SD329 Block 1 & 2 Definitions

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All the bold text definitions in block 1 & 2 of SD329.
Glen Rooney
Flashcards by Glen Rooney, updated more than 1 year ago
Glen Rooney
Created by Glen Rooney over 2 years ago
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Question Answer
Neuron A type of cell in the nervous system specialised to transmit information
Glia/Glial Cell Non-neuronal cells found in the nervous system. They have a range of vital support roles for neurons, which include guiding the connections formed between neurons during brain development, or producing the myelin that acts as an insulator for neuronal axons.
Afferent Carrying information towards more central structures
Efferent Carrying information from the central structures of the brain
Cerebral hemispheres The two halves of the main brain mass lying on either side of the sagittal plane above the brainstem and cerebellum
Cerebral cortex The outer layer of neurons that covers the cerebral hemispheres of mammals and is responsible for sensations perceptions, learning, voluntary movement, speech and cognition
Brain stem The collective name for the midbrain and the pons and medulla of the hindbrain
Cerebellum The portion of the brain located beneath the occipital and temporal lobes. A component, together with the pons and medulla, of the hindbrain. It is primarily a movement control centre.
Spinal cord The part of the central nervous system that is located within the column of vertebrae that make up the spine
Frontal lobe One of four lobes of the cerebral cortex situated at the front of the brain. It is associated with motor control and higher mental processes.
Parietal lobe One of the four lobes of the cerebral cortex situated at the top of the brain. It is associated with bodily sensations and perceiving spatial relationships.
Temporal lobe One of the four lobes of the cerebral cortex situated at the base of the brain. It is associated with the sense of hearing.
Occipital lobe One of the four lobes of the cerebral cortex situated at the rear of the brain. It of associated with the sense of vision.
Dorsal Below the neck, its the direction towards the back. Above the neck, its towards the top of the brain.
Posterior Below the neck, its the direction towards the back (also called dorsal)
Ventral Below the neck, its the direction towards the front. Above the neck, its towards the base of the brain.
Anterior Below the neck, its the direction towards the front (also called ventral)
Alpha-amino acids Compounds with molecules having an amino group and a carboxyl group attached to the same carbon atom. The constituents of the naturally occurring group of molecules called proteins. There are 20 different amino acids found in proteins.
Absolute refractory period The period of time after the generation of an action potential when no amount of depolarization can initiate another action potential
Action potential A momentary and localised change in electrical potential across the membrane of a neuron (or muscle cell) caused by a rapid change in the membranes permeability to Na+
Active transport Transport of a substance across a biological membrane against its concentration gradient. This process requires energy.
Adaptation 1. The change in perception of a sensory experience with time while the stimulus is unchanged. 2. Sensory receptor adjustment to different levels of stimulation which allows systems to operate over a wide dynamic range. (See 'sensory adaptation')
Additive Primary Colours The 3 colours of light (red, green and blue) that are sufficient to create any colour of the visible spectrum.
Ageusia The absence of the sense of taste.
All-or-nothing Response The response of the neuron once the threshold potential has been reached, i.e. the firing of the action potential. Below the threshold there is no response.
Amplitude The maximum departure of an oscillating system from its average value.
Anosmia The absence of the sense of smell.
Arachidonic Acid (AA) A polyunsaturated fatty acid that can act as an intracellular messenger. It is released by the cell membranes by the action of an enzyme which is activated by G-proteins (and by some other stimuli). It acts to stimulate a variety of intracellular signalling pathways and is a precursor of other signalling molecules such as prostaglandins.
Association Axon Axon which links two areas of the cerebral cortex
Astrocyte A type of star-shaped glial cell found in large numbers in the CNS. Astrocytes give structural support to neurons and are thought to be involved in the regulation of their metabolism
Axon Hillock The region of the cell body from which the axon emerges, and where the action potential is usually first generated
Axon The extension of a neuron that by virtue of its excitable membrane, conducts action potentials away from the cell body
Axon Terminal Small terminal expansion of the axon at the synapse where neurotransmitter molecules are stored and released
Axoplasm The intracellular constituents within an axon
Background Firing Rate The spontaneous rate of generation of action potentials in a neuron in the absence of stimulation, e.g. the activity observed in retinal ganglion cells when their receptive fields are uniformly illuminated
Blood-Brain Barrier A barrier formed by special cells, with tight seals between them, that line the blood vessels of the brain; it regulates the movement of chemicals from the blood to the fluid that bathes the neurons of the brain
Bodily Senses (somatic sensory system) The part of the peripheral nervous system concerned with the bodily or general senses of touch, pain, temperature, proprioception and kinesthesis
Brainstem The collective name for the midbrain and the pons and medulla of the hindbrain
Brodmann's areas The 47 separate zones of the brain differentiated by the German neuroscientist Korbinan Brodmann on the basis of their visually distinctive anatomical appearance.
Carriers Also called transporters, these membrane proteins transfer small specific molecules and ions across membranes. They bind to a solute molecule (or ion) and release it on the other side of the membrane. Carrier-mediated transport can be either passive or active.
Caudal Below the neck, it's the direction towards the feet; above the neck, it's towards the back of the brain.
Central Canal The tube running down the centre of the spinal cord, filled with cerebrospinal fluid (CSF)
Central Nervous System (CNS) The brain and the spinal cord
Cerebellum The portion of the brain located beneath the occipital and temporal lobes. A component, together with the pons and medulla, of the hind brain. Primarily a movement control centre. https://www.youtube.com/watch?v=Fir-v6EoZNE
Cerebral Cortex The outer layer of neurons that covers the cerebral hemispheres of mammals and is responsible for sensations, perceptions, learning, voluntary movement, speech and cognition https://www.youtube.com/watch?v=mGxomKWfJXs
Cerebral Hemispheres The two halves of the main brain mass lying on either side of the sagittal plane above the brainstem and cerebellum
Cerebrospinal Fluid (CSF) The fluid produced in the ventricular system, which fills the ventricles and central canal of the spinal cord as well as the subarachnoid space around the brain and spinal cord. It acts both as a cushion for the brain within the skull and as a source of nutrients for it. https://www.youtube.com/watch?v=yWR3nML_R8Q
Channels Membrane proteins that enable transfer of the small specific substances (usually ions) across membranes. Channels provide an aqueous pore in the membrane through which solutes can pass. Channels allow only passive movement of solutes. https://www.youtube.com/watch?v=gWLqXEyEWM0
Chemical Senses The sense of smell and taste
Chemical Synapse A synapse where information is exchanged between cells as a chemical signal in the form of molecules called neurotransmitters. https://www.youtube.com/watch?v=mItV4rC57kM
Chemoreceptor A receptor activated by interaction with a molecule
Cochlea The coiled structure of the inner ear that contains the receptor cells for hearing where sound stimuli are converted to electrical signals. https://www.youtube.com/watch?v=WeQluId1hnQ
Collaterals The axon branches of neurons (e.g pyramidal cells)
Complementary Colours Those colours (wavelengths) of light which, when added in equal proportions, produce white (uncoloured) light. E.g red and cyan, blue and yellow.
Conduction Velocity The speed at which an action potential travels along an axon.
Contralateral On the opposite side of the central plane
Convergent Inputs Axons from many neurons which all synapse on a single cell
Coronal Plane Any plane that divides the brain vertically into a front section and a rear section
Corpus Callosum The thick bundle of axons that forms a bridge between the two cerebral hemispheres. It is composed of axons which connect the corresponding areas of each hemisphere. https://www.youtube.com/watch?v=xMvVAfZcU1s
Cutaneous Of the skin
Cytoskeleton System of long filament-like protein polymers, which confer shape and support to the cell and mediate many types of cellular movement. https://www.youtube.com/watch?v=oIrnecBfHzg
Dendrite Extension of a neuron that receives many synapses from other neurons. It does not usually conduct action potentials.
Dendritic Spines Small protrusions on the surface of dendrites which are contacted by, usually, one pre-synaptic terminal.
Depolarization A change in membrane potential towards a LESS negative value.
Depth Cue A specific feature of the two-dimensional image of an object that enables the visual system to interpret the three-dimensional structure of that object.
Dermatome The area of skin whose sensory receptors are sensory neurons that lie in one single dorsal root ganglion. https://www.youtube.com/watch?v=ZZ0nNplN_KE
Distal Further from the centre of origin
Divergent Outputs The outputs of one neuron that form the inputs to a number of other neurons.
Dorsal Below the neck it's the direction towards the back. Above the neck it's the direction towards the top of the brain.
Dorsal Column Nuclei The nuclei in the dorsal part of the medulla where the axons of the dorsal columns terminate. The neurons of the dorsal column nuclei relay touch information to the ventrobasal nucleus of the thalamus on the opposite side of the brain. https://www.youtube.com/watch?v=nQfRUehU4zQ
Dorsal Columns The bundles of uncrossed axons that ascend from the dorsal spinal cord to the medulla and transmit information about touch
Dorsal Horn The dorsal part of the central grey matter of the spinal cord. It contains neurons that receive inputs from sensory axons.
Dorsal Root The bundle of sensory axons that enter the dorsal part of the spinal cord
Dorsal Root Ganglia A swelling of the dorsal root just before it enters the spinal cord. Contains the cell bodies of the sensory neurons in the dorsal root.
Efferent Carrying information from the central structures of the brain
Electrical Synapse A synapse where information is passed between cells as an electrical signal
Electroencephalography (EEG) This is a direct functional imaging technique that detects electrical activity associated with brain function via arrays of electrodes that are attached to the scalp
Endocytosis A process by which a cell takes in substances or particles by surrounding them with part of the cell membrane, which then becomes detached to form a 'bubble' (vacuole) within the cell. The opposite process is exocytosis. Endocytosis is important in the re-uptake of neurotransmitter molecules into the pre-synaptic cell or glial cells.
Endorphins A group of endogenous peptides that activate opiate receptors, producing a feeling of wellbeing and tolerance to pain.
Enkephalin An endogenous pentapeptide with the structure H-Tyr-Gly-Gly-Phe-Xaa-OH (where Xaa is one of the two amino acid residues Met or Leu), which activates opiate receptors.
Enteroceptor A receptor that responds to a change in the internal conditions within an animals body.
Exafferent Stimulation of sensory receptors by changes in the external environment that do not result from one's own movement
Excitatory Post-synaptic Potential (EPSP) A change in local potential occurring at the synapse which depolarizes the post-synaptic cell and thus makes an action potential more likely. https://www.youtube.com/watch?v=u3DLs3eGc48
Exocytosis The process by which molecules are released from cells. Secreted molecules are stored in membrane-bound vesicles, which fuse with the plasma membrane. The opposite process is endocytosis. https://www.youtube.com/watch?v=VOzV4d0HKis
Exteroceptor A receptor that responds to stimuli external to the animal.
Extracellular Outside the cell
Firing The passage of action potentials
Frequency The number of complete cycles of a periodic process in one second
Frontal Lobe One of the four lobes of the cerebral cortex situated at the front of the brain. It is associated with motor control and higher mental processes.
Functional Imaging One of several techniques such as MEG, EEG, PET and fMRI, which have become increasingly associated with experiments to locate distinct anatomical regions of the brain that perform particular sensory, motor or cognitive functions, and in what order, in response to carefully controlled stimulus.
Functional Magnetic Resonance Imaging (fMRI) An indirect functional imaging technique which, in one version, is able to detect local increases in blood flow in activated areas of the brain and display these as highlighted areas on a conventional MRI scan.
Fundamental The component with the lowest frequency in a complex wave.
G-protein Receptor A receptor molecule that typically spans the cell membrane seven times. When it binds to its ligand (which can be a neurotransmitter or a hormone) intracellular G proteins are activated. https://www.youtube.com/watch?v=N7o0Fkz9iGE
Glia / Glial Cell Non-neuronal cells found in the nervous system. They have a range of vital support roles for neurons, which include guiding the connections formed between neurons during brain development, or producing the myelin that acts as an insulator for neuronal axons. https://www.youtube.com/watch?v=AwES6R1_9PM
Golgi Apparatus (Golgi Complex) The cell organelle that processes and packages proteins into membrane-bound vesicles for delivery to different parts of the cell, or out of the cell. https://www.youtube.com/watch?v=fqXGKDmV9Vs
Grey Matter The regions of the central nervous system such as the central region that consist mainly of neuronal cell bodies.
Gyrus (pl. Gyri) A ridge on the cerebral cortex
Harmonic A sine wave component of a complex wave, with a frequency that is a whole number multiple of the fundamental frequency.
Height-in-the-field A depth cue resulting from the position of an object in a picture relative to the horizon. (See also 'relative height)
Horizontal Plane A plane that divides the brain horizontally.
Hyperpolarization A change in the membrane potential to a value MORE negative than the resting value.
Hypogeusia Impaired sense of taste.
Hyposmia Impaired sense of smell.
Illumination A measure of the amount of light falling upon a surface
Illusion A misperception of physical reality usually caused by misleading interpretations of the signals received by our senses by the misapplication of particular cues.
Impossible Figures A type of visual illusion in which two-dimensional images containing conflicting depth cues represent three-dimensional figures that therefore could not exist in reality.
Inferior Above the neck it's the direction towards the base of the brain. (See also 'ventral')
Inhibitory Post-synaptic Potential (IPSP) A change in the membrane potential of a neuron produced by synaptic activity that decreases the overall depolarization of the post-synaptic cell and makes the neuron less likely to generate an action potential. https://www.youtube.com/watch?v=NUIGGvzLd3g
Innervation The distribution of nerves to an organ
Interneurons Neurons that form connections between other neurons. Strictly speaking, they are all interneurons except for the first sensory afferent in any pathway and the final motor efferent.
Interposition A depth cue resulting from the obscuring of more distant objects by nearer ones.
Intrinsic Neurons Neurons whose axons remain within the area where the cell bodies are located, e.g in the cerebral cortex
Ionotropic Receptor A receptor molecule that, when activated by binding to a ligand, forms a channel that spans the membrane.
Ipsilateral On the same side of the bodies central plane
Kinesthesis The sense that provides information about the movement of individual body parts. Also known as dynamic proprioception.
Labelled Line Code A system of coding information whereby a particular neuron, or pathway of neurons, would be sensitive to and transmit information on a particular quality of stimulus, such as touch. https://www.youtube.com/watch?v=PwrYg_dr6Nc
Lateral Further away from the bodies central plane.
Lateral Geniculate Nucleus The specific thalamic nucleus whose neurons relay visual information to the primary visual cortex. https://www.youtube.com/watch?v=fkzdUBseKek
Lateral Inhibition The process whereby, through inhibitory interneurons, it is possible to have antagonistic relationships between two areas of a receptive field and thus to accentuate locations where there is a stimulus discontinuity. https://www.youtube.com/watch?v=lYmQWm3ZtlA
Lesions Regions of damaged brain tissue.
Ligand A molecule, such as a neurotransmitter, that binds specifically to a receptor to form a receptor-ligand complex.
Lightness The perception corresponding to surface reflectance
Lightness Constancy The capacity of the visual system to interpret surface reflectance consistently despite differences in lighting conditions
Linear Perspective The depth cue that makes use of the appearance of parallel lines converging as they recede into the distance
Longitudinal Wave A wave with the oscillations being along the direction of travel of the wave
Luminance A measure of the amount of light projected by a surface
Magnetoencephalography (MEG) A direct functional imaging technique that is able to detect, and locate, the very weak magnetic fields associated with the electrical currents caused by neural activity
Mechanoreceptor A sensory receptor cell activated by mechanical forces such as pressure. They are involved in hearing, balance and touch sensations
Medial Closer to the body's central plane
Medial Geniculate Nucleus The specific thalamic nucleus whose neurons relay auditory information to the primary auditory cortex https://www.youtube.com/watch?v=R0LnPupYHyw
Medulla The most inferior part of the brainstem that connects with the spinal cord. Dorsally it comprises the dorsal column nuclei. Other medullary neurons help to control breathing and blood circulation. https://www.youtube.com/watch?v=R6XtJOeuhNg
Meissner's Corpuscle A type of cutaneous sensory receptor cell that responds to light touch and vibration. Found in glabrous skin. https://youtu.be/vF80u3qJkkQ?t=65
Membrane Potential Difference in electrical voltage between the inside and outside of a living cell produced by selective permeability of the membrane to ions. A value of -70mV (inside negative with respect to the outside) is typical for a human neuron.
Merkel's Discs A type of cutaneous sensory receptor cell that responds to light touch and pressure https://youtu.be/vF80u3qJkkQ?t=52
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