Ross & Wilson Anatomy and Physiology in Health and Illness (214 page)

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

Normal values

Note.
Some biological measures have been extracted from the text and listed here for easy reference. In some cases slightly different ‘normals’ may be found in other texts and used by different medical practitioners.

Metric measures, units and SI symbols

Decimal multiples and submultiples of the units are formed by the use of standard prefixes.