Sdk125 - Book 2

Front 1

pain

Back 1

An unpleasant sensory and emotional experience traditionally associated with actual or potential tissue damage and which normally is felt to arise in a particular location in the body. The term can also be used to refer to experiences triggered by social loss.

Front 2

subjective experience

Back 2

An experience which is accessible only to the person who experiences it in terms of the contents of his or her conscious mind. Such experience is not open to objective observation or measurement by any other individual and hence is contrasted with ‘objective experience’.

Front 3

psychobiological approach

Back 3

An approach to explanation which implies two closely related things: (i) both biological and psychological sciences have central roles in the explanation, and (ii) a given phenomenon to be studied within this perspective, such as pain, has both biological and psychological aspects.

Front 4

mind

Back 4

A difficult and controversial term to define, in spite of its everyday use. It describes all the information processing carried out by the brain.

Front 5

acute pain

Back 5

Pain of relatively short duration and associated with actual damage to tissues.

Front 6

chronic pain

Back 6

Pain that lasts for months or years and which typically persists beyond the time of tissue healing.

Front 7

noxious stimuli

Back 7

Stimuli that are associated with actual or potential damage to body tissues.

Front 8

nociception

Back 8

The process of detecting stimuli that cause actual or potential damage to the tissues of the body.

Front 9

nociceptive pain

Back 9

Pain that is triggered by a stimulus that causes actual or potential damage to the tissues of the body.

Front 10

psychogenic stimuli

Back 10

Stimuli to pain that are associated with social loss such as bereavement, marital breakdown.

Front 11

psychogenic pain

Back 11

Pain that arises from psychological triggers such as social loss; e.g. bereavement, marital breakdown.

Front 12

pain matrix

Back 12

A collection of different brain regions that is activated in response to painful stimuli and is associated with the experience of pain.

Front 13

adaptive value

Back 13

The value of a characteristic in terms of its contribution to the survival and reproductive chances of an animal.

Front 14

nerve

Back 14

A bundle of the axons of neurons in the peripheral nervous system. (Occasionally employed informally to refer to a bundle of axons within the central nervous system.)

Front 15

spinal cord

Back 15

A collection of neurons and other cells that is located within the protection of the backbone.

Front 16

cognition

Back 16

Certain kinds of activity with which the brain is engaged, i.e. the processing of information that is summarised by the term ‘mind’. It is exemplified by thinking, memory, reasoning and interpreting.

Front 17

cognitive processes

Back 17

Information processing within the brain, which is exemplified by thinking, memory, reasoning and interpreting.

Front 18

affect

Back 18

The dimension of positive and negative feelings, exemplified by, respectively, happiness and pain.

Front 19

physiology

Back 19

The study of the relationship between structure and function of body systems.

Front 20

body systems

Back 20

Also known as ‘organ systems’; combinations of organs and tissues that function in a coordinated way; e.g. the circulatory system, the nervous system, the respiratory system.

Front 21

nervous system

Back 21

The combination of the brain, spinal cord and peripheral nerves located throughout the body.

Front 22

organs

Back 22

Complex structures in the body formed from a number of different tissues, which serve a particular function, e.g. the heart, the brain, the lungs.

Front 23

neuron

Back 23

A type of cell that is found within the nervous system and which is specialised to transmit and process information.

Front 24

axon

Back 24

The part of a neuron that consists of a long wire-like projection, ending in a terminal which participates in a synapse with another cell. Action potentials are transmitted along axons.

Front 25

lock-and-key interaction

Back 25

The binding that occurs between a signalling molecule and its specific receptor. The specificity of the binding is analogous to that of a particular key in a particular lock; e.g. the binding between a neurotransmitter and its receptor, or a hormone and its receptor.

Front 26

negative feedback

Back 26

A process whereby a parameter is maintained at a nearly constant value because deviations from its normal value tend to trigger actions that ‘negate’ the deviation and return it to normality; e.g. a fall in body temperature is fed back via the nervous system, which triggers shivering and this tends to raise body temperature back to normal.

Front 27

homeostasis

Back 27

A property of the body in which a number of its important parameters are held near to constant and any deviation from their normal value triggers action that tends to restore normality. It is exemplified by the maintenance of body temperature, or of oxygen concentration in the bloodstream, etc.

Front 28

central nervous system (CNS)

Back 28

The part of the nervous system consisting of the brain and spinal cord.

Front 29

peripheral nervous system

Back 29

That part of the nervous system that is not within the central nervous system. It is made up of nerves throughout the body.

Front 30

sensory neuron

Back 30

A class of neuron that detects the presence of stimuli in the world, such as tactile events, heat, cold or tissue damage.

Front 31

interneuron

Back 31

A class of neuron that is neither sensory nor motor.

Front 32

reflex

Back 32

The system underlying an automatic and unconscious reaction to a particular stimulus. It is exemplified by the withdrawal reflex, which causes the movement of a limb away from a noxious stimulus.

Front 33

potential difference

Back 33

An electrical difference across the membrane of cells that arises from an unequal concentration of ions on either side. It is also termed ‘voltage’.

Front 34

action potential

Back 34

A sudden change in potential difference (voltage) across the cell membrane of neurons, consisting of an increase in the resting potential and a sudden return to the resting value. Action potentials are transmitted along axons and constitute the principal ‘language’ of communication within nervous systems.

Front 35

synapse

Back 35

The junction where a neuron influences another cell, the latter being either another neuron or a muscle cell.

Front 36

neurotransmitter

Back 36

A chemical that is stored within the axon terminal of a neuron and is released in response to electrical activity within that neuron. It passes the short distance to a neighbouring cell (neuron or muscle) where it has an effect. The term ‘synapse’ describes the location of these events.

Front 37

excitatory synapse

Back 37

A synapse at which the release of neurotransmitter from a presynaptic neuron has an excitatory effect on a postsynaptic cell, e.g. it excites further action potentials in a second neuron.

Front 38

inhibitory synapse

Back 38

A synapse at which the release of neurotransmitter from a presynaptic neuron has an inhibitory effect on a postsynaptic cell, i.e. it inhibits the appearance of action potentials in the second neuron.

Front 39

agonist

Back 39

A chemical that has the effect of mimicking the action of a natural substance such as a neurotransmitter.

Front 40

opioid (oh-pee-oyd)

Back 40

A class of natural neurotransmitters that have a similar structure and action to morphine and heroin.

Front 41

antagonist

Back 41

A chemical that has the effect of blocking the action of a natural substance such as a neurochemical.

Front 42

cerebral hemisphere

Back 42

Much of the brain is divided down its midline into two halves, the left and right cerebral hemispheres (or just ‘hemispheres’); also referred to as the ‘left brain’ and the ‘right brain’.

Front 43

cortex

Back 43

The outer layer of the brain, also known as the ‘cerebral cortex’.

Front 44

brain imaging

Back 44

A technique for monitoring the activity of the different regions of the brain. One method involves injecting a radioactive tracer substance and measuring its later appearance in different brain regions; high concentrations correspond to regions of high activity in the neurons located there.

Front 45

somatic nervous system (SNS)

Back 45

That part of the nervous system that exerts control over the skeletal muscles and thereby over behaviour.

Front 46

autonomic nervous system (ANS)

Back 46

That part of the nervous system which exerts an influence over a number of the internal organs of the body, such as the gut, heart and blood vessels. The term ‘autonomic’ describes its ability to function without conscious intervention.

Front 47

threshold of excitation

Back 47

The level of intensity of stimulation of a neuron at which it first shows activity. The term is used particularly in the context of sensory neurons.

Front 48

neurogenic pain

Back 48

Pain that arises from damage to neurons either within the central nervous system or in the periphery of the body.

Front 49

plasticity

Back 49

A term that refers to the fact that the connections between neurons are not static. Rather, they are subject to change as result of activity within the neurons concerned. Plasticity can mean, over a period of time, increased sensitivity of connections between neurons in the circuits that give rise to pain and hence increasing levels of pain.

Front 50

phantom pain

Back 50

Pain that appears to arise in a part of the body that no longer exists, e.g. in a limb that has been amputated.

Front 51

analgesia

Back 51

The process of reducing pain, e.g. by taking morphine.

Front 52

analgesics

Back 52

Substances that have the effect of reducing pain.

Front 53

side-effects

Back 53

Effects of a treatment that are unintended and often undesirable.

Front 54

opiates

Back 54

A class of substances arising from outside the body, but which bear a close similarity to naturally occurring opioids in their structure and effect; they include heroin derived from the opium poppy, and morphine.

Front 55

transcutaneous electrical nerve stimulation (TENS)

Back 55

A therapeutic technique where low-level stimulation is given to the skin and which has the effect of reducing pain.

Front 56

cognitive-behavioural therapy (CBT)

Back 56

A technique where people learn to change their thought patterns and behaviour to create feelings of coping and self-efficacy; e.g. people in chronic pain might be taught to place a less catastrophic interpretation on their pain.

Front 57

hypnosis

Back 57

A technique in which a person is placed in a particular psychological state and, in response to suggestions made by the hypnotist, can experience alterations in perception, memory and voluntary action.

Front 58

placebo effect

Back 58

A beneficial effect deriving from a procedure with no intrinsic benefit. It relies upon the context in which the intervention is made; e.g. a sugar pill might serve as a placebo if the patient believes that it will bring some benefits.

Front 59

extinction

Back 59

A process whereby a stimulus that owes its power to conditioning loses this power by being repeatedly presented on its own; e.g. extinction of the capacity of a bell to trigger salivation occurs if the bell is repeatedly sounded, but without food being given.

Front 60

classical conditioning

Back 60

A form of conditioning in which a stimulus with no intrinsic capacity to trigger a particular response acquires such a capacity by being paired with a stimulus that does trigger the response; e.g. a bell can come to trigger salivation in a dog if it is repeatedly presented at the time food is given.

Front 61

blind study

Back 61

A study in which the participants do not know into which group they have been allocated, e.g. whether they have received a drug or a placebo.

Front 62

double-blind study

Back 62

A study in which neither the participants (e.g. patients) nor the experimenters (e.g. therapists) know into which group the participants have been allocated (e.g. either drug or placebo groups).

Front 63

hard problem of consciousness

Back 63

The problem of trying to explain how the subjective feelings of consciousness arise from the physical matter of the brain.

Front 64

electrons

Back 64

Negatively charged particles that surround the nucleus of an atom.

Front 65

protons

Back 65

Positively charged particles found in the nucleus of atoms. The number of protons balances the number of negatively charged electrons.

Front 66

atom

Back 66

The smallest unit of an element that still has the properties of the element. Atoms are made up of a nucleus, containing protons and neutrons, surrounded by electrons.

Front 67

chemical compound

Back 67

A substance made up of two or more elements; it may be composed of molecules or ions.

Front 68

molecule

Back 68

Two or more atoms held together by chemical bonds, e.g. hydrogen (H2), water (H2O), carbon dioxide (CO2).

Front 69

element

Back 69

A substance that cannot be broken down into a simpler substance; it is composed of just one type of atom; e.g. hydrogen, oxygen, nitrogen, sodium, chlorine, mercury.

Front 70

hormone

Back 70

A substance produced by an endocrine gland that is carried by the bloodstream to other organs or tissues where it acts to alter their structure or function.

Front 71

endocrine system (end-oh-krin)

Back 71

A system of glands (also known as ductless glands), each of which secretes one or more hormones directly into the bloodstream.

Front 72

proxy measure

Back 72

A readily measured statistic or parameter that can be used in place of a more complex statistic, or to ‘stand in for’ one that is impossible to measure directly; e.g. disease statistics are often used as proxy measures of the ‘health’ of a population; the number of prescriptions for antidepressants can be used as a proxy measure for the number of people with depression in a population.

Front 73

evolutionary trade-off

Back 73

An aspect of a characteristic that represents an adaptive compromise between two opposing evolutionary pressures; e.g. the human pelvis represents a compromise between being narrow, which is necessary for running at speed, and being wide, which is necessary for giving birth to a baby with a large head.

Front 74

ANS

Back 74

An abbreviation for ‘autonomic nervous system’.

Front 75

cells

Back 75

The basic structural units of all organisms; there are many different kinds of cell in multicellular organisms such as humans; e.g. neurons, red blood cells, epidermal cells, muscle cells, liver cells.

Front 76

CNS

Back 76

An abbreviation for ‘central nervous system’.

Front 77

gate theory

Back 77

A theory of pain that was first proposed by Patrick Wall and Ronald Melzack in 1965. It suggests that there is, metaphorically speaking, a ‘gate’ within the spinal cord such that, if the gate is closed, nociceptive messages can be blocked. If the gate is open, the nociceptive signal can gain access to the brain and hence trigger pain.

Front 78

motor neuron

Back 78

A class of neurons that convey information from the central nervous system to the muscles.

Front 79

referred pain

Back 79

Pain that arises from tissue damage in one part of the body, but which is felt to be arising in a different part of the body. It is said to be ‘referred to’ a part that is not damaged.

Front 80

wind-up

Back 80

A form of plasticity within the connections between the neurons that underlie nociception and pain, such that, over time, increasing levels of pain are experienced.