Neurobiology Part 2 Flashcards
Encephalitis
Unknown but the most common diagnosed cause Is viral infections
can be developed after or during an infection with any of several viral illness including: influenza, measle, herpes, rabies, chickenpox and arbovirus.
Children and elderly due to weaker immune system
Brain and spinal cord can be inflamed within one or two weeks of getting their virus
What are the symtpms of the encephalitis ?
Severe headache Fever Confusion or agitation Seizures Muscle Weakness Double vision Vomiting Memory loss
arbovirus infection: symptoms goes away between 3-5 days and are resolved without becoming anything serious.
In severe cases of encephalitis:
=> Swelling of the brain put pressure on the brain stem (control respiration and heartbeat).
=> If too severe pressure functions can cease and cause death.
Epilepsy ( CNS dysfunction)
Chronic brain disorder characterized by seizures (abnormal, rapid, intense neuronal discharge)
Types of seizures:
Generalized (gran mal)
Involve entire body, unconscious
Partial: part of the body is involve, conscious
Petit mal: momentary, frequent unconscious episodes
Brain Source of Epilepsy
All brain functions – including feeling, seeing, thinking, and moving muscles – depend on electrical signals passed between nerve cells in the brain
A seizure occurs when too many nerve cells in the brain “fire” too quickly causing an “electrical storm”
What causes Epilepsy ?
In about 70 % with epilepsy , the cause is not known
30 % , cause :
- Head trauma
- Infection of brain tissue
- Brain tumour and stroke
- Heredity
- Prenatal disturbance of brain development
What are the two parts which occur ?
Generalized seizure
Involve the whole brain and loss of consciousness
Absence: characterized by brief loss of consciousness
Tonic-clonic: characterized by rhythmic jerking of muscles
Partial seizure
Involve only part of the brain; may or may not include loss of consciousness
What is Subdural Hematoma ?
Condition occurs when tiny veins run between the brain protective membrane and the brain rupture caused by head injury .
Cerebral Concussion
Disruption of brain function without actual physical brain injury
Typically follows a blow to the head
Often, not always, has loss of consciousness
S/S: headache, nausea, dizziness, amnesias, disorientation, vertigo, photophobia
Spinal Cord Injuries
Impact with persistent or transient compression
2. Flexion, Extension, Rotation
(forcible shearing or stretching of the SC, and/or its blood supply, in the axial plane)
3. Distraction (pulling apart of the spine)
4. Laceration to complete transection
What are some diforders which causes paralysis ?
Hemiplegia
Loss of muscle control & sensation on one side of the body (L or R)
Paraplegia
Loss of muscle control & sensation on the lower part of the trunk and lower extremities
Quadriplegia
Paralysis of all four extremities
Parkinson Disease
Parkinson’s disease (PD) is the second most common neurodegenerative disease after Alzheimer’s and a major cause of disability and premature death in elderly populations
The decreased levels of dopamine cause the neurons of the striatum to fire uncontrollably, preventing the patient to be able to direct motor function.
Characterised by the development of motor symptoms, such as bradykinesia (slowness of movement) , rigidity and tremor.
What is Dopamine ?
Dopamine is the neurotransmitter that controls voluntary movements of the body and is associated with the reward mechanism of the brain.
Regulates the pleasurable emotions
Drugs like cocaine, heroin, nicotine, opium and even alcohol increase the level of this neurotransmitter, for which the user of such drugs feels good.
Decreased level of dopamine is associated with Parkinson’s disease, while the patients of schizophrenia are usually found to have excess dopamine in the limbic system of the brain.
What is Dopamine Synthesis ?
It is made from the amino acid tyrosine, which is converted to L-dihydroxyphenylalanine (L-DOPA) by the enzyme tyrosine hydroxylase.
L-DOPA is converted to dopamine by the enzyme DOPA decarboxylase (or aromatic amino acid decarboxylase) which is found in the cytoplasm.
What is dopamine broken down by ?
monoamine oxidase A (MAOA) inside the nerve terminal
MAOA and MAOB1 in glia e.g. astrocytes
What are the three types of Degenerative brain disoders ?
Alzheimer’s disease - progressive degenerative disease of the brain that results in dementia (usually frontotemporal)
Parkinson’s disease – degeneration of the dopamine-releasing neurons of the substantia nigra
Huntington’s disease – a fatal hereditary disorder caused by accumulation of the protein huntingtin that leads to degeneration of the basal nuclei
