deviations cause the activation of an effector

control center

describes a position above or higher than another part of the body proper; also referred to as superior

cranial

division of the posterior (dorsal) cavity that houses the braina

cranial cavity

describes a position farther from the surface of the body

deep

changes an organism goes through during its life

development

process by which unspecialized cells become specialized in structure and function

differentiation

describes a position farther from the point of attachment or the trunk of the body

distal

describes the back or direction toward the back of the body; also referred to as posterior

dorsal

posterior body cavity that houses the brain and spinal cord; also referred to the posterior body cavity

dorsal cavity

posterior body cavity that houses the brain and spinal cord; also referred to the posterior body cavity

effector

two-dimensional, vertical plane that divides the body or organ into anterior and posterior portions

frontal lobe

study of the larger structures of the body, typically with the unaided eye; also referred to macroscopic anatomy

gross anatomy

process of increasing in size

growth

steady state of body systems that living organisms maintain

homeostasis

describes a position below or lower than another part of the body proper; near or toward the tail (in humans, the coccyx, or lowest part of the spinal column); also referred to as caudal

inferior

describes the side or direction toward the side of the body

lateral

medical imaging technique in which a device generates a magnetic field to obtain detailed sectional images of the internal structures of the body

magnetic resonance imaging (MRI)

describes the middle or direction toward the middle of the body

medial

sum of all of the body’s chemical reactions

metabolism

study of very small structures of the body using magnification

microscopic anatomy

homeostatic mechanism that tends to stabilize an upset in the body’s physiological condition by preventing an excessive response to a stimulus, typically as the stimulus is removed

negative feedback

range of values around the set point that do not cause a reaction by the control center

normal range

chemical obtained from foods and beverages that is critical to human survival

nutrient

functionally distinct structure composed of two or more types of tissues

organ

group of organs that work together to carry out a particular function

organ system

living being that has a cellular structure and that can independently perform all physiologic functions necessary for life

organism

sac that encloses the heart

pericardium

serous membrane that lines the abdominopelvic cavity and covers the organs found there

peritoneum

science that studies the chemistry, biochemistry, and physics of the body’s functions

physiology

imaginary two-dimensional surface that passes through the body

plane

serous membrane that lines the pleural cavity and covers the lungs

pleura

mechanism that intensifies a change in the body’s physiological condition in response to a stimulus

positive feedback

medical imaging technique in which radiopharmaceuticals are traced to reveal metabolic and physiological functions in tissues

positron emission tomography (PET)

describes the back or direction toward the back of the body; also referred to as dorsal

posterior

posterior body cavity that houses the brain and spinal cord; also referred to as dorsal cavity

posterior cavity

force exerted by a substance in contact with another substance

pressure

face down

prone

describes a position nearer to the point of attachment or the trunk of the body

proximal

study of the structures that contribute to specific body regions

regional anatomy

process by which worn-out cells are replaced

renewal

process by which worn-out cells are replaced

reproduction

ability of an organisms or a system to adjust to changes in conditions

responsiveness

two-dimensional, vertical plane that divides the body or organ into right and left sides

sagittal plane

in anatomy, a single flat surface of a three-dimensional structure that has been cut through

section

(also, receptor) reports a monitored physiological value to the control center

sensor

membrane that covers organs and reduces friction; also referred to as serous membrane

serosa

membrane that covers organs and reduces friction; also referred to as serosa

serous membrane

ideal value for a physiological parameter; the level or small range within which a physiological parameter such as blood pressure is stable and optimally healthful, that is, within its parameters of homeostasis

set point

division of the dorsal cavity that houses the spinal cord; also referred to as vertebral cavity

spinal cavity

describes a position nearer to the surface of the body

superficial

describes a position above or higher than another part of the body proper; also referred to as cranials

superior

face up

supine

study of the structures that contribute to specific body systems

systemic anatomy

division of the anterior (ventral) cavity that houses the heart, lungs, esophagus, and trachea

thoracic cavity

group of similar or closely related cells that act together to perform a specific function

tissue

two-dimensional, horizontal plane that divides the body or organ into superior and inferior portions

transverse plane

application of ultrasonic waves to visualize subcutaneous body structures such as tendons and organs

ultrasonography

describes the front or direction toward the front of the body; also referred to as anterior

ventral

larger body cavity located anterior to the posterior (dorsal) body cavity; includes the serous membrane-lined pleural cavities for the lungs, pericardial cavity for the heart, and peritoneal cavity for the abdominal and pelvic organs; also referred to as anterior body cavity

ventral cavity

form of high energy electromagnetic radiation with a short wavelength capable of penetrating solids and ionizing gases; used in medicine as a diagnostic aid to visualize body structures such as bones

X-ray

compound that releases hydrogen ions (H⁺) in solution

acid

amount of energy greater than the energy contained in the reactants, which must be overcome for a reaction to proceed

activation energy

nucleotide containing ribose and an adenine base that is essential in energy transfer

adenosine triphosphate (ATP)

building block of proteins; characterized by an amino and carboxyl functional groups and a variable side-chain

amino acid

atom with a negative charge

anion

smallest unit of an element that retains the unique properties of that element

atom

number of protons in the nucleus of an atom

atomic number

compound that accepts hydrogen ions (H⁺) in solution

base

electrical force linking atoms

bond

solution containing a weak acid or a weak base that opposes wide fluctuations in the pH of body fluids

buffer

class of organic compounds built from sugars, molecules containing carbon, hydrogen, and oxygen in a 1-2-1 ratio

carbohydrate

substance that increases the rate of a chemical reaction without itself being changed in the process

catalyst

atom with a positive charge

cation

form of energy that is absorbed as chemical bonds form, stored as they are maintained, and released as they are broken

chemical energy

liquid mixture in which the solute particles consist of clumps of molecules large enough to scatter light

colloid

substance composed of two or more different elements joined by chemical bonds

compound

number of particles within a given space

concentration

chemical bond in which two atoms share electrons, thereby completing their valence shells

covalent bond

type of catabolic reaction in which one or more bonds within a larger molecule are broken, resulting in the release of smaller molecules or atoms

decomposition reaction

change in the structure of a molecule through physical or chemical means

denaturation

deoxyribose-containing nucleotide that stores genetic information

deoxyribonucleic acid (DNA)

pair of carbohydrate monomers bonded by dehydration synthesis via a glycosidic bond

disaccharide

covalent bond formed within a polypeptide between sulfide groups of sulfur-containing amino acids, for example, cysteine

disulfide bond

subatomic particle having a negative charge and nearly no mass; found orbiting the atom’s nucleus

electron

area of space a given distance from an atom’s nucleus in which electrons are grouped

electron shell

substance that cannot be created or broken down by ordinary chemical means

element

protein or RNA that catalyzes chemical reactions

enzyme

type of chemical reaction in which bonds are both formed and broken, resulting in the transfer of components

exchange reaction

group of atoms linked by strong covalent bonds that tends to behave as a distinct unit in chemical reactions with other atoms

functional group

dipole-dipole bond in which a hydrogen atom covalently bonded to an electronegative atom is weakly attracted to a second electronegative atom

hydrogen bond

substance that does not contain both carbon and hydrogen

inorganic compound

atom with an overall positive or negative charge

ion

attraction between an anion and a cation

ionic bond

one of the variations of an element in which the number of neutrons differ from each other

isotope

energy that matter possesses because of its motion

kinetic energy

class of nonpolar organic compounds built from hydrocarbons and distinguished by the fact that they are not soluble in water

lipid

large molecule formed by covalent bonding

macromolecule

sum of the number of protons and neutrons in the nucleus of an atom

mass number

physical substance; that which occupies space and has mass

matter

two or more atoms covalently bonded together

molecule

monomer of carbohydrate; also known as a simple sugar

monosaccharide

heavy subatomic particle having no electrical charge and found in the atom’s nucleus

neutron

class of organic compounds composed of one or more phosphate groups, a pentose sugar, and a base

nucleotide

substance that contains both carbon and hydrogen

organic compound

covalent bond formed by dehydration synthesis between two amino acids

peptide bond

arrangement of the elements in a table according to their atomic number; elements having similar properties because of their electron arrangements compose columns in the table, while elements having the same number of valence shells compose rows in the table

periodic table of the elements

negative logarithm of the hydrogen ion (H⁺) concentration of a solution

pH

a lipid compound in which a phosphate group is combined with a diglyceride

phospholipid

addition of one or more phosphate groups to an organic compound

phosphorylation

molecule with regions that have opposite charges resulting from uneven numbers of electrons in the nuclei of the atoms participating in the covalent bond

polar molecule

compound consisting of more than two carbohydrate monomers bonded by dehydration synthesis via glycosidic bonds

polysaccharide

stored energy matter possesses because of the positioning or structure of its components

potential energy

one or more substances produced by a chemical reaction

product

lipid compound derived from fatty acid chains and important in regulating several body processes

prostaglandin

class of organic compounds that are composed of many amino acids linked together by peptide bonds

protein

heavy subatomic particle having a positive charge and found in the atom’s nucleus

proton

nitrogen-containing base with a double ring structure; adenine and guanine

purine

nitrogen-containing base with a single ring structure; cytosine, thiamine, and uracil

pyrimidine

unstable, heavy isotope that gives off subatomic particles, or electromagnetic energy, as it decays; also called radioisotopes

radioactive isotope

one or more substances that enter into the reaction

reactant

ribose-containing nucleotide that helps manifest the genetic code as protein

ribonucleic acid (RNA)

homogeneous liquid mixture in which a solute is dissolved into molecules within a solvent

solution

(also, sterol) lipid compound composed of four hydrocarbon rings bonded to a variety of other atoms and molecules

steroid

reactant in an enzymatic reaction

substrate

liquid mixture in which particles distributed in the liquid settle out over time

suspension

type of anabolic reaction in which two or more atoms or molecules bond, resulting in the formation of a larger molecule

synthesis reaction

lipid compound composed of a glycerol molecule bonded with three fatty acid chains

triglyceride

outermost electron shell of an atom

valence shell

form of transport across the cell membrane that requires input of cellular energy

active transport

describes a molecule that exhibits a difference in polarity between its two ends, resulting in a difference in water solubility

amphipathic

third stage of mitosis (and meiosis), during which sister chromatids separate into two new nuclear regions of a dividing cell

anaphase

consecutive sequence of three nucleotides on a tRNA molecule that is complementary to a specific codon on an mRNA molecule

anticodon

breakdown of cells by their own enzymatic action

autolysis

lysosomal breakdown of a cell’s own components

autophagy

life cycle of a single cell, from its birth until its division into two new daughter cells

cell cycle

membrane surrounding all animal cells, composed of a lipid bilayer interspersed with various molecules; also known as plasma membrane

cell membrane

small, self-replicating organelle that provides the origin for microtubule growth and moves DNA during cell division

centriole

region of attachment for two sister chromatids

centromere

cellular structure that organizes microtubules during cell division

centrosome

membrane-spanning protein that has an inner pore which allows the passage of one or more substances

channel protein

progress point in the cell cycle during which certain conditions must be met in order for the cell to proceed to a subsequence phase

checkpoint

substance consisting of DNA and associated proteins

chromatin

condensed version of chromatin

chromosome

small appendage on certain cells formed by microtubules and modified for movement of materials across the cellular surface

cilia

contractile ring that forms around a cell during cytokinesis that pinches the cell into two halves

cleavage furrow

consecutive sequence of three nucleotides on an mRNA molecule that corresponds to a specific amino acid

codon

difference in the concentration of a substance between two regions

concentration gradient

one of a group of proteins that function in the progression of the cell cycle

cyclin

one of a group of enzymes associated with cyclins that help them perform their functions

cyclin-dependent kinase (CDK)

final stage in cell division, where the cytoplasm divides to form two separate daughter cells

cytokinesis

internal material between the cell membrane and nucleus of a cell, mainly consisting of a water-based fluid called cytosol, within which are all the other organelles and cellular solute and suspended materials

cytoplasm

“skeleton” of a cell; formed by rod-like proteins that support the cell’s shape and provide, among other functions, locomotive abilities

cytoskeleton

clear, semi-fluid medium of the cytoplasm, made up mostly of water

cytosol

movement of a substance from an area of higher concentration to one of lower concentration

diffusion

condition marked by the presence of a double complement of genetic material (two sets of chromosomes, one set inherited from each of two parents)

diploid

enzyme that functions in adding new nucleotides to a growing strand of DNA during DNA replication

DNA polymerase

process of duplicating a molecule of DNA

DNA replication

difference in the electrical charge (potential) between two regions

electrical gradient

import of material into the cell by formation of a membrane-bound vesicle

endocytosis

cellular organelle that consists of interconnected membrane-bound tubules, which may or may not be associated with ribosomes (rough type or smooth type, respectively)

endoplasmic reticulum (ER)

export of a substance out of a cell by formation of a membrane-bound vesicle

exocytosis

one of the coding regions of an mRNA molecule that remain after splicing

exon

fluid exterior to cells; includes the interstitial fluid, blood plasma, and fluid found in other reservoirs in the body

extracellular fluid (ECF)

diffusion of a substance with the aid of a membrane protein

facilitated diffusion

appendage on certain cells formed by microtubules and modified for movement

flagellum

phase of the cell cycle, usually entered from the G₁ phase; characterized by long or permanent periods where the cell does not move forward into the DNA synthesis phase

G0 phase

first phase of the cell cycle, after a new cell is born

G1 phase

third phase of the cell cycle, after the DNA synthesis phase

G2 phase

functional length of DNA that provides the genetic information necessary to build a protein

gene

active interpretation of the information coded in a gene to produce a functional gene product

gene expression

entire complement of an organism’s DNA; found within virtually every cell

genome

coating of sugar molecules that surrounds the cell membrane

glycocalyx

protein that has one or more carbohydrates attached

glycoprotein

cellular organelle formed by a series of flattened, membrane-bound sacs that functions in protein modification, tagging, packaging, and transport

Golgi apparatus

enzyme that functions to separate the two DNA strands of a double helix during DNA replication

helicase

family of proteins that associate with DNA in the nucleus to form chromatin

histone

describes two copies of the same chromosome (not identical), one inherited from each parent

homologous

describes a substance or structure attracted to water

hydrophilic

describes a substance or structure repelled by water

hydrophobic

describes a solution concentration that is higher than a reference concentration

hypertonic

describes a solution concentration that is lower than a reference concentration

hypotonic

membrane-associated protein that spans the entire width of the lipid bilayer

integral protein

type of cytoskeletal filament made of keratin, characterized by an intermediate thickness, and playing a role in resisting cellular tension

intermediate filament

entire life cycle of a cell, excluding mitosis

interphase

fluid in the small spaces between cells not contained within blood vessels

interstitial fluid (IF)

fluid in the cytosol of cells

intracellular fluid (ICF)

non-coding regions of a pre-mRNA transcript that may be removed during splicing

intron

describes a solution concentration that is the same as a reference concentration

isotonic

region of a centromere where microtubules attach to a pair of sister chromatids

kinetochore

molecule that binds with specificity to a specific receptor molecule

ligand

membrane-bound cellular organelle originating from the Golgi apparatus and containing digestive enzymes

lysosome

nucleotide molecule that serves as an intermediate in the genetic code between DNA and protein

messenger RNA (mRNA)

second stage of mitosis (and meiosis), characterized by the linear alignment of sister chromatids in the center of the cell

metaphase

linear alignment of sister chromatids in the center of the cell, which takes place during metaphase

metaphase plate

the thinnest of the cytoskeletal filaments; composed of actin subunits that function in muscle contraction and cellular structural support

microfilament

the thickest of the cytoskeletal filaments, composed of tubulin subunits that function in cellular movement and structural support

microtubule

one of the cellular organelles bound by a double lipid bilayer that function primarily in the production of cellular energy (ATP)

mitochondrion

division of genetic material, during which the cell nucleus breaks down and two new, fully functional, nuclei are formed

mitosis

phase of the cell cycle in which a cell undergoes mitosis

mitotic phase

network of microtubules, originating from centrioles, that arranges and pulls apart chromosomes during mitosis

mitotic spindle

describes the condition of being able to differentiate into different types of cells within a given cell lineage or small number of lineages, such as a red blood cell or white blood cell

multipotent

change in the nucleotide sequence in a gene within a cell’s DNA

mutation

membrane that surrounds the nucleus; consisting of a double lipid-bilayer

nuclear envelope

one of the small, protein-lined openings found scattered throughout the nuclear envelope

nuclear pore

`small region of the nucleus that functions in ribosome synthesis

nucleolus

unit of chromatin consisting of a DNA strand wrapped around histone proteins

nucleosome

cell’s central organelle; contains the cell’s DNA

nucleus

`describes the condition of being more specialized than multipotency; the condition of being able to differentiate into one of a few possible cell types

oligopotent

any of several different types of membrane-enclosed specialized structures in the cell that perform specific functions for the cell

organelle

diffusion of water molecules down their concentration gradient across a selectively permeable membrane

osmosis

form of transport across the cell membrane that does not require input of cellular energy

passive transport

membrane-associated protein that does not span the width of the lipid bilayer, but is attached peripherally to integral proteins, membrane lipids, or other components of the membrane

peripheral protein

membrane-bound organelle that contains enzymes primarily responsible for detoxifying harmful substances

peroxisome

endocytosis of large particles

phagocytosis

endocytosis of fluid

pinocytosis

describes the condition of being able to differentiate into a large variety of cell types

pluripotent

chain of amino acids linked by peptide bonds

polypeptide

simultaneous translation of a single mRNA transcript by multiple ribosomes

polyribosome

region of DNA that signals transcription to begin at that site within the gene

promoter

first stage of mitosis (and meiosis), characterized by breakdown of the nuclear envelope and condensing of the chromatin to form chromosomes

prophase

full complement of proteins produced by a cell (determined by the cell’s specific gene expression)

proteome

a group of extremely reactive peroxides and oxygen-containing radicals that may contribute to cellular damage

reactive oxygen species (ROS)

protein molecule that contains a binding site for another specific molecule (called a ligand)

receptor

endocytosis of ligands attached to membrane-bound receptors

receptor-mediated endocytosis

RNA that makes up the subunits of a ribosome

ribosomal RNA (rRNA)

cellular organelle that functions in protein synthesis

ribosome

enzyme that unwinds DNA and then adds new nucleotides to a growing strand of RNA for the transcription phase of protein synthesis

RNA polymerase

stage of the cell cycle during which DNA replication occurs

S phase

feature of any barrier that allows certain substances to cross but excludes others

selective permeability

one of a pair of identical chromosomes, formed during DNA replication

sister chromatid

(also, Na⁺/K⁺ ATP-ase) membrane-embedded protein pump that uses ATP to move Na⁺ out of a cell and K⁺ into the cell

sodium-potassium pump

all cells of the body excluding gamete cells

somatic cell

complex of enzymes that serves to splice out the introns of a pre-mRNA transcript

spliceosome

the process of modifying a pre-mRNA transcript by removing certain, typically non-coding, regions

splicing

cell that is oligo-, multi-, or pleuripotent that has the ability to produce additional stem cells rather than becoming further specialized

stem cell

final stage of mitosis (and meiosis), preceding cytokinesis, characterized by the formation of two new daughter nuclei

telophase

embryonic cells that have the ability to differentiate into any type of cell and organ in the body

totipotent

process of producing an mRNA molecule that is complementary to a particular gene of DNA

transcription

one of the proteins that regulate the transcription of genes

transcription factor

molecules of RNA that serve to bring amino acids to a growing polypeptide strand and properly place them into the sequence

transfer RNA (tRNA)

process of producing a protein from the nucleotide sequence code of an mRNA transcript

translation

consecutive sequence of three nucleotides on a DNA molecule that, when transcribed into an mRNA codon, corresponds to a particular amino acid

triplet

describes the condition of being committed to a single specialized cell type

unipotent

membrane-bound structure that contains materials within or outside of the cell

vesicle