CNS Overview

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  • Created by: LBCW0502
  • Created on: 03-11-18 12:14
What are the sub-divisions of the NS?
CNS and PNS - Somatic NS, Autonomic NA and Enteric NS - Parasympathetic and Sympathetic NS
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What is the function of the sensory inputs?
Receives information on temperature, pressure, tissue damage from different parts of the body
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What is the function of the motor outputs?
Impulses sent to muscle or gland to produce a response in order to maintain homeostasis
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Where do afferent neurons carry information?
To the CNS
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Where do efferent neurons carry information?
From the CNS
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Where are interneurons located?
Within the CNS - involved in signal processing
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Give examples of glial cells
Ependymal cells, oligodendrocytes, microglia, astrocytes and satellite cells - maintain environment surrounding neurons and support specific functions
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Describe features of ependymal cells
Line the ventricular system - a series of connected cavities in the CNS - include those that secrete the CSF that fills the ventricular system
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Describe features of oligodendrocytes
Form the myelin insulation of axons in the CNS whilst Schwann cells do this in the periphery
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Describe features of microglia
Macrophage-life cells that are important for immune defence and tissue repair in the brain and spinal cord
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Describe features of astrocytes
Regulate and maintain the chemical composition of the extracellular space and maintain a gateway - BBB - between blood vessels and CNS
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Describe features of satellite cells
Small cells that surround neurons in sensory, sympathetic and parasympathetic ganglia and regulate the external chemical environment
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Describe features of a typical nerve cell (neuron) - 1
Dendrites (branched processes, dendritic tree, receives info from other neurons). Cell body (soma, contains nucleus, drives maintenance/metabolism, integrates info received from dendrites). Axon (terminals, release neurotransmitters, pass on info)
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Describe features of a typical nerve cell (neuron) - 2
Axon hillock (where action potential is initiated). Axon is of variable length/conducts action potential, may be insulated by myelin or not. Insulated axons conduct more quickly than uninsulated axons. Neurons - different shapes/sizes
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Describe how neurons act as passive coincidence detectors (1)
Dendritic tree receives different inputs (excitatory/inhibitory). Hyperpolarising/depolarising influences converge and spread to soma. If converge leads to sufficient depolarisation of axon hillock, action potential is generated
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Describe how neurons act as passive coincidence detectors (2)
Action potential propagated along axon to nerve terminal where neurotransmitters are released
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Describe features of the nucleus accumbens
Within the CNS, soma are collected together in nuclei. Also known as locus coeruleus or nucleus reticularis para gigantocellularis. Involved in brain function e.g. pain processing. Small interneurons communicate info between neurons within nucleus
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What are larger interneurons with longer axons called?
Projection or relay interneurons - carry information between different nuclei
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State areas of the brain
Cerebrum, brain stem, cerebellum, spinal cord, corpus callosum, thalamus, hypothalamus, pons, medulla, ventricle, basal ganglia
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What is the function of the cerebral cortex?
Sensory perception, voluntary control of movement, language, personality traits, sophisticated mental events, thinking, memory, decision making, creativity, self-consciousness
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What is the function of the basal ganglia?
Co-ordination of movement
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What is the function of the thalamus?
Relay station for sensory inputs, determines whether we perceive such inputs e.g. do we perceive a damaging stimulus a painful
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What is the function of the hypothalamus?
Regulates several key functions e.g. body temperature, fluid and food intake, key link between nervous and endocrine systems
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What is the function of the cerebellum?
Maintenance of balance, co-ordination of skilled voluntary muscle activity
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What is the function of the brain stem?
Origin of majority of cranial nerves, cardiovascular/respiratory, digestive control centres, regulation of muscle reflexes in equilibrium/posture, reception/integration of all sensory input from spinal cord, arousal/activation
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What are the components in a transverse cross-section of the spinal cord?
Dorsal (back), dorsal horn, grey matter, white matter, ventral horn, ventral (front), ventral root, dorsal root ganglion, dorsal root
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Describe the process of a simple monosynaptic reflex arc
Sensory afferent nerve with soma in dorsal root ganglion. Motor efferent nerve in ventral root (relevant to organ). Second order projection interneuron ascends in white matter of spinal cord (spino-thalamic tract in pain processing)
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What are the four major features which help to protect the CNS from injury?
Cranium and vertebral column (enclosed/hard bony structures, surround brain and spinal cord). Three protective/nourishing membranes, meninges between bony covering and nervous tissue. CSF. BBB limits access of bloodborne materials to brain tissue
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Describe features of the blood-brain barrier
Endothelial cells lining capillaries joined by tight junctions. Barrier supported by astrocytes. Lipid soluble substances can pass. Water/other materials regulated by carrier-mediated systems. Difficult to get drugs across to treat CNS disorders
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Other cards in this set

Card 2

Front

What is the function of the sensory inputs?

Back

Receives information on temperature, pressure, tissue damage from different parts of the body

Card 3

Front

What is the function of the motor outputs?

Back

Preview of the front of card 3

Card 4

Front

Where do afferent neurons carry information?

Back

Preview of the front of card 4

Card 5

Front

Where do efferent neurons carry information?

Back

Preview of the front of card 5
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