Nervous System Flashcards
Divisions of the NS
CNS and PNS
Divisions of the PNS
Afferent (Sensory) and Efferent (Motor)
Divisions of the Efferent NS
Autonomic and Somatic
Divisions of the ANS
Sympathetic and Parasympathetic
What are the two cells of the NS ?
Neurones and Glial cells
What do astrocytes do ?
- Form the BBB
- Provide neurones with nutrients
What do microglia do ?
They act as phagocytes and are important in immune response.
What do Oligodendrocytes do ?
They form the myelin sheath for neurones in the CNS
What do Schwann cells do ?
They form the myelin sheath for neurones of the PNS
What function do Ependymal cells carry out ?
They act as cilia in the ventricles and subarachnoid space wafting the CSF.
What makes up the BBB ?
- Thick basal lamina
- Tight junctions between endothelial cells of the capillaries
- Astrocytes
What is the job of Satellite cells ?
They help to regulate the movement of substances within the PNS. Same job as astrocytes.
What are the features of a multipolar neurone ?
- Multiple dentrites
- One axon
What is the function of a multipolar neurone ?
Motor neurone
What is the function of a pseudounipolar neurone ?
Sensory neurone
What are the features of a bipolar neurone ?
- One cell body in centre
- One axon
- One dendrite
What are the features of a pseuounipolar neurone ?
- One cell body in centre
- One axon that splits into two
Name the 3 primary brain vesicles
Pink Mice Rule
Prosecencephalon
Mesencephalon
Rhombencephalon
Name the 5 secondary brain vesicles
Telencephalon Diencephalon Mesencephalon Metencephalon Myelencephalon
What does the Telencephalon form ?
- Lateral ventricles
- Cerebral hemispheres
What does the Diencephalon form ?
- 3rd ventricle
- Thalamus
- Hypothalamus
What does the Mesencephalon form ?
- Midbrain
- Cerebral aqueduct
What does the Metencephalon form ?
- Pons
- Cerebellum
- 4th ventricle
What does the Myelencephalon form ?
- Medulla
- 4th ventricle
What do ganglia of the ANS form from ?
Neural crest cells
What does the CNS form from ?
Neural tube
What do motor neurones form from ?
Neural tube
What do sensory neurones form from ?
Neural crest cells
Cells on the dorsal side form which plate ?
Alar plate - Dorsal horn
Cells on the ventral side form which plate ?
Basal plate - Ventral horn
Where are sympathetic ganglion located ?
In the prevertebral and paravertebral ganglia
What type of the synapses are between the pre and post-ganglionic cells in the sympathetic nervous system?
Cholinergic and nicotinic
What type of the synapses between the pre and post-ganglionic cells in the parasympathetic nervous system are ?
Cholinergic and nicotinic
What type of synapses are between the post-ganglionic and target organs in the parasympathetic nervous system ?
Cholinergic and muscarinic
What type of synapses are between the post-ganglionic and target organs in the sympathetic nervous system ?
Adrenergic - Beta and Alpha receptors
4 facts about the post-ganglionic cells of the adrenal medulla
- Have no axons
- Part of the Sympathetic NS
- Involved in mass activation
- Release adrenaline into the blood
What is the neurotransmitter to the cholingeric neurones ?
Ach
How does the sympathetic system affect the eye ?
Causes contraction of the dilator pupillae and relaxation of the ciliaris muscle.
What may eye drops that dilate the pupil contain ?
A muscarinic antagonist or an alpha 1 agonist
What affect does parasympathetic activity have on the heart ?
Causes the release of acetylcholine and decreases HR.
What affect does the sympathetic activity have on blood vessels ?
Causes them to vasoconstrict due to A1 mainly but in some causes vasodilation due to activation of B2.
What happens to the body in CNS ?
Disease which affects the CNS and causes demyelination of axons in the white mater.
How would a patient present with MS ?
They may have had a relapse which has resolved. Could present with
- Optic neuritis
- Bladder and bowel problems
- Ataxia
- Limb weakness
- Sensory symptoms
Medical definition of MS
Episodes of demyelination desalinated in space and time
Are more relapses seen during pregnancy or less ?
Less
Are women at a higher risk or lower risk of relapsing postpartum ?
More at risk
What other factor can increase chances of releasing in MS ?
Infection
What are the 3 types of MS ?
- Primary progressive
- Relapsing remitting
- Secondary progressive
How is MS diagnosed ?
Usually diagnosed clinically using Poser’s criteria or via MRI using McDonald’s criteria.
What chemical is used to held us see episodes of demyelination on MRI ?
Gadolinium
What other investigations may be done to rule out differential diagnosis to MS ?
- Bloods
- Lumbar puncture
What is MS associated with ?
Autoimmune disease
What treatment is given in MS for acute relapses ?
- Prednisolone
- Rehabilitation
- Symptomatic treatment
What treatment is given in MS to modify the disease ?
1st line
- Beta interferons (IV or SC)
- Dimethyl fumarate (oral)
What treatment is given in MS to modify the disease ?
2nd line
Natalizumab
Alemtuzumub
What do disease modifying agents do ?
Lower the chances of relapses
What symptomatic treatment may be used in people with MS ?
Constipation - Laxatives
Erectile dysfunction - Sildenafil
Spasticity - Antispasmodics/Physiotherapy
Urinary dysfunction - Catheterisation
What occurs during synaptic transmission ?
- Na flood into terminal as action potential
- Calcium ions start to move into presynaptic terminal
- Triggers the packaging of transmitter into vesicles and they begin to move to surface
- Exocytosis of transmitter occurs and it diffuses across cleft
- Transmitter binds to postsynaptic receptors
- If not uptakes back into presynaptic cell then it is broken down in the gap
- Transmitter is metabolised within cells
How could you reduce the synaptic transmission ?
- Block voltage gated sodium channels
- Increase the uptake of transmitters and their breakdown
- Decrease the synthesis and packaging of transmitter
What do spider toxins do ?
Block calcium channels
How could you increase the synaptic transmission ?
- Increase synthesis and packaging of neurotransmitters
- Activate postsynaptic receptors using agonists
- Block neurotransmitter uptake and breakdown
Where is dopamine found ?
In the brainstem, limbic system and basal ganglia
What type of receptors are dopamine ones ?
Metabotropic
What are metabotropic receptors ?
G-protein coupled receptors
What are ionotropic receptors ?
Ion channel receptors
What are dopamines receptors called ?
D1-5
What are the 5 drug classes that can be used to treat Parksinson’s disease ?
- Levodopa
- Carbidopa
- MAO inhibitors
- COMT inhibitors
- Dopamine agonists
What are the side effects of dopaminergic drugs ?
- N/V
- Hallucinations
- Tremors
- Abnormal behaviour
What are the side effects of long-term dopaminergic drug use ?
- Balance
- Slurred speech
Is the vommiting centre inside or outside the BBB ?
Outside
What drug can be used to treat Parkinson’s but doesn’t cause N/V ?
Domperidone
Define dyskinesia
Abnormal involuntary movements
How do tricyclic antidepressants and MAO inhibitors work ?
Block noradrenaline uptake
What does SSRI’s stand for and what is their main use ?
Selective serotonin re-uptake inhibitors and antidepressants
What are triptans used for ?
Migraine treatment
How do triptans work ?
5HT agonists - so they mimic serotonin
What can GABA agonists be used for ?
Anti-epileptic and anti-anxiety
How does GABA work ?
Decreases the activity of the NS
