Chapter 2: Cells, Tissues, Organs, Body Structure Key Terms

ATP

The energy compound of the cell; stores energy needed for cell activities. ATP stands for adenosine triphosphate

Carbohydrate

The category of organic compounds that includes sugars and starches

Cell

The basic structural and functional unit of the living organism; a microscopic unit that combines with other cells to form tissues

Chromosome

A threadlike body in a cell's nucleus that contains genetic information

Cytology

study of cells

Cytoplasm

The fluid that fills a cell and holds the organelles

DNA

The genetic compound of the cell; makes up the genes. DNA stands for deoxyribonucleic acid

Enzyme

An organic substance that speeds the rate of metabolic reactions

Gene

A hereditary unit composed of DNA and combined with other genes to form the chromosomes

Glucose

A simple sugar that circulates in the blood; the main energy source for metabolism

Histology

study of tissues

Homeostasis

A steady state; a condition of internal stability and constancy

Lipid

A category of organic compounds that includes fats

Membrane

A simple very thin, and pliable sheet of tissue that might cover an organ, line a cavity, or separate structures

Metabolism

The sum of all the physical and chemical reactions that occur within an organism

Mitosis

cell division

Mucus

A thick fluid secreted by cells in membranes and glands that lubricates and protects tissues (adj: mucous)

Nucleus

The cell's control center; directs all cell activities based on the information contained in its chromosomes

Organ

A part of the body with a specific function. A component of a body system

Organelle

A specialized structure in the cytoplasm of a cell

Protein

A category of organic compounds that includes structural materials, enzymes, and some hormones

RNA

An organic compound involved in the manufacture of proteins within cells. RNA stands for ribonucleic acid

Tissue

A group of cells that acts together for a specific purpose

Amino acids

The nitrogen-containing compounds that make up proteins

Anabolism

The type of metabolism in which body substances are made; the building phase of metabolism

Catabolism

The type of metabolism in which substances are broken down for energy and simple compounds

Collagen

A fibrous protein found in connective tissue

Cortex

The outer region of an organ

Glycogen

A complex sugar compound stored in liver and muscles; broken down into glucose when needed for energy

Interstitial

Between parts, such as the spaces between cells in a tissue

Medulla

The inner region of an organ; marrow

Parenchyma

The functional tissue of an organ

Parietal

Pertaining to a wall; describes a membrane that lines a body cavity

Soma

the body

Stem cell

An immature cell that has the capacity to develop into any of a variety of different cell types. A precursor cell

Visceral

Pertaining to the internal organs; describes a membrane on the surface of an organ

Anterior (ventral)

toward or at the front (belly) of the body

Posterior (dorsal)

toward or at the back (dorsum) of the body

Medial

toward the midline of the body

Lateral

toward the side of the body

Proximal

nearer to the point of attachment or to a given reference point

Distal

farther from the point of attachment or from a given reference point

Superior

above, in a higher position

Inferior

below, in a lower position

Cranial (cephalad)

toward the head

Caudal

toward the lower end of the spine (Latin cauda means “tail”); in humans, in an inferior direction

Superficial (external)

closer to the surface of the body

Deep (internal)

closer to the center of the body

Abdominal cavity

The larger ventral cavity below the diaphragm and above the pelvic cavity

Abdominopelvic cavity

The larger ventral cavity between the diaphragm and pelvis that includes the abdominal and pelvic cavity

Anatomic position

Standard position for anatomic studies, in which the body is erect and facing forward, the arms are at the sides with palms forward, and the feet are parallel

Cranial cavity

The dorsal cavity that contains the brain

Diaphragm

The muscle that separate the thoracic from the abdominal cavity

Frontal (coronal) plane

Plane of section that separates the body into anterior (front) and posterior (back) portions

Pelvic cavity

The ventral cavity that is below the abdominal cavity

Peritoneum

The large serous membrane that lines the abdominopelvic cavity and cover the organs with it

Sagittal plane

Plane that divides the body into right and left portions

Spinal cavity (canal)

dorsal cavity that contains the spinal cord

thoracic cavity

The ventral cavity above the diaphragm; the chest cavity

transverse (horizontal) plane

Plane that divides the body into superior (upper) and inferior (lower) portions

digit

A finger or toe (adjective, digital)

epigastrium

the epigastric region

Fundus

The base or body of a hollow organ; the area of an organ farthest from its opening

Hypochondrium

The hypochondriac region (left or right)

Lumen

The central opening within a tube or hollow organ

Meatus

A passage or opening

Orifice

the opening of a cavity

os

mouth; any body opening

Septum

a wall dividing two cavities

Sinus

a cavity, as within a bone

Sphincter

a circular muscle that regulates an opening

LLQ

left lower quadrant

LUQ

left upper quadrant

RLQ

right lower quadrant

RUQ

right upper quadrant