Abduction Movement of a body part away from the midline of the body
Accommodation Focussing adjustment of the eyes to view close objects
Acid Substance that releases hydrogen ions in solution
Acidosis Situation when blood pH falls below the normal pH range
Action potential The electrical current (impulse) conducted along a nerve cell (neurone)
Active transport Movement of substances across a cell membrane, up the concentration gradient, and requiring energy
Acute Of sudden onset
Adaptation Lessening of response by sensory receptors to prolonged stimulation
Adduction Movement of a body part towards the midline of the body
Adenosine triphosphate (ATP) Molecular store of chemical energy for chemical reactions
Adipose tissue Fat tissue
Aerobic Requiring oxygen
Aetiology Cause of a disease
Afferent Carrying or travelling towards an organ
Afterload The resistance to blood flow from the heart, determined mainly by the diameter of the arteries
Agranulocyte White blood cell with no granules in its cytoplasm (i.e. lymphocytes and monocytes)
Alkali Substances that accepts hydrogen ions in water or solution
Alkalosis Situation when blood pH rises above the normal pH range
Allele The form of a gene carried on a chromosome
Alveolar ventilation The amount of air reaching the alveoli with each breath
Alveolus (pl. alveoli) An air sac in the lungs; also the milk secreting sacs in the mammary glands
Amino acid The building blocks of protein
Anabolism Synthesis of larger molecules from smaller ones
Anaerobic Not requiring oxygen
Anaphase Third phase of mitosis
Anastomosis A blood vessel (except a capillary) joining two blood vessels
Anatomical position 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
Aneurysm A weakness in the wall of an artery
Anion A negatively charged ion
Anterior (ventral) Describes a body part nearer the front
Antibody Defensive protein synthesised by B-lymphocytes in response to the presence of antigen
Antigen A protein that stimulates the body’s immunological defences
Antimicrobial A substance or mechanism that kills or inhibits growth of micro-organisms
Appendicular skeleton (cf. axial skeleton) The shoulder girdle, upper limbs, pelvic girdle and lower limbs
Arrhythmia An abnormal heart rhythm
Arteriole A small artery
Artery A blood vessel that carries blood away from the heart
Articulation A joint
Autoregulation The ability of a tissue to independently control its own blood supply
Autorhythmicity The ability of a tissue to generate its own electrical signals
Autosome Any one of the chromosomes in pairs 1–22 (i.e. all but the sex chromosomes)
Axial skeleton (cf. appendicular skeleton) The skull, vertebral column, sternum (breastbone) and ribs
Bacterium (pl. bacteria) Single-celled micro-organism, common in the external environment, some of which can cause disease
Baroreceptor Sensory receptor sensitive to pressure (stretch)
Basal metabolic rate The energy use of the body when at rest in a warm environment, without having eaten for 12 hours
Benign Non-cancerous or a non-serious condition for which treatment may be required
Bradycardia Abnormally slow heart rate
Bronchodilation Widening of the larger airways and bronchioles
Buffer A substance that resists a shift in pH of body fluids
Capacitance vessel A vessel that can expand to contain large quantities of blood at low pressure (veins)
Capillary A tiny blood vessel between an arteriole and a venule, which has leaky walls to allow exchange of substances between the blood and tissues
Carbohydrate Group of organic compounds including the sugars and starches
Carcinogen A cancer-causing substance
Carcinoma A tumour arising from epithelial tissue
Cardiac output (CO) The amount of blood ejected by one ventricle every minute: CO = heart rate (HR) × stroke volume (SV)
Catabolism Breaking down of larger molecules into smaller ones
Catalyst A substance that speeds up a biochemical reaction without taking part in it
Cation A positively charged ion
Central nervous system The brain and spinal cord
Cerebrospinal fluid (CSF) The fluid bathing the brain and spinal cord
Chemoreceptor A sensory receptor sensitive to chemicals in solution
Chemotaxis The movement of a cell towards a chemical attractant
Chondrocyte Mature cartilage cell
Chromatin The uncoiled state of chromosomes during interphase
Chromosome Sausage-shaped structure consisting of a tightly coiled molecule of DNA visible at the end of interphase
Chronic Long-standing or recurring
Cilia (sing. cilium) Microscopic cell extensions for moving materials through the lumen of a tube
Circadian rhythm The regular, predictable fluctuation of a physiological function over a 24-hour period
Circumduction Movement of a body part to describe a cone shape
Citric acid cycle Important sequence of aerobic metabolic reactions in cellular energy production
Coagulation Blood clotting
Co-dominance The situation when more than one form of a gene is dominant
Commensal A harmless micro-organism 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
Compound A molecule containing more than one element
Concentration gradient Where two areas of, e.g., liquid have different concentrations of a solute
Congenital Inherited
Convergence The turning of the eyes inward to focus on a close object
Cortex The outer layer of a gland or structure
Cytoplasm The contents of a cell except the nucleus (i.e. cytosol + organelles)
Deamination Removal of the amine group from an amino acid
Defaecation Expulsion of faeces from the rectum
Deglutition Swallowing
Dehydration Excessive loss of body water
Deoxyribonucleic acid (DNA) The molecule in which the genetic code is written, and packaged into chromosomes in the nucleus
Diapedesis Movement of an independently motile cell from one place to another
Diaphysis The shaft of a long bone
Diastole Resting period of the heart or its individual chambers
Diastolic blood pressure The pressure recorded in the 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
Diffusion Movement of substances down a concentration gradient, which does not require energy or presence of a membrane
Diploid A cell with 46 chromosomes, the whole complement of 23 pairs
Distal Further from the origin of a body part or point of attachment of a limb
Diuresis The passing of urine
Dominant In genetics, the preferential expression of one form of a gene over another
Efferent Carrying or travelling away from an organ
Electrolyte An inorganic ion in body fluids, which conducts electricity
Element A chemical whose atoms are all of the same type
Embolus A blood clot or other substance that travels in a blood vessel and may lodge blocking a smaller vessel
Endocrine gland A ductless gland that secretes a hormone which travels to its target organ in the bloodstream
Endogenous Internal, produced by the body
Endothelium Epithelium lining blood vessels
Enzyme A protein substance that speeds up (catalyses) chemical reactions
Epidermis The outermost layer of the skin
Epinephrine Another term for adrenaline
Epiphysis Each end of a long bone
Epithelium Tissue that lines and covers most body organs
Erythropoiesis Production of red blood cells
Essential nutrient A nutrient that must be eaten in the diet
Eversion Turning the soles of the feet outwards
Exocrine gland Gland that secretes its product into ducts for transport
Exocytosis Process by which particulate waste is expelled from a cell
Exogenous External; not produced by the body
Extension An increase in the angle between two bones, straightening a limb
External respiration Exchange of gases in the lungs
Extracellular Outside a cell
Extrinsic pathway Clotting process triggered by damaged extravascular tissues
Facilitated diffusion A form of diffusion that requires carrier proteins for transfer of substances across cell membranes
Faeces Waste product of digestion excreted through the anus
Fascia Fibrous membrane that supports, covers and separates muscles
Fertilisation The penetration of an ovum by a spermatozoon to form a zygote that can grow into a fetus
Fibre Muscle cell; in nutrition, the indigestible part of the diet also known as non-starch polysaccharide
Fibrinolysis The breakdown of a blood clot
Fibroblast Connective tissue cell that produces collagen fibres
Filtration The movement of small molecules, by hydrostatic pressure, through a selectively permeable membrane
Flagella (sing. flagellum) Long cell extensions used for cellular propulsion
Flexion The reducing of the angle between two bones; straightening a limb
Follicle A small secretory gland
Gamete An ovum or spermatozoon (reproductive cell)
Gene An area on a chromosome that codes for one particular protein
Genome All the genes in a cell
Genotype The genetic make-up of an individual
Gestation Pregnancy
Glia Nervous tissue that supports neurones
Globulin One class of plasma protein, including antibodies
Glucocorticoids Group of steroid (fat-based) adrenal cortex hormones essential for life
Gluconeogenesis The production of glucose from non-carbohydrate molecules
Glucose Simple sugar used by cells for energy
Glycogen Storage, very high molecular weight form of glucose
Glycolysis The anaerobic breakdown of glucose to release some of its stored energy
Granulation tissue Newly formed repair tissue following tissue damage
Granulocyte General term for a white blood cell without cytoplasmic granules
Granulopoiesis The production of white blood cells
Gustation Taste
Haematemesis Vomiting of blood
Haemolysis The breakdown of red blood cells
Haemopoiesis The production of blood cells
Haemorrhage Profuse blood loss
Haemostasis The cessation of blood flow
Haploid A cell with 23 chromosomes (half the total chromosome complement)
Hepatic Of the liver
Heterozygous Genetically, a form of a gene on one chromosome that is different to the form of the same gene on the other chromosome of the pair
Hilum Indented area of an organ where blood vessels, nerves and ducts enter and leave
Homeostasis Maintenance of a stable internal environment
Homozygous 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
Hormone A substance secreted by an endocrine gland that is transported in the blood and acts on specific target cells elsewhere in the body
Hydrophilic Water loving
Hydrophobic Water hating
Hydrostatic pressure The pressure exerted by a fluid on the walls of its container, e.g. of blood on the walls of blood vessels
Hypersecretion Abnormally high secretion of a body product, e.g. a hormone
Hypertension Abnormally high blood pressure
Hypertonic A solution with a solute concentration higher than body fluids
Hyperventilation Abnormally high respiratory effort, associated with loss of excessive amounts of carbon dioxide
Hyposecretion Abnormally low secretion of a body product, e.g. a hormone
Hypotension Abnormally low blood pressure
Hypothermia An abnormally low body temperature (core temperature <35°C)
Hypotonic A solution with a solute concentration lower than body fluids
Hypoventilation An abnormally low respiratory effort, associated with retention of carbon dioxide
Hypoxia Inadequate levels of oxygen in the tissues
Iatrogenic A condition resulting from a healthcare intervention
Idiopathic A condition of unknown cause
Immunity Body defence mechanisms against a specific disease
Incontinence Inability to control the voiding of urine
Infarction Death of a region of tissue due to interruption of its blood supply
Infection The invasion of body tissues by pathogenic organisms
Inferior Structure further from the head
Inflammation Non-specific tissue response to damage
Insensible water loss Loss of water through the skin and respiratory tract
Insertion Point of attachment of a muscle to a bone that moves most during muscle contraction
Internal respiration Exchange of gases in the tissues
Interphase Phase of the cell cycle when there is no division
Interstitial fluid Fluid situated between body cells, also known as tissue fluid
Intracellular Inside a cell
Intrinsic pathway Clotting process triggered by damaged blood vessels
Inversion The turning of the soles of the feet to face each other
Ion A charged atom (which has either lost or acquired electrons)
Ionising radiation 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
Ischaemia Impaired blood supply to a body part
Isometric 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
Isotonic 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 the same as body tissues
Isotope A form of an element that has a different number of neutrons from the principal form
Karyotype Photographic presentation of a cell’s chromosomes as matched pairs in descending order of size
Lactation Production of breast milk
Lateral Structure further from the midline or at the side of the body
Leukocyte General term for a white blood cell
Leukopenia A low blood white cell count
Ligament Band of connective tissue that binds one bone to another
Lipase Enzyme that breaks down fat
Lipolysis Breakdown of fat
Lymph Watery fluid drained by the lymphatic system from the tissue spaces
Lysis Destruction of a cell, e.g. haemolysis
Lysozyme An antimicrobial enzyme present in some body fluids
Macrophage A phagocytic cell usually found in connective tissue
Malignant Cancerous
Mastication Chewing
Medial Structure that is nearer to the midline
Median plane An imaginary line that divides the body longitudinally into right and left halves
Medulla The inner layer of a gland or structure
Meiosis Process of cell division by which gametes are formed
Melaena Blood in the faeces
Menopause Time of the female life span when reproductive function ceases
Menstruation (menses) Regular shedding of uterine lining, usually monthly, during the reproductive period of the female life span
Metabolic pathway Sequence of metabolic steps in cellular biochemistry
Metabolism All the chemical reaction that take place within the body
Metaphase Second phase of mitosis
Metastasis (pl. metastases) Secondary deposits from a primary malignant tumour
Microbe Micro-organism, e.g. a fungus, bacterium or virus
Micturition Passing urine
Mitosis Cell division giving two identical daughter cells
Mole In chemistry, the quantity of a substance representing its molecular weight in grams
Motor nerve or neurone An efferent nerve that carries impulses from the central nervous system to muscles or glands
Mucosa Lining of body tracts (also mucous membrane)
Necrosis Cell death following loss of oxygen supply
Negative feedback [system] A physiological control mechanism that corrects deviations from a normal range
Neoplasm A new growth which may be benign or malignant
Nephron The structure in the kidneys responsible for the formation of urine
Neuromuscular junction The synapse between a motor nerve and a skeletal muscle cell
Neurone Nerve cell
Neurotransmitter Chemical that transmits an impulse between one nerve and the next, or between a nerve and the neuromuscular junction
Non-specific defence The defence mechanisms of the body that are effective against different types of threat, e.g. the skin, inflammation, complement
Norepinephrine Alternative name for noradrenaline
Nucleotide Building block of nucleic acids
Nutrient Any substance that is digested, absorbed and used to promote body function
Oedema Tissue swelling due to collection of fluid in the intercellular spaces
Olfaction Sense of smell
Oncogenic Cancer-causing
Organ Body part, composed of different tissues, that carries out a specific body function
Organelle Intracellular structure that carries out a specific function
Organic A molecule or substance containing carbon
Origin Point of attachment of a muscle to a bone that moves least during muscle contraction
Osteon Structural unit of compact bone
Osmoreceptors Specialised sensory receptors sensitive to solute concentration
Osmosis Movement of water down its concentration gradient across a semipermeable membrane
Osmotic pressure The pressure exerted by water in a solution
Ossicles Bones of the middle ear: hammer, anvil and stirrup
Ossification The production of bone tissue
Ovulation The release of a mature ovum from the ovary
Oxidative phosphorylation The aerobic high energy-generating metabolic process of cellular respiration
Oxyhaemoglobin The oxygenated form of haemoglobin
Parasympathetic nervous system Division of the autonomic nervous system that prepares the body for ‘rest and repair’
Parietal layer A layer of serous membrane lining a body cavity (cf. visceral layer)
Parturition Childbirth
Passive transport Any form of transport within the body that does not require the use of energy
Pathogen Micro-organism capable of causing disease
Peptidase An enzyme that breaks down protein
Peripheral nervous system Nervous tissue that is not part of the brain or spinal cord
Peripheral resistance The force against which the blood has to push to move through the arterial circulation, determined mainly by the diameter of the arterioles
Peristalsis Rhythmical contraction of smooth muscle in the walls of hollow organs and tubes, e.g. the alimentary canal
pH scale Scale of measurement of acidity or alkalinity
Phagocytosis Defence mechanism by which body cells consume and destroy foreign materials, ‘cell eating’
Phenotype The expression of the genes in an individual, e.g. hair colour, height, etc.
Phospholipid Fat-based molecule containing phosphate, essential to the structure of the cell membrane
Pinocytosis Ingestion of small vacuoles into a cell, ‘cell drinking’
Plasma Clear, straw coloured liquid portion of the blood
Plasma protein Any one of a group of important proteins synthesised by the liver and carried in the plasma, with diverse physiological functions, e.g. as antibodies or clotting proteins
Platelet (thrombocyte) Small cell fragments involved in blood clotting
Polymophonuclear leukocyte A general term for a white blood cell with an irregular nucleus (i.e. basophils, eosinophils and neutrophils)
Polyuria Production of large quantities of urine
Positive feedback [system] Physiological control mechanism that causes progressive deviation from normal limits; examples are limited, but include the progressive stimulation of the uterine muscle during childbirth
Posterior (dorsal) Lying to the back of the body
Preload The amount of blood in the ventricle just prior to ventricular contraction, determined mainly by venous return
Pressure ulcer Damage to superficial tissues caused by prolonged pressure and interrupted blood supply, usually over a bony prominence
Primary wound healing Simple repair of relatively minor tissue damage
Prognosis Likely outcome of a disease
Prophase First phase of mitosis
Pronation The turning of the palms to face backwards
Proximal Nearer the origin of a body part or point of attachment of a limb
Puberty The stage of life in males or females where reproductive maturity is achieved
Pulmonary Of the lungs
Pulse The pressure wave generated by the heart, felt along an arterial wall where that artery lies close to the body surface
Pulse pressure Diastolic blood pressure subtracted from the systolic value
Pyrexia Fever
Pyrogen A substance that causes fever
Radiation The transmission of energy in waves
Receptor A molecule, usually on the cell surface, that 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
Recessive Genetically, a form of a gene that can only be expressed if it is present as two identical forms on the chromosome pair
Refraction The bending of light rays as they pass through a lens, e.g. the lens of the eye
Renal Of the kidneys
Resistance vessel 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
Reticulocyte Immature red blood cell
Retroperitoneal Lying behind the peritoneum
Ribonucleic acid (RNA) Molecule used to transfer genetic instructions from DNA to cytoplasmic ribosomes
Rotation The movement of a body part around its long axis
Rugae Folds in the internal surface of a hollow organ when the organ is relaxed
Salt The product of a reaction between an acid and a base
Saltatory conduction The ‘jumping’ of a nerve impulse along a myelinated nerve axon, from one node of Ranvier to the next
Scar tissue The nonfunctional tissue that replaces damaged tissue
Secondary wound healing Repair of tissue after extensive damage; a more complex and intense process than primary wound healing
Semipermeability (selective permeability) A property of cell membranes that allows passage of some substances but not others
Sensory nerve or neurone An afferent nerve that carries impulses to the central nervous system
Sex chromosome The X or Y chromosome (pair 23)
Sign An abnormality observed by people other than a patient
Simple propagation The continuous conduction of an impulse along an non-myelinated nerve fibre
Specific defence mechanisms Immunity; body’s protective mechanisms raised against a specific threat or antigen
Sphincter Circle of muscle surrounding an internal passageway or orifice, used to regulate passage through the opening
Spinal reflex Involuntary, usually protective, action controlled at the level of the spinal cord (i.e. independent of the brain)
Stroke volume The volume of blood ejected by the ventricle when it contracts
Superior Towards the upper part of the body
Supination Turning the palm to face forwards
Sympathetic nervous system Division of the autonomic nervous system that prepares the body for ‘fight or flight’
Symptom An abnormality described by a patient
Synapse The junction between a nerve and the cell it supplies
Syndrome A collection of signs and symptoms that tend to occur together
Systemic circulation The blood supply to all body organs except for the pulmonary arteries and veins
Systole Contraction period of the heart or its individual chambers
Systolic blood pressure The pressure 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
Tachycardia Abnormally fast heart rate
Telophase Fourth (final) phase of mitosis
Thrombosis The inappropriate, pathological formation of stationary blood clots within blood vessels
Thrombus (pl. thrombi) Stationary blood clot (clots)
Tissue fluid Fluid between body cells, also known as interstitial fluid
Tract A bundle of axons in the central nervous system
Transcription Production of mRNA from DNA
Translation Production of protein from mRNA
Trophic hormone Hormone released that causes the release of a second hormone
Tumour Mass of cells growing outwith the body’s normal control mechanisms
Tunica adventitia The outer, supportive lining of blood vessels
Tunica intima The lining of blood vessels (also called endothelium)
Tunica media The middle layer of tissue in larger blood vessels
Urine Liquid waste product made in the kidneys
Vasoconstriction Decrease in diameter (narrowing) of a blood vessel
Vasodilation Increase in diameter (widening) of a blood vessel
Vein A blood vessel that carries blood towards the heart
Venule A small vein
Virus Non-living particle, which may be capable of causing disease
Visceral layer A layer of serous membrane covering a body organ
Voluntary control Conscious control of a body function
Zygote Fertilised egg formed by fusion of an ovum and spermatozoon