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
What is the pathophysiology of hypoxic-ischaemic?
moderate decrease in cerebral perfusion triggers cerebral arteries to redistribute the blood to:
-posterior circulation
and maintain adequate perfusion to:
-brainstem
-basal ganglia
-cerebellum
What is cerebral palsy?
-A neurodevelopmental brain condition, causing paralysis
-its a non-progressive condition, so doesn’t get worse overtime
-its cause is difficult to identify but may be due to environmental factors e.g radiation/ infection, or a genetic mutation
What is spastic cerebral palsy?
-tight/ stiff muscles due to lesion in upper motor neurone
-can cause a scissor gait, when adductor muscles remain contracted
What is dyskinetic cerebral palsy?
-damage to basal ganglia, causing lost ability to prevent movements, either dystonia (slow) or chorea (random dance like)
What is ataxic cerebral palsy?
-damage to cerebellum causes shaky, uncoordinated movements
-this results in a variety of issues including poor balance, pain, abnormal posture, sleep disorders, eating disorders, difficulties in speaking, vision, learning disabilities
What is spina bifida?
-a birth defect where the tissue in the left and right side of the back doesn’t meet (close), leaving an opening down the middle of the back
What is myelomeningocele spina bifida?
-spinal cord and meninges Gertrude out of an opening in the spinal vertebrae, held together by a sack of skin out of the back
-open spina bifida is where there is no sack of skin, leaving the nerves exposed
-this can cause loss of sensation, paralysis, bladder and bowel movements, seizures
What is meningocele spina bifida?
-prenatal spinal deformities only occur in the meninges and not spinal nerves
-least common and no severe symptoms
what is spina bifida occult?
-spinal cord and tissue don’t protrude, therefore usually have no symptoms, only a hair, dimple or birthmark above lesion sight
-most common and mild form
What are the risk factors for spina bifida?
-folate deficiency
-obseity
-poorly controlled diabetes
-certain anti-seizure medications
How is spina bifida diagnosed and treated?
-diagnosed prenatally
-treated with surgery, but additional interventions may be required e.g catheterisation/ crutches
What is ADHD?
-Attention Deficit Hyperactivity Disorder
-cause is unknown, but combination of environmental and genetic factors
-low levels of neurotransmitters dopamine and noredinephrine contribute to symptoms of ADHD
What are the symptoms of ADHD?
-inattentive, careless mistakes, not listening, easily distracted
-hyperactive, impulsive, fidgeting, overly active
What is Autism Spectrum Disorder?
-removing one self from social interaction, communicating both social communication and interaction deficits, and restrictive, repetitive interests or behaviours
What is the cause and treatment of ASD?
-cause is thought to be genetic, affecting brain development
-treatment is tailored to each child through educational programs and behaviour therapy
