Glossary of Terms Used in Human Anatomy and Physiology

Glossaries of terms are very helpful and important in many aspects. If you want to know or learn the correct definition, glossaries are essential.

Glossary ensures that everyone is discussing the same definition for the terms. Here we are providing the glossary of terms for human anatomy and physiology.

Whereas terminologies might differ all around the world and definitions change over time or some new terms might get added, hence we try our best to keep this dictionary of human anatomy and physiology up to date.

Terms with Letter A

In vertebrates that part of the body cavity contains the digestive organs, and in mammals separated from the thoracic cavity by the diaphragm.

Division of the anterior (ventral) cavity that houses the abdominal and pelvic viscera.

The passage of material into a cell; the passage of nutrients from the intestines into the blood vessels associated with them.

Movement of a body part away from the midline of the body.

A pus-filled cavity within a tissue.

Situation when blood pH falls below the normal pH range.

The habituation of an organism or animal to another climate i.e. becoming acclimated.

Focusing adjustment of the eyes to view close objects.

Shortening of long bones of the limbs is caused by a disturbance in the ossification process (bone formation) during the growth of the bone.

The electrical current (impulse) is conducted along with a nerve cell (neuron).

The maintenance of the correct ratio of acids to bases in the blood to maintain the correct pH.

Behavior brought about by conditioning and learning.

Adrenocorticotropic hormone.

Of sudden onset.

Movement of body parts towards the midline of the body.

Molecular store of chemical energy for chemical energy.

Fat tissue.

Requiring oxygen.

Cause of disease

Carrying or traveling towards an organ.

The resistance to blood flow from the heart, determined mainly by the diameter of the arteries.

White Blood cell with no granules in its cytoplasm (i.e. lymphocytes and monocytes).

The form of a gene carried on a chromosome.

Targeting and destruction of harmless antigens by the immune system, often with detrimental effects on normal body tissues.

The amount of air reaching the alveoli with each breath.

An air sac in the lungs; also the milk-secreting sacs in the mammary glands.

The building blocks of protein.

A protozoan shape that is subject to constant change due to its ability to form and retract limb-like projections which aid its mobility.

Resembling an amoeba in shape, in properties, or locomotion.

The constructive chemical processes in living organisms that involve the synthesis of large molecules from smaller ones, and then taking up and storage of energy.

Not requiring oxygen.

The growth phase of feathers.

Third phase of mitosis.

The severest form of allergy, with multiple, potentially fatal, systemic effects.

Joining together of adjacent tubes e.g. i) in blood vessels where there are no capillary beds, (ii) following surgery.

A weakness in the wall of an artery.

Negatively Charged ion.

The science of the structure of plants and animals as observed by dissection i.e. how they are constructed.

Nearer the head end; facing outwards from the axis.

Used to maintain consistency of anatomical descriptions – the body is upright, with the head facing forward, the arms at the sides with the palms of the hands facing forward, and the feet together.

Defensive protein synthesized by B-lymphocytes in response to the presence of antigen.

A protein that stimulates the body’s immunological defenses.

A substance or mechanism that kills or inhibits the growth of microorganisms.

The shoulder girdle, upper limbs, pelvic girdle, and lower limbs.

To form a mobile joint usually with two surfaces in contact or close association.

An abnormal heart rhythm.

A small artery.

A blood vessel that carries blood away from the heart.

A joint.

Decrease in cell size resulting in shrinking of an organ or body part.

Related to hearing.

Targeting and sometimes destruction of one’s own or ‘self’ tissues by the immune system.

The ability of a tissue to independently control its blood supply.

The ability of a tissue to generate its electrical signals.

Any one of the chromosomes in pairs 1–22 (i.e. all but the sex chromosomes).

The skull, vertebral column, sternum (breastbone), and ribs.

Terms with Letter B

Single-celled microorganism, common in the external environment, some of which can cause disease.

Sensory receptor is sensitive to pressure (stretch).

The energy use of the body when at rest in a warm environment, without having eaten for 12 hours.

Non-cancerous or a non-serious condition for which treatment may be required.

With two eyes. Being able to see the same object or field with both eyes at the same time. This facilitates the perception of range or distance.

The hollow ball of cells that, during fetal development, embeds in the uterine wall.

The collective term given to the physiological adaptations in the central nervous system that prevents many blood-borne substances from accessing it.

The ball of food when swallowed.

Abnormally slow heart rate.

Widening of the larger airways and bronchioles.

A substance that resists a shift in pH of body fluid.

Terms with Letter C

A vessel that can expand to contain large quantities of blood at low pressure (veins).

A tiny blood vessel between an arteriole and a venule, which has leaky walls to allow the exchange of substances between the blood and tissues

Group of organic compounds including the sugars and starches

A cancer-causing substance.

A tumor arising from epithelial tissue.

Of the heart.

The amount of blood ejected by one ventricle every minute: CO = heart rate (HR) × stroke volume (SV).

A substance that speeds up a biochemical reaction without taking part in it.

A positively charged ion.

Breaking down of larger molecules into smaller ones

Towards the tail end or posterior.

The brain and spinal cord.

The fluid bathing the brain and spinal cord.

A sensory receptor sensitive to chemicals in solution.

The movement of a cell towards a chemical attractant.

Mature cartilage cell.

The opening from the nasal cavity into the roof of the mouth. Choanal means ‘funnel-like '.

The uncoiled state of chromosomes during interphase.

Sausage-shaped structure consisting of a tightly coiled molecule of DNA visible at the end of interphase.

Microscopic cell extensions for moving materials through the lumen of a tube.

The regular, predictable fluctuation of a physiological function over a 24-hour period.

Movement of a body part to describe a cone shape.

Important sequence of aerobic metabolic reactions in cellular energy production.

The cavity that develops very early in the embryo later becomes the pericardial, pleural, and peritoneal cavities.

Cells that are very long i.e. longer than they are broad; like a column.

Cone-like structure.

The deep-seated layer of the skin or lining.

Blood clotting.

The situation when more than one form of a gene is dominant.

The act of sexual intercourse.

A harmless microorganism that lives in the body or on its surfaces, which may bring advantages to its host, e.g. by producing vitamins, or by preventing the growth of pathogens.

Transferable from one person to another.

The stretchability of a tissue.

A molecule containing more than one element.

Where two areas of, e.g., liquid have different concentrations of a solute.


Narrowing of a tube or vessel due to contraction of a circular muscle in its wall.

The turning of the eyes inward to focus on a close object.

The outer layer of a gland or structure.

Related to the ribs.

Towards the head end.

The contents of a cell except for the nucleus (i.e. cytosol + organelles).

Terms with Letter D

Removal of the amino group from an amino acid.

A body structure or part that is not close to the body surface.

Expulsion of feces from the rectum.


Excessive loss of body water.

The molecule in which the genetic code is written, and packaged into chromosomes in the nucleus.

Movement of an independently motile cell from one place to another.

The shaft of a long bone.

Resting period of the heart or its chambers.

 The pressure is recorded in the surface systemic circulation (often at the arm) when the pressure is at its lowest, corresponding to relaxation of the myocardium; the lower of the two measurements used to denote a blood pressure recording.

 The process of cell specialization.

 Movement of substances down a concentration gradient, which does not require energy or the presence of a membrane.

 Widening of a tube or vessel due to relaxation of circular muscle in its wall.

Having two different forms because of sex e.g. the males and females are different in appearance.

A cell with 46 chromosomes, the whole complement of 23 pairs.

Further from the origin of a body part or point of attachment of a limb.

 The passing of urine.

In genetics, the preferential expression of one form of a gene over another.

Towards the back or dorsal.

Terms with Letter E

The outer layer of embryo cells.

 Carrying or traveling away from an organ.

The ability of a tissue to stretch and recoil to its original length or shape.

An inorganic ion in body fluids, which conducts electricity e.g. sodium chloride, potassium chloride.

 A chemical whose atoms are all of the same types.

 A blood clot or other substance that travels in a blood vessel and may lodge blocking a smaller vessel.

In humans, the first eight weeks of development after fertilization following which it is referred to as the fetus.

The membrane lining the interior of the heart.

 A ductless gland that secretes a hormone that travels to its target organ in the bloodstream.

Inner or bottom layer of cells of an embryo from which systems such as the digestive system and its glands and the respiratory system develop.

Internal, produced by the body.

Epithelium lining blood vessels.

A protein substance that speeds up (catalyzes) chemical reactions

 The outermost layer of the skin

 Another term for adrenaline

  Each end of a long bone

 Tissue that lines and covers most body organs.

 The state of physiological balance or equivalence.

 Production of red blood cells.

A nutrient that must be eaten in the diet.

 Turning the soles of the feet outwards.

 Gland that secretes its product into ducts for transport.

Process by which particulate waste is expelled from a cell.

 External; not produced by the body.

 The physical process of breathing out.

An increase in the angle between two bones, straightening a limb.

Exchange of gases in the lungs.

Outside a cell.

Clotting process triggered by damaged extravascular tissues.

Terms with Letter F

 A form of diffusion that requires carrier proteins for the transfer of substances across cell membranes.

 Waste product of digestion excreted through the anus.

 Fibrous membrane that supports, covers, and separates muscles.

 The penetration of an ovum by a spermatozoon to form a zygote that can grow into a fetus.

  Muscle cell; in nutrition, the indigestible part of the diet is also known as a non-starch polysaccharide.

The breakdown of a blood clot.

Connective tissue cell that produces collagen fibers.

 The movement of small molecules, by hydrostatic pressure, through a selectively permeable membrane.

 An abnormal passageway between two organs or an organ and the body surface.

Long cell extensions used for cellular propulsion.

The reducing of the angle between two bones; straightening a limb.

 A small secretory gland.

Terms with Letter G

An ovum or spermatozoon (reproductive cell).

 Of the stomach.

 An area on a chromosome that codes for one particular protein.

All the genes in a cell.

 The genetic make-up of an individual.

The group of cells on the yolk of the egg from which the embryo develops.

 Pregnancy. Glia Nervous tissue that supports neurons.

 One class of plasma protein, including antibodies.

Group of steroid (fat-based) adrenal cortex hormones essential for life.

 The production of glucose from noncarbohydrate molecules.

 Simple sugar used by cells for energy.

Storage, very high molecular weight form of glucose

The anaerobic breakdown of glucose releases some of its stored energy.

Sex organs; ovaries in the female and testes in the male.

Hormones (follicle-stimulating hormone and luteinizing hormone) secreted by the pituitary gland affect the function of the sex organs or gonads.

Newly formed repair tissue following tissue damage.

General term for a white blood cell without cytoplasmic granules.

 The production of white blood cells.


Terms with Letter H

Vomiting of blood.

The breakdown of red blood cells.

The production of blood cells.

Profuse blood loss.

The cessation of blood flow

A cell with 23 chromosomes (half the total chromosome complement).

Of the liver.

Either acidic or basic in reaction.

Genetically, a form of a gene on one chromosome that is different from the form of the same gene on the other chromosome of the pair.

A lipid/protein complex in the bloodstream important in transporting cholesterol to the liver for disposal.

Indented the area of an organ where blood vessels, nerves, and ducts enter and leave.

Maintenance of a stable internal environment.

Animals regulate their temperature to maintain a generally constant temperature of their deep organs.

Genetically, a form of a gene on one chromosome that is the same as the form of the same gene on the other chromosome of the pair.

 A substance secreted by an endocrine gland that is transported in the blood and acts on specific target cells elsewhere in the body.


Water hating.

The pressure exerted by a fluid on the walls of its container, e.g. of blood on the walls of blood vessels.

Abnormally high secretion of a body product, e.g. a hormone.

An abnormal immune response directed either against a harmless antigen (allergy) or a ‘self’ antigen (autoimmunity).

 Abnormally high blood pressure.

Body temperature above normal.

Body temperature below normal.

 A solution with a solute concentration higher than body fluids.

An increase in cell size resulting in enlargement of an organ or body part.

 Abnormally high respiratory effort, associated with loss of excessive amounts of carbon dioxide.

Abnormally low secretion of a body product, e.g. a hormone.

 Abnormally low blood pressure.

 An abnormally low body temperature (core temperature <35 p="">

A solution with a solute concentration lower than body fluids.

An abnormally low respiratory effort, associated with retention of carbon dioxide.

 Inadequate levels of oxygen in the tissues.

Terms with Letter I

A condition resulting from a healthcare intervention.

 A condition of unknown cause.

Body defense mechanisms against a specific disease.

Inability to control the voiding of urine.

Death of a region of tissue due to interruption of its blood supply.

The invasion of the body by infectious agents such as bacteria or viruses usually causes a disease condition.

 Structure further from the head.

 Nonspecific tissue response to damage.

Invasion of the body either internally or externally by parasites e.g. lice and worms.

Taking in substances orally, i.e. through the mouth.

  Loss of water through the skin and respiratory tract.

The point where a muscle is attached to the bone in moves.

 The physical process of breathing in.

Of the skin.

Exchange of gases in the tissues.

 Phase of the cell cycle when there is no division.

Fluid is situated between body cells, also known as tissue fluid.

Inside a cell

 A protein secreted by the stomach is required for the absorption of vitamin B12 (the extrinsic factor).

Clotting process triggered by damaged blood vessels.

The turning of the soles of the feet to face each other.

 Not under conscious control.

 A charged atom (which has either lost or acquired electrons).

Radiation that generates ions when it passes through atoms; can damage cells by changing the atoms in the molecules that make up living tissue, e.g. X-rays.

 Impaired blood supply to a body part.

Muscle work where the tension in the muscle rises but the muscle does not shorten, e.g. if trying to lift a weight that is too heavy to move.

Muscle work where the muscle shortens as the tension rises, allowing, e.g., a load to be lifted by the arm; in chemistry, solutions with a solute concentration are the same as body tissues.

 A form of an element that has a different number of neutrons from the principal form.

Terms with Letter J

No terms updated yet.

Terms with Letter K

Photographic presentation of a cell’s chromosomes as matched pairs in descending order of size.

Terms with Letter L

Production of breast milk.

Structure further from the midline or at the side of the body.

General term for a white blood cell.

A low blood white cell count.

 Band of connective tissue that binds one bone to another.

 Enzyme that breaks down fat.

The general term for any substance that does not dissolve in water but dissolves in non-polar solvents like alcohol.

Breakdown of fat.

Lengthwise; along the length of the body.

A lipid/protein complex in the bloodstream associated with deposition of cholesterol in arterial walls.

The central passageway within an internal tube or duct.

Semilunar (half-moon) e.g. types of valves found in the heart.

Watery fluid drained by the lymphatic system from the tissue spaces.

Destruction of a cell, e.g. hemolysis.

An antimicrobial enzyme is present in somebody's fluids.

Terms with Letter M

A phagocytic cell is usually found in connective tissue.



 An opening into a passage.

Structure that is nearer to the midline.

An imaginary line that divides the body longitudinally into right and left halves.

  The region between the lungs, containing the heart, great vessels, trachea, and other important structures.

 The inner layer of a gland or structure.

Process of cell division by which gametes are formed.

Blood in the feces.

The onset of puberty in females, marked by the start of menstruation.

 Time of the female life span when reproductive function ceases.

Regular shedding of the uterine lining, usually monthly, during the reproductive period of the female life span.

The layer of embryo cells developing between the endoderm and the ectoderm.

Sequence of metabolic steps in cellular biochemistry.

All the chemical reactions that take place within the body.

Second phase of mitosis.

Secondary deposits from a primary malignant tumor.

 Microorganism, e.g. a fungus, bacterium, or virus.

Passing urine.

Cell division giving two identical daughter cells.

In chemistry, the quantity of a substance representing its molecular weight in grams.

An efferent nerve that carries impulses from the central nervous system to muscles or glands.

Lining of body tracts (also mucous membrane).

Any substance that causes mutation.

A genetic change that arises during cell division.

A fatty substance that surrounds the axons of myelinated nerves.

The muscle tissue of the heart.

Intracellular protein threads within muscle cells, made either of actin or myosin, are responsible for muscle cell contraction.

Terms with Letter N

Cell death is caused by an injury or a pathological condition.

Any control mechanism that resists and reverses any change from normal in a physiological system.

New; as in the respiration cycle.

A new growth which may be benign or malignant.

The structure in the kidneys is responsible for the formation of urine.

The synapse between a motor nerve and a skeletal muscle cell.

Nerve cell.

Chemical transmits an impulse between one nerve and the next, or between a nerve and the neuromuscular junction.

The defense mechanisms of the body that are effective against different types of threat, e.g. the skin, inflammation, complement.

Alternative name for noradrenaline.

Building block of nucleic acids.

Any substance that is digested, absorbed, and used to promote body function.

Terms with Letter O

Tissue swelling due to collection of fluid in the intercellular spaces.

  Sense of smell.


Body part, composed of different tissues, that carries out a specific body function.

Intracellular structure that carries out a specific function.

A molecule or substance containing carbon.

Point of attachment of a muscle to a bone that moves least during muscle contraction.

The organic constituent of bone tissue.

Structural unit of compact bone.

Age-related bone degeneration.

Specialised sensory receptors are sensitive to solute concentration.

Movement of water down its concentration gradient across a semipermeable membrane.

The pressure exerted by water in a solution.

Bones of the middle ear: hammer, anvil, and stirrup.

The production of bone tissue.

The release of a mature ovum from the ovary.

The female gamete; that part of the egg yolk fertilized by the sperm.

The aerobic high energy-generating metabolic process of cellular respiration.

The oxygenated form of hemoglobin.

Terms with Letter P

Old; as in the respiration cycle.

A nipple or pimple-like structure is often associated with ducted glands.

Division of the autonomic nervous system that prepares the body for ‘rest and repair’.

A layer of the serous membrane lining a body cavity (cf. visceral layer).


Any form of transport within the body that does not require the use of energy.

Microorganism capable of causing disease.

An enzyme that breaks down protein.


To does with the heart i.e. around the heart.

Nervous tissue that is not part of the brain or spinal cord.

The force against which the blood has to push to move through the arterial circulation, determined mainly by the diameter of the arterioles.

Rhythmical contraction of smooth muscle in the walls of hollow organs and tubes, e.g. the alimentary canal.

To does with the intestines and/or abdomen.

 Scale of measurement of acidity or alkalinity, neutral is 7, acid below 7, and alkaline above 7.

A white blood cell with the ability to engulf and consume foreign bodies e.g. bacteria.

Defence mechanism by which body cells consume and destroy foreign materials, ‘cell eating’.

The expression of the genes in an individual, e.g. hair color, height, etc.

Fat-based molecule containing phosphate, essential to the structure of the cell membrane.

Dealing with the function and activities of organisms i.e. how they work.

Ingestion of small vacuoles into a cell, ‘cell drinking’.

The sole of the foot.

 Clear, the straw-colored liquid portion of the blood.

Any one of a group of important proteins synthesized by the liver and carried in the plasma, with diverse physiological functions, e.g. as antibodies or clotting proteins.

Small cell fragments involved in blood clotting.

Related to the lungs.

A network formed by a collection of nerves or blood vessels.

Animals do not maintain a relatively constant deep body temperature and as a result, their body temperature varies with their environmental temperature.

A general term for a white blood cell with an irregular nucleus (i.e. basophils, eosinophils, and neutrophils).

Production of large quantities of urine.

A control mechanism that increases and accelerates any change from normal in a physiological system; much rarer than negative feedback control.

Lying to the back of the body.

The amount of blood in the ventricle just before ventricular contraction, determined mainly by venous return.

 Irreversible hearing loss, usually due to aging, which results from degeneration of the cochlea and begins with an inability to hear high-pitched sounds.

Stiffening of the lens, usually due to aging, impairs the ability of the eye to change focus (accommodate).

Damage to superficial tissues caused by prolonged pressure and interrupted blood supply, usually over a bony prominence.

Simple repair of relatively minor tissue damage.

Likely outcome of a disease.

First phase of mitosis.

The turning of the palms to face backward.

A large polypeptide.

Nearer is the origin of a body part or point of attachment of a limb.

The stage of life in males or females where reproductive maturity is achieved.

  Of the lungs.

The pressure wave generated by the heart, felt along an arterial wall where that artery lies close to the body surface.

Diastolic blood pressure subtracted from the systolic value.

Special muscle fibers are found in hearts that have a higher rate of conduction of the contractile impulse. They transmit the impulse at a faster rate.


  A substance that causes fever.

Terms with Letter Q

No terms updated yet.

Terms with Letter R

The transmission of energy in waves.

 A molecule, usually on the cell surface, detects and responds to chemicals in the cell’s external environment, e.g. a neurotransmitter. Also, a sensory nerve ending that detects physical changes in the local environment, e.g. a baroreceptor measuring pressure.

 Genetically, a form of a gene that can only be expressed if it is present as two identical forms on the chromosome pair.

The bending of light rays as they pass through a lens, e.g. the lens of the eye.

Of the kidneys.

 A blood vessel, usually an arteriole, with a thick layer of smooth muscle in its tunica media, that constricts or dilates to regulate blood flow and blood pressure.

 Immature red blood cell.

Lying behind the peritoneum.

Molecule used to transfer genetic instructions from DNA to cytoplasmic ribosomes.

The movement of a body part around its long axis.

Folds in the internal surface of a hollow organ when the organ is relaxed.

Terms with Letter S

Section or division in the median longitudinal plane. Cut along the length of a system, organ, or tissue.

 An imaginary vertical line dividing the body into right and left halves either down the midline (midsagittal) or on either side of the midline (sagittal).

  The product of a reaction between an acid and a base.

The ‘jumping’ of a nerve impulse along a myelinated nerve axon, from one node of Ranvier to the next.

 The nonfunctional tissue that replaces damaged tissue.

Containing or secreting fatty matter.

Repair of tissue after extensive damage; a more complex and intense process than primary wound healing.

A property of cell membranes that allows passage of some substances but not others.

Cell aging and the decline in function that accompanies it.

An afferent nerve that carries impulses to the central nervous system.

The general term for protein-containing fluid secreted by certain membranes, e.g. serous pericardium and visceral pleura.

A very thin membrane of connecting tissue.

The X or Y chromosome (pair 23).

An abnormality observed by people other than a patient.

The continuous conduction of an impulse along with a non-myelinated nerve fiber.

The accepted mechanism by which actin and myosin filaments within muscle cells slide over one another to permit muscle shortening (contraction).

Immunity; the body’s protective mechanisms raised against a specific threat or antigen.

Circle of muscle surrounding an internal passageway or orifice used to regulate passage through the opening.

Involuntary, usually protective, action controlled at the level of the spinal cord (i.e. independent of the brain)

Flattened (epithelial cells).

Epithelium cells arranged one layer on top of the other.

The microscopic appearance of a striped pattern on skeletal and cardiac muscle cells.

The volume of blood ejected by the ventricle when it contracts.

Near the body surface

Towards the upper part of the body.

Turning the palm to face forwards.

Division of the autonomic nervous system that prepares the body for ‘fight or flight’.

An abnormality described by a patient.

The junction between a nerve and the cell it supplies.

A mass of protoplasm with multiple nuclei but without differentiation into separate cells.

A collection of signs and symptoms that tend to occur together.

The blood supply to all body organs except for the pulmonary arteries and veins.

Contraction period of the heart or its chambers.

  The pressure is recorded in the systemic circulation (often at the arm) when the pressure is at its highest, immediately following ventricular contraction; the higher of the two measurements used to denote a blood pressure recording.

Terms with Letter T

Abnormally fast heart rate.

The resting phase of feather growth.

Fourth (final) phase of mitosis.

Non-coding sections of DNA that cap and protect the ends of each chromosome.

A band of fibrous tissue connecting muscle to bone.

Any substance or agent known to cause abnormal fetal development.

That part of the body cavity carrying the heart and lungs. In mammals, it is separated from the abdominal cavity by the diaphragm.

The inappropriate, pathological formation of stationary blood clots within blood vessels.

Stationary blood clot (clots).

Fluid between body cells, also known as interstitial fluid.

The ability of the immune system and its defensive cells and mechanisms to identify, and not attack, ‘self’ tissues.

A bundle of axons in the central nervous system.

Production of mRNA from DNA.

Production of protein from mRNA.

An imaginary line slicing the body into an upper and a lower part.

Hormone released that causes the release of a second hormone.

 Outer cell layer of the blastocyst that forms the placenta.

Mass of cells growing out with the body’s normal control mechanisms.

The outer, supportive lining of blood vessels.

The lining of blood vessels (also called endothelium).

The middle layer of tissue in larger blood vessels.

Terms with Letter U

No terms updated yet.

Terms with Letter V

 Decrease in diameter (narrowing) of a blood vessel.

Increase in diameter (widening) of a blood vessel.

A blood vessel that carries blood towards the heart.

 A small vein.

Towards the lower or abdominal surface.

The ability to cause disease.

Nonliving particle, which may be capable of causing disease.

 A layer of the serous membrane covering a body organ.

Conscious control of a body function.

Terms with Letter W

No terms updated yet.

Terms with Letter X

No terms updated yet.

Terms with Letter Y

No terms updated yet.

Terms with Letter Z

Fertilised egg formed by fusion of an ovum and spermatozoon.

Sources and References

Holmes, Sandra. (1985) Henderson’s Dictionary of Biological Terms, 9th Ed. Longman, London.