Interstitial growth Growth from within, as in the growth of cartilage.
Also called endogenous growth (en-DOJ-e-nus).
Intervertebral disc (in'-ter-VER-te-bral) A pad of fibrocartilage
located between the bodies of two vertebrae.
Intestinal gland A gland that opens onto the surface of the intestinal
mucosa and secretes digestive enzymes. Also called a crypt of
Intracellular fluid (ICF) (in'-tra-SEL-u-lar) Fluid located within cells.
Also called cytosol (ST-to-sol).
Intramembranous ossification (in'-tra-MEM-bra-nus os'-i'-fi-KA-shun)
The method of bone formation in which the bone is formed
directly within mesenchyme arranged in sheetlike layers that
Intraocular pressure (IOP) (in'-tra-OK-u-lar) Pressure in the eyeball,
produced mainly by aqueous humor.
Intrapleural pressure Air pressure between the two pleurae of the
lungs, usually subatmospheric. Also called intrathoracic pressure.
Intrinsic (in-TRIN-sik) Of internal origin.
Intrinsic pathway (of blood clotting) Sequence of reactions leading
to blood clotting that is initiated by damage to blood vessel endo-
thelium or platelets; activators of this pathway are contained
within blood itself or are in direct contact with blood.
Intrinsic factor (IF) A glycoprotein, synthesized and secreted by the
parietal cells of the gastric mucosa, that facilitates vitamin B12
absorption in the small intestine.
In utero (0-ter-o) Within the uterus.
Invagination (in-vaj'-i-NA-shun) The pushing of the wall of a cavity
into the cavity itself.
Inversion (in-VER-zhun) The movement of the sole medially at the
Ion (T-on) Any charged particle or group of particles; usually formed
when a substance, such as a salt, dissolves and dissociates.
Ionization (T'-on-i-ZA-shun) Separation of inorganic acids, bases, and
salts into ions when dissolved in water. Also called dissociation.
Iris The colored portion of the vascular tunic of the eyeball seen
through the cornea that contains circular and radial smooth
muscle; the hole in the center of the iris is the pupil.
Irritable bowel syndrome (IBS) Disease of the entire gastrointestinal tract
in which a person reacts to stress by developing symptoms (such as
cramping and abdominal pain) associated with alternating patterns of
diarrhea and constipation. Excessive amounts of mucus may appear
in feces, and other symptoms include flatulence, nausea, and loss
of appetite. Also known as irritable colon or spastic colitis.
Ischemia (is-KE-me-a) A lack of sufficient blood to a body part due to
obstruction or constriction of a blood vessel.
Isometric contraction (T'-so-MET-rik) A muscle contraction in which
tension on the muscle increases, but there is only minimal muscle
shortening so that no visible movement is produced.
Isotonic (i'-so-TON-ik) Having equal tension or tone. A solution hav-
ing the same concentration of impermeable solutes as cytosol.
Isotonic contraction Contraction in which the tension remains the
same; occurs when a constant load is moved through the range
of motions possible at a joint.
Isotopes (F-so-tops') Chemical elements that have the same number
of protons but different numbers of neutrons. Radioactive iso-
topes change into other elements with the emission of alpha or
beta particles or gamma rays.
Isthmus (IS-mus) A narrow strip of tissue or narrow passage con-
necting two larger parts.
Jaundice (JAWN-dis) A condition characterized by yellowness of the
skin, the white of the eyes, mucous membranes, and body fluids
because of a buildup of bilirubin.
Jejunum (je-JOO-num) The middle part of the small intestine.
Joint kinesthetic receptor (kin'-es-THET-ik) A proprioceptive receptor
located in a joint, stimulated by joint movement.
Keratin (KER-a-tin) An insoluble protein found in the hair, nails, and
other keratinized tissues of the epidermis.
Keratinocyte (ke-RAT-in'-o-sFt) The most numerous of the epidermal
cells; produces keratin.
Ketone bodies (KE-ton) Substances produced primarily during exces-
sive triglyceride catabolism, such as acetone, acetoacetic acid,
and b-hydroxybutyric acid.
Ketosis (ke-TO-sis) Abnormal condition marked by excessive produc-
tion of ketone bodies.
Kidney (KID-ne) One of the paired reddish organs located in the lum-
bar region that regulates the composition, volume, and pressure
of blood and produces urine.
Kidney stone A solid mass, usually consisting of calcium oxalate, uric
acid, or calcium phosphate crystals, that may form in any portion
of the urinary tract. Also called a renal calculus (KAL-ku-lus).
Kinesiology (ki-ne'-se-OL-o-je) The study of the movement of body
Kinesthesia (kin-es-THE-ze-a) The perception of the extent and direc-
tion of movement of body parts; this sense is possible due to
nerve impulses generated by proprioceptors.
Korotkoff sounds (ko-ROT-kof) The various sounds that are heard
while taking blood pressure.
Krebs cycle A series of biochemical reactions that occurs in the
matrix of mitochondria in which electrons are transferred to
coenzymes and carbon dioxide is formed. The electrons carried
by the coenzymes then enter the electron transport chain, which
generates a large quantity of ATP. Also called the citric acid cycle
or tricarboxylic acid (TCA) cycle.
Kyphosis (kF-FO-sis) An exaggeration of the thoracic curve of the
vertebral column, resulting in a "round-shouldered" appearance.
Also called hunchback.
Labia majora (LA-be-a ma-JO-ra) Two longitudinal folds of skin
extending downward and backward from the mons pubis of the
Labia minora (min-OR-a) Two small folds of mucous membrane lying
medial to the labia majora of the female.