Glossary

 

Aggregation- Clumping together.

 

Amyloid Protein- An insoluble fibrous protein responsible for the plaques formed in Alzheimer’s disease.

 

Apoptosis- A mechanism of cell death, also called Programmed Cell Death (PCD).  It does not cause an inflammatory response or damage neighbouring cells. The DNA condenses and is broken up, the cell shrinks and small pieces of it called apoptotic bodies break off to be consumed by macrophages.

 

Apoptotic Body- The small pieces of a cell that break off during apoptosis and are engulfed by macrophages.

 

Axon- Part of a neuron that carries a signal away from the cell body to other cells and synapses with them.  Can be very long, up to half a metre.

 

Basal Forebrain- A group of structures in front of the striatum near the front and base of the brain.  It is important in the production of the neurotransmitter acetylcholine which is important in synaptic plasticity, a feature of learning and memory.

 

BDNF- Brain Derived Neurotrophic Factor, a neurotrophin.

 

Ca²⁺ - A calcium ion

 

Caudate- Part of the Striatum

 

Cell body- The part of a neuron that contains the nucleus, does not include any of the axons or dendrites.

 

Central Nervous System- The brain and spinal cord.

 

Cerebellum- An area of the brain important in somatic motor activity, balance and muscle tone.

 

Cerebral Cortex- The outer portion of the cerebrum, the top part of the brain.  It is important in thought, memory, personality, attention, language and awareness.

 

Chromosome- A strand of DNA.  There are 46 in the human genome.

 

CNTF- Ciliary Neurotrophic Factor

 

Cytokine- A small molecule released from cells that has roles in cell-cell communication and behaviour.

 

Cytoplasmic- Refers to the cytoplasm; the part of a cell surrounded by the plasma membrane but not including the organelles.

 

Dendrites- Part of a neuron that receives signals from other cells via synapses and carries them to the cell body.

 

Dementia- A progressive decline in cognitive function

 

Differentiation- The process where a cell develops into a certain cell type rather than remaining pluripotent.

 

DNA- Deoxyribonucleic Acid.  A molecule that stores the genetic information of the cell via a pattern of base molecules.  Some of these bases are grouped into threes called codons, each codon encodes one amino acid that is a building block for a protein.  Many codons make up a gene. Other bases form regulatory sequences that control expression of genes, others are known as “junk” DNA for which there is no known purpose.  DNA is stored within the nucleus.

 

Dopamine- A neurotransmitter

 

Dopaminergic Neuron- A neuron that secretes the neurotransmitter dopamine.

 

Endocrine- Relating to hormones

 

Enzyme- a protein with the ability to break molecules apart via a chemical reaction.

 

Free Radical- A very reactive molecule with unpaired electrons.   

 

GDNF- Glial Derived Neurotrophic Factor

 

Gene- A portion of DNA that codes for a particular protein.

 

Glial Cell- Are not neurons but are cells of the nervous system.  They surround neurons to provide mechanical and physical support as well as insulating neurons from each other.

 

Glutamate- a neurotransmitter

 

Growth Hormone- A hormone that stimulates growth and cell reproduction.

 

HGF/SF- Hepatocyte Growth Factor/ Scatter Factor

 

Hippocampus- An area of the brain important in the storage of long-term memory.

 

Huntington’s Disease- An inherited neurodegenerative disease characterised by loss of neurons in the striatum and cerebral cortex

 

Huntingtin- The protein that is mutated in Huntington’s Disease and causes damage and aggregation of neurons.

 

Hydrostatic Pressure- The pressure exerted by a liquid as a result of its potential energy, ignoring its kinetic (movement) energy.

 

IGF-1- Insulin Like Growth Factor-1

 

Insulin- A hormone that increases the uptake of glucose by cells and the formation of it into glycogen by the liver.

 

Ion- a charged atom or molecule

 

K⁺ - A potassium ion

 

Ligand- The molecule that binds to a receptor.

 

Lysosomal- refers to lysosomes; cell organelles that contain enzymes.

 

Macrophage- A white blood cell that forms part of the body’s immune system.  It engulfs unwanted foreign bodies or waste products and breaks them down.

 

Mg²⁺ - A magnesium ion

 

Mitochondria- A cell organelle that is responsible for energy production via respiration. 

 

Motor Neuron – A neuron that carries signals to muscles.  Upper motor neurons originate in the brain and terminate in the spinal cord, lower motor neurons start in the spinal cord and directly innervate muscles.

 

Na⁺ - A sodium ion

 

NCS1- Neuronal Calcium Sensor 1.  Has many roles including improving neuronal survival.

 

Necrosis- A mechanism of cell death that follows a traumatic injury to the cell.  The cell is broken down by enzymes; this can cause an inflammatory response and harm other cells nearby.

 

Neural Crest- A group of embryonic cells that give rise to the spinal and autonomic ganglia, glial cells, melanocytes, chromaffin cells and haematopoietic cells.

 

Neurodegenerative Disorder- A disease characterised by excess loss of neurons.

 

Neuron- The messenger cell of the body.  It is excitable, with the ability to transmit signals, or action potentials over long distances.  Many together make up nerves.

 

Neurotransmitter- A substance released by a neuron at a synapse that is detected by another neuron or target cell where it causes a response.

 

Neurotrophin- A molecule that increases the chance of a neuron surviving when it binds to a receptor on the neuron.

 

NGF- Nerve Growth Factor, a neurotrophin.

 

NMDA receptor- N Methyl D Aspartate Receptor, binds glutamate.  Has a role in neuron survival.

 

NT-3- Neurotrophin-3

 

NT-4- Neurotrophin-4

 

Oestrogens- A group of steroid hormones released from the ovaries.  The primary female sex hormone

 

Organelle- a structure within a cell surrounded by its own membrane. E.g. nucleus and mitochondria.

 

P75 receptor- Binds to the neurotrophin family, can either increase or decrease a neuron’s chances of survival.

 

Parkinson’s Disease- Neurodegenerative disease characterised by the loss of dopaminergic neurons in the substantia nigra.

 

Peripheral Nervous System- The nervous system that does not include the brain and spinal cord.

 

PET Scan- Positron Emission Tomography Scan.  An imaging technique that measures gamma radiation from a positron emitting tracer in the body.

 

Proneurotrophin- The form that neurotrophins are made in which are then cleaved by enzymes to release the mature neurotrophin.  The proneurotrophin can have a different or completely opposite effect to the neurotrophin.

 

Putamen- Part of the Striatum

 

Pyknosis- The condensing of nuclear material during apoptosis.

 

Receptor- A protein that binds a certain molecule to exert an effect within a cell.

 

Sensory neuron- A neuron that carrying information about what is present or happening around in the body or surrounding environment.

 

Substantia Nigra- An area of the brain that secretes dopamine onto the striatum to inhibit it.

 

Superior Cervical Ganglion- A ganglion (group of cells) on the level of the second and third cervical vertebrae.  Contains mostly sympathetic neurons.

 

Striatum- Part of the brain, inhibits motor function.

 

Sympathetic neuron- A neuron that forms part of the sympathetic nervous system, the system responsible for the “fight or flight” response.  When this system is activated the results are the release of noradrenalin from the sympathetic neurons and adrenaline from the adrenal gland.   This leads to an increase in heart rate, pupil dilation, increased blood flow to skeletal muscles and decreased blood flow to the gut.

 

Synapse- Where two neurons or a neuron and a target cell meet and transfer information across the gap (synaptic cleft) between them.  The pre-synaptic neuron releases neurotransmitter into the cleft when an action potential reaches the synapse, the neurotransmitter diffuses across the cleft and binds to receptors on the post-synaptic membrane which triggers another action potential.

 

Testosterone- The primary male sex hormone, released from the testis or and in small amounts from the adrenal gland.

 

TGF-beta Family- Transforming Growth Factor- beta Family.  A family of molecules that interacts with serine/threonine kinase receptors and causes signal formation within cells using proteins called SMADs.  They have roles in growth, differentiation, homeostasis and regulation of the immune system.

 

Transcription- The process where the information encoded by DNA bases is converted into mRNA by the enzyme RNA polymerase. The mRNA is then used to assemble the protein in a process known as transcription.

 

Trk receptors- Receptors for the neurotrophin family that set up a survival signal within a neuron.

 

Trophic Factor- A molecule or protein that increases a cell’s chances of survival when it binds to one of the cells receptors.

 

Tyrosine Kinase- A molecule with the power to add a phosphate group onto a tyrosine (a type of amino acid) residue in a protein.