Glossary (ch. 1-10, 22) Flashcards
abdominal cavity
body cavity located below the diaphragm; contains liver, stomach, pancreas, spleen, kidneys, urinary bladder, intestines, and gonads; also called the abdominopelvic cavity
ABO blood group:
red-blood-cell antigen group consisting of antigens A and B
abscisic acid
hormone that signals plant tissues to remain dormant; also called ABA
abscission layer
special cell layer that forms to cut a leaf or fruit from a stem
absorption
movement of water, digested food, and other dissolved substances from the small intestine into the bloodstream
accommodation
increase in the curvature of the eye’s lens to focus on nearby objects
achene
simple fruit consisting of a seed and a shell, much thinner than the shell of a nut
action potential
brief pulse of positive charge that travels down the axon of a neuron that has been triggered to fire
active transport
movement of molecules across the cell membrane from a place of lower concentration to a place of higher concentration with the expenditure of energy
acute confusion
disturbance of the brain caused by physical illness elsewhere in the body
adipose cell
fat cell
adventitious root
root that grows from an unexpected region of a plant
agar
gelling agent, derived from red algae, used as a culture medium for growing bacteria in the laboratory
agent dispersal
seed dispersal in which an outside agent carries the seeds
aggregate fruit
fruit that forms from a flower that has several pistils
albumin
blood protein that helps regulate the water content of the blood
alga
member of the group containing the smallest green, chlorophyll-containing organisms
algin
gummy substance derived from kelp and used to hold liquids in an emulsion
alimentary canal
tube leading from the mouth to the anus that forms the main portion of the digestive system
all-or-none principle
principle stating that when a muscle fiber is stimulated to contract it does so completely and then relaxes completely
alternate
leaf pattern in which only one leaf grows from each node in an alternating pattern up the branch
alternation of generations
life cycle, found in ferns, mosses, and some other plants, that involves both asexual and sexual production in alternating generations
alveolus
one of the microscopic air sacs of the lungs in which gas exchange takes place; plural ‘alveoli’
Alzheimer’s disease
disease similar to dementia but much more severe and sometimes occuring much earlier in life
amino acids
group of about 20 types of simple molecules that combine to produce proteins
amnesia
memory loss
anemia
disorder resulting from too little oxygen being transported to body cells
angiosperm
plant with flowers that produce seeds covered by fruit
Animalia
animal kingdom; consists of multicellular eukaryotes without cell walls
annual
plant that develops from a seed and produces new seeds in a single growing season
annual growth ring
distinct layer in the xylem of a woody stem formed by annual variation in the rate of secondary growth
anther
enlarged pollen-producing structure at the tip of a stamen
anthocyanin
pigment in leaves that produces bright red, blue, and purple colors
Anthophyta
phylum consisting of angiosperms
antigen
carbohydrate molecule on the surface of a cell that functions as an identification unit
antioxidant
substance that neutralizes harmful free radicals
anus
valve that closes the rectum and serves as the digestive tract’s second opening to the exterior
aorta
the body’s largest artery, from which all other systemic arteries branch
aortic semilunar valve
heart valve that allows blood to exit the left ventricle and enter the aorta
apoptosis
process through which a cell can trigger its own death when it is no longer needed or no longer able to survive; also called programmed cell death
appendictis
condition caused by infection of the vermiform appendix
appendicular skeleton
division of the skeletal system that includes the shoulders, hips, and appendages
appendix
small, fingerlike structure attached to the cecum
aqueous humor
clear fluid in the eye that fills the space between the cornea and the iris and lens
Archaebacteria
kingdom consisting of prokaryotes that do not contain peptidoglycan in their cell walls
arteriole
small blood vessel connecting an artery to capillaries
arteriosclerotic dementia
dementia caused by death of brain cells due to blockage in the arteries
artery
thick-walled blood vessel that transports blood away from the heart
arthritis
inflammation of the joints
astigmatism
focusing problem in which the light rays entering the eye are bent incorrectly, usually caused by an incorrectly curved cornea
atherosclerosis
form of arteriosclerosis in which a buildup of plaque and scar tissue narrow the inside of an artery
ATP
special phosphorus compound that serves as the energy carrier of the cell; short for adenosine triphosphate
ATP synthase
molecular machine that generates ATP using power provided by the flow of hydrogen ions
atrium
either of the two thin-walled upper chambers of the heart; plural ‘atria’
atrophy
muscle degeneration
auditory nerve
nerve connecting the hairlike nerve cells of the cochlea to the brain
autonomic nervous system
portion of the peripheral nervous system that controls the heart and other internal organs
autotroph
organism that makes its own food using an inorganic energy source; also called a producer
auxin
any of a group of plant growth hormones that are involved in many tropisms, cause the apical stem to remain dominant, and stimulate root growth and fruit formation
A-V valve
either of the two heart valves that allow blood to flow from an atrium into a ventricle
axial skeleton
division of the skeletal system that includes the head, spine, and rib cage
axon
long extension of a neuron that relays nerve impulses from the cell body to other neurons
ball-and-socket joint
joint in which the rounded head of a bone fits into a hollow socket in another bone, allowing the bone to move in two planes and rotate in place
bark
outer section of a woody stem, which provides protection and helps transport food
basidium
microscopic, club-shaped, spore-producing structure of a club fungus; plural ‘basidia’
behaviorism
philosophy that the behavior of a person is determined by his environment, not his mind
berry
simple fruit in which the entire ovary is freshy and juicy throughout
biceps brachii
muscle on the front of the upper arm that bends the forearm; also called ‘biceps’
bicupsid
any of the four light-grinding teeth next to the cupsids (one pair on each side) on each jaw; also called ‘premolar’
bicupsid valve
heart valve connecting the left atrium and left ventricle; also called ‘mitral valve’
biennial
plant that lives through two growing seasons to complete its life cycle
bile
greenish substance secreted from the liver that helps in the digestion of fats
bile salts
group of substances in bile that emulsify fats
binomial nomenclature
system of assigning scientific names to organisms by using two words (genus and species) for each scientific name
biology
study of living things
blade
flat, green portion of a leaf
blind spot
spot on the retina where the optic nerve exits the eye and there are no light-sensitive cells
blood
thick fluid that transports gases, nutrients, and wastes as part of the circulatory system
blood pressure
force that blood exerts upon the walls of the blood vessels
blood-brain barrier
system of tightly sealed capillary walls that prevents bacteria, viruses, and harmful molecules from entering the brain and spinal cord
bolus
small ball into which food is formed by the tongue
bone conduction
transmission of vibrations (caused by speech, etc.) from the jawbone to the inner ear
botany
study of plants
botulism
severe food poisoning caused by the bacterium Clostridium botulinum
bract
special leaf that looks like a flower petal
brain
principal organ of the nervous system; the chief organ of the mind
brain stem
portion of the brain that connects the rest of the brain to spinal cord; includes three regions responsible for most automatic body functions
bran
shell-like fruit covering of a wheat kernel
broadleaf tree
tree that has broad, flat leaves
bronchial asthma
allergic condition characterized by spasms of the bronchial tube muscles
bronchial tube
a bronchus or any of its branches
bronchiole
small tube, branching from a secondary bronchus, that ends in alveoli
bronchitis
inflammation of the lining of the bronchial tubes
bronchus
either of the two tubes into which the trachea divides, one going to each lunch; plural ‘bronchi’
bryophyte
spore-bearing novascular plant
bud
part of a stem that allows it to grow in length or develop new stems, flowers, or leaves
bud scale
any of the scales that cover a bud in winter to protect it from frost injury and drying out
budding
form of grafting in which the scion is a bud
bud-scale scar
ring that circles a stem, indicating where last year’s growth started
bulb
structure made of a special stem and leaves that stores food underground
bundle scar
marking on a leaf scar that indicates a passage point of vascular tissue from the stem to the leaf petiole
Calorie
unit used to measure the energy content of food; equal to the amount of energy needed to raise the temperature of one kilogram (or one liter) of water by one degree Celsius
calyx
collective term for a flower’s sepals
cambium
internal layer of meristematic tissue that enables stems and roots to grow in diameter
capillarity
upward movement of liquids through a very narrow tube due to differences in adhesion and cohesion; also called capillary action
capillary
microscopic blood vessel, linking an artery and vein, in which the exchanges between body cells and blood take place
capsule
spore case of a moss plant
carbohydrate
organic compound consisting of the elements carbon, hydrogen, and oxygen in about a 1:2:1 ratio
cardiac conduction system
system of special cardiac muscle fibers that generate electrical impulses and distribute them to all parts of the heart
cardiac muscle
self-stimulating striated cardiac tissue found in the heart
cardiac veins
system of veins that collect blood from the heart tissues and carry it to the right atrium
cardiologist
doctor specializing in the heart and its disorders
cardiovascular system
another name for the circulatory system
carotene
pigment in leaves that produces yellowish-orange colors
carpal
any of the eight bones of the wrist
carrageenan
gelatinous substance that comes from the alga Irish moss and is used in many food products
cartilage
tough, rubbery connective tissue that cushions the joints between bones
catalyst
substance that speeds up a chemical change but is not consumed in the process
catkin
long, tassel-like cluster formed by the flowers of some trees
cecum
pouch in the large intestine at the junction with the small intestine
cell
basic unit of structure and function of living things
cell biology
another name for cytology, the study of cells
cell body
central portion of neuron, which contains the nucleus and most of the cytoplasm
cell cycle
life cycle of a cell
cell membrane
thin, flexible barrier that surrounds a cell, separates it from its environment, and regulates what enters and leaves the cell; also called plasma membrane
cell theory
idea that all living things are composed of living units called cells and of cell products and that all cells come only from preexisting cells
cell wall
rigid, boxlike structure outside the cell membrane of a plant cell that stiffens, supports, and protects the cell
cellular respiration
process through which a cell breaks down chemical substances such as sugars and combines them with oxygen (oxidizes them) to release energy; also called aerobic respiration
cellulase
enzyme that weakens the cell walls of the abscission layer
cellulose
complex carbohydrate that forms the cell wall of plants and is a form of insoluble fiber
cementum
bonelike substance that fastens the root of a tooth to the jaw
central nervous system
portion of the nervous system that consists of the brain and spinal cord
centrosome
microtubule-organizing center of a human or animal cell
cereal
any of the types of grass used by man for food; the grain of such a plant
cerebellum
portion of the brain that coordinates skeletal muscle activity
cerebral cortex
outer layer of the cerebrum, which contains much of the brain’s gray matter
cerebral palsy
damage to the cerebral motor area, resulting in reduced motor abilities without affecting intelligence
cerebrospinal fluid
clear fluid that circulates through the fibers of the arachnoid mater
cerebrum
portion of the brain responsible for consciousness, memory, voluntary actions, thinking, and intelligence
cervical
of or related to the neck
cervical vertebra
any of the seven vertebrae of the neck
chaff
husk of a wheat kernel
chamber
any of the four internal hollow spaces of the heart
cheese mold
any of the molds used to make some types of cheese
chemical sense
any of the senses that result from chemical stimuli
chemoreceptor
receptor for a chemical sense
chlorophyll
green pigment of plants that enables them to capture the energy of light
chloroplast
organelle, found in the cells of green plants, that is a tiny chemical “factory” that uses light to manufacture food
cholesterol
lipid used by the body to make bile, vitamin D, and important hormones and used in cell membranes
choroid
layer of tissue within the uvea that provides most of the cell’s nourishment
chromosome
individual DNA molecule within a cell
chyme
thick liquid formed in the stomach, consisting of digestive juices and partially digested food
ciliary body
muscular structure near the front of the uvea that adjusts the lens of the eye to focus at varying distances
cilium
tiny hairlike projection extending from the cell membrane of some cells
circulatory shock
potentially lethal condition in which the body’s blood pressure falls to a critical low
circulatory system
body system that brings food, water, and oxygen to the cells and carries away carbon dioxide and waste products; also called cardiovascular system
cirrhosis
buildup of fatty deposits and fibrous tissue in the liver
class
level of taxonomy between phylum and order
clavicle
collarbone
club fungi
group of fungi that produce spores in club-shaped basidia
club moss
creeping vascular plant that has an erect stem and bears spores in club-shaped, cone-like structures; also called ground pine
coccyx
bone, consisting of four separate vertebrae that are fused in adults, that is an attachment for muscles involved in standing and the elimination of wastes; also called tailbone
cochlea
coiled tube in the inner ear that detects vibrations and sends them to the brain
coenzyme
molecule that assists a cell’s enzymes in performing their jobs
collagen
tough, resilient protein fiber that reinforces bone and, with elastin, gives skin its strechability and elasticity
colon
long, tubular section of the large intestine that absorbs water from undigested food
colony
group of single-celled algae clumped together and living as a group
colorblind
unable to distinguish one or more of the primary colors of light
coma
prolongued unconscious state that may not be reversible
common bile duct
duct through which bile enters the small intestine from the gallbladder
common cold
most common respiratory disease, caused by any of over a hundred different types of viruses
compact bone
strong, dense tissue composing the outer layer of a bone
complete flower
flower that has all four basic flower parts (sepals, petals, stamens, and pistils)
complex carbohydrate
carbohydrate formed from a long chain of simple carbohydrates; also called polysaccharide
compound fracture
fracture in which the broken bone pierces through the skin; also called open fracture
compound leaf
leaf that has more than one blade on every petiole
concussion
period of paralysis of the central nervous system accompanied by a short period of unconsciousness
cone
type of cell in the retina that detects colors
conifer
cone-bearing gymnosperm
connective tissue
any of the tissues that connect parts of the body
constipation
condition that occurs when feces are so dry that defecation is difficult
cork
plant structural tissue that forms the bark of woody plants
cork cambium
cambium tissue that produces a new cork tissue
corm
swollen stem that stores food underground; distinguished from a bulb by a thicker stem and thinner leaves
corn smut
smut that attacks the tassels and ears of corn plants, forming large, shiny blisters
cornea
transparent structure that replaces the sclera at the front of the eye
corolla
collective term for a flower’s petals
coronary arteries
two arteries that branch from the base of the aorta to supply blood to the cardiac muscle cells
coronary circulation
portion of systemic circulation in which blood flows to the heart muscle and back to the right atrium
corpus callosum
mass of nerve fibers through which the cerebral hemispheres communicate
cortex
food-storage tissue in a herbaceous stem in which the vascular bundles are embedded; similar tissue in a root or young woody stem
cotyledon
portion of an angiosperm embryo that contains stored food used to supply the energy for sprouting
cranial cavity
body cavity containing the brain
cranial nerve
any of the twelve pairs of nerves that branch directly from the brain stem
cranium
portion of the skull that protects the brain; also called braincase
cross-pollination
pollination in which the pollen from one plant is transferred to another plant
crown
bushy head of a tree OR part of a tooth that is exposed above the gums
cuspid
either of two tearing teeth flanking the incisors on each jaw; also called canine
cutaneous membrane
another term for the skin
cuticle
waxy layer that usually covers the epidermal tissue of a plant’s shoot system
cutting
piece of stem or root that can grow into a new plant; also called a slip
cyanobacteria
group of bacteria that form colonies resembling those of unicellular algae; also called blue-green algae
cyad
palmlike tropical gymnosperm
cystic fibrosis
recessive genetic disease caused by a defect that affects the chlorine gates of lung cell membranes; abbreviated CF
cytokinesis
process in which the cytoplasm of a cell separates to form two separate cells
cytokinin
any of a group of plant growth hormones that promote cell division and stimulate lateral buds to grow into new shoots
cytology
study of cells; also called cell biology
cytoplasm
jellylike fluid medium of the cell, containing organelles and numerous dissolved chemicals
cytoskeleton
intricate internal skeleton that helps a cell maintain its shape
deciduous
describes a tree that loses its leaves each fall
deltoid
muscle that forms the curve of the shoulder; lifts the upper arm away from the body
dendrite
short, branched extension of a nerve cell that receives nerve impulses from other neurons and conducts them toward the cell body
denitrifying bacteria
bacteria in the soil that convert unused nitrates back into atmospheric nitrogen
dental caries
disease in which acid attacks the teeth, penetrating the enamel and dentin; also called tooth decay and cavities
dentin
bonelike layer that surrounds the pulp of a tooth
depressant
substance that slows the central nervous system
desmid
any of a large group of unicellular freshwater green algae characterized by a beltlike constriction that divides cells into two identical semicells
diaphragm
thick sheet of muscle that separates the thoracic cavity from the abdominal cavity
diaphysis
shaft of a long bone
diarrhea
condition that occurs when insufficient water is removed from feces, resulting in soft and watery feces and frequent defecation
diastole
relaxing and filling phase of heart action
diatom
any of a group of yellow algae characterized by rigid cell walls composed of silica
diatomaceous earth
substance formed from packed layers of diatom shells; also called diatomite
dicot
plant with two cotyledons per seed; typically characterized by flower petals that are arranged in groups of four or five, leaves that are usually broad and flat with branching venation, and a taproot system
dietary fiber
group of complex carbohydrates that are not digested or incorporated into the body
diffusion
process of mixing molecules of one substance through another by random molecular motion
digestion
process that changes food substances with large, complex chemical molecules into substances with smaller, less complex molecules
digestive enzyme
any of the enzymes involved in digestion
digestive gland
secreting body that produces digestive enzymes and digestive juices
digestive system
body system that breaks down food into a form that can be absorbed by the bloodstream
dinoflagellate
unicellular aquatic alga that has two unlike flagella used for locomotion
dioecious
having staminate and pistillate flowers borne by separate plants
disk flower
one of the flowers in the center of a composite flower head
dislocation
injury in which a joint is overstressed to the extent that a bone pops out of alignment
DNA
chemical, found in the nucleus, that stores the genetic information needed for cellular function; short for deoxyribonucleic acid.
dormancy
period of inactivity, which helps prevent seeds from sprouting when conditions are unfavorable for the growth of young plants
drupe
simple fruit that has an outer fleshy layer and an inner woody layer
dry fruit
fruit that has a dry ovary
duodenum
first and shortest section of the small intestine
dysentery
painful infection of the colon that causes severe diarrhea and cramps accompanied by blood in the feces
dyspepsia
gastric indigestion
eardrum
membrane stretched across the ear canal that vibrates in response to sound waves
edema
condition in which the body tissues absorb extra fluids and cannot maintain proper water balance
egg cell
female reproductive cell
electrocardiogram
medical procedure in which the tiny electrical currents in the heart are detected by electrodes taped to the patient’s skin; abbreviated EKG or ECG
ellipsoid joint
joint that consists of a bone with a convex surface that fits into a concave portion of another bone and that allows movement in two planes but does not permit rotation; also called condyloid joint
embryo
living part within a seed that develops into a new plant
emphysema
progressive deterioration of the alveoli caused by malfunctioning enzymes
emulsification
process of breaking large droplets into smaller droplets
enamel
mineral substance that covers the crown of a tooth
endocardium
inner layer of the heart, which provides a smooth coating for the heart’s interior
endocrine gland
any of the glands within the endocrine system, which secrete hormones into the bloodstream
endocrine system
body system containing hormone-producing glands
endocytosis
process by which a cell takes in large substances
endoplasmic reticulum
network of interconnected sacs and tubules that is connected to the nucleus and extends through much of the cell; abbreviated ER
endosperm
part of a seed that provides nutrition to the growing embryo, such as the starchy part of a wheat kernel
enzyme
large protein molecule that is a catalyst to carry out chemical reactions
epicardium
layer of slippery tissue covering the outside of the heart to allow the heart to move easily within the pericardial sac
epidermal tissue
plant structural tissue that protects and covers leaves, roots, stems, and other exposed areas and prevents excessive water loss and injury by outside agents
epidermis
outer layer that provides covering and protection to plant structures
OR
outermost layer of the skin
epiglottis
small flap of cartilage in the pharynx that closes the top of the trachea during swallowing
epilepsy
disorder in which neurons malfunction and begin to fire together over and over, disrupting ordinary cerebral processing and causing unconsciousness
epiphysis
bulged end of a long bone
epithelial tissue
any of the tissues that line body parts, cover and protect organs, regulate temperature, and regulate what enters and exits organs
ER
abbreviation for endoplasmic reticulum
ER lumen
internal cavity of the edoplasmic reticulum
erector spinae
muscle that extends along the spinal column from the upper back to the pelvis; straightens the back
esophagus
foot-long muscular tube connecting the pharynx to the stomach
ethylene
hydrocarbon that functions as a plant hormone to signal leaf abscission and to trigger green fruits to ripen
Eubacteria
bacteria kingdom; consists of prokaryotes with cell walls made of peptidoglycan
eukaryote
organism that has a membrane-bound nucleus and membrane-enclosed organelles
eustachian tube
tube connecting the throat to the middle ear
evergreen
describes a tree that retains its leaves throughout the winter
excretory system
body system that excretes waste materials from the body
exhalation
process in breathing in which air rushes from the lungs due to increased pressure
exocytosis
process by which waste products are eliminated from the cytoplasm
external oblique
muscle that connects the ribs to the pelvis but more to the side than does the rectus abdominis
external respiration
process of breathing
extracellular fluid
fluid that surrounds the body’s cells
extrinsic muscles
set of six muscles that move the eye
eye (in plants)
node consisting of buds and small leaves, found on a tuber
eyelid
protective skin structure that blinks to keep foreign objects from entering the eye and cleans and moistens the eyeball
facial skeleton
bones that are the framework fo the face and jaw
family
level of classification between order and genus
farsightedness
the ability to see distant objects better than near objects due to the eye being too short or the lens being too flat; also called hyperopia
fascia
tough, translucent sheath encasing a muscle; also called epimysium
fat
molecule consisting of three fatty acid molecules attached to a single glycerol molecule; also called triglyceride
fat-soluble vitamin
any of the vitamins that are insoluble in water and can accumulate in the body if ingested in excess
fatty acid
simplest type of lipid molecule, made of carbon and oxygen atoms attached to a long chain of carbon and hydrogen atoms
feces
undigested waste materials from the digestive process
feedback mechanism
body mechanism that helps maintain homeostatis by directing changes in the body and directing the body to respond appropriately
femur
thigh bone
fermentation
process by which cells produce ATP when the oxygen required for cellular respiration is not available; also called anaerobic respiration
fern
nonflowering vascular plant with spore-bearing leaves and horizontal underground stems
fertilization
process in which a sperm cell fuses with an egg cell to form a new organism
fibrinogen
blood protein that helps in blood clotting
fibrous root
type of root system in which the primary root remains small and many slender secondary roots grow from it in all directions
fibula
thin bone of the lower leg
filament
slender, elongated part of a stamen
OR
hairlike structure formed by green algae that join end to end, forming a long chain of cells
flagellum
whiplike tail that extends from a cell and is used for propulsion; plural flagella
flat bone
bone that has a flattened shape
fleshy fruit
fruit that has a fleshy ovary
fleshy root
taproot that enlarges to store large quantities of food
flower
reproductive structure of an angiosperm
fontanel
tough connective-tissue membrane connecting the bones of an infant’s cranium
food poisoning
gastrointestinal disease caused by consumption of food contaminated with bacteria or bacterial toxins
forage grass
any of the types of grass used to feed livestock
fovea
small depression on the retina where the light-sensitive cells are most densely packed
fracture
crack or break in a bone
freely movable joint
type of joint that allows a wide range of motion; also called synovial joint
frond
fern leaf
frontal lobe
lobe of the cerebrum corresponding to the frontal bone; associated with personality, judgement, and self-control; includes motor area
fruit
ripened ovary of a flower
fruiting body
umbrella-shaped reproductive structure formed by mushrooms; similar reproductive structure formed by another club fungus
Fungi
fungus kingdom; consists of multicellular eukaryotes that have cell walls and do not conduct photosynthesis
gallbladder
saclike organ that stores bile
gamete
reproductive cell (sperm cell or egg cell)
gametophyte
sexually reproducing generation in alteration of generations
ganglion
mass of neuron cell bodies; plural ganglia
gastric juice
digestive juice formed by the secretions of the stomach
gastrocnemius
muscle that forms the bulge on the upper calf; extends the foot downward
genus
level of classification between family and species; plural genera
geotropism
growth of a plant in response to gravity
germ
embryo of a wheat kernel
germination
process in which a seed sprouts
gibberellin
any of a group of plant growth hormones that help regulate normal plant growth and trigger germination of dormant seeds
gill
basidia-containing “spoke” on the underside of a mushroom cap
gingivitis
periodontal disease in which the gums become tender and inflamed due to accumulation of plaque and tartar
ginkgo
unique oriental gymnosperm with fan-shaped leaves; also called maidenhair tree
glaucoma
condition in which the pressure of the fluid inside the eye becomes much higher than normal, causing permanent damage to the retina
glial cell
cell that helps support and insulate nerve tissue
gliding joint
joint in which one bone merely slides across the surface of another
globulin
any of a broad group of blood proteins that help transport fat throughout the body and fight infections
glucagon
pancreatic hormone that signals the liver to convert glycogen to glucose and release the glucose into the bloodstream
glucose
simple sugar produced by photosynthesis (C_6H_12O_6)
gluteus maximus
muscle that pulls the upper leg downward
Golgi apparatus
organelle that serves as a shipping center of a cell
gonad
reproductive organ of a human or animal that produces gametes
grafting
process of transplanting living tissue from one plant to another
OR
light and dark streaks in wood formed by differences in the size of springwood and summerwood vessels
grain
fruit of a grass plant
graminoid
general term for a member of the grass family
gray matter
portion of the brain and spinal cord that consists largely of neuron cell bodies
guard cell
either of a pair of crescent-shaped cells that expand and contract to open and close a stoma
gulfweed
common name for the brown algae of the genus Sargassum
gymnosperm
plant that does not produce flowers but does produce seeds
habitat
region where a particular organism normally lives; the organism’s environment or home
hamstrings
group of three muscles in the back of the thigh that bend the leg at the knee
hardwood
another term for a broadleaf tree
head
flower cluster of a member of the composite family, which superficially resembles a single flower
heart
pump that propels blood through the circulatory system
heart attack
type of heart failure caused by a blockage of blood flow to the heart muscle
heart murmur
abnormal rushing or blowing heart sound produced by valve damage
heartbeat
“lub-dup” sounds produced by the heart during the cardiac cycle
heartwood
inner portion of a woody stem, made of older xylem tubes that have become clogged and been sealed off
hemisphere
right or left half of the cerebrum or cerebellum
hemoglobin
iron-containing blood protein, found in red blood cells, that carries oxygen in the blood
hemophilia
recessive sex-linked disease in which clots cannot form due to a hereditary defect in any of several blood-clotting proteins
herb
herbaceous plant
herbaceous
nonwoody
heteroecious
refers to a parasite that must have two hosts to complete its life cycle
heterotroph
organism that cannot produce its own food and must obtain energy from organic sources; also called a consumer
hinge joint
joint that allows a bone to move back and forth in a single plane
holdfast
special type of anchoring cell found in certain types of algae
homeostasis
condition of having and maintaining a stable internal environment, as in an individual cell or in the body as a whole
hormone
chemical produced by humans, plants, or animals to control or stimulate specific processes and regulate body activities; produced by the endocrine glands in humans and animals
horsetail
spore-producing vascular plant with unique hollow, jointed stems and very small leaves
horticulturist
agricultural technician who specializes in growing flowers, fruits, vegetables, and shrubs
human anatomy and physiology
study of the physical structure and function of the human body
humerus
upper-arm bone
husk
outer layer of a wheat kernel; also called chaff
hybrid
organism resulting from a cross between two different species of teh same kind of plant or animal
hydrochloric acid
component of gastric juice that softens food, kills bacteria, reacts with certain minerals to make them soluble, and provides the acid medium required for the enzyme pepsin
hydrogenated oil
vegetable oil with hydrogen added to change it from liquid to solid or semisolid
immune system
body system that defends against bacteria, viruses, and other invaders
hydroxyapaptite
rigid mineral that gives bones its hardness [Ca_10(PO_4)(OH)_2]
impacted
describes a tooth (usually a wisdom tooth) that has erupted too close to the adjacent tooth and become stuck
hyoid bone
U-shaped bone that is the foundation of many of the tongue muscles and of certain muscles involved in swallowing
incisor
any of the four front cutting teeth on each jaw
hypertension
condition in which resting blood pressure exceeds either 140 mmHg sytolic or 90 mmHg diastolic; also called high blood pressure
incomplete flower
flower that lacks one or more of the four basic flower parts
hypertrophy
enlargement of muscles through use
hyphae
threadlike filaments that form the body of a fungus
hypothalamus
portion of the limbic system that controls the autonomic nervous system and endocrine system and is responsible for the physical effect of emotions
incus
second bone of the middle ear; also called anvil
ileum
third and longest section of the small intestine
inferior vena cava
vein that returns blood from the lower part of the body to the heart
inflorescence
flower cluster
influenza
viral respiratory disease that causes fever, aching muscles, headache, and chest pain
inhalation
process in breathing in which air rushes into the lungs due to decreased pressure
inner ear
portion of the ear that is the actual organ of hearing
insectivorous plant
plant that uses special leaves to trap and digest small insects
insulin
pancreatic hormone that signals the liver and muscles to remove glucose from the blood and store it as glycogen
intercostal muscles
gruop of muscles located between the ribs; lift the rib cage to aid breathing
internal respiration
exchange of oxygen and carbon dioxide between blood cells and tissue cells
interneuron
neuron that relays signals between neurons or groups of neurons and is involved in information processing
internode
portion of a stem between nodes
interphase
stage of the cell cycle between cell divisions
interstitial fluid
fluid that fills the area around and between tissues
intervertebral disk
disk of flexible cartilage between vertebrae
intestinal glands
digestive glands in the small intestine that produce intestinal juice
intracellular fluid
fluid inside the body’s cells
involuntary muscles
cardiac and smooth muscles
iris
front-most muscular portion of the uvea, which forms the colored portion of the eye and controls the size of the pupil
irregular bone
bone that cannot be easily classified as a long bone, short bone, or flat bone
jejunum
middle section of the small intestine
joint
place where bones join
kelp
any of the group containing the largest brown algae
kilocalorie
unit of energy sometimes used in physics, equal to one food Calorie
kind
group of similar organisms that are all descended from a single group of originally created organisms
kingdom
one of the main groups into which all organisms are divided in the Linnaean system of classification
lacrimal gland
tear gland
lacteal
tubelike lymph vessel that carries absorbed fats out of a villus
large intestine
tubelike organ that prepares undigested food for expulsion from the body
laryngeal muscles
muscles in the larynx that move the vocal cords
larynx
special enlargement of the trachea in which speech originates; also called voice box
lateral bud
bud that allows growth of a new stem from the side of the main stem; also called axillary bud
lateral root
root that originates from the taproot; also called secondary root
latissimus dorsi
muscle that connects the humerus to the lumbar region of the spine and pulls the arms to the rear
layering
method of vegetative propagation that involves causing an existing plant to generate adventitious roots at a node
leaf hair
one of the hairlike structures that cover the epidermis of certain plant leaves
leaf scar
scar left on a stem where a leaf was previously attached
leaflet
one of the small blades of a compound leaf
legume
plant of the pea family; a simple fruit consisting of a pod enclosing several seeds, which is characteristic of members of this family
lens
portion of the eye that focuses the rays of light
lenticel
opening in the bark of a stem that allows air to enter the stem
leukemia
form of cancer in which white blood cells are produced in uncontrolled numbers
lichen
single unit formed by a fungus and an alga living in close relationship
ligament
tissue that joins bones to other bones
limbic system
collective term for the brain structures, clustered around the brain stem, that coordinate the activity of the parts of the brain and seem to be involved in emotions
Linnaeus, Carolus
Swedish naturalist who devised the modern system of biological classification
lipid
any of a group of macronutrient compounds that are characterized by their insolubility in water
liver
large abdominal organ that functions as the body’s chemical factory; produces bile; filters blood; and stores glycogen, vitamins, minerals, and reserve blood
liverwort
bryophyte that grows along the surface of the soil and often looks like tiny leaves
lobe
any of the main regions into which the hemispheres of the cerebrum are divided
long bone
bone longer than it is wide
lumbar
of or related to the lower back
lumbar vertebra
any of the five vertebrae of the lower back
lung
either of the two large, spongy organs that are the primary organs of the respiratory system
lysosome
special type of vesicle that functions as a recycling center
lysozyme
enzyme, found in tears, that kills bacteria by destroying their cell walls
macronutrient
any of the group of nutrients, consisting of carbohydrates, proteins, and fats, that are needed in relatively large amounts
malleus
first bone of the middle ear; also called hammer
margin
edge of a leaf blade
masseter
muscle that, with the temporalis, connects the mandible to the cranium and helps close the jaw
mastication
chewing
matrix
material surrounding cells in a tissue
maturation region
region of a root where cells organize into the vascular cylinder
mechanical dispersal
seed dispersal in which fruits scatter their seeds by bursting open and catapulting the seeds to a new location
mechanoreceptor
any of a group of sensory receptors responsible for sensations of touch and pressure and for muscle sense
medulla oblongata
lowest part of the brain stem; monitors and regulats various vital body functions
medullary cavity
cavity in the diaphysis of a long bone that stores red marrow (in infants and children) or yellow marrow (in adults); also called marrow cavity
membrane skeleton
network of flexible reinforcement fibers found beneath a cell membrane
meninges
triple layer of protective tissues surrounding the brain and spinal cord
meningitis
inflammation and swelling inside the skull, usually caused by an infection
meristematic region
region near the tip of a root where cell division takes place
meristematic tissue
plant tissue responsible for the growth and repair of plants
mesophyll
middle portion of a leaf, where most of the photosynthesis takes place
metabolism
general term for the chemical processes of life
metacarpal
any of the five bones that form the base of the hand and the palm
metaphase
second phase of mitosis, in which the spindle apparatus attaches to the replicated chromosomes and pulls them to the equatorial plane of the cell
metatarsal
any of the five bones that form the framework of the instep and the ball of the foot
micronutrient
any of the group of nutrients, consisting of vitamins and minerals, that are needed in relatively small amounts
microtubule
hollow, rodlike filament composed of tubulin
microvilli
fine extensions of the cell membrane on epithelial cells of the small intestine
midbrain
region of the brain stem above the pons; helps coordinate eye movements, adjust pupil size, and operate the lens muscles
middle ear
chamber containing the malleus, incus, and stapes
midrib
large vein running down the center of a leaf blade; major vein of a leaf with pinnate venation
mineral
inorganic nutrient
mint family
family of plants that has square stems and whose members are often very aromatic
mitochondrion
organelle that serves as the power plant of a cell; plural mitochondria
mixed nerve
nerve that includes both sensory and motor fibers
molar
any of the six heavy grinding teeth (three to a side) at the back of each jaw
monocot
plant with only one cotyledon per seed; typically characterized by flower petals that are arranged in groups of three, leaves that are usually long and narrow with parallel venation, and a fibrous root system
monoecious
having staminate and pistillate flowers produced by the same plant
moss
nonvascular spore plant that undergoes alternation of generations
motor area
portion of the frontal lobe that controls voluntary movement of skeletal muscles
motor nerve fiber
axon that carries impulses from the brain and spinal cord to muscles and organs
motor neuron
neuron that relays signals from the central nervous system to the other parts of the body
motor unit
motor neuron and the group of muscle cells it controls
mucous membrane
type of membrane that lines openings to the outside
mucus
slimy substance that lubricates the mucous membrane of the oral cavity
multiple fruit
fruit that forms from several flowers
multiple sclerosis
disease that occurs when the body’s immune system attacks the glial cells that provide myelin sheaths for central-nervous-system axons
muscle fiber
individual muscle cell of a skeletal muscle
muscle sense
the brain’s total awareness of body movements
muscle tissue
tissue that moves the body and its parts
muscular system
body system that functions together with the skeletal and nervous systems to make body movements possible
mushroom
club fungus that consists of a mass of subterranean hyphae and, at reproduction, produces an umbrella-shaped fruiting body
mycelium
mass of hyphae forming the main body of a fungus
myelin
white, specialized covering found on axons of nerve cells
myocardium
middle layer of the heart, containing the actual heart muscle tissue
myofibril
long cylinder inside a muscle fiber that contains the contraction machinery
nasal cavity
cavity inside the nose that warms, moistens, and filters air
nasal meatus
irregularly shaped pocket in the nasal cavity
nearsightedness
ability to see only near objects clearly due to the lens being too thick or the eye being too long; also called myopia
neck (oral cavity)
part of a tooth at the gum line
nectar
sweet-tasting, watery liquid produced by plants
nerve
bundle of nerve fibers (axons) branching from the brain and spinal cord
nerve center
group of nerve cell bodies in the brain or spinal cord
nerve tissue
tissue that cotnrols organs and coordinates their functions
nervous system
body system that coordinates the activities of the body
neuritis
degeneration and inflammation of nerves
neurobiologist
biologist who studies the nervous system
neurologist
physician who specializes in disorders of the nervous system
neuromuscular junction
point at which a neuron connects to a muscle cell
neuron
nerve cell
neurotransmitter
chemical released into a synapse by a neuron to cause an action in the receiving cell (e.g. making a muscle contract or a neuron fire)
night blindness
condition in which the eyes do not become adjusted to darkness
nitrate
any of the special compounds of nitrogen and oxygen that plants can use to make proteins
nitrifying bacteria
bacteria that provide nitrates to the soil from decomposing plants and animals
nitrogen cycle
biogeochemical cycle involving the movement of nitrogen from the air, into the soil, and back into the air
nitrogen-fixing bacteria
bacteria that grow on the roots of legumes and convert nitrogen in the air into ammonia and nitrates
node
one of the points at which leaves grow from the stem
nonseed plant
any vascular plant that does not reproduce using seeds
nonvascular plant
any nonseed plant that does not have vascular tissue
nuclear envelope
double-layered structure that separates the nucleus from the rest of the cell
nuclear pore
large protein complex in the nuclear envelope that serve as a gate to regulate the transport of large molecules into and out of the nucleus
nucleolus
distinct region within the nucleus that assembles ribosomes
nucleus
“control center” of a cell, which stores the DNA
nut
simple dry fruit consisting of a seed enclosed in a hard shell
obesity
being severely overweight due to excess body fat
occipital lobe
lobe of the cerebrum corresponding to the occipital bone; associated with vision
oil
fat that is liquid at room temperature
olfactory nerve
nerve connecting the nose’s sensory receptors to the brain
opposite (plants)
leaf pattern in which two leaves grow from each node
optic nerve
nerve that connects the eye to the brain
oral cavity
inside of the mouth
order
level of classification between class and family
organ
structure within a system that has a definite form and performs a definite function or functions for the system
organelle
“little organ” within the cytoplasm of a cell
organism
individual living thing
osmosis
one-way diffusion through a semipermeable membrane
ossification
process by which cartilage is replaced with bone
osteoblast
cell that moves through a Haversian canal, constructing new collagen fibers and hydroxyapatite crystals
osteoclast
cell that continually moves through a bone removing old material
outer ear
portion of the ear consisting of the visible sound-collecting structure and the ear canal
ovary
swollen base of a pistil; contains ovules
ovulate cone
cone that produces seeds; also called seed cone
ovule
one of a plant’s future seeds, which contain the female reproductive cells
pain receptor
any of a group of sensory receptors that consist of a bare dendrite activated by extreme heat or cold, excessive mechanical stress, damage to body cells, etc.
palate
structure that forms the roof of the mouth
palmate venation
leaf venation in which two or more major veins extend outward from one point
pancreas
organ that produces pancreatic juice and contains the islets of Langerhans
pancreatic juice
digestive juice, produced by the pancreas, that contain digestive enzymes needed in the small intestine
papillae
taste-bud-containing projections on the tongue
parallel venation
leaf venation in which the veins are usually parallel to each other along the length of the leaf
paralysis
inability of muscles to move
parasite
organism that lives on or in another living organism and derives its nutrition from that organism
parasympathetic division
portion of the autonomic nervous system that counteracts the sympathetic division
parenchyma
plant structural tissue that makes and stores food
parietal lobe
lobe of the cerebrum corresponding to the parietal bones; analyzes senses to feel temperature, pressure, pain, shape, and texture
Parkinson’s disease
disease characterized by tremors and stiffness of the limbs that appears to result from a lack of dopamine
passive transport
movement of molecules across the cell membrane from a place of higher concentration to a place of lower concentration without the expenditure of energy
patella
kneecap
peat
compressed accumulation of various partially decayed plant materials that collect in swamps and marshes
peat moss
large, branching type of swamp-dwelling moss that helps prevent soil erosion and has antiseptic qualities
pectoral girdle
collective term for the shoulder bones, which attach the arms to the axial skeleton
pectoralis major
largest chest muscle; pulls arms forward
pedicel
special stem on which a flower forms; flower stalk
pelvic bone
either of the two large, heavy bones that attach to the sacrum and form most of the pelvic girdle
pelvic girdle
collective term for the bones that form the hips and attach the legs to the axial skeleton
pelvis
another name for the pelvic girdle
peptic ulcer
ulcer caused by the digestive action of pepsin; includes both gastric and duodenal ulcers
perennial
plant that lives from year to year and blooms each season
pericardium
tough, white sac in which the heart is encased
periodontitis
periodontal disease in which the gums detach from the teeth and eventually the bones supporting the teeth are destroyed
peripheral nervous system
portion of the nervous system that consists of nerves
peristalsis
rhythmic wave of muscular contractions that moves food through the digestive tract
permanent wilting
wilting that occurs when there is a drought and there is not sufficient soil water to replace that lost by transpiration; results in the loss of leaves and possibly the death of the plant
persistence of vision
phenomenom in which an object’s image on the retina persists for about 1/10 second after the object is gone
petal
most conspicuous part of a flower
petiole
part of a leaf that attaches the blade to the stem
phalanx
any of the bones of the fingers and toes; plural phalanges
pharynx
throat
phloem
plant vascular tissue that transports food manufactured in the leaves downward
phospholipid
special type of lipid molecule of which the cell mebrane is composed
photoperiodism
phenomenom in which a plant requires a definite period of light and darkness before it will flower
photosynthesis
process whereby a plant’s chloroplasts capture the radiant energy of light and convert it into the chemical energy of food
phototropism
growth response of a plant to move toward light
phylum
one of the main groups into which a kingdom is divided; also called a division in botany; plural phyla
pinnate venation
leaf venation in which the veins are in a branching pattern characterized by a midrib with smaller veins extending out from it
pinocytosis
form of endocytosis involving the intake of liquids
pistil
elongated, vase-shaped structure of a flower that contains the female reproductive structures
pistillate
describes a female flower, which lacks stamens and bears only pistils
pith
water-storage region at the center of a young woody stem
pivot joint
joint in which one bone rotates in place against another bone
plankton
collective term for microorganisms that float near the surface of the water and provide food for larger organisms
Plantae
plant kingdom; consists of multicellular eukaryotes that have cell walls and usually perform photosynthesis (green plants)
plaque
sticky, colorless film of bacteria that forms on and between teeth
OR
deposit of fatty material and calcium formed on the inside of an artery
plasma
straw-colored liquid part of the blood
platelet
tiny disk-shaped cell fragment that helps patch blood vessels during clotting
pleura
double membrane that provides lubrication between the ribs and the surface of the lungs
pleurisy
inflammation of the pleura
plexus
large mass of ganglia grouped together
plumule
tiny shoot within a seed that will develop into the shoot system
pneumonia
bacterial or viral infection of the linings in the lungs that cause the lungs to secrete large quantities of fluid
poliomyelitis
disease caused by a virus that attacks motor neurons of the spinal cord, paralyzing muscles connected to the brain by these neurons
pollen
plant reproductive structure, produced by the anther of the stamen, that contains the sperm cells
pollen tube
tube formed by a pollen grain through which the sperm cells reach the ovule
pollination
transfer of pollen from an anther to the stigma of a pistil
pome
simple fruit with an outer fleshy layer and an inner papery core
pons
portion of the brain stem that links the cerebrum and cerebellum; assists the medulla oblongata in regulating breathing and helps coordinate some eye movements and facial expressions
portal circulation
portion of systemic circulation in which blood moves from the digestive organs and spleen to the liver
presbyopia
inability to focus on near objects as the lens becomes less elastic with age
primary color
any of the three colors corresponding to those absorbed most strongly by the three different types of cone cells
primary growth
growth of a stem in length
primary odor
any of the seven basic odors of which all other odors are thought to be composed
primary root
root that grows directly from the plant embryo; taproot
prokaryote
organism that does not have a membrane-bound nucleus
prophrase
first stage of mitosis, in which the cell packages the chromosomes, forms the spindle apparatus, and dismantles the nucleolus and nuclear envelope
protein
any of a group of complex organic molecules used to build and maintain living cells; made of a long chain of amino acids
Protista
kingdom consisting of eukaryotes that are not green plants, fungi, or multicellular animals
Protococcus
type of sehprical, unicellular green alga that often grows on the trunks of trees and on unpainted buildings and fenceposts
protoplasm
gel or slime of which cells were thought to consist before modern discoveries of cell complexity
pulmonary artery
either of two blood vessels that carry deoxygenated blood from the heart to the lungs
pulmonary circulation
movement of blood between the heart and the lungs
pulmonary semilunar valve
heart valve that allows blood to exit the right ventricle and enter the pulmonary arteries
pulmonary vein
either of two pairs of blood vessels that carry oxygenated blood from the lungs back to the heart
pulp
inner part of a tooth consisting mainly of blood vessels and nerves
pulse
rhythmic blood-pressure changes in the arteries as the heart beats
pupil
opening through which light enters the eye
pyloric sphincter
muscle structure that opens and closes to control the movement of food from the stomach to the small intestine
quadriceps femoris
group of four muscles in front of the thigh that straighten the leg at the knee
radicle
portion of a plant embryo that develops into the root system
radius
bone of the forearm on the same side as the thumb
Ray, John
17th-century English clergyman and naturalist who introduced a precise concept of species, wrote books on plants, and described how man can learn of God’s power by studying His creation
ray flower
one of the petal-like flowers arranged around the edge of a composite flower head
receptacle
enlarged end of a pedicel, designed to hold the devolping seeds
rectum
section of the large intestine that stores feces until they are expelled from the body
rectus abdominis
group of muscles extending from the bottom of the sternum to the front of the pelvic girdle
red blood cell
blood cell that carries oxygen in hemoglobin molecules; also called erythrocyte
red fiber
muscle fiber that contains many mitochondria and large amounts of myoglobin
red marrow
special tissue, found in bones, that manufactures red blood cells and white blood cells
red tide
phenomenom that occurs when a certain dinoflagellate blooms, producing great quantities of a highly toxic nerve poison
reflex
quick, automatic response
reflex arc
nerve pathway controlling a reflex, which allows nerve impulses to bypass the brain for a speedy response
region of elongation
region in a root where cells increase in length
REM sleep
period of sleep in which the eyes move rapidly as if they were watching the events of a dream
renal circulation
portion of systemic circulation in which blood moves through the kidneys
reproduction system
body system that carries out the process of reproduction and is responsible for the continuation of the human race
respiratory system
body system that takes oxygen into the body and releases carbon dioxide from the body
reticular formation
intricate network of neurons within the brain stem that serves as the “master switch” of the cerebrum
retina
light-sensitive innermost layer of the eye
Rh blood group
red-blood-cell antigen group whose most important member is the Rh factor
Rh factor
most important antigen in the Rh blood group
rhizoid
hairlike thread that acts as a bryophyte “root”
rhizome
thick stem that grows horizontally underground to provide food storage and cause vegetative reproduction, such as the underground stem of a fern
rhodopsin
light-absorbing substance in rod cells
rib
long, curved bone that attaches to the thoracic vertebrae in back and to the sternum in front
ribosome
cell structure that performs translation to manufacture proteins based on mRNA “blueprints” from the nucleus
rickets
childhood disease in which the bones are weak and deformed due to vitamin D deficiency
rind
outer covering of a monocot stem
ripening
process in which a flower ovary grows larger and develops into a fruit
rockweed
brown alga that lives attached to rocks along the seashore and has gas-filled air bladders that serve as floats
rod
type of cell in the retina that detects light of all colors
root
part of a plant that is ordinarily underground, anchoring the plant, and that functions in absorption of nutrients and storage of food
OR
part of a tooth that anchors it below the gum
root cap
cone-shaped structure that covers and protects the tip of a plant root
root cortex
region of a plant root where food is stored
root hair
fingerlike projection of epidermal cells that increases the water-absorbing surface area of a plant root
rosette
leaf pattern in which a cluster of leaves grows around the base of the plant; also called a basal arrangement
rust
any of a group of parasitic club fungi that leave rusty-colored spores on their hosts
sac fungi
group of fungi with saclike spore-producing structures
sacral vertebra
any of the five vertebrae (fused into the sacrum in adults) that are joined rigidly to the hip bones; also called pelvic vertebra
saddle joint
joint in which a saddle-shaped portion of one bone nestles into a saddle-shaped portion of another bone
saliva
sticky digestive juice produced by the salivary glands
salivary amylase
digestive enzyme produced by the salivary glands that begins the digestion of starch
salivary gland
any of the six saliva-secreting digestive glands of the mouth
salmonellosis
common food infection caused by bacteria of the genus Salmonella
samara
fruit consisting of a small dry seed with one or more winglike structures attached to it
sap
sweet liquid found within the vascular tissue of plants
sap stream
upward flow of water and minerals through the xylem
saprophyte
organism that obtains nutrition from dead organisms
sapwood
younger, functioning xylem tissue found in the outer portion of a woody stem
sarcomere
repeated unit within a myofibril, consisting of overlapping protein fibers that give skeletal muscle its striated appearance
sartorius
muscle that extends diagonally downward from the front of the pelvic bone and passes around the side of the thigh to connect it to the tibia; lifts the lower leg and turns it inward
saturated fatty acid
fatty acid in which every possible bond to hydrogen is occupied
scab
fibrin and platelet structure formed by a blood clot on the surface of the skin
scapula
shoulder blade
Schwann cell
type of glial cell that produces layers of myelin sheathing on nerves in the peripheral nervous system
sciatica
condition, characterized by pain in the lower back and the back of the thigh, caused by a pinching of the sciatic nerve
scion
branch that will be grafted onto a stem growing on another tree
sclera
tough outer layer of the eye; the white of the eye
scoliosis
severe lateral curvature of the spine
seaweed
large seawater alga
secondary bronchi
branches into which a bronchus divides after entering the lungs
secondary growth
growth of a stem in width
seed
fully developed and mature ovule that can produce a new plant
seed coat
protective covering of a seed
seed plant
any vascular plant that produces seeds (an angiosperm or gymnosperm)
self-pollination
pollination that occurs within a flower
semicircular canals
assembly of fluid-filled tubes in the inner ear that serve as balance sensors
semilunar valve
either of the two heart valves that allow blood to flow to the body from the ventricles
senile dementia
disorder that results from the slow process of natural nerve cell loss
sense organ
intricately designed organ for a special sense
sensorineural deafness
partial or complete hearing loss caused by repeated or prolongued exposure to excessively loud sounds
sensory nerve fiber
axon that carries sensory impulses to the spinal cord and brain
sensory neuron
neuron that transmits information from the senses to the central nervous system
sensory receptor
specialized neuron that obtains sensory information and relays it to the brain and spinal cord
sepal
leaflike structure attached to the edge of a flower’s receptacle
septum
thick vertical wall dividing the left and right sides of the heart
serous membrane
type of membrane that lines enclosed body cavities that do not open to the exterior
sessile
describes a leaf that lacks a petiole
sexual reproduction
form of reproduction in which genetic material is contributed by two parents through the union of sperm and egg
sheath
bottom portion of a grass leaf, which wraps partially around the stem
shelf fungi
group of shelflike club fungi that grow slowly and do not have gills; also called bracket fungi
shoot system
the part of the plant that is usually found above ground, holding the leaves toward the sun for the manufacturing of food and providing for the production of flowers, fruits, and seeds
short bone
bone that is roughly cube shaped
shrub
plant that has several low, woody stems near the ground and can stand without support
sickle cell anemia
genetic disease that causes hemoglobin molecules to clump together, making red blood cells brittle and sickle shaped under certain conditions
sieve plate
perforated plate at the end of a woody-stem phloem cell
sieve tube
phloem cells connected end to end at the sieve plates to conduct food through a woody plant
silica
hard substance in sand, glass, and diatom cell walls; chemical formula SiO_2
simple carbohydrate
either a monosaccharide or disaccharide
simple fracture
fracture in which the bone cracks or breaks but does not pierce through the skin; also called closed fracture
simple fruit
fruit that forms from a flower that has only one pistil
simple leaf
leaf that has one blade on every petiole
sinoatrial node
portion of the cardiac conduction system that functions as the heart’s pacemaker; also called S-A node
sinus
hollow space within the design of a skull bone
skeletal muscle
any muscle whose primary function is to move the parts of the skeleton
skeletal system
body system that provides support and rigidity and serves as the framework of the body
skull
bones forming the structure of the head
slime mold
jellylike organism that oozes into its environment to engulf bacteria and other particles
small intestine
long, tubular organ that is the primary organ of digestion and absorption
smooth muscle
involuntary muscle tissue used to perform functions such as operating sphincters, adjusting tension in blood-vessel walls, squeezing food through the alimentary canal, and adjusting the focus of the lenses in the eyes
smut
any of a group of parasitic club fungi that produce masses of black spores on their hosts
socket
portion of the skull that protects the eye by surrounding it with heavy bone; also called orbit
sodium bicarbonate
chemical produced by the pancreas to neutralize stomach acid in chyme that enters the small intestine
somatic sense
any of the senses that detect touch, temperature, pain, etc.
sorus
small, brownish dot on the underside of a fern frond that contains spore cases; plural sori
special leaf
leaf that has a special design for a special task; also called a modified leaf
special sense
any of the senses that are provided by neurons in sense organs
species
group of very similar organisms that can interbreed freely in nature; lowest of the seven main levels of the Linnaean classification system
sperm cell
male reproductive cell
Sphagnum
genus of peat moss
spinal cavity
body cavity containing the spinal cord
spinal cord
thick bundle of nerve fibers within the spinal cavity by which the brain communicates with most of the body
spinal nerve
any of the thirty-one pairs of nerves that branch from the spinal cord
spindle apparatus
structure, consisting of centrosomes and microtubules, that pulls chromatids apart during mitosis
spine
special protective leaves that have no chlorophyll
spirelike branching
type of branching in which a tree grows tall and straight with branches coming from a large central stem
spirogyra
filamentous green alga characterized by ribbonlike chloroplasts arranged in a spiral
spleen
hand-sized lymphatic organ that holds a large emergency supply of blood and red blood cells; cleans the blood of microbes; and works with the liver to destroy old, worn-out red blood cells
spongy bone
lightweight, porous tissue composing the interior of a bone’s epiphyses
sporangium
spore case of a fern; plural sporangia
spore
tiny, one-celled reproductive structure that can grow into a distinct or independent organism under the proper conditions
sporophyte
asexually reproducing generation in alternation of generations
sprain
injury that occurs when the ligaments of a joint are overstrained
spreading branching
type of branching in which a tree develops several main branches, usually close to the ground
stamen
pollen-producing organ within a flower
staminate
describes a male plant reproductive structure that produces only pollen, such as a flower that lacks a pistil and has only stamens or a pollen-producing cone
stapes
second bone of the middle ear; also called stirrup
starch
mixture of long, chainlike molecules that consist of thousands of glucose molecules linked together, manufactured by plants for glucose storage
sternocleidomastoid
muscle that connects the temporal bone to the sternum and clavicles; moves head forward and helps turn the head from side to side
sternum
breastbone
stigma
tip of the pistil, which receives pollen grains during pollination
OR
eyespot of certain green algae
stock
tree that receives a new stem by grafting
stolon
creeping special stem that grows above the ground and produces new plants wherever a node touches the soil; common in grass plants; also called a runner
stoma
tiny opening in the surface of a leaf that allows gases to enter and leave the leaf; also called leaf pore; plural stomata
stomach
muscular digestive organ that thoroughly mixes food with digestive juices
stone
inner woody layer of a drupe
striated muscle
muscle tissue that has a striated (striped) appearance under the microscope; skeletal and cardiac muscle tissue
stroke
death of brain tissue caused by internal blockage or rupture of a blood vessel in the brain
structural tissue
type of tissue that composes most of the body of a plant
style
stalklike portion of a pistil, which connects the ovary to the stigma
sucrose
table sugar
sugar
any of a group of small carbohydrates
superior vena cava
vein that returns blood from the upper part of the body to the heart
support and strengthening tissue
plant structural tissue consisting of fibers that run through roots, stems, and large veins of leaves
suture
jagged joint line that connects cranial bones tightly
symbiosis
close relationship between two different species over a period of time, especially one in which they mutually benefit
sympathetic division
portion of the autonomic nervous system that responds to increased activity and emergency situations
synapse
enclosed junction between two neurons or a neuron and another cell
synovial fluid
lubricating fluid inside a freely movable joint
synovial mebrane
type of membrane that lines the joint cavities
system
group of structures designed to function together as a unit to perform a particular job for an organism’s body
systemic circulation
movement of blood through all parts of the body except the lungs
systole
contracting and pumping phase of heart action
taproot
root system in which the primary root grows straight down and remains larger than the secondary roots that branch off from it, penetrating the soil with relatively little branching
tarsal
any of the seven bones of the ankle and heel
tartar
hard deposit on teeth formed by plaque not removed by daily brushing and flossing; medically called calculus
taste bud
organ of taste, consisting of chemoreceptors for different types of taste
taxonomy
process of arranging organisms into group based on similarities
tear
fluid secreted by the lacrimal glands to clean and moisten the eye
telophase
fourth and final stage of mitosis, in which the chromosomes are unpacked and the nuclear envelope and nucleolus reform
temporal lobe
lobe of the cerebrum corresponding to the temporal bones; associated with senses of hearing, taste, and smell
temporalis
muscle that, with the masseter, connects the mandible to the cranium and helps close the jaw
temporary wilting
wilting that occurs when transpiration takes place faster than the roots can absorb soil water; plant recovers at night, when transpiration is reduced
tendon
strong “cable” of fibers that attaches a muscle to a bone
tendril
special leaf or stem that has the unique function of holding a plant upright by coiling around some support structure
terminal bud
bud that allows a stem to grow in length; also called apical bud
tetanus
disease produced by the soil bacterium Clostridium tetani, whose toxin damages motor nerves, resulting in death if untreated; also called lockjaw
thalamus
structure in the limbic system that acts as a switchboard, routing signals to the appropriate area of the cerebral cortex
thermoreceptor
sensory receptor that responds to temperature changes
thoracic
of or related to the chest
thoracic cage
cagelike bone structure in the chest that protects the organs of the thoracic cavity
thoracic cavity
chest cavity, containing the heart, lungs, esophagus, trachea, thymus, and aorta
thoracic vertebra
any of the twelve vertebrae that are the attachments for the thoracic cage
thorn
long, sharp special stem that provides protection to a plant
thylakoid
one of the special chlorophyll-containing disks inside a chloroplast
tibia
main weight-bearing bone in the lower leg; the shin bone
tidal volume
volume of air inhaled and exhaled during normal breathing
tinnitus
ringing in the ears
tissue
group of similar cells that work together to form a particular task for an organ
tissue culturing
method of vegetative propagation in which seedlings are produced from individual plant cells grown in the laboratory
tongue
muscular organ that pushes food between the teeth, mixes it with mucus and saliva, and prepares chewed food for swallowing
tooth
structure in the mouth that cuts, breaks, or crushes food into smaller pieces
trace element
any of the mineral nutrients that are needed only in extremely small quantities
trachea
tube that carries air from the pharynx to the lungs; also called windpipe
tracheid
long, narrow, rod-shaped cell that helps conduct water in the xylem of a woody stem
transpiration
loss of water vapor from leaves and stems of a plant
transpiration pull
force that draws sap up a stem as leaf cells pull water into themselves
trapezius
muscle in the back of the shoulder; pulls the shoulders and head back and helps turn the head from side to side
tree
plant with a single tall, woody stem capable of standing erect without support
triceps brachii
muscle located in the back of the upper arm that extends the forearms; also called triceps
tricupsid valve
heart valve connecting the right atrium and right ventricle
triglyceride
another name for a fat
tropism
response in which an organism moves either toward or away from a stimulus
trunk
main stem of a tree
tuber
bud-containing special stem that grows underground to store food
tuberculosis
severe respiratory disease caused by infection with Myobacterium tuberculosis
turf grass
any of the grasses used as coverings for lawns, athletic fields, golf courses, and playgrounds
turgid
swollen, distended
turgor pressure
pressure produced by water within guard cells; causes stomata to open and close
typhoid fever
serious illness acquired from food or water contaminated with the bacteria Salmonella Typhi
ulcer
open sore in the mucous membrane of the digestive tract
ulna
bone of the forearm on the same side as the little finger
unsaturated fat
fat containing unsaturated fatty acids
unsaturated fatty acid
fatty acid in which the hydrogen-carbon chain can form one or more additional pairs of bonds to hydrogen
urea
waste substance made from excess amino acids
uterus
hollow muscular organ in a woman’s lower abdomen that provides a place for an unborn child to develop; also called womb
uvea
middle layer of the eye
vacuole
structure in a cell that stores food materials, fluid substances, and minerals
valve
half a diatom’s cell wall
OR
structure in the heart that pevents blood from flowing in the wrong direction
vascular bundle
bundle of xylem and phloem cells found in a herbaceous stem
vascular cambium
cambium tissue that produces new vascular tissue
vascular cylindar
innermost portion of a root, containing xylem and phloem; also called stele
vascular plant
any of the plants that have vascular tissue; also called tracheophyte
vascular ray
structure found in most mature trees that helps transport materials between the center and edges of the tree
vascular tissue
sap-conducting tissue of plants, composed of elongated, tubular cells
vegetative propagation
process of deliberately using vegetative reproduction to start a new plant
vegetative reproduction
formation of a new plant from a stem, leaf, or root
vein
one of the tubes running through the mesophyll of a leaf that contains the leaf’s vascular tissue
OR
relatively thin-walled blood vessel that returns blood to the heart
venae cavae
two large veins that return deoxygenated blood from the body to the heart; sing. vena cava
venation
pattern of the veins within a leaf
ventricle
thick-walled lower chamber of the heart
ventricular fibrillation
type of heart failure in which the heart twitches randomly instead of beating
venule
small blood vessel connecting capillaries and veins
vertebra
bone of the vertebral column; plural vertebrae
vertebral column
chief structural member of the body, made of 33 vertebrae; the support to which all the other parts of the skeleton are attached; also called backbone, spinal column, and spine
vesicle
container within a cell that serves purposes such as transporting proteins
vessel
large water-conducting tube in the xylem of a woody stem
vestigal
describes organs that allegedly serve no useful purpose today
viable
able to germinate and grow
villus
tiny, hairlike projection of the small intestine that absorbs digested food; plural villi
vine
any plant with a long, thin stem that grows along the ground or has tendrils that twine around a wall or other support
viral hepatitis
liver infection that can be acquired by skin contact, contaminated food, blood transfusions, and intravenous drug use
viscera
general term for the soft internal organs within the thoracic and abdominal cavities
vital capacity
maximum volume of air that can be inhaled and exhaled
vitamin
any of a group of organic substances needed in small amounts for proper function of metabolism
vitreous humor
transparent, jellylike fluid that fills the space between the lens and the rear of the eye
vocal cords
structures in the larynx that vibrate to produce sound
voluntary muscle
any of the muscles that are generally under conscious control; a skeletal muscle
volvox
colonial green alga that lives in pale-green globular colonies containing hundreds or thousands of individual cells
water-soluble vitamin
any of the vitamins that are soluble in water and can be easily eliminated from the body
wheat rust
widespread rust fungus that lives on wheat and barberry bushes
whiplash
injury, caused by the body being jolted, to the spinal nerves that branch from the spinal cord in the neck
white blood cell
blood cell that functions as part of the immune system, helping the body fight disease; also called leukocyte
white fiber
muscle fiber containing fewer mitochondria and less myoglobin than red fibers
white matter
portion of the brain and spinal cord composed of axons and glial cells that are white because of their myelin content
whorled
leaf pattern in which three or more leaves grow from each node
wilting
effect of a high rate of transpiration on a plant
wisdom tooth
last molar on each side of the jaw
Wolff’s law
principle that bones adjust their shapes to the physical stress placed upon them
Wollemi pine
unusual Australian conifer only known from fossils until a grove of living trees was discovered in 1994
wood
strong, relisient inner section of a woody stem
woody plant
plant that produces wood
xanthophyll
pigment in leaves that produces yellowish colors
xylem
plant vascular tissue that transports water and dissolved minerals upward from the roots to the leaves
yeast
small, colorless, single-celled sac fungus that feeds on cells containing sugar, converting the sugar into alcohol and carbon dioxide
yellow marrow
fat-storing tissue found in the diaphyses of adult bones
zoology
study of animals
