Neuro Flashcards
How many lobes are there in the brain (basic)?
4
Name the lobes in the brain
Frontal, parietal, occipital and temporal
What is the frontal lobe’s function?
Voluntary contralateral motor control, control of speech and writing (from dominant sphere) and higher thinking centres
What is the parietal lobe’s function?
interprets sensations including pain, 2-point discrimination, pressure, size, shape and body part awareness (proprioception)
What is the occipital lobe’s function?
understanding visual images and written word meanings
What is the temporal lobe’s function?
understanding spoken words (Wernicke’s), sounds as well as memory and emotion
Name 4 prominent sulci found in the cerebrum
central sulcus, lateral sulcus, post-central sulcus, and per-central sulcus
What is another name for the lateral sulcus?
the Sylvius fissure
Name 3 prominent gyri in the cerebrum and their function
Precentral gyrus (PMC), postcentral gyrus (SSC) and superior temporal gyrus (auditory processing)
Where is the superior temporal gyrus found?
Inferior to the lateral sulcus
Where is the precentral and postcentral gyrus found?
anterior to the central suclus and posterior to the central sulcus respectively
What is the falx cerebri?
Tough piece of dura mater found in the medial longitudinal fissure that separates the 2 hemispheres
What is the tentorium cerebelli?
Tough dura mater seperating the occipital lobe from the cerebellum
What is the function of the Broca’s area of the brain?
Language production
Where is Broca’s area located?
Frontal lobe, dominant hemisphere (usually left), Brodmann 44
What is the function of Wernicke’s area of the brains?
Language comprehension
Where is Wernicke’s area located?
Posterior part of the superior temporal gyrus, dominant hemisphere (usually left), Brodmann 22
What is the theory of dominance?
Most cognitive processes are on one side of the brain e.g. Broca’s and Wernicke’s
What is the homunculus?
Contralateral inverted somatotropic representation of the body in motor and somatosensory cortex
Is the homunculus proportionally divided?
No, it is distorted. Beginning from the toes at the top of the hemispheres, it moves up the body as it moves down the brain generating an upside-down man with arms raised and a flipped face. His lips, face, hands and feet are disproportionally large.
What is the rule in terms of the cortex and body part innervation?
Size of area in the cortex = degree of innervation to that body part
Function of the ventricles?
Produce and transport CSF
Function of CSF?
Protects brain and provides a stable chemical environment
What produces CSF?
Ependymal cells from the choroid plexus
Go through the route CSF takes in the brain
Produced (mostly) in the lateral ventricles, though the foramen of Monroe to the 3rd ventricle, through the cerebral aqueduct to the 4th ventricle and finally into the spinal canal and sub arachnoid cistern
What is the corpus callosum?
Large white matter structure made up of commisural fibers (fibers that connect the hemispheres)
Describe it’s basic anatomy
Small rostrum (beak-like), genu (knee), body, splenium
2 major divisions of the corpus callosum and what do they connect?
Forceps minor connects frontal lobes, forceps major connects occipital lobes
What are 5 functions of the brainstem?
Special senses, sensory and motor control for head and neck via CNS, autonomic regulation of the body, regulating consciousness, pathway between brain and spinal cord
Where is the midbrain located?
Around the cerebral aqueduct
3 divsions of the midbrain
o Tectum:
-Dorsal part of midbrain (most superior)
-Superior colliculus – visual processing
-Inferior colliculus – auditory processing
o Tegmentum:
- Ventral part of midbrain (most inferior)
- Contains periaqueduct grey, substantia nigra, red nucleus
o Cerebral peduncles (crus cerebri):
- Most anterior part of midbrain
- Everything in midbrain apart from tectum (includes tegmentum)
-Contains ascending and descending tracts
Punction of the pons
o Function = bridge to cerebellum
o Communication pathway between L and R cerebral hemispheres (striated appearance = corticopontocerebellar fibres)
o Posterior pons = rhomboid fossa = floor of 4th ventricle
o Pontocerebellar communication – inferior and middle cerebellar peduncles
Function of the medulla
o Most caudal part of brainstem -> connects pons to spinal cord through foramen magnum
o Anterior median fissure separates pyramids until they decussate – pyramids = descending tracts
o Posterior surface – posterior medial sulcus separates ascending tract (fasciculus and gracilis)
What are the 2 main divisions of the skull?
Calvarium (top part) and cranial (bottom part)
How many bones are there in the skull?
6: 1 frontal, 2 parietal, 2 temporal and 1 occipital
What are the sutures in the brain?
Coronal which connects the frontal and parietal bones, saggital which connects the parietal and temporal bones, lambdoid which connects the parietal and occipital bones
List the 9 openings in the skull and their nerves
o Cribiform plate – olfactory nerve
o Optic canal – optic nerve
o Superior orbital fissure – oculomotor, trochlear, ophthalmic trigeminal, abducens
o Foramen rotundum – maxillary trigeminal nerve
o Foramen ovale – mandibular trigeminal nerve
o Lacerum – internal carotid artery
o Internal acoustic meatus – facial, vestibulocochlear
o Jugular foramen – glossopharyngeal, vagus, accessory
o Hypoglossal canal – hypoglossal
Describe the meninges in the brain
o Dura mater – tough fibrous outer layer, falx cerebri + tentorium cerebelli, forms sinuses (cerebral venous drainage)
o Arachnoid mater – middle layer, transfers CSF from brain to bloodstream, major brain blood vessels lie in sub-arachnoid space
o Pia mater – layer covering brain, fuses with ependymal cells in ventricles to form choroid process
Describe and explain the BBB
formed by tight junctions between endothelial cells and astrocytic foot processes and protects brain from blood hcemical composition fluctuation by the addition of toxin
What is the arterial supply to the brain?
Internal carotid artery - branches into ophthalmic, posterior communicating, anterior and middle cerebral arteries.
Vertebral artery - arises froms ubclavian to converge and form the basilar artery
Go through the Circle of Willis
o Basilar artery – supplies pontine, cerebellar and posterior cerebral artery
o Posterior cerebral artery – supplies occipital lobe
o Posterior communicating artery – connects posterior and middle cerebral artery
o Middle cerebral artery – supplies lateral region of brain (temporal lobe)
o Anterior communicating artery – connects bothz anterior cerebral artery
o Anterior cerebral artery – supplies medial region of brain (frontal/parietal lobe)
What is a Berry aneurysm?
bulge in the blood vessel at the junction between cerebral arteries and circle of Willis (increased risk of haemorrhagic stroke)
Go through the venous drainage of the brain
o Venous blood collects between 2 layers of dura mater – sinuses
o 3 sinuses – superior/inferior sagittal and straight -> drain into transverse sinus
o Transverse sinus drains into internal jugular vein
o Superficial veins = superior, middle, inferior vs deep veins = great cerebral vein
Go through the origin, where it leaves the skull and special sensation function of each CN
• CNI – olfactory:
o Doesn’t arise from brainstem
o Leaves skull via cribiform plate
o Special sensation function – sense of smell
• CNII – optic:
o Doesn’t arise from brainstem
o Leaves skull via optic canal
o Special sensation function – sense of vision
• CNIII – oculomotor:
o Airses from midbrain
o Leaves skull via superior orbital fissure
o Motor function – innervates all muscles of the eye apart from lateral rectus (VI) and superior oblique (IV)
• CNIV – trochlear:
o Arises from midbrain
o Leaves skull via superior orbital fissure
o Motor function – innervates superior oblique muscle
• CNV – trigeminal:
o Arises from pons
o Opthalmic division:
Leaves skull via superior orbital fissure
Sensory function – sensation above nose
o Maxillary division:
Leaves skull via foramen rotundum
Sensory function – sensation between nose and mouth
o Mandibular division:
Leaves skull via foramen ovale
Sensory function – sensation below mouth
Motor function – innervates muscles of mastication
• CNVI – abducens:
o Arises from pons
o Leaves skull via superior orbital fissure
o Motor function – innervates lateral rectus (abduction of eyeball)
• CNVII – facial:
o Arises from pons
o Leaves skull via internal acoustic meatus
o 5 divisions – temporal, zygomatic, buckle, mandibular, cervical
o Motor function – innervates muscles of facial expression
o Special sensory function – sense of taste for anterior 2/3 of tongue
o Parasympathetic function – submandibular and sublingual glands
• CNVIII – vestibulocochlear:
o Arises from pons
o Leaves skull via internal acoustic meatus
o Sensory function – cochlear nerve = auditory, vestibular nerve = balance
• CNIX – glossopharyngeal:
o Arises from medulla
o Leaves skull via jugular foramen
o Sensory function – sensory information for oropharynx and carotid bodies
o Special sensory function – sense of taste for posterior 1/3 of tongue
o Motor function – innervates stylopharyngeus muscle
o Parasympathetic function – parotid gland
• CNX – vagus:
o Arises from medulla
o Leaves skull via jugular foramen
o Sensory function – laryngopharynx and superior part of larynx (superior laryngeal)
o Parasympathetic function – heart and GI tract
o Motor function – innervates the muscles of the pharynx and larynx (via superior and recurrent laryngeal muscles)
• CNXI – accessory
o Arises from medulla
o Leaves skull via jugular foramen
o Motor function – innervates sternocleidomastoid and trapezius muscles
• CNXII – hypoglossal
o Arises from medulla
o Leaves skull via hypoglossal canal
o Motor function – innervates intrinsic and extrinsic muscles of the tongue
What is the mnemonic to help remember the CNs?
Oh Oh Oh To Touch And Feel Very Good Velvet. Such Heaven!
What is the function of the vertebral column?
Protect spinal cord, carry body weight above pelvis and act as a central axis
Break down vertebral column by sections
7 cervical, 12 thoracic, 5 lumbar, 5 fused sacral and 4 fused coccyx (33 in total)
What is the vertebral body?
weight bearing portion of vertebrae lined with hyaline cartilage
What is the vertebral arch?
Pedicles (first part), transverse process (sides of pedicles and connect to ribs), lamina (connects pedicles to spinous process) and spinous process (projects inferiorly and site of muscle attachment)
Structure of the cervical vertabrae
triangle vertberal foramen, bifid spinous prcoess (2 projections), transverse formaina with hole sin the transverse process
Describe C1 and C2 structure vertebral anatomy
o C1 (atlas) – no vertebral body or spinous processes, transverse ligament of atlas attaches o C2 (axis) – peg extends superiorly and articulates with articular facet in C1, allows head rotation independent of torso
Desrcibe the structure of the thoracic vertebrae
o Heart shaped vertebral body
o Circular vertebral foramen
o Costal facets on transverse processes articulate with ribs
o Long spinous processes slanted inferiorly – spinal cord protection
Describe the structure of the lumbar vertebrae
o Large kidney shaped vertebral body
o Triangular vertebral foramen
o No special characteristics
What are the intervertebral discs?
Fibrocartilaginous discs that act as a shock absorber for the spine
Go through the ligaments of the spine
o Longitudinal ligaments – strengthen cartilaginous joints
o Ligamentum flavum – lamina to lamina
o Interspinous ligament – spinous process to spinous process
o Intertransverse ligament – transverse process to transverse process
Go through the muscles of the spine
o Superficial – shoulder movement - trapezius, latissimus dorsi, rhomboids
o Intermediate – rib movement - superior and inferior serratus
o Deep - back movement - (not sure if need to know name or not)
Go through the DCML pathway
o Fine touch, vibration, proprioception
o First order neurones:
Run from peripheral nerves to medulla through dorsal column
Medial = fasciculus gracilis = lower limbs
Lateral = fasciculus cuneatus = upper limbs
o Second order neurones:
Originate in gracilis/cuneate nucleus
Decussate in medulla
Travel in medial lemniscus to contralateral thalamus
o Third order neurones:
Thalamus -> internal capsule -> sensory cortex
Go through the anterolateral spinothalmic pathway
o Anterior = crude touch and pressure, lateral = pain and temperature
o First order neurones:
Peripheral nerves -> synapse with substansia gelatinosa
o Second order neurones:
Decussate in spinal cord
Form anterior and lateral spinothalamic tract
Travel up to thalamus
o Third order neurones:
Thalamus -> internal capsule -> sensory cortex
Go through the corticospinal tract
o Inputs from motor and premotor cortex
o Internal capsule -> crus cerebri (midbrain) -> pons -> medulla
o Medulla – neurones splits into anterior and lateral corticospinal tract
o Lateral corticospinal tract:
Decussates – contralateral innervation
85% of fibres
Motor innervation to limbs and digits
o Anterior corticospinal tract:
Decussates at spinal level of innervation
15% of fibres
Motor innervation to trunk
o Upper motor neurones -> synapse with lower motor neurones in ventral horn
Go through the corticobulbar tract
o Motor and premotor cortex -> internal capsule -> brainstem
o Synapse with cranial nerve nuclei (lower motor neurones)
o Most corticobulbar fibres innervated bilaterally (1 hemisphere -> both nuclei)
o Facial nerve innervated contralaterally – stroke only affects one side of face
What are 4 other descending tract?
o Vestibulospinal tract – ipsilateral, balance and posture
o Rubrospinal tract – contralateral from red nucleus, fine hand movements
o Reticulospinal tract – ipsilateral, regulates voluntary movement
o Tectospinal tract – contralateral, head movement and visual stimuli
What is Brown-Sequard sydrome?
o Hemi section of spine
o Ipsilateral paralysis – corticospinal system
o Ipsilateral loss of touch and proprioception – DCML system
o Contralateral loss of pain and temperature – spinothalamic system
What is working memory used for?
Short term, higher centres, mental maths
What are the types of long term memory?
o Explicit – episodic = autobiographical, semantic = general knowledge
o Implicit – learned movements in cerebellum
What are the main brain structures involved in memory
o Hippocampus – consolidates short term into long term memory
o Amygdala – emotional memory
o Parietal lobe – short term verbal memory
Go through the simple strucutre of a neurone
o Cell body – genetic and metabolic centre
o Axon – conducting system of neurones, myelinated with nodes of Ranvier
o Dendrites – creates connections between neighbouring neurones
Go through the process of NT release
- Action potential at presynaptic membrane -> calcium release
- Calcium causes vesicles containing neurotransmitter to fuse with synaptic membrane -> neurotransmitter released
- Neurotransmitter diffuses across synaptic cleft and binds to receptors on post synaptic membrane
- Neurotransmitter binding -> post synaptic sodium channels open -> post synaptic depolarisation
What are the types of NT in the CNS and PNS?
1. Central: Excitatory – glutamate Inhibitory – GABA Modulatory – dopamine 2. Peripheral: Sympathetic – noradrenaline Parasympathetic – acetylcholine
What is the resting potential of neurones?
o -70mv due to anions unable to leave cell
o High intracellular potassium concentration, high extracellular sodium concentration
o Sodium/potassium pump – active transport, pumps 3 Na out and 2 K in
Go through the process of generating an AP
- Impulse reaches axon, causing partial depolarisation
- -60mv threshold reached -> sodium channels open
- Influx of sodium into cell -> depolarisation
- +30mv threshold reached -> sodium channels to close, potassium channels to open
- Efflux of potassium out of cell -> repolarisation
- Hyperpolarisation – potential becomes more negative to prevent another impulse
- Na/K pump returns ions to original concentrations
Why is a neuronal AP known as self-perpetuating?
Self-perpetuating process – change in membrane potential affects ion channels, ion channels affect membrane potential
What is saltatory conduction?
propagation occurs at nodes of Ranvier, causes faster conduction
What are the 2 ways of summation of APs?
o Spatial – impulses from multiple neurones cause depolarisation
o Temporal – multiple impulses from one neurone causes depolarisation
Define pain, nociceptive pain and neuropathic pain
o Pain – an unpleasant sensory and emotional experience associated with actual or perceived tissue damage
o Nociceptive pain – arises from damaged or threatened non-neuronal tissue, associated with nociceptors
o Neuropathic pain – direct result of a disease/lesion in the somatosensory system
What is the difference between anaesthesia and analgesia?
Anaesthesia = blocking all sensation, analgesia = just blocking pain
Name the types of pain fibres
Alpha delta fibres - myelinated axons carrying sharp pain, and C fibres - unmyelinated axons carrying dull pain
What are nociceptors?
o Sensory receptors that detect internal and external pain
o Cell bodies found in dorsal root – lateral spinothalamic
o Poly modal neurones can sense thermal, chemical and mechanical stimuli
Go through the mechanism of pain
- Noxious stimuli cause damaged cells to release substance P
- Nociceptors activated on alpha delta and C fibres, lowering threshold
- Action potential generated in pain fibres -> synapse in substantia gelatinosa
- 2nd order neurones -> lateral spinothalamic tract -> thalamus
What is the gate-control theory?
non-painful sensory input (vibration) overpowers painful input
What are the typical areas of the brain assocaited with pain?
o Somatosensory cortex – sensation
o Insular cortex – subjective pain sensation
o Amygdala – emotional dimension of pain
How do opioids effect pain sensation?
o Inhibits nociceptive impulses from reaching thalamus
o Inhibits presynaptic calcium movement
o Potassium release hyperpolarises membrane
Go through the neuromuscluar transmission
- Acetylcholine released from presynaptic terminal and diffuses towards muscle
- Acetylcholine binds to nicotinic receptors on sarcolemma
- Depolarisation of the sarcolemma causes calcium ions to be released by sarcoplasmic reticulum
What is the motor end plate?
Connection between the synapse and muscle fibre
What is a motor unit?
o Single alpha motor neuron and all the muscle fibres it innervates
o Depolarisation of motor neuron = contraction of all muscle fibres
o Muscle fibres spread throughout muscle – more even contraction
Go through the fibres in skeletal muslce descending from size
Skeletal muscle, msucle fasciculi, muslce fibre, myofibril
What is muscle spindle?
o Intrafusal fibres innervated by gamma motor neurones
o Detect muscle stretch regardless of current length
o Gamma motor neurones prevent spindle going slack during muscle contraction – optimum stretch detection
What is a Golgi tendon organ?
o Collagen fibres in tendon innervated by afferent fibres
o Detect degree of stretch exerted by motor units
o Tension exerted -> collagen straightened -> nerve endings disrupted
What is the stretch reflex?
- Patellar tendon pushed down -> quadricep stretched
- Muscle spindle detects stretch in muscle -> activates afferent fibres
- Afferent fibres stimulate alpha motor neurones -> quadricep contracts
What is the withdrawal reflex?
- Painful stimulation on skin activates nociceptors
- Activates flexor and inhibits extensor on ipsilateral leg
- Body moves away from noxious stimuli
Name common NM problems
o Upper motor neurone – weakness, altered muscle tone, fast twitching
o Lower motor neurone – paralysis and decreased muscle tone
o Neuromuscular junction – muscle weakness and fatigue
What are the 3 main divisons of the eye anatomy?
Firbous, vascular and inner
Go through the fibrous part of the eye
Sclera – fibrous layer around eye, attachment for ocular muscles
Cornea – transparent layer over iris, refracts light
Go through the vascular part of the eye
Choroid – blood vessels that supply outer retinal layers
Ciliary muscles – affect lens shape
Iris – has pupil in middle, size controlled by circular and radial muscles
Lens – between vitreous humour and pupil
Go through the inner part of the eye
Retina - neural and pigmented layer, fovea in macula = high acuity vision
Vitreous humour – gel that fills up inside of eye
Go through the visual fields
o Retinal ganglion cells -> optic nerve -> optic canal -> optic chiasm
o Nasal fibres decussate in optic chiasm, lateral fibres remain ipsilateral
o Optic tract -> lateral geniculate nucleus (thalamus) -> visual cortex
What is bitemporal hemianopia?
Pituitary tumour presses on optic chiasm
Nasal fibres that decussate are affected -> peripheral vision lost
What are the muscles in the eye?
o Levator palpabrae – CN III, control eyelid movement
o Lateral rectus – CN VI, inserts onto lateral side, abducts eyeball
o Medial rectus – CN III, inserts onto medial side, adducts eyeball
o Superior rectus – CN III, inserts onto superior side, elevates and medially rotates
o Inferior rectus – CN III, inserts onto inferior side, depresses and laterally rotates
o Superior oblique – CN IV, trochlear pulley system, medially rotates
o Inferior oblique – CN III, laterally rotates
o Superior and inferior oblique compensate for their respective rectus muscles
What are the three divisions of the auditory system?
Outer ear, middle ear and inner ear
Go through the outer ear
Sound enters external auditory canal
Tympanic membrane vibrates at same frequency as sound
Go through the middle ear
3 bones transfer vibration from tympanic membrane to oval window – malleus, incus, stapes
Tensor tympani and stapedius contract to prevent damage to bones
Go through the inner ear
Formed of cochlea and semi-circular canal
Cochlea – cochlear duct contains basilar membrane with organ of Corti
Vibration enters from oval window -> cochlear duct -> basilar membrane vibrates
Formed of cochlea and semi-circular canal
Cochlea – cochlear duct contains basilar membrane with organ of Corti
Vibration enters from oval window -> cochlear duct -> basilar membrane vibrates
What is the Organ of Corti?
o Contains hair cells – mechanoreceptors with protruding stereocilia
o 1 row of inner hair cells and 3 rows of outer hair cells
o Inner hair cells protrude into endolymph, outer hair cells embedded in tectorial membrane – both respond to vibration
Go through auditory transduction
- Pressure waves displace basement membrane -> stereocilia bends
- Potassium channels open -> K influx -> depolarisation
- Calcium channels open on basement membrane -> stimulates glutamate release
- Cochlear branch of CNVIII stimulated -> superior olivary body
- Inferior colliculus -> medial geniculate nucleus (thalamus) -> auditory cortex
What are the vestibular components of the ear?
o Utricle and saccule – linear acceleration and gravity
o Semi-circular canals – angular rotation in 3 axes
What are the semi-circular canals of the ear?
o Filled with endolymph, cupula has embedded stereocilia
Go through head rotation
- Semi-circular canal moves -> endolymph does not
- Moving cupula pushes against stationary endolymph and distorts
- Stereocilia bend -> mechanical ion channels open
- Glutamate released -> vestibular nerve stimulated
What comprises the limbic system? What is their function?
o Basal ganglia – control of movement o Amygdala – emotion o Thalamus – neural relay station o Hypothalamus – autoregulation of body (links endocrine system) o Hippocampus – long term memory o Cingulate gyrus – emotion and learning
Basal ganglia parts and function of each
o Dorsal striatum: Caudate nucleus Putamen o Ventral striatum o Lentiform nucleus: Globus pallidus Putamen o Globus pallidus o Substantia nigra o Subthalamic nucleus o Caudate nucleus, putamen and globus pallidus involved in motor control, cognition and non-motor behaviour
What is the inhibitory group of the basal ganglia?
o Rostral
o GABAergic
o Striatum and globus pallidus
What is the excitatory group of the basal ganglia?
o Caudal
o Glutamatergic and dopaminergic
o Subthalamic nucleus and substantia nigra
Go through the cortical loop in the excitatory
- Excitatory impulse from cortex to striatum
- Inhibitory impulse from striatum to internal globus pallidus
- Inhibitory striatic impulse inhibits inhibitory impulse from globus pallidus to thalamus
- Thalamus fires excitatory connection to cortex -> motor function executed
Go through the sub corticol loop (inhibitory)
- Excitatory impulse from cortex to striatum
- Inhibitory impulse from striatum to external globus pallidus
- Subthalamic nucleus sends excitatory impulse to internal globus pallidus
- Inhibitory impulse from globus pallidus to thalamus -> motor function inhibited
What is the function of the cerebellum?
• Function: coordinates voluntary movement and balance, voluntary equilibrium and muscle tone
What is the anatomy of the cerebellum?
o 2 hemispheres separated by vermis
o 3 lobes – anterior, posterior, floculonodular
What are the 2 inputs for the cerebellum?
o Mossy fibres: Enters from middle peduncle (connects pons and cerebellum) Innervates granular cells o Climbing fibres: Enters from inferior peduncle Innervates singular Purkinje cell
What is the output from the cerebellum?
Purkinje fibres:
o Cell axons travel to dentate nucleus
o Main connection between cerebellum and rest of brain
Go through the cerebral peduncles
o Superior – connects with midbrain nuclei and cerebrum, efferent pathway
o Middle – connects to pons, tells cerebellum about motor input
o Inferior – connects to medulla, proprioception and vestibular input
Go through the cerebral function from each peduncle
knows current motor command (middle peduncle) and body position (inferior peduncle) – projects back to motor cortex -> computes motor error -> adjusts cortical command
How is the cerebellum separated from the brainstem?
• Separated from the dorsal brainstem by the 4th ventricle which forms part of its roof
What is it made up of?
• Made up of folded cortex, white matter and deep inner nuclei
Go through 4 common cerebellar injuries and the result of having them?
o Asynergia = loss of coordination and motor movement
o Intentional tremor = movement tremors
o Hypotonia = weak muscles
o Nystagmus = abnormal eye movements
What are the 5 main types of glial cells and their functions?
• 5 main types:
1. Oligodendrocytes
CNS
Myelinating
Myelinate multiple axons
Metabolic support
2. Schwann cells
PNS
Myelinating
Myelinate single neurones
3. Astrocytes
Regulate ECF by removing potassium ions and neurotransmitters (like glutamate)
Stimulate tight junction formation between cells and at capillary walls in CNS (forming BBB)
Sustain neurones metabolically
Protoplasmic found in grey matter, fibrous found in white matter
Most numerous glial cells in CNS
4. Microglia
Macrophage-like cells perform immune functions CNS
Proliferate from injury sites (phagocytotic)
More branched in grey matter
Can be damaging if too sensitive causing excessive inflammation
5. Ependymal cells
Lines fluid-filled cavities within brain (i.e. ventricles) and spinal cord and regulate flow and production of CSF
Have cilia, microvilli and desmosomes
Provides barrier between CSF and brain
• MND, depression, Alzheimer’s and MS diseases of both neurones and glial cells, epilepsy disease of just neurones
What is the function of glial cells?
• Glial cells nerve cells and provide them with physical and metabolic support
