The Human Body Flashcards
(356 cards)
1
Q
abduction
A
The action of moving a limb farther from the midline of the body. In muscle names, abductor indicates a muscle that has this action.
2
Q
acetylcholine
A
A major neurotransmitter in the body, conveying signals from nerves to muscles as well as between many nerves.
3
Q
action potential
A
The electrical nerve impulse that travels along the axon of a nerve cell (neuron).
4
Q
adduction
A
The action of moving a limb closer to the midline of the body. In muscle names, adductor indicates a muscle that has this action.
5
Q
adrenal glands
A
Also called suprarenal glands. A pair of glands found one on top of each kidney. Each gland consists of an outer adrenal cortex, which secretes corticosteroid hormones, and an inner adrenal medulla, which secretes epinephrine.
6
Q
afferent
A
In blood vessels, carrying blood toward an organ, and in nerves, conducting impulses toward the central nervous system.
7
Q
allergy
A
An unnecessary and sometimes dangerous immune response that targets otherwise non-threatening foreign material, such as plant pollen.
8
Q
alveolus (pl. alveoli)
A
A small cavity; specifically, one of the millions of tiny air sacs in the lungs where exchange of gases with the blood takes place; also, the technical term for a tooth socket.
9
Q
amino acid
A
Proteins are made from up to 20 different types of these small, nitrogen-containing molecules; amino acids also play various other roles in the body.
10
Q
amnion
A
The membrane that encloses the developing fetus within the uterus (womb). The fluid inside it (amniotic fluid) helps cushion and protect the baby.
11
Q
anastomosis
A
An interconnection between two otherwise separate blood vessels (e.g. two arteries or an artery and a vein).
12
Q
androgen
A
Steriod hormones that tend to promote male body and behavioral characteristics. They are secreted in larger amounts by men than women.
13
Q
anemia
A
Damagingly low amounts of hemoglobin in the blood. Anemia can have many causes, from undetected bleeding to vitamin deficiencies.
14
Q
angio-
A
A prefix relating to blood vessels.
15
Q
angiography
A
In medical imaging: any technique for obtaining images of blood vessels in the living body.
16
Q
antagonist
A
- A muscle that has the opposite action to another muscle.
2. A drug that interferes with the action of a hormone, neurotransmitter, etc. by binding to its receptor.
17
Q
anterior
A
Towards the front of the body, when considered in a standing position. Anterior to means in front of.
18
Q
antibiotic
A
Any of various chemical compounds, natural or synthetic, that destroy or prevent the growth of microorganisms (e.g. bacteria, yeasts, and fungi).
19
Q
antibody
A
Defensive proteins produced by white blood cells that recognize and attach to particular “foreign” chemical components (antigens), such as the surface of an invading bacterium or virus. The body is able to produce thousands of different antibodies targeted at different invaders and toxins.
20
Q
anticoagulant
A
A substance that prevents blood clotting.
21
Q
antigen
A
Any particle or chemical substance that stimulates the immune system to produce antibodies against it.
22
Q
aorta
A
The body’s largest artery, conveying blood pumped by the left ventricle of the heart. It extends to the lower abdomen, where it divides into the two common iliac arteries.
23
Q
aponeurosis
A
A flattened, sheetlike tendon.
24
Q
arteriole
A
A very small artery, leading into capillaries.
25
artery
A vessel carrying blood from the heart to the tissues and organs of the body. Arteries have thicker, more muscular walls than veins.
26
articulation
A joint, especially one allowing movement; also, a location within a joint where two bones meet in close proximity. A bone in a joint is said to articulate with the other bone(s) of the joint.
27
-ase
A suffix denoting an enzyme. For example, sucrase is an enzyme that breaks down sucrose.
28
ATP
Short for adenosine triphosphate, an enerty-storing molecule used by all living cells.
29
atrium (pl. atria)
Either of the two smaller chambers of the heart that receive blood from the veins and pass it on to the corresponding ventricle.
30
autoimmunity
A situation where the immune system attacks the body's own tissues, often leading to disease.
31
autonomic nervous system
The part of the nervous system that controls non-conscious processes such as the activity of the body's glands and the muscles of the gut. It is divided into the sympathetic nervous system, the roles of which include preparing the body for "fight or flight," and the parasympathetic nervous system, which stimulates movement and secretions in the gut, produces erection of the penis during coitus, and empties bladder.
32
axon
A wirelike extension of a nerve cell (neuron) along which electrical signals are transmitted away from the cell.
33
bacterium (pl. bacteria)
Any member of a large group of single-celled living organisms, some o which are dangerous pathogens. Bacterial cells are much smaller than animal and plant cells, and lack nuclei.
34
basal ganglia
Groups of nerve cells deep in the cerebrum; consists of the caudate nucleus, putamen, globus pallidus, and subthalamic nucleus. Functions include controlling movement.
35
basophil
A type of leukocyte (white blood cell).
36
belly (of muscle)
The widest part of skeletal muscle, which bulges further when it contracts.
37
bilateral
Concerning or affecting both sides of the body or a body part.
38
bile
A yellow-green fluid produced by the liver, stored in the gallbladder, and discharged into the intestine via the bile duct. It contains excretory products together with bile acids that help with fat digestion.
39
biopsy
A sample taken from a living body to test for infection, cancerous growth, etc.; also the sampling process.
40
blood-brain barrier
The arrangements by which the brain is relatively protected from unwanted substances entering it from the blood. It includes capillaries that are less permeable to large molecules than elsewhere in the body.
41
brachial
Relating to the arm.
42
brain stem
The lowest part of the brain, leading down from the rest of the brain to the spinal cord. In descending order, it consists of the midbrain, pons, and medulla oblongata.
43
bronchus (pl. bronchi)
The air tubes branching from the trachea and leading into the lungs; right and left main bronchi enter each lung respectively and divide into lobar bronchi, and eventually into much smaller tubes called bronchioles.
44
cancer
an uncontrolled growth of cells with the potential to spread and form colonies elsewhere in the body. Cancer cells typically look different from their non-cancerous equivalents under the microscope. Cancers can arise in many different tissues.
45
cannula
A tube inserted into any part of the body to drain fluid, introduce drugs, etc.
46
capillaries
The smallest blood vessels, with a wall only one cell thick, supplied by arterioles and draining into veins. Capillaries from networks, and are the sites where nutrients, gases, and waste products are exchanged between body tissue and blood.
47
carbohydrates
Naturally occurring chemical substances containing carbon, hydrogen, and oxygen atoms, e.g. sugars, starch, cellulose, and glycogen.
48
cardiac
Relating to the heart.
49
carpal
Relating to the wrist.
50
cartilage
A rubbery or tough supportive tissue (colloquially "gristle") found in various forms around the body.
51
catheter
A tube inserted into the body, for example, a urinary catheter may be inserted into the urethra to drain urine from the bladder.
52
cecum
The first part of the large intestine.
53
cell
A tine structure containing genes, a surrounding fluid (cytoplasm) that carries out chemical reactions, organells, and an enclosing membrane.
54
central nervous system
The brain and spinal cord, as distinct from the nerves that run through the rest of the body (the peripheral nervous system).
55
cerebellum
An anatomically distinct region of the brain below the back of the cerebrum, responsible for coordinating the details of complex bodily movements, and managing balance and posture.
56
cerebrospinal fluid
The clear fluid that fills the ventricles of the brain and surrounds the brain and spinal cord, helping to provide a constant environment and acting as a shock absorber.
57
cerebrum
The larges part of the brain and the locus of most "higher" mental activities. It is divided into two halves called cerebral hemispheres.
58
cervical
1. Relating to the neck.
| 2. Relating to the cervix (neck) of the uterus.
59
cervix
The narrow "neck" of the uterus, opening into the upper end of the vagina; widens during childbirth.
60
cholesterol
A natural chemical that is an essential constituent of the body's cell membranes and is an intermediate molecule in the production of steroid hormones. It is a constituent of the plaques that cause the arteries to narrow in atherosclerosis.
61
chromosomes
The microscopic packages in the nucleus of a cell that contain genetic information in the form of DNA. Humans have 12 pairs of chromosomes, with a complete set present in nearly every cell of the body. Each chromosome consists of a single DNA molecule combined with various proteins.
62
cilium (pl. cilia)
A microscopic, beating, hairlike structure found in large numbers on the surfaces of some cells - for example in the air tubes of the lungs, where they help remove foreign particles.
63
circadian rhythm
An internal, daily body rhythm. It is kept accurate by reference to external light and dark.
64
clone
An identical copy or set of copies. Depending on the context, it can refer to: copied DNA molecules; a set of identical descendants of a given cell; or an animal bred artificially using genetic material from another adult individual.
65
cochlea
The complex spiral structure in the inner ear that translates sound vibrations in the fluid it contains into electrical impulses to be sent to the brain.
66
collagen
A tough, fibrous, structural protein that is widespread in the body (particularly in bone, cartilage, blood-vessel walls, and skin.)
67
colon
The main part of the large intestine; comprises the ascending, transverse, and descending colon.
68
commissure
A link between to structures, especially any of several nerve tracts in the brain and spinal cord that crosses the midline of the body.
69
compartment (as in anatomical grouping or area)
In the case of muscles, used to define an anatomically and functionally discrete group of muscles, e.g. flexor compartment of the forearm.
70
condyle
A rounded, knuckle-like projection on a bone that forms part of a joint.
71
connective tissue
Any tissue comprising cells embedded in an acellular matrix; includes cartilage, bone, tendon, ligament, and blood.
72
cornea
The tough, transparent, protective layer at the front of the eye; helps focus light on the retina.
73
coronal section
A real or imagined section down the body that divides it form side to side; it is perpendicular to a sagittal section.
74
corpus callosum
A large tract of nerve fibers (commissure) that links the brain's two cerebral hemispheres.
75
cortex
The Latin word for bark, used for the outer parts of some organs, especially:
1. The cerebral or cerebellar cortex - the surface layers of cells (the "gray matter") of these parts of the brain.
2. ) The adrenal cortex - the outer part of the adrenal glands.
76
corticosteroid
Any of several steroid hormones produced by the adrenal cortex. Examples include cortisone and cortisol (hydrocortisone), which have many effects on the body's metabolism and also suppress inflammation. The mineral-regulating hormone aldosterone is also corticosteroid.
77
cranial
1. Related to the cranium
| 2. Toward the head.
78
cranial nerves
Pairs of nerves that lead directly from the brain rather than from the spinal cord. They mainly supply structures in the head and neck.
79
cranium
Together with the mandible (jaw), forms the skull.
80
CFS
Short for cerebrospinal fluid
81
CT
Short for computed tomography, a sophisticated x-ray technique that produces images in the form of "slices" through the patient's body.
82
cutaneous
Relating to the skin.
83
cyst
A fluid-filled cavity in the body. Also, an old term for the bladder; hence cystitis.
84
deficiency disease
Any disease caused by a lack of an essential component of the diet, e.g. a protein or vitamin.
85
dendrite
A branchlike outgrowth of a nerve cell (neuron) that carries incoming electrical signals to that cell. A neuron usually has many dendrites.
86
depressor
Term used in names of several muscles that act to pull down, e.g. depressor anguli oris (pulls down the angle of the mouth).
87
diabetes
Short for diabetes mellitus, a condition involving high levels of glucose (sugar) in the blood, caused by insufficient production of the hormone insulin.
88
diaphragm
A sheet of muscle that separates the thorax from the abdomen. When relaxed it is domed upward; it flattens when contracted, to increase thoracic volume and draw air into the lungs. It is the most important muscle used in breathing.
89
diastole
The phase of the cardiac cycle when the heart relaxes and the ventricles refill with blood.
90
diffusion
The net movement of molecules in a fluid (gas or liquid) from regions of high to lower concentration.
91
dilated
Opened or stretched wider.
92
distal
Relatively farther away from the center of the body or from the point of origin.
93
DNA
Short for deoxyribonucleic acid, a very long molecule made up of small individual units or nucleotides, containing one of four bases. DNA is found in the chromosomes of living cells; the order of the bases "spells out" the genetic instructions of the animal.
94
dopamine
A neurotransmitter secreted mainly by groups of neurons whose cell bodies lie deep in the brain. Dopamine-producing regions are involved in the motivation, mood, control of movement, and other functions.
95
dorsal
Relating to the back or back surface of the body, or to the top of the brain; also, relating to the back (dorsum) of the hand or the upper surface of the foot.
96
duodenum
The first part of the small intestine, leading out of the stomach.
97
efferent
In the case of blood vessels, carrying blood away from an organ; in the case of nerves, conducting impulses away from the the central nervous system.
98
electrocardiography
Recording the electrical activity produced by the heart muscle, using electrodes applied to the patient's skin.
99
embryo
The earliest stage of a developing unborn individual in the uterus, from fertilization until 8 weeks of gestation (after which is known as a fetus).
100
endocrine system
The system comprising glands that produce hormones.
101
endomentrium
The inner lining of the uterus.
102
endorphins
Neurotransmitters in the brain; their functions include diminishing the perception of pain.
103
endothelium
The cell layer that forms the inner lining of blood vessels.
104
enzyme
Any of a large variety of different molecules (most of which are proteins) that catalyze a particular chemical reaction in the body.)
105
eosinophil
A type of leukocyte (white blood cell).
106
epicondyle
A small bulge found on some bones near a joint, usually forming a site for muscle attachment.
107
epidermis
The outermost layer of skin, with a surface consisting of dead cells packed with the tough protein keratin.
108
epiglottis
A flexible flap of cartilage in the throat that helps cover the trachea (windpipe) during swallowing.
109
epinephrine
A hormone released by the adrenal glands in the response to stressful situations. It prepares the body for a "fight or flight" response by increasing heart rate, diverting blood flow to muscles, etc.
110
epithelium
Any tissue that forms the surface of an organ or structure. It may consist of a single layer of cells, or several layers.
111
erythrocyte
A red blood cell.
112
esophagus
The gullet: the tubular part of the alimentary canal between the pharynx and the stomach.
113
estrogens
Steroid hormones produced predominantly by theo ovary, and which regulate female sexual development and physiology. Artificial estrogens are used in oral contraceptives and hormone therapy.
114
extension
The movement that increases the angle of, or straightens, a joint. The name extensor indicates a muscle that has this action, e.g. extensor digitorum extends the fingers.
115
external
In anatomy: closer to the outer surface.
116
extracellular
Outside the cell; often used in reference to the fluid or matrix between cells of a connective tissue.
117
fallopian tube
Another name for the oviduct or uterine tube; two oviducts attach to the uterus, extending to the ovary on each side; the ovum travels down this tube after ovulation.
118
fascia (pl. fasciae)
Layers of fibrous tissue between and around muscles, vessels, and organs.
119
fertilization
The union of a sperm with an unfertilized egg (ovum), the first step in the creation of a new individual.
120
fetus
The unborn individual in the uterus, from 8 weeks after fertilization, when it begins to take on a recognizably human appearance.
121
flexion
The bending movement at a joint. The name flexor indicates a muscle that has this action, e.g. flexor carpi ulnaris bends the wrist.
122
follicle
A small cavity or saclike structure: e.g. the hair follicle from which a hair grows.
123
foramen
An opening, hole, or connecting passage.
124
fossa
A shallow depression or cavity.
125
frontal
Relating to or in the region of the forehead; frontal bone, the skull bone of the forehead; frontal lobe, the foremost lobe of each cerebral hemisphere, lying behind the forehead.
126
gallbladder
The hollow organ into which bile (formerly known as gall) secreted by the liver is stored and concentrated before being transferred to the intestine.
127
gamete
A sperm or an ovum (egg0. Gametes contain just one set of 23 chromosomes, whereas normal body cells have two sets (46 chromosomes). When sperm and egg combine during fertilization, the two-set condition is restored.
128
ganglion
1. A concentration of nerve cell bodies, especially one outside of the central nervous system.
2. A swelling on a tendon sheath.
129
gastric
Relating to the stomach.
130
gene
A length of a DNA molecule that contains a particular genetic instruction. Many genes are blueprints for making particular protein molecules, while some have a role in controlling other genes. Among them, the thousands of different genes in the body provide the instructions for a fertilized egg to grow into an adult, and for all essential activities of the body to be carried out. Nearly every cell in the body contains an identical sets of genes, although different genes are "switched on" in different cells.
131
genome
The complete set of genes found in a human or other living species. The human genome is thought to contain about 20,000-25,000 different genes.
132
genotype
The genetic makeup of a particular individual. Idential twins, for example, have the same genotype because they share identical versions of all their genes.
133
gland
A structure in teh body, the main purpose of which is to secrete particular chemical substances or fluids. Glands are either exocrine, releasing their secretions through a duct onto an external or internal surface, such as the salivary glands, or endocrine, releasing hormones into the bloodstream.
134
glial cells
Cells in the nervous system that are not neurons but play various supportive and protective roles withing the nervous system.
135
globulin
A general name for various proteins found in the blood that have roughly spherical shape.
136
glomerulus
A cluster of nerve endings or capillaries, such as the tiny knot of capillaries enclosed in the cuplike Bowman's capsule of a nephron.
137
gloss-, glosso-
Prefixes relating to the tongue.
138
glucagon
A hormone produced by the pancreatic islets that increases glucose levels in the blood; its effect is opposite to that of insulin.
139
glucose
A simple sugar that is the main energy source used by the body's cells.
140
glycogen
A carbohydrate made up of long, branched chains of connected glucose molecules. The body stores glucose in the form of glycogen, especially in the muscles and liver; also called animal starch.
141
gonad
An organ that produces sex cells (gametes) - I.e. an ovary or a testix. A gonadotropin is a hormone that specifically affects the gonads.
142
gyrus (pl. gyri)
One of the folds on the outer surface of the brain.
143
head (of a muscle)
Where a muscle has several origins or proximal attachments, these may be referred to as "heads," as in the long and short heads of biceps brachii.
144
hemoglobin
The red pigment within erythrocytes that gives blood its color ad carries oxygen to the tissues.
145
hepatic
Relating to the liver.
146
histamine
A substance produced by damaged or irritated tissues that stimulates an inflammatory response.
147
homeostasis
The maintenance of stable conditions in the body, e.g. in terms of chemical balance or temperature.
148
hormone
A chemical messenger produced by one part of the body that affects other organs or parts. There also exist local hormones that affect only nearby cells and tissues. Chemically, most hormones are either steroids, peptides, or small molecules related to amino acids.
149
hypothalamus
A small but vital region at the base of the brain, which is the control center for the autonomic nervous system, regulating the processes such as body temperature and appetite. Also controls the secretion of hormones from the pituitary gland.
150
ileum
The last part of the small intestine, ending at the junction with the large intestine (colon), N.B: Not the same as the ilium, one of the bones of the hip.
151
immune response
The body's defensive reactions to invasion by a bacterium, virus, toxin, etc. It includes general responses such as inflammation, as well as specific responses in which an invader is targeted by a particular antibody so that it can be recognized and destroyed or disabled.
152
immune system
The molecules, cells, organs, and processes that are involved in defending the body against disease.
153
immunity
Resistance to attack by a pathogen (disease-causing organism); specific immunity develops as a result of the body's immune system being primed to resist a particular pathogen.
154
immunotherapy
Any of various treatments involving either the stimulation or suppression of the activity of the immune system.
155
implantation
The attachment of an early embryo to the lining of the uterus. It occurs during the first week after fertilization, and is followed by the development of the placenta.
156
inferior
Lower down in the body, when considered in a standing position(i.e. nearer the feet).
157
inflammation
An immdiate reaction of body tissue to damage, in which the affected area becomes red, hot, swollen, and painful, as white blood cells accumulate at the site to attack potential invaders.
158
inguinal
Relating to, or in the region of, the groin.
159
inner ear
The fluid-filled innermost part of the ear, which contains the organs of balance (the semicircular canals) and the organs of hearing within the cochlea.
160
insertion
The point of attachment of a muscle to the structure that typically moves when the muscle is contracted.
161
insulin
A hormone produced by the pancreatic islets (see pancreas) that promotes the uptake of glucose from the blood, and the conversion of glucose to the storage molecule, glycogen.
162
integument
The external protective covering of the body.
163
internal
In anatomy: inside the body, distant from the surface.
164
interneuron
Any nerve cell whose connections are only with other neurons, as distinct form a sensory or motor neuron.
165
interstitial
Relates to being between things, such as other cells or tissues, e.g. interstitial fluid surrounds cells.
166
intra-
Prefix meaning within, as in intracellular or intramuscular.
167
intrinsic
Situated within or originating within a particular organ or body part.
168
ion
An electrically charged atom or molecule.
169
ischemia
Reduction of blood supply to part of the body.
170
-itis
Suffix meaning "inflammation," used in words such as tonsillitis and laryngitis.
171
joint
Any junction between two or more bones, whether or not movement is possible between them.
172
keratin
A tough protein that forms the substance of hair and nails, gives strength to the skin, etc.
173
labia (sing. labium)
Either of the two paired folds that form part of the vulva in females: the outer labia majora and the more delicate inner labia minora.
174
labial
Relating to the lips, or to the labia of the female genitals.
175
lactation
Secretion of milk by the breasts.
176
larynx
The voicebox: a complex structure situated at the top of the trachea. It includes the vocal cords, structures that function to seal off the trachea when necessary, as well as creating sound when their edges are made to vibrate during breathing.
177
leukocyte
A white blood cell. There are several types, acting in different ways to protect the body against disease as part of its immune response. Leukocytes are found in lymph noes and other tissues generally, as well as in the blood.
178
levator
Term used in the names of several muscles whose action is to lift up, such as the levator scapula (lifts the shoulder blade).
179
ligament
A tough fibrous band that holds two bones together.
180
limbic system
Several regions at the base of the brain, involved in memory, behavior, and emotion.
181
lingual
Referring to the tongue
182
lipid
Any of a large variety of fatty or fatlike substances that are found naturally in living things and are relatively insoluble in water.
183
lumbar
Relating to the lower back and sides of the body between the lowest ribs and the top of the hip bone. The lumbar vertebrae are the vertebrae that lie within this region.
184
lumen
The space inside a tublar structure, such as a blood vessel or glandular duct.
185
lymph node
A small lymphoid organ; lymph nodes serve to filter out and dispose of bacteria and debris, such as cell fragments.
186
lymphocyte
A specialized leukocyte that produces antibiodies including natural killer cells, T-cells and B-cells.
187
lymphoid tissue
The tissue of the lymphatic system, which has an immune function, including lymph nodes, the thymus, and the spleen.
188
macromolecule
A large molecule, especially one that consists of a chain of small similar "building blocks" joined together. Proteins, DNA, and starch are examples of macromolecules.
189
macrophage
A large type of leukocyte that can engulf and dispose of cell fragments, bacteria, etc.
190
mamary
Of, or relating to the breasts.
191
marrow
In anatomical contexts, usually short for bone marrow, the soft material located in the cavities of bones; in some areas this tissue is mainly fat; in others, it is blood forming tissue.
192
matrix
The exracelular material in which the cells of connective tissues are embedded. It may be hard, as in bone; tough, as in cartilage; or fluid, as in blood.
193
meatus
A channel or passage. For example, the external auditory meatus, the ear canal.
194
medial
Toward the midline of the body.
195
medulla
1. Short for medulla oblongata, the elongated lower part of the brain that connects with the spinal cord.
2. The central part or core of some organs such as the kidneys and adrenal glands.
196
melanin
A dark brown naturally occurring pigment molecule, which occurs in greater amounts in tanned or darker skin, and protects deeper tissues from ultraviolet radiation.
197
melatonin
A hormone secreted by the pineal gland in the brain, which plays a role in the body's sleep-wake cycle.
198
membrane
1. A thin sheet of tissue covering an organ , or separating one part of the body from another.
2. The outer covering of a cell (and similar structures within the cell). A cell membrane is composed of a double layer of phospholipid molecules with other molecules such as proteins embedded in it.
199
meninges
Membranes that enclose the outside of the brain and spinal cord. Meningitis is inflammation of the meninges, usually resulting from infection.
200
menopause
The time in a woman's life when ovulation and the menstrual cycle permanently cease.
201
menstrual cycle
The monthly cycle that takes place in the uterus of a non-pregnant woman of reproductive age. The endometrium (lining of the uterus) grows thicker in preparation for possible pregnancy; an egg is release from the ovary (ovulation); then, if the egg is not fertilized, the endometrium breaks down and is discharged through the vagina in a process known as menstration.
202
mental
1. Relating to the mind (Latin mens).
| 2. Relating to the chin (Latin mentum).
203
mesentery
A folded sheet of peritoneum, forming a connection between the intestines and the back of the abdominal cavity.
204
metabolism
The chemical reactions taking place in the body. The metabolic rate is the overall rate at which these reactions are occurring.
205
midbrain
The upper part of the brain stem.
206
middle ear
The air-filled chamber of the ear, between the inner surface of the eardrum and the inner ear.
207
molecule
The smallest unit of a chemical compound that can exist, consisting of two or more atoms joined together by chemical bonds. The water molecule is a simple example, consisting of two hydrogen atoms joined to one oxygen atom.
208
monocyte
A type of leukocyte with various roles in the immune system, including giving rise to macrophages.
209
motor
Adjective relating to the control of muscle movements, as in motor neuron, motor function, etc.
210
MRI scan
Short for magnetic resonance imaging scan, a medical imaging technique based on the energy released when magnetic fields are applied then removed from the body; it can produce very detailed images of the soft tissues of the body.
211
mucosa (pl. mucosae)
A membrane that secretes mucus.
212
mucus
A thick fluid produced by some membranes of the body for protection, lubrication, etc. (Adjective mucous.)
213
mutation
Any change to the genetic makeup of a cell, caused for example by accidents or mistakes during cell division. Mutations in sex cells (gametes) may cause offspring to have unusual genetic features not present in their parents.
214
myelin
Fatty substance forming a layer around some nerve axons, called myelinated axons, insulating them and speeding their nerve impulses.
215
myelo-
1. Prefix relating to the spinal cord.
| 2. Prefix relating to bone marrow.
216
myo-
Prefix relating to muscle
217
natural killer (NK) cell
A type of lymphocyte that can attack and kill cancer cells and virus-infected cells.
218
necrosis
The death of part of an organ or tissue.
219
neocortex
All the cortex of the cerebrum except the region concerned with smell and the hippocampal formation.
220
nephron
The filtering unit of the kidney, which regulates the volume and composition of body fluids by filtering the blood to produce urine. Waste produces, such as urea and uric acid, are also excreted by the nephron. There are more than a million nephrons in each kidney.
221
nerve
A cable like structure transmitting information and control instructions in the body. A typical nerve consists of axons of many separate nerve cells (neurons) running parallel to, but insulated from, each other; the nerve itself is surrounded by an overall protective sheath of fibrous tissue. Nerves may contain nerve fibers controlling muscles or glands (efferent fibers), while others contain fibers carrying sensory information back to the brain (afferent fibers); some nerves carry both types of nerve fiber.
222
neurohormone
A hormone released by a nerve cell rather than from a gland.
223
neurology
The branch of medicine that specializes in disorders of the nervous system. The adjective neurological includes any symptom or disorder that might fall within the province of neurology.
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neuron
A nerve cell. A typical neuron consists of a rounded cell body; brachlike outgrowths called dendrites that carry incoming electrical signals to the neuron; and a single, long, wirelike extension, called an axon, which transmits outgoing messages. There are many variations on this basic pattern, however.
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neurotransmitter
Any of various chemical substances released at synapse by the ends of nerve cells, where they function to pass a signal on to another nerve cell or muscle. Some neurotransmitters act mainly to stimulate the action of other cells, others to inhibit them.
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neutrophil
The most common type of leukocyte (white blood cell). Neutrophils move quickly toward sites of damage and engulf invading bacteria, etc.
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nondisjunction
Failure of chromosomes to separate from each other properly during cell division, resulting in daughter cells that have either too many or too few chromosomes.
228
norepinephrine
A neurotransmitter important in the sympathetic nervous system.
229
nucleus (pl. nuclei)
1. The structure within a cell that contains the chromosomes
2. Any of various concentrations of nerve cells within the central nervous system.
3. The central part of an atom.
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occipital
Relating to the back of the head. The occipital bone is the skull bone forming the back of the head. The occipital lobe is the rearmost lobe of each cerebral hemisphere, lying below the occipital bone.
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olfactory
Relating to the sense of smell.
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optic nerve
The nerve that transmits visual information from the retina of the eye to the brain.
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oral
Relating to the mouth.
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orbit
The bony hollow in the skull within which the eye is contained.
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organelle
Any of a variety of small structures inside a cell, usually enclosed within a membrane, which are specialized for functions such as energy production or secretion.
236
origin
The point of attachment of a muscle to the structure that typically remains stationary when the muscle is contracted.
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osmosis
Phenomenon in which water moves from a less concentrated solution to a more concentrated one if the two solutions are separated by a semipermeable membrane.
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ossi-, osteo-
Prefixes relating to the bone.
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ossicles
Three small bones of the middle ear that transmit vibrations caused by sound waves from the eardrum to the inner ear.
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ovary
Either of the two organs in females that produce and release egg cells (ova). They also secrete sex hormones.
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ovulation
The point in the menstrual cycle at which an egg cell (ovum) is released from the ovary and begins to travel toward the uterus.
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ovum (pl. ova)
An unfertilized egg cell.
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oxytocin
A hormone secreted by the pituitary gland involved in dilation of the cervix and uterine contractions during childbirth, in lactation, and in sexual responses.
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palate
The roof of the mouth, comprising the bony hard palate in the front and the muscular soft palate behind it.
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pancreas
A large, elongated gland lying behind the stomach, with a dual role in the body. The bulk of its tissue secretes digestive enzymes into the duodenum, but it also contains scattered groups of cells called pancreatic islets or islets of Langerhans that produce important hormones, including insulin and glucagon.
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pancreas
A large, elongated gland lying behind the stomach, with a dual role in the body. The bulk of its tissue secretes digestive enzymes into the duodenum, but it also contains scattered groups of cells called pancreatic islets or islets of Langerhans that produce important hormones, including insulin and glucagon.
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parasympathetic nervous system
See autonomic nervous system.
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parathyroid glands
Four small gland s that are often embedded in but are separate from the thyroid gland. They produce parathyroid hormone, which regulates calcium metabolism in the body.
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parietal
A term (derived from the Latin word for "wall") with various applications in anatomy. The parietal bones form the side walls of the skull, and parietal lobes of the brain lie beneath those bones. Membranes (such as the pleura and the peritoneum) are described as parietal where they are attached to the body wall.
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pathogen
Any disease-causing agent, including bacteria and viruses.
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pathology
The study of disease; also, the physical manifestations of a disease.
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pelvic girdle
The hip bones attach to the sacrum to form the pelvic girdle, linking the leg bones to the spine.
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pelvis
1. The cavity enclosed by the pelvic girdle, or the area of the body containing the pelvic girdle.
2. The renal pelvis is the cavity in the kidney where the urine collects before passing down the ureter.
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peptide
Any molecule consisting of two or more amino acids joined together, usually in a short chain. There are many types, some of which are important hormones. Proteins are polypeptides:long chains of amino acids.
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peri-
Prefix meaning round or surrounding.
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peripheral
Toward the outside of the body or to the extremities of the body. The term peripheral nervous system refers to the whole of the nervous system except for the brain and spinal cord.
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peristalsis
A wavelike contraction of muscles, produced by muscular tubes, such as that which propels digested food through the gut, or urine through the ureters, for example.
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peritoneum
A thin, lubricated sheet of tissue that enfolds and protects most of the organs of the abdomen.
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phagocyte
Any cell that can engulf and dispose of foreign bodies such as bacteria, as well as broken fragments of the body's own cells.
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pharynx
The muscular tube behind the nose, mouth, and larynx, leading into the esophagus.
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phospholipid
A type of lipid molecule with a phosphate (phosphorus plus oxygen) group at one end. The phosphate group is attracted to water while the rest of the molecule is not. This property makes phospholipids ideal for forming cell membranes if two layers of molecules are situated back-to-back.
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physiology
The study of the normal functioning of body processes; also, the body processes themselves.
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pituitary gland
Also called the hypophysis, a complex pea-sized structure at the base of the brain, sometimes described as the body's "master gland." It produces various hormones, some affecting the body directly and others controlling the release of hormones by other glands.
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placenta
The organ that develops on teh inner wall of the uterus during pregnancy, allowing the transfer of substances, including nutrients and oxygen, between maternal and fetal blood.
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plasma
Blood minus its cellular components (red and white blood cells, and platelets).
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platelets
Specialized fragments of cells that circulate in teh blood and are involved in blood clotting.
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pleura (pl. pleurae)
The lubricated membrane that lines the inside of the thoracic cavity and the outside of the lungs.
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plexus
A network, usually in reference to nerves or blood vessels.
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pneum-, pneumo-
1. Prefix relating to air.
| 2. Prefix relating to the lungs.
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portal vein
The large vein carrying blood from the intestines to the liver; previously known as the hepatic portal vein.
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posterior
Toward the back of the body, when considered in a standing position. Posterior to, behind.
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process
In anatomy: a projection or extended part of a bone, cell, etc.
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progesterone
A steroid hormone produced by the ovaries and placenta, which plays a role in the menstrual cycle and in the maintenance and regulation of pregnancy.
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prolactin
A hormone produced by the pituitary gland, the effects of which include stimulating the breasts to produce milk.
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pronation
The rotation of the radius around the ulna in the forearm, turning the palms of the hand to face downward or backward. In muscle names, pronator indicates a muscle that has this action, e.g. pronator teres.
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prostate gland
A gland located below the male bladder; its secretions contribute to semen.
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proteins
Large molecules consisting of long folded chains of small linked units (amino acids). There are thousands of different kinds in the body. Nearly all enzymes are proteins, as are the tough materials keratin and collagen.
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proximal
Relatively closer to the center of the body or from the point of oritin.
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puberty
The period of sexual maturation between childhood and adulthood.
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pulmonary
Relating to the lungs.
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pyloric
Relating to the last part of the stomach, or pylorus. The muscle wall of the end of the pylorus is thickened to form the pyloric sphincter.
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radiation therapy
Cancer treatment using ionizing radiation, carried out by directing beams of radiation at the cancer, or introducing radioactive substances to the body.
283
receptor
1. Any sense organ, or the part(s) of a sense organ responsible for collecting information.
2. A molecule in a cell, or on a cell's outer membrane, that responds to an outside stimulus, such as a hormone molecule attaching to it.
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rectum
The short final portion of the large intestine, connecting it to the anal canal.
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rectus
In muscle names, a straight muscle.
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reflex
An involuntary response in the nervous system to certain stimuli, for example the "knee-jerk" response. Some reflexes, called conditioned reflexes, can be modified by learning.
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renal
Relating to the kidneys.
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respiration
1. Breathing.
2. Also called cellular respiration, the biochemical processes within cells that break down fuel molecules to provide energy, usually in the presence of oxygen.
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retina
The light-sensitive layer that lines the inside of the eye. Light falling onto cells in the retina stimulates the production of electrical signals, which are transmitted to the brain via the optic nerve.
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ribosomes
Particles within cells involved in protein synthesis.
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RNA
Short for ribonucleic acid, a long molecule similar to DNA, but usually single - rather than double-stranded. RNA has many important roles including making copies of the DNA code for the protein synthesis.
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sacral
Relating to or in the region of the sacrum, the bony structure made up of fused vertebrae at the base of the spine that forms part of the pelvic girdle.
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sagittal section
A real or imagined section down the body, or part of the body, that divides it into right and left sides.
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scrotum
The loose pouch of skin holding the testes in males.
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sebum
An oil, lubricating substance secreted by sebaceous glands in the skin.
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semen
The fluid released through the penis when the male ejaculates; it contains sperm and a mixture of nutrients and salts. Also called seminal fluid.
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sensory
Concerned with transmitting information coming from the sense organs of the body.
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serotonin
A neurotransmitter in the brain that affects many mental activities, including mood. It is also active in the gut.
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serous membrane
A type of body membrane that secretes lubricating fluid and envelops various internal organs and body cavities. The pericardium, pleura, and peritoneum are all serous membranes.
300
shock
Medical or circulatory shock: a potentially fatal failure of the blood flow to support the body's needs, as a result of blood loss or other causes. The term is also used more loosely to refer to psychologiclal responses to trauma, etc.
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sinua
A cavity; especially:
1. One of the air-filled cavities in the bones of the face that connect to the nasal cavity.
2. An expanded portion of a vlood vessel, for example the carotid sinus and coronary sinus.
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skeletal muscle
A type of muscle also known as voluntary or striated muscle, usually under voluntary control. Appears striped under the microscope. Many - but not all - skeletal muscles attach to the skeleton, and are important in movement of the body.
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smooth muscle
Muscle tissue that lacks stripes when viewed under a microscope, in contrast to striated muscle. Smooth muscle is found in the walls of internal organs and structures, including blood vessels, the intestines, and the bladder. It is not under conscious control, but controlled by the autonomic nervous system.r
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somatic
1. Of or relating to the body, e.g. somatic cells.
2. Relating to the body wall.
3. Relating to the part of the nervous system involved in voluntary movement and sensing the outside world.
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somatosensory
Related to sensations received from the skin and internal organs, including senses such as touch, temperature, pain, and awareness of joint position, or proprioception.
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sperm
A male sex cell (gamete), equipped with a long moving "tail" (flagellum) to allow it to swim toward the fertilize an egg in the body of the female. Colloquially the word is also used to mean semen.
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sphincter
A ring of muscle that allows a hollow or tubular structure in the body to be drawn closed (e.g. the pyloric sphincter and anal sphincter).
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spinal cord
The part of the central nervous system that extends down from the bottom of the brain through the vertebral column, which protects it. Most nerves that supply the body originate in the spinal cord.
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spleen
A structure in the abdomen composed of lymphoid tissue. It has various roles, including blood storage.
310
starch
A plant carbohydrate made up of long, branched chains of glucose molecules linked together.
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stem cell
A cell in the body that can divide to give rise to more cells. This could be either more stem cells, or a range of more specialized types of cell. Stem cells contrast with highly specialized cells, which play specific roles in the body, and which may have lost the ability to divide completely - such as nerve cells.
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steroids
Substances that share a basic molecular structure, consisting of four rings of carbon atoms fused together. Steroids, which may be naturally occurring or synthetic, are classified as lipids. Many of the body's hormones are steroids, including estrogen, progesterone, testoserone, and cortisol.
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straited muscle
A muscle with tissue that presents a striped appearance under a microscope. Striated muscle includes skeletal muscles and cardiac (heart) muscle.
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sugar
1. Commonly used foodstuff, also called sucrose.
2. Any of a number of naturally occurring substances that are similar to sucrose. They are all carbohydrates with relatively small molecules, in contrast to other carbohydrates that are macromolecules, such as starch.
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sulcus (pl. sulci)
One of the grooves on the folded outer surface of the brain.
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superficial
Near the surface; superficial to, nearer the surface than. (Opposite term: deep.)
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superior
Higher up the body, when considered in a standing position.
318
supination
The rotation of the radius around the ulna in the forearm, turning the palms of the hand to face upward or forward. The opposite to pronation. IN muscle names, supinator indicates a muscle having this action, e.g. the supinator of the forearm.
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suture
1. A stitched repair to a wound.
| 2. A rigid joint between two bones, as between the bones of the skull.
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symphysis
A cartilaginous joint between two bones, containing fibrocartilage.
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synapse
A close contact between two nerve cells (neurons) allowing signals to be passed from the end of the first neuron on to the next. Synapses can either be electrical (where the information is transmitted electrically) or chemical (where neurotransmitters are released from one neuron to stimulate the next one). Synopses also exist between nerves and muscles.
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synovial joint
A lubricated, movable joint, such as the knee, elbow, or shoulder. In synovial joints the ends of the bones are covered with smooth cartilage and lubricated by a slippery liquid known as synovial fluid.
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systemic
Relating to or affecting the body as a whole, not just one part of it. The systemic circulation is the blood circulation supplying all of the body apart from the lungs.
324
systole
The part of the heartbeat where the ventricles contract to pump blood.
325
tarsal
1. Relating to the ankle.
| 2. One of the bones of the tarsus, the part of the foot between the tibia ad fibula, and the metatarsals.
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temporal
Relating to the temple - the area on either side of the head. The temporal bones are two bones, one on each side of the head, tat form part of the cranium. The temporal lobes of the brain are located roughly below the temporal bones.
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tendon
A tough fibrous cord that attaches one end of a muscle to a bone or other structure.
328
testis (pl. testes)
Either of the pair of organs in the men that produce male sex cells (sperm). They also secrete the sex hormone testosterone.
329
testosterone
A steroid hormone produced mainly in the testes, which promotes the development of and maintains male body and behavioral characteristics.
330
thalamus
Paired structures deep within the brain, forming a relay station for sensory and motor signals.
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thorax
The chest region, which includes the ribs, lungs, heart, etc.
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thrombus
A stationary clot in a blood vessel, potentially interfering with circulation. Thrombosis is the process by which such a clot is formed.
333
thymus
A gland in the chest composed of lymphoid tissue. Largest and most active in childhood, its roles include the maturation of T-lymphocytes.
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thyroid gland
An endocrine gland located at the front of the throat, close to the larynx (voicebox). Thyroid hormones such as thyroxin are involved in controlling metabolism, including regulating overall metabolic rate. The hormone calcitonin, which helps regulate the body's calcium, is also secreted by the thyroid.
335
tissue
Any type of living material in the body that contains distinctive types of cells, usually together with extracellular material, performing a specific fucntion. Examples of tissues include bone, muscle, nerve, and connective tissue.
336
trachea
The windpipe: the tube leading between the larynx and the bronchi. It is reinforced by rings of cartilage to keep it from collapsing.
337
tract
An elongated structure or connection that runs through a certain part of the body. In the central nervous system, the term is used instead of nerve for bundles of nerve fibers that connect different body regions.
338
translocation
1. Transport of material from one part of the body to another.
2. A type of mutation in which a chromosome, or part of one, becomes physically attached to another chromosome or to a different part of the original chromosome.
339
umbilical cord
The cord that attaches the developing fetus to the placenta of the mother, within the uterus. Blood from the fetus passes through blood vessels inside the cord, transporting nutrients, dissolved gases, and waste products between the placenta and the fetus.
340
urea
A small nitrogen-containing molecule formed in the body as a convenient way of getting rid of other nitrogen-containing waste products. It is excreted in the urine.
341
ureter
Either of two tubes that convey urine form the kidneys to the bladder.
342
urethra
The tube that conveys urine from the bladder to the outside of the body; in men it also conveys semen during ejaculation.
343
uterus
The womb, in which the fetus develops during pregnancy.
344
vascular system
The network of arteries, veins, and capillaries that conveys blood around the body.
345
vaso-
Prefix relating to blood vessels.
346
vein
A vessel carrying blood from the tissues and organs of the body back to the heart.
347
ventral
Relating to the front of the body, or the bottom of the brain.
348
ventricle
1. Either of the two larger muscular chambers of the heart. The right ventricle pumps blood to the lungs to be oxygenated, while the stronger-muscled left ventricle pumps oxygenated blood to the rest of the body.
2. One of the four cavities in the brain that contain cerebrospinal fluid.
349
venule
A very small vein, carrying blood away from capillaries.
350
vertebra (pl. vertebrae)
Any of the individual bones forming the vertebral column or spine.
351
villi (sing. villus)
Small, closely packed, fingerlike protrusions on the lining of the small intestine, giving the surface a velvety appearance and providing a large surface area, which is essential for the absorption of nutrients.
352
virus
A tiny parasite that lives inside cells, often consisting of only a length of DNA or RAN surrounded by protein. Viruses are much smaller than cells, and operate by "hijacking" cells to make copies of themselves. They are unable to replicate by themselves. Many viruses are dangerous pathogens.
353
viscera
Another term for organs. The adjective visceral applies to nerves or blood vessels, for example, that supply these organs.
354
vitamin
Any of a variety of naturally occurring substances that are essential to the body in small amounts, but which the body cannot make itself and so must obtain from the diet.
355
vulva
The outer genitalia of females, comprising the entrance to the vagina and surrounding structures.
356
zygote
A cell formed by the union of two gametes at fertilization.
