Topic 8 key terms

Question 1

Relay neurons

Answer 1

A type of neurone that exists in the CNS and connects sensory neurones with motor neurones.

Question 2

Motor neurones

Answer 2

A type of neurone that transmits impulses from the CNS to effectors.

Question 2

Sensory neurone

Answer 2

A type of neurone that transmits impulses from receptors to relay neurones in the CNS.

Question 3

Dendron

Answer 3

An extension from a nerve cell that carries impulses towards the cell body.

Question 4

Axon

Answer 4

An extension from a nerve cell that carries impulses away from the cell body

Question 5

Schwann cells

Answer 5

Cells that form the myelin sheath around nerve cells in the peripheral nervous system.

Question 6

Myelination

Answer 6

The formation of a myelin sheath around nerve cells by Schwann cells

Question 7

Stimulus

Answer 7

A change in internal or external conditions which brings about a response

Question 8

Receptor

Answer 8

A structure which acts as a transducer by detecting changes in the environment and converting them into electrochemical impulses.

Question 9

Effector

Answer 9

A muscle or gland which produces a response to a stimulus.

Question 10

Pupil

Answer 10

The hole in the centre of the iris which can contract and dilate using the iris to alter the amount of light which contacts the retina.

Question 11

Iris

Answer 11

The pigmented muscular ring that surrounds the pupil and controls its diameter.

Question 12

Retina

Answer 12

The structure at the back of the eye which is composed of photoreceptors and is specialised to detect light.

Question 13

Saltatory conduction

Answer 13

The setting up of localised circuits between nodes of Ranvier which allows for the rapid propagation of an action potential.

Question 14

Nodes of Ranvier

Answer 14

Unmyelinated sections of nerve cells which allow for the propagation of an action potential due to their many ion channels.

Question 15

Depolarisation

Answer 15

The rapid influx of sodium ions into the cell which cause it to lose its negative charge and the membrane potential to increase.

Question 16

Hyperpolarization

Answer 16

The drop in membrane potential below the resting potential after repolarization due to open potassium ion channels.

Question 17

Resting potential

Answer 17

The potential difference across the cell membrane of a neurone at rest which is typically between -60 and -70 millivolts (mV).

Question 18

Acetylcholine

Answer 18

A neurotransmitter used in the parasympathetic nervous system

Question 19

Synapse

Answer 19

The junction between two nerve cells or a nerve cell and an effector.

Question 20

All-or-nothing principle

Answer 20

The principle that describes how any generator potential which reaches or exceeds the threshold potential will produce an action potential of equal magnitude

Question 21

Rods

Answer 21

A type of photoreceptor found in the retina which is specialised to work in dim light.

Question 22

Rhodopsin

Answer 22

A protein found in rod cells that converts dim light into an electrochemical impulse

Question 23

Opsin

Answer 23

A GPCR that forms part of rhodopsin along with retinal and is involved in converting detected photons into electrochemical signals

Question 24

Retinal

Answer 24

A protein that makes up rhodopsin along with opsin and forms the light sensitive part of the complex.

Question 25

Phytochrome

Answer 25

Light sensitive pigments found in plants used to detect changes to external light conditions

Question 26

Indoleacetic acid (IAA)

Answer 26

A type of auxin mainly produced at growing plant tips which is used to promote cell growth and elongation.

Question 27

Hypothalamus

Answer 27

The region of the brain located near the pituitary gland that is involved in homeostatic control including thermoregulation.

Question 28

Medulla oblongata

Answer 28

A region of the brainstem which controls involuntary actions such as heart rate and breathing

Question 29

Cerebellum

Answer 29

A region of the brain that controls voluntary movement and coordination

Question 30

Magnetic resonance imaging (MRI)

Answer 30

A medical imaging technique that uses radio waves and a magnetic field to produce images of internal body structures.

Question 31

Functional magnetic resonance imaging (fMRI)

Answer 31

A medical imaging technique that uses radio waves and a magnetic field to assess brain function through the visualisation of blood flow in brain capillaries.

Question 32

Positron emission tomography (PET)

Answer 32

A medical imaging technique used to assess organ and tissue metabolic function through the use of radioactive molecules and computer analysis.

Question 33

Computed tomography (CT) scan

Answer 33

A type of medical imaging technique that uses several x-rays and computer software to create detailed images of structures and organs inside the body

Question 34

The critical period

Answer 34

A period during visual cortex development where exposure to many different visual stimuli is very important for the full development of neuronal connections.

Question 35

Habituation

Answer 35

The effect seen where animals gradually stop responding to a stimulus after they have been exposed to it repeatedly.

Question 36

Moral issues

Answer 36

Issues that conflict with an individual’s sense of right and wrong

Question 37

Ethical issues

Answer 37

Issues that conflict with the general moral views of society.

Question 38

Parkinson’s disease

Answer 38

A neurodegenerative disease which affects the dopamine secreting neurones and leads to a decrease in motor functions and tremors in resting muscles.

Question 39

L-DOPA

Answer 39

The precursor molecule to the neurotransmitter dopamine which can be given as a treatment for Parkinson’s disease as it is able to cross the blood-brain barrier

Question 40

MDMA

Answer 40

An illegal drug that enhances the release of the neurotransmitters dopamine, noradrenaline and serotonin and can produce symptoms like increased energy and hallucinations when taken.

Question 41

Genetically modified organism (GMO)

Answer 41

An organism which has had its genetic makeup altered through artificial means.

Question 42

Human genome project (HGP)

Answer 42

A collaborative research project by many different institutions to sequence the entire human genome which was finished in 2003.

Question 43

Resting potential

Answer 43

The potential difference across the cell membrane of a neurone at rest which is typically between -60 and -70 millivolts (mV).