| tissues | Collections of cells adapted to
perform a specific function.
|
 |
|
|
| organ | A group of tissues designed to perform
a specific function—for example, the
heart, which contains muscle tissue, nerve
tissue, and so on.
|
|
|
|
| organ system | A collection of organs that
work together to perform an overall function.
|
|
|
|
| organelles | Compartments, particles, or filaments
that perform specialized functions
within a cell.
|
|
|
|
| phospholipid | Any of a class of fat-related
substances that contain phosphorus, fatty
acids, and a nitrogen-containing component.
Phospholipids are an essential part of every
cell.
|
|
|
|
| enzyme | A compound that speeds the rate of
a chemical process but is not altered by that
process. Almost all enzymes are proteins.
|
|
|
|
| cytoplasm | The fluid and organelles (except
the nucleus) in a cell.
|
|
|
|
| anaerobic | Not requiring oxygen.
|
|
|
|
| mitochondria | The main sites of energy
production in a cell. They also contain the
pathway for oxidizing fat for fuel, among
other metabolic pathways.
|
|
|
|
| aerobic | Requiring oxygen.
|
|
|
|
| cell nucleus | An organelle bound by its own
double membrane and containing chromosomes,
the genetic information for cell protein
synthesis and cell replication.
|
|
|
|
| deoxyribonucleic acid (DNA) | The site of
hereditary information in cells; DNA directs
the synthesis of cell proteins.
|
|
|
|
| gene | A specific segment on a chromosome.
Genes provide the blueprint for the production
of cell proteins.
|
|
|
|
| chromosome | A single, large DNA molecule
and its associated proteins; contains many
genes to store and transmit genetic
information.
|
|
|
|
| ribonucleic acid (RNA) | The single-stranded
nucleic acid involved in the transcription of
genetic information and translation of that
information into protein structure.
|
|
|
|
| ribosomes | Cytoplasmic particles that
mediate the linking together of amino acids to
form proteins; may exist freely in the cytoplasm
or attached to endoplasmic reticulum.
|
|
|
|
| endoplasmic reticulum (ER) | An organelle
in the cytoplasm composed of a network of
canals running through the cytoplasm. Part of
the endoplasmic reticulum contains ribosomes.
|
|
|
|
| Golgi complex | The cell organelle near the
nucleus that processes newly synthesized
protein for secretion or distribution to other
organelles.
|
|
|
|
| secretory vesicles | Membrane-bound
vesicles produced by the Golgi apparatus;
contains protein and other compounds to be
secreted by the cell.
|
|
|
|
| lysosome | A cellular organelle that contains
digestive enzymes for use inside the cell for
turnover of cell parts.
|
|
|
|
| peroxisome | A cell organelle that destroys
toxic products within the cell.
|
|
|
|
| hydrogen peroxide | Chemically, H2O2.
|
|
|
|
| epithelial tissue | The surface cells that line
the outside of the body and all external passages
within it.
|
|
|
|
| connective tissue | Protein tissue that holds
different structures in the body together. Some
structures are made up of connective tissue—
notably, tendons and cartilage. Connective
tissue also forms part of bone and the
nonmuscular structures of arteries and veins.
|
|
|
|
| muscle tissue | A type of tissue adapted to
contract in order to cause movement.
|
|
|
|
| nervous tissue | Tissue composed of highly
branched, elongated cells, which transport
nerve impulses from one part of the body to
another.
|
|
|
|
| urea | Nitrogenous waste product of protein
metabolism; major source of nitrogen in the
urine.
|
|
|
|
| cardiovascular system | The body system
consisting of the heart, blood vessels, and
blood. This system transports nutrients, waste
products, gases, and hormones throughout
the body, and plays an important role in
immune responses and regulation of body
temperature.
|
|
|
|
| lymphatic system | A system of vessels and
lymph that accepts fluid surrounding cells
and large particles, such as products of fat
absorption. Lymph eventually passes into the
bloodstream from the lymphatic system.
|
|
|
|
| plasma | The fluid, extracellular portion of the
circulating blood. This includes the blood
serum plus all blood-clotting factors. In contrast,
serum is the fluid that remains after
clotting factors have been removed from
plasma.
|
|
|
|
| artery | A blood vessel that carries blood away
from the heart.
|
|
|
|
| capillary | A microscopic blood vessel that
connects the smallest arteries and veins; site
of nutrient, oxygen, and waste exchange
between body cells and the blood.
|
|
|
|
| vein | A blood vessel that carries blood to the
heart.
|
|
|
|
| portal circulation | The portion of the
circulatory system that utilizes a large vein
(portal vein) to carry nutrient-rich blood from
capillaries in the intestines and portions of
the stomach to the liver.
|
|
|
|
| nervous system | The body system consisting
of the brain, spinal cord, nerves, and sensory
receptors. This system detects sensations,
directs movements, and controls physiological
and intellectual functions.
|
|
|
|
| neuron | The structural and functional unit of
the nervous system. Consists of a cell body,dendrites, and an axon.
|
|
|
|
| synapse | The space between one neuron and
another neuron (or cell).
|
|
|
|
| neurotransmitter | A compound made by a
nerve cell that allows for communication
between it and other cells.
|
|
|
|
| myelin sheath | A lipid and protein combination
(lipoprotein) that covers nerve fibers.
|
|
|
|
| endocrine system | The body system consisting
of the various glands and the hormones
these glands secrete. This system has major
regulatory functions in the body, such as
reproduction and cell metabolism.
|
|
|
|
| endocrine gland | A hormone-producing
gland.
|
|
|
|
| thyroid hormone | Hormones produced by
the thyroid gland that among their functions
increase the rate of overall metabolism in the
body.
|
|
|
|
| receptor | A site in a cell at which compounds
(such as hormones) bind. Cells that contain
receptors for a specific compound are partially
controlled by that compound.
|
|
|
|
| immune system | The body system consisting
of white blood cells, lymph glands and
vessels, and various other body tissues. The
immune system provides defense against
foreign invaders, primarily due to the action
of various types of white blood cells.
|
|
|
|
| lysozyme | An enzyme produced by a variety
of cells; it can destroy bacteria by rupturing
their cell membranes.
|
|
|
|
| immunoglobulins | Proteins found in the
blood that bind to specific antigens; also
called antibodies. The five major classes of
immunoglobulins play different roles in
antibody-mediated immunity.
|
|
|
|
| antigen | Any substance that induces a state
of sensitivity and/or resistance to microorganisms
or toxic substances after a lag period;
foreign substance that stimulates a specific
aspect of the immune system.
|
|
|
|
| antibody | Blood protein (immunoglobulin)
that binds foreign proteins found in the body.
This helps to prevent and control infections.
|
|
|
|
| white blood cells | One of the formed elements
of the circulating blood system; also
called leukocytes. White blood cells are able
to squeeze through intracellular spaces and
migrate. They phagocytize bacteria, fungi,
and viruses, as well as detoxify proteins that
may result from allergic reactions, cellular
injury, and other immune system cells.
|
|
|
|
| phagocytosis | A process in which a cell
forms an indentation, and particles or fluids
entering the indentation are then engulfed by
the cell.
|
|
|
|
| cell-mediated immunity | A process in
which certain white blood cells come in actual
contact with the invading cells in order to
destroy them.
|
|
|
|
| digestive system | The body system consisting
of the gastrointestinal tract and accessory
structures such as the liver, gallbladder, and
pancreas. This system performs the mechanical
and chemical processes of digestion,
absorption of nutrients, and elimination of
wastes.
|
|
|
|
| digestion | The process by which large
ingested molecules are mechanically and
chemically broken down to produce basic
nutrients that can be absorbed across the
wall of the GI tract.
|
|
|
|
| absorption | The process by which substances
are taken up from the GI tract and enter the
bloodstream or the lymph.
|
|
|
|
| gastrointestinal (GI) tract | The main sites in
the body used for digestion and absorption of
nutrients. It consists of the mouth, esophagus,
stomach, small intestine, large intestine, rectum,
and anus. Also called the digestive tract.
|
|
|
|
| motility | Generally, the ability to move spontaneously.
It also refers to movement of food
through the GI tract.
|
|
|
|
| umami | A brothy, meaty, savory flavor in
some foods. Monosodium glutamate
enhances this flavor when added to foods.
|
|
|
|
| salivary amylase | A starch-digesting enzyme
produced by salivary glands.
|
|
|
|
| mucus | A thick fluid secreted by many cells
throughout the body. It contains a compound
that has both carbohydrate and protein parts.
It acts as a lubricant and means of protection
for cells.
|
|
|
|
| amylase | Starch-digesting enzyme produced
by the salivary glands and pancreas.
|
|
|
|
| lipase | Fat-digesting enzyme produced by the
salivary glands, stomach, and pancreas.
|
|
|
|
| protease | Protein-digesting enzyme produced
by the stomach, small intestine, and pancreas.
|
|
|
|
| esophagus | A tube in the GI tract that connects
the pharynx with the stomach.
|
|
|
|
| pharynx | The organ of the digestive tract and
respiratory tract located at the back of the
oral and nasal cavities, commonly known as
the throat.
|
|
|
|
| epiglottis | The flap that folds down over the
trachea during swallowing.
|
|
|
|
| bolus | A moistened mass of food that is
swallowed from the oral cavity into the
pharynx.
|
|
|
|
| lower esophageal sphincter | A circular
muscle that constricts the opening of the
esophagus to the stomach. Also called the
gastroesophageal sphincter.
|
|
|
|
| chyme | A mixture of stomach secretions and
partially digested food.
|
|
|
|
| pyloric sphincter | The ring of smooth muscle
between the stomach and the small intestine.
|
|
|
|
| villi (singular, villus) | The fingerlike protrusions
into the small intestine that participate
in digestion and absorption of food.
|
|
|
|
| absorptive cells | A class of cells that line
the villi; these cells participate in nutrient
absorption.
|
|
|
|
| ileocecal sphincter | The ring of smooth
muscle between the end of the small intestine
and the large intestine.
|
|
|
|
| gallbladder | An organ attached to the
underside of the liver; site of bile storage,
concentration, and eventual secretion.
|
|
|
|
| bile | A liver secretion that is stored in the
gallbladder and released through the common
bile duct into the first segment of the small intestine.
It is essential for the absorption of fat.
|
|
|
|
| enterohepatic circulation | A continual
recycling of compounds between the small
intestine and the liver; bile acids are one
example of a recycled compound.
|
|
|
|
| ulcer | Erosion of the tissue lining, usually in
the stomach or the upper small intestine. As a
group these are generally referred to as peptic
ulcers.
|
|
|
|
| NSAIDs | Nonsteroidal anti-inflamatory drugs;
includes aspirin, ibuprofen (Advil®), and
naproxen (Alleve®).
|
|
|
|
| histamine | A breakdown product of the
amino acid histidine that stimulates acid
secretion by the stomach and has other
effects on the body, such as contraction of
smooth muscles, increased nasal secretions,
relaxation of blood vessels, and changes in
relaxation of airways.
|
|
|
|
| constipation | A condition characterized by
infrequent bowel movements.
|
|
|
|
| laxative | A medication or other substance
that stimulates evacuation of the intestinal
tract.
|
|
|
|
| urinary system | The body system consisting
of the kidneys, urinary bladder, and the ducts
that carry urine. This system removes waste
products from the circulatory system and regulates
blood acid-base balance, overall chemical
balance, and water balance in the body.
|
|
|
|
| pH | A measure of relative acidity or alkalinity
of a solution. The pH scale is 0 to 14. A pH
below 7 is acidic; a pH above 7 is alkaline.
|
|
|
|
| erythropoietin | A hormone secreted mostly
by the kidneys that enhances red blood cell
synthesis and stimulates red blood cell release
from bone marrow.
|