Term
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Definition
| a collection of neuronal cell bodies in the CNS. |
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Term
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Definition
| group or ‘bundle’ of functionally related axons in the CNS. These axons can belong to either afferent or efferent neurones. |
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Term
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Definition
| a bundle of axons in the PNS |
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Term
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Definition
| a collection of neuronal cell bodies in the PNS. |
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Term
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Definition
| bundles of axons that carry sensory information from the periphery into the CNS. |
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Term
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Definition
| collection of nerve fibres that exit the spinal cord carrying motor commands to effectors. |
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Term
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Definition
| cells specialised for the conduction and transmission of electrical signals within the nervous system. Also called ‘nerve cells’. |
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Term
| How much does the brain weigh? |
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Definition
Weighs 1.3-1.4kg.
2.5% of body weight |
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Term
| What % of the body's energy does the brain consume? |
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Definition
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Term
| How is the nervous system divide? |
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Definition
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Term
| What does the CNS contain? |
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Definition
| consistsofthebrain(cerebral hemispheres, diencephalon, cerebellum and brainstem) and the spinal cord. |
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Term
| What does the PNS contain? |
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Definition
| consists of all the sensory neurons that link sensory receptors on the body surface (or deeper within it) to relevant processing circuits in the CNS. |
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Term
| How is the PNS further divided? |
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Definition
| afferent and efferent divisions |
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Term
| Describe the afferent division of the PNS |
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Definition
| sensory information detected by receptors is transmitted to sites in the CNS for processing. |
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Term
| Describe the efferent division of the PNS |
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Definition
| motor commands sent by the CNS (in response to signals received from sensory receptors) are transmitted to effectors. |
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Term
| Which division of the PNS is further divided? and what into? |
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Definition
| The efferent division of the PNS is again divided into two parts: somatic nervous system and autonomic nervous system. |
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Term
| What does the somatic nervous system control? |
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Definition
| skeletal muscle (voluntary actions) |
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Term
| What does the autonomic nervous system control? |
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Definition
| controls smooth muscle, cardiac muscle, glandular secretions and adipose tissue. |
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Term
| Which division of the efferent PNS is further divided? and what into? |
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Definition
The autonomic nervous system is further divided into two parts:
1. Sympathetic division: ‘fight or flight’ emergency response.
2. Parasympathetic division :‘relax and eat’ nothing’s going on. |
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Term
| What does the somatic NS control? |
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Definition
| processes under voluntary control, concerned with external environment. |
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Term
| What neurones are found in somatic NS? |
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Definition
1. Motor ‘efferent’ neurones.
2. Sensory ‘afferent’ neurones. |
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Term
| What pathways are found in somatic nervous systems? |
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Definition
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Term
| Where are the cell bodies of somatic lower motor neurones found? what do they connect? |
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Definition
CNS
connect brainstem and spinal cord to muscle fibres |
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Term
| Where are the cell bodies and axons found in motor 'efferent' neurones? |
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Definition
Cell body is in the CNS
Axons are (mostly) in the PNS and are heavily myelinated. |
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Term
| Where are motor 'efferent' neurones derived from? |
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Definition
| Derived from motor neurones in the ventral root of the spinal cord. |
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Term
| What NT do motor 'efferent' neurones use? |
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Definition
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Term
| Where are the cell bodies and axons found in sensory 'afferent' neurones? |
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Definition
Cell body is in the PNS.
Axons are (mostly) in the PNS and can be myelinated or unmyelinated. |
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Term
| Where are sensory 'afferent' neurones derived from? |
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Definition
| sensory neurones in the dorsal root of the spinal cord. |
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Term
| What NT do sensory 'afferent' neurones use? |
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Definition
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Term
Draw a spinal cord section and label
- grey matter
- white matter
- dorsal root
- dorsal root ganglion cell
- ventral root
- spinal nerve |
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Definition
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Term
| What does the autonomic NS control? |
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Definition
| involuntary processes, concerned with internal environment. |
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Term
| What divisions are there in the ANS? |
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Definition
1. Sympathetic
2. Parasympathetic
3. Enteric: an extensive network of neurones in the walls of the digestive tract. |
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Term
| What neurones does the ANS contain? |
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Definition
| it is arranged so that it contains pre-ganglionic and post-ganglionic neurones. |
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Term
| What pathways are found in autonomic nervous systems? |
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Definition
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Term
| Where are cell bodies of autonomic lower motor neurones found and what do they connect? |
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Definition
| connect brainstem and spinal cord to muscle fibres lie outside the CNS. |
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Term
| Describe the anatomy of the sympathetic division of ANS |
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Definition
- Ganglia are close to the CNS
- Pre-ganglionic neurones are short and are myelinated - Post-ganglionic neurones are long and branch extensively but are unmyelinated. |
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Term
| What NT are in the sympathetic division of ANS? |
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Definition
Pre-ganglionic transmitter: ACh
Post-ganglionic transmitter: noradrenaline |
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Term
| Describe the anatomy of the parasympathetic division of ANS |
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Definition
- Ganglia are close to, or in, target tissues.
- Pre-ganglionic neurones are long and are myelinated.
- Post-ganglionic neurones are short and branch minimally and are unmyelinated. |
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Term
| What NT are in the parasympathetic division of ANS? |
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Definition
Pre-ganglionic transmitter: ACh
Post-ganglionic transmitter: ACh |
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Term
| Where are nicotinic receptors found in the nervous system? |
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Definition
| occur on ganglion cells of both sympathetic and parasympathetic divisions and neuromuscular junctions of the somatic nervous system. |
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Term
| What is the effect of ACh on nicotinic receptors? |
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Definition
| ACh always causes excitation of the ganglionic neurone or muscle fibre; it works by opening chemically gated channels on the postsynaptic membrane. |
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Term
| Where are muscarinic receptors found in the nervous system? |
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Definition
| occur at cholinergic neuromuscular or neuroglandular junctions in the parasympathetic division. They also occur at the few cholinergic junctions in the sympathetic division. |
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Term
| How do muscarinic receptors compare to nicotinic receptors? |
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Definition
- Muscarinic receptors are G-proteins.
- Their stimulation produces longer lasting effects than those of the stimulation of nicotinic receptors.
- Their response may be excitatory or inhibitory depending on the activation or inactivation of specific enzymes. |
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Term
| Where does the brain and spinal cord originate from? |
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Definition
| the neural tube which runs the length of the embryo. |
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Term
| Describe neural tube development |
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Definition
1. Neural groove forms – it runs rostral to caudal – and the walls of the groove are called neural folds which subsequently move together and fuse dorsally forming the neural tube.
2. The entire nervous system develops from the walls of the neural tube.
3. As the walls come together some neural ectoderm is ‘pinched’ and comes to
lie just laterally to the neural tube; this tissue is called neural crest.
4. All neurones with cell bodies in the PNS (autonomic nervous system) derive from the neural crest. |
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Term
| Define the prosencephalon, mesencephalon and rhombencephalon |
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Definition
Prosencephalon: the most superior portion of the neural tube.
Mesencephalon: the middle portion of the neural tube.
Rhombencephalon: the most inferior portion of the neural tube, above the spinal cord. |
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Term
| What does the prosencephalon give rise to? |
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Definition
| the telencephalon, which itself will eventually give rise to the structures of the forebrain; cerebral cortex, hippocampus, basal ganglia, basal forebrain nuclei and olfactory bulb and the diencephalon, which will eventually give rise to the thalamus, hypothalamus and optic cups (from which the retina will form). |
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Term
| What does the mesencephalon give rise to? |
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Definition
| the structures of the midbrain; tectum (Latin: ‘roof’), tegmentum (Latin: ‘floor’) and the cerebral peduncles (everything in the mesencephalon except for the tectum). |
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Term
| What does the rhombencephalon give rise to? |
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Definition
| the metencephalon, which will eventually give rise to the structures of the hindbrain; cerebellum and pons and the myelencephalon, which will eventually give rise to the medulla oblongata. |
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Term
| How does the spinal cord form? |
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Definition
With the expansion of the tissue in the walls, the cavity of the tube constricts to form the tiny CSF-filled spinal canal.
It then obviously differentiates into grey matter (neurones are here) and white matter (surrounding the grey matter). |
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Term
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Definition
| (central, rich in neuronal cell bodies in CNS) |
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Term
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Definition
| (outer, large axon tracts in CNS). |
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Term
| What does the spinal cord consist of? |
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Definition
1. Grey matter and white matter
2. Dorsal (afferent) roots and ventral (efferent) roots.
3. Spinal nerves |
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Term
| What spina nerves are there? |
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Definition
mixed afferent and efferent fibres that carry motor, sensory and
autonomic signals between the spinal cord and the body. Humans have 31 pairs of left-right spinal nerves each roughly corresponding to one segment of the vertebral column. |
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Term
| What tracts are in the spinal cord and how are they named? |
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Definition
The major sensory (ascending) and motor (descending) tracts of the spinal cord are named with regard to the destination of the axons:
- if the name of a tract begins with the prefix spino-, the tract starts in the spinal cord and ends in the brain, and it therefore is ascending so carries sensory information.
- if the name of a tract ends in –spinal, its axons start in the higher centres and end in the spinal cord therefore it is a descending pathway so carries motor commands.
- the rest of the tracts name indicates the associated nucleus or cortical area of the brain. |
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Term
| Name the 3 sensory pathways |
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Definition
1. Posteriorcolumn pathway.
2. Spinothalamic pathway.
3. Spinocerebellar pathway. |
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Term
| Where are the axons of the sensory pathways found? |
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Definition
| These will all have their axons in the dorsal root – because it’s sensory! |
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Term
| Name the 3 motor pathways |
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Definition
1. Corticospinal pathway.
2. Medial pathway.
3. Lateral pathway. |
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Term
| Where are the axons of the motor pathways found? |
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Definition
| These will all have their axons in the ventral root – because it’s motor! |
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Term
| Define a first order neurone |
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Definition
| a sensory neurone that delivers sensations to the CNS. |
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Term
| Define a second order neurone |
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Definition
| the axon of the first-order neurone synapses on this interneuron which may be located in the brainstem or spinal cord. |
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Term
| Define a third order neurone |
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Definition
| the second-order neurone synapses on this in the thalamus so the sensation reaches our awareness. |
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Term
| What does the Posterior (dorsal) column pathway carry? |
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Definition
| sensations of highly localised – ‘fine’ – touch, pressure, vibration and proprioception (position of joints and muscles). |
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Term
| What is Posterior (dorsal) column pathway also known as? |
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Definition
| dorsal column-medial lemniscus pathway |
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Term
| Where does the Posterior (dorsal) column pathway begin and end? |
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Definition
| begins at a peripheral receptor and ends at the primary sensory cortex of the cerebral hemispheres. |
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Term
| Where do the first order neurones reside and where do they make contact with the second order neurones in the Posterior (dorsal) column pathway? |
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Definition
first order reside in dorsal root ganglion
make contact with second in medulla and cross over
second order meet at the thalamus and go to cerebral cortex |
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Term
| What does the spinothalamic pathway carry? |
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Definition
| Provides conscious sensations of poorly localised – ‘crude’ – touch, pressure, pain and temperature. |
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Term
| Describe the neurones in the spinothalamic pathway |
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Definition
| he axons of first-order neurones would enter the spinal cord and synapse with second-order neurones and these interneurons ascend ‘contralaterally’ (cross over to the other side of the spinal cord) before ascending to the thalamus. The third-order neurone synapses in the primary sensory cortex. |
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Term
| What are the four types of glial cells in the CNS? |
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Definition
1. Ependymalcells
2. Astrocytes
3. Oligodendrocytes
4. Microglia |
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Term
| Describe Ependymal cells? |
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Definition
| line the central canal (in spinal cord) and ventricles (in brain), (both fluid-filled), where they form an epithelium known as an ependyma. |
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Term
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Definition
| number of functions including; maintenance of the blood-brain barrier and formation of scar tissue after injury. |
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Term
| Describe oligodendrocytes |
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Definition
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Term
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Definition
| remove cell debris, wastes and pathogens by phagocytosis. |
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Term
| What are the two types of glial cells in the PNS? |
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Definition
| satellite and Schwann cells |
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Term
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Definition
| surround neurone cell bodies in ganglia and regulate O2, CO2, nutrient and neurotransmitter levels around neurones in ganglia. |
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Term
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Definition
| surround all the axons in the PNS; they are responsible for myelination of peripheral axons and participate in the repair process after injury. |
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