Neurons and Glia (Physiology 2)

Neurons and Glia - Dr Dean Semmens Lecture Outline Welcome to the Neurons and Glia lecture. Nerve cells form the electrical circuits that underpin all aspects of our daily activities, from exploring the world around via our sensory systems to generating motor responses to experienced events. We understand, think, plan and remember. Glial cells used to be thought of as little more than packing material, but we now know that they are as important to neural function as the nerve cells themselves. This lecture will look at how we learned about the structural components and features of these cells, and how the structures revealed via increasing sophisticated microscopy techniques have illuminated the function of neurons and neuronal circuits. Desired Learning Outcomes By the end of this lecture, students should be able to: Discuss key techniques that are used to study microanatomical features of the brain Describe the structure and function of a prototypical neuron Describe the function of different types of glial cell Session Resources You can find the full set of PowerPoint slides for the lecture HERE Download HERE. You can find a Kahoot! quiz for the lecture HERELinks to an external site.. Further Reading If you would like to read further or consolidate your knowledge on the topic, I would recommend the following further reading: Neuroscience: Exploring the Brain 3rd or 4th Edition (Bear, Connors, Paradiso) Chapter 2. Any Questions? If you have any questions on the lecture, please feel free to add it to the Padlet discussion board below. Alternatively, please do me email me (dsemmens@sgul.ac.uk) and I'll be very happy to help. I have left some student questions from last year on the Padelt discussion board, just incase this may help with any similar questions that you may have: Made with Padlet Glossary Anterograde transport – A cellular process responsible for the movement of substance from the cell body to the distal parts of a cell Aspinous neuron – A neuron lacking dendritic spines Astrocyte – A star-shaped glial cell of the central nervous system ATP – Adenosine triphosphate, a high-energy molecular found in every cell Axon – The long thread-like part of a neuron along which impulses are conducted from the cell body to other cells Axon collateral – Branches off a neuron’s main axon Axon hillock – The site in the soma where membrane potentials propagated from synaptic inputs are summated before being transmitted to the axon Axon terminal (bouton) – The enlarged club-shaped endings by which axons make synaptic connections with other neurons or effector cells Axoplasmic transport – A cellular process responsible for the movement of substances from the soma down the axon Bipolar neuron – A neuron with two neurites extending from the soma Cell body – The nucleus-containing part of a cell Cytoplasm – The material or protoplasm within a living cell, excluding the nucleus Cytoskeleton – A microscopic network of protein filaments and tubules in the cytoplasm of many living cells, giving them shape and coherence Cytosol – The aqueous component of the cytoplasm of a cell, within which various organelles and particles are suspended Dendrite – A short branched extension of a neuron, along which impulses received from other cells at synapses are transmitted to the cell body Dendritic tree – The structure formed by multiple dendrites from the same neuron Dendritic spine – A small membranous protrusion from a neuron’s dendrite that typically receives input from a single axon at the synapse, supported by an actin cytoskeleton DNA – Deoxyribonucleic acid, a self-replicating material which is present in nearly all living organisms as the main constituent of chromosomes. It is the carrier of genetic information. Endoplasmic reticulum – A network of membranous tubules within the cytoplasm of a eukaryotic cell, continuous with the nuclear membrane. It usually has ribosomes attached and is involved in protein and lipid synthesis. istology – The study of the microscopic structure of tissues. Gene – A unit of heredity; a distinct sequence of nucleotides forming part of a chromosome, the order of which determines the order of monomers in a polypeptide or nucleic acid molecule which a cell may synthesise Gene expression – The processes of DNA transcription and translation Genetic engineering – The deliberate modification of the characteristics of an organism by manipulating its genetic material. Genome – The complete set of genes present in a cell or organism Glial cell – Supporting cells of the nervous system. Three types (astrocytes, oligodendrocytes and Schwann cells) are created from the neuroepithelial cells of the neural tube, and are hence siblings of nerve cells. Golgi apparatus – A complex of vesicles and folded membranes within the cytoplasm of most eukaryotic cells, involved in secretion and intracellular transport Golgi stain – A silver staining technique that is used to visualise nervous tissue under light microscopy. Green fluorescent protein – A protein that glows green under fluorescent light. Interneuron – A neuron which transmits impulses between other neurons. Microglia – Immune cells that migrated in to the central nervous system during early development, that function as macrophages. Microfilament – A small rod-like structure present in numbers in the cytoplasm of many eukaryotic cells. Microtubule – A microscopic tubular structure present in numbers in the cytoplasm of many eukaryotic cells, sometimes aggregating to form more complex structures. Mitochondrion – An organelle in which the biochemical process of respiration and energy production occur. Multipolar neuron – A neuron with multiple neurites extending from the soma Myelin – A mxture of proteins and phospholipids forming an insulating sheath around neurons. Neurite – Neuronal processes extending from the soma, namely axons and dendrites Neurofilament – Intermediate filaments found in the cytoplasm of neurons. Neuron – A specialised cell that transmits nerve impulses. Neuronal membrane – The cell membrane of the axon, soma and dendrites of a neuron. Neurotransmitter – A chemical substance which is released at the end of a nerve fibre by the arrival of an action potential, by diffusing across the synapse or junction, effects the transfer of the impulse to another neuron, muscle fibre, or other structure. Nissl stain – A method for staining RNA to visualise neurons Node of Ranvier – A gap in the myelin sheath of a neuron Nucleus – A dense organelle present in most eukaryotic cells, containing the genetic material. Oligodendrocyte – A glial cell concerned with the production of myelin in the central nervous system. Organelle – A specialised structure within a living cell Perikaryon – The cell body of a neuron, containing the nucleus. Also known as the soma. Primary sensory neuron – Neurons with neurites in the sensory surfaces of the body. Protein – Nitrogenous organic compounds which have large molecules composed of one or more long chains of amino acids. Protein synthesis – The process by which amino acids are linearly arranged into proteins, termed translation. Receptor – A protein in a cell membrane which responds specifically to a particular neurotransmitter, hormone, antigen, or other substance. Retrograde transport – A cellular process responsible for the movement of substance from the distal parts of a cell to the cell body Ribosome – A particle consisting of RNA and associated proteins; they bind mRNA and transfer RNA to synthesise polypeptides and proteins. RNA – ribonucleic acid, its principal role is to act as a messenger carrying instructions from DNA for controlling the synthesis of proteins. Schwann cell (neurolemmocyte) - A glial cell concerned with the production of myelin in the peripheral nervous system. Soma – The cell body of a neuron, containing the nucleus. Also known as the perikaryon. Spiny neuron – A neuron with dendritic spines Synapse - A junction between two neurons, consisting of a minute gap across which impulses pass by diffusion of a neurotransmitter. Synaptic cleft – See ‘synapse’. Synaptic transmission – The process by which one neuron communicates with another via release and detection of a neurotransmitter. Synaptic vesicle – A small secretory vesicle that contains neurotransmitter, found inside an axon near the presynaptic membrane, and releases its contents into the synaptic cleft after fusing with the membrane. Terminal bouton – The specialised presynaptic terminal at the end of an axon. Transgenic mice – A genetically modified mouse that has had its genome altered through the use of genetic engineering techniques. Unipolar neuron – A neuron with a single neurite extending from the soma