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80 Cards in this Set
- Front
- Back
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Astrocytes |
nourish neurons and form the blood-brain barrier |
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Microglia |
phagocytic cells that ingest and break down waste products and pathogens in the CNS |
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Schwann Cells |
myelinate axons in the PNS |
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Oligodendrocytes |
myelinate axons in the CNS |
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Glial cells |
- cells in the nervous system that play both structural and supportive roles for neurons - includes astrocytes, microglia, Schwann cells, and oligodendrocytes |
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Sensory neurons |
- receive information from the external world and convey this information to the brain via the spinal cord - specialized for each sense |
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Motor neurons |
relay movement commands from the spinal cord to muscles |
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Interneurons |
- integrate information: connect sensory and motor neurons as well as other interneurons - processes cognitive processes (eg. memory, language, reasoning, morality) |
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Neurons |
Cells in the nervous system that communicate with one another to perform information-processing tasks. |
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What are the parts of a neuron and their function? |
1. Dendrites - receives information from other neurons and relays it to the cell body 2. Cell body (soma) - coordinates information-processing tasks, and keeps the cell alive through functions such as protein synthesis, energy production, and metabolism 3. Axon - carries information to other neurons or effectors (glands and muscles) |
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Axon hillock |
integrates incoming signals |
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Myelin sheath |
an insulating layer of fatty material that speeds up neural transmission |
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Nodes of Ranvier |
breaks in the myelin sheath |
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Terminal buttons |
knob-like structures that branch out from an axon |
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How does a neuron send a signal down the axon? |
conduction of electrical signals |
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How does a neuron send signals to the next neuron? |
through chemical messengers called neurotransmitters |
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Resting potential |
- difference in electric charge between the inside and outside of a neuron's cell membrane - approximately -70 mV |
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"All or none" principle |
- electric stimulation below threshold fails to produce an action potential - electric stimulation at or above threshold produces an action potential with the same characteristics and magnitude every time |
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How do neurons communicate variations in intensity of a stimulus? |
by varying the frequency of firing (more signals = more intense stimulus) |
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Depolarization |
- increase in membrane potential due to an influx of cations (especially Na+) |
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Repolarization |
restoration of negative membrane potential following an action potential, through the efflux of positively charged potassium ions
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Hyperpolarization |
lowering of membrane potential below resting potential, due to an overshoot of effluxing K+ ions |
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Action potential |
an electric signal that is conducted along a neuron's axon to a synapse |
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Saltatory conduction |
"jumping" of electric signal from node to node down the axon |
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What is Multiple Sclerosis? |
an autoimmune disorder where the immune system attacks the myelin sheath, compromising neurons |
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What are the symptoms of Multiple Sclerosis? |
depends on which neurons and what part of the brain is affected: for example, damage of the visual pathway can lead to blindness |
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Synapse |
junction/region between the axon of one neuron and the dendrites/cell body of another neuron |
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Vesicles |
sacs that contain neurotransmitters |
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Neurotransmitters |
chemicals that transmit information across the synapse to a receiving neuron's dendrites |
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Receptors |
parts of the cell membrane that receive neurotransmitters and either initiate or prevent a new electrical signal |
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What causes vesicles to release their neurotransmitters into the synaptic cleft? |
When an action potential reaches the terminal buttons, calcium ions flood into the cell through voltage-gated channels, causing vesicles to fuse with the cell membrane at the synapse. |
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How can a neurotransmitter be removed from the synaptic cleft? |
- enzyme deactivation - reuptake - brings NT back into the presynaptic neuron, where it can be recycled for future use - autoreceptors (on presynaptic neuron) - signal neuron to stop releasing NT when it is in excess |
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How do neurons have different functions? |
depends on where the neuron is in the brain and which NTs it uses |
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Glutamate |
- most common, major excitatory NT in the brain - linked strongly to learning and memory, esp. the creation of new memories |
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Gamma-aminobutyric acid (GABA) |
- primary inhibitory NT in the brain - responsible for depression of CNS activity |
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Dopamine |
- depending on its location in the brain, this NT can be involved in reward, movement, working memory, motivation, and emotional arousal - reward: dopamine release associated with pleasurable feelings so you are more likely to do that action again - could lead to addiction |
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Serotonin |
- involved in the regulation of mood, sleep and wakefulness, eating, and aggressive behaviour - low levels linked to depression |
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Norepinephrine |
involved in (sympathetic) arousal: states of vigilance, or heightened awareness of dangers in the environment |
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Acetylcholine |
involved in memory, attention, voluntary motor control, among others |
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Agonists |
increase the effect of a NT |
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Antagonsists |
reduce the effect of a NT |
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Yerkes-Dodson Curve |
a plot of performance against different levels of NT in the brain |
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What are the four lobes of the cerebral cortex? |
1. Frontal Lobe 2. Parietal Lobe 3. Temporal Lobe 4. Occipital Lobe |
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Frontal lobe |
- motor cortex - controls language (specifically speech) - higher order functions: planning, abstract thinking, memory, judgement |
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Parietal lobe |
- touch cortex: allows you to sense which part of the body is touched - attention |
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Temporal lobe |
- processes auditory information - important for language/speech comprehension - involved in creating new memories, but also an important site for storing long-term memory |
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Occipital lobe |
- processes visual information |
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Thalamus |
- relays and filters information from the senses (except smell), transmitting this information (or not) to the cerebral cortex - important for consciousness |
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Hippocampus |
- critical for creating new memories and integrating them into a network of knowledge so that they can be stored indefinitely in other parts of the cerebral cortex |
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Amygdala |
- important for many emotional processes, esp. the formation of emotional memories
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Corpus Callosum |
a thick band of nerve fibers that connects large areas of the cerebral cortex on each side of the brain and supports communication of information across the hemispheres |
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Basal ganglia |
- directs intentional movement |
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Hindbrain |
- coordinates information coming into and out of the spinal cord
- consists of the medulla, pons, reticular formation, and cerebellum |
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Tectum |
- a part of the midbrain that orients an organism in the environment (ie. toward a stimulus - eg. localization of sound) |
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Tegmentum |
- a part of the midbrain involved in movement and arousal - also helps to orient an organism toward sensory stimuli - contains the substantia nigra, which produces dopamine and sends it to the striatum in the basal ganglia to control movement |
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Pons |
relays information from the cerebellum to the rest of the brain (cerebral cortex) |
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Medulla |
an extension of the spinal cord into the skull that coordinates heart rate, circulation, and respiration |
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Cerebellum |
controls fine motor skills |
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Reticular formation |
regulates sleep, wakefulness, and levels of arousal |
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Sensation |
simple stimulation of a sense organ |
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Perception |
the organization, identification, and interpretation of a sensation in order to form a mental representation |
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Transduction |
process where sensors in the body convert physical signals from the environment into encoded neural signals sent to the CNS |
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Retina |
light-sensitive tissue lining the back of the eyeball |
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Accomodation |
process by which the eye maintains a clear image on the retina |
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Cataracts |
blurring of the lens (often due to age), resulting in blurry images |
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Glaucoma |
buildup of fluid and pressure in the eye which can compress the retina and damage it |
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Macular degeneration |
degeneration of macula and fovea causing distortion of vision and blurriness in the central field of vision |
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Papilledema |
brain swelling which can be seen through the eye through an enlarged optic nerve |
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Fovea |
an area of the retina where vision is the clearest and there are no rods at all |
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Blind spot |
a location in the visual field that produces no sensation on the retina |
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Bipolar cells |
collect neural signals from rods and cones and transmits them to retinal ganglion cells |
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Retinal ganglion cells |
organizes signals from the bipolar cells and sends them to the brain |
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Trichromatic theory |
every colour you see is some combination of Red, Green, Blue, as the pattern across cones yields unique colours |
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Color opponent theory |
- pairs of visual neurons work in opposition - use to explain colour after-image |
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Visual Area 1 (V1) |
the part of the occipital lobe containing the primary visual cortex |
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Visual Area 4 (V4) |
the part of the occipital lobe responsible for processing colour |
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Cerebral achromatopsia |
a type of colourblindness caused by damage to V4 |
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Visual Area 5 (V5)/MT |
the part of the occipital lobe responsible for processing motion |
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Akinetopsia |
damage to V5, leading the person to see "snapshots" of reality as opposed to smooth visual movement |
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Visual form agnosia |
inability to recognize objects by sight |
