Cognition Flashcards
What is an excitatory neurone? Give examples
-stimulate or excite the post-synaptic neurone to send the impulse
-acetylcholine
-adrenaline
-glutamate
-nitric oxide
What is an inhibitory neurone? Give examples
-inhibit or prevent the post-synaptic neurone sending the impulse
-gaba
-glycine
-serotonin
-dopamine
Give examples of neurotransmitters that can either be excitatory or inhibitory depending on the receptor present on the post-synaptic neurone
-noradrenaline
-dopamine
histamine
What is the difference between an ionotropic neurone and a metabotropic neurone?
-ionotropic= made of of proteins
-metabotrphic= single protein with different domains
What are the key parts of a neurones structure?
-cell body
-dendrites
-axon
-myelin sheath
-axon terminals
what is the cerebral cortex?
-the outer layer of the brain that lies on top of the cerebrum
-the cerebrum divides your brain into two halves called hemispheres
-the hemispheres are attached by a bundle of nerve fibers called the corpus callosum
What are the key stages of embryological development of the neurological system?
17 days= flat, 3 layered embryo
20 days= neural folds to form neural plate
22 days= neural folds close to form neural plate
How does the brain develop in embryological development?
week 4:
-primary vesicles develop into fore, mid and hind brain
weeks 5-11:
-secondary vesicles develop to form the different parts of the brain (telencephalon, diencephalon, mesencephalon, metencephalon, myelencephalon)
-growth continues to around 30 weeks gestation
-peripheral nervous system develops from the neural crest
What problems can occur in embryological neurological development? (before and post 20 weeks)
before 20 weeks:
-division of hemispheres
-development of neuones
-neural migration
-development of the cerebellum
20 weeks onwards:
-destructive lesions
-often secondary to infection, haemorrhage and ischaemia
What neural tube defects may occur?
failure of the neural tube to close 18-26 days after ovulation can lead to:
-anencephaly
-encephalocele
-spina bifida/ spina bifida occulta
What are the 2 areas that the developing skull forms from the mesenchyme?
- neurocranium (the protective case)
- viscerocranium (facial skeleton)
Explain the key developments of the brain/ skull from birth to adolescence
-by 1 years old- brain doubles in size
-by 2 years old- brain is 75% of its future brain weight as an adult
-by 6 years old- this is 90%
-by 10 years old- this is 100%
At what age does the anterior and posterior fontanelle close?
-anterior fontanelle- 12-18 months
-posterior fontanelle- 4-6 weeks
What is epilepsy?
-recurring unpredictable seizures
-seizure symptoms all depend on what neurones are affected in the brain
How can seizures be caused by too much neurone excitation?
-main excitatory neurotransmitter is glutamate
-glutamate’s receptor is NMD, that responds by letting (too many) positive calcium ions inside the cell
How can seizures be caused by too little neurone inhibition?
-main inhibitory neurotransmitter is GABA
-GABA’s receptor is GABA, which inhibits signals by opening ion channels that allows (too many) negative chloride ions in
What is a partial/ focal seizure? What 2 types are there?
-one hemisphere or lobe is affected
-can either be simple partial (patient remains conscious)
-or complex partial (patient loses consciousness)
What is a generalised seizure? What are the few types of generalised seizures?
-both hemispheres of brain are affected
-may start as focal but develop into general
-tonic= becomes stiff and flexed
-atonic= becomes floppy and relaxed
-clonic= have violent muscle contractions (convulsions)
-tonic clonic (most common)= muscles first tense up, then clonic phase
-myoclonic= short muscle twitches
-absence seizures= lose consciousness then regain consciousness
What is status epilepticus?
seizures last for more then 5 minutes, this is considered a medical emergency and can be life threatening if not treated immediately
What is Todd’s paralysis?
temporary but severe suppression of activity in brain area
-lasts for an average of 15 hours
How is epilepsy diagnosed?
-brain imaging= MRI or CT to look for abnormalities
-electroencephalogram (EEG)= detects electrical signals in the brain
How can epilepsy be treated?
-daily medications e.g anticonvulsants
-epilepsy surgery- remove cause of seizures
-nerve stimulation- stimulates vagus nerve to release neurotransmitters
-ketogenic diet- forces body to burn fat instead of carbohydrates, producing ketone bodies used by the brain instead of glucose
What are febrile seizures?
seizures that occur in children when they have a fever, usually between the ages of 6 months and 5 years
What is hypoxic-ischaemic encephalopathy?
-an event that occurs during the prenatal, intrapartum or postpartum period where adequate cerebral blood flow is prevented from providing oxygen to the brain
