Midterm Flashcards
With UMN muscle mass is ______
Preserved
What is the Vagus Nerve?
The 10th cranial nerve which contain most of the afferent connection between the CNS and bodily organs
What are the benefits of Ischemic Preconditioning in someone who suffers a global ischemic stroke following a TIA?
Improved neuronal survival
Damage to LMNs results in an inability to tell muscle to ______ contracting
Start
Without inhibition LMN keeps telling muscle to ______, result is ______ contraction that leads to ______ and ______ of muscles (spasticity)
Contract
Sustained
Stiffness and Rigidity
Which type of cell death results in an inflammatory response, which can lead to further distress?
Necrosis
For HD, some genetic components have been identified in _______% of patients
10-15%
Necroptosis
Programmed Necrosis
How does a TBI occur?
When a blow to the head is sufficiently forceful the CSF is unable to protect the brain resulting in a collision of the brain with the skull
What is Tramautic Brain Injury (TBI)?
A sub-category of ABI which includes only damage to brain caused by an external mechanical force
What treatment is there for ALS?
No cure for ALS
One drug which extends life expectancy 2-3 months - Riluzole (blocks sodium channels and decreases Glu)
In ALS when motor neurons degenerate they have no way of telling your muscles to ______
Contract
Cortisol
Gluccocorticoid hormone which has metabolic and immune effects
The environment can cause certain genes to be turned on and off by changing accessibility via ______ markers, which ______ or ______ chromatin
Epigenetic
Tighten or Loosen
What is Oxidative Stress?
The result of an imbalance of ROS and antiOX
What are some Cognitive symptoms of HD?
Restlessness
Agitation/Irritability
Lack of concentration
Short-term memory problems
What is the penumbra of a stroke and how is it affected?
Outskirts of lesion, receive blood flow from other vessels
Receives between 20-40% of normal blood flow
Results in Apoptosis due to Ripple Effect (toxic signalling cascades spilling over from core)
How are Astrocytes invovled in ALS?
Astrocytes (which usually protect and nourish motor neurons) release toxins which lead to motor neuronal death (Necroptosis - prgrammed necrosis)
How does Excitotoxicty effect neurons?
Glu continously binds to and activates post-synaptic receptors which causes neurons to depolarize and fire leading to influx of Ca2+ and K+
Ca2+ (Calcium) ends up sequestered in mitochondira which disrupts production of ATP and increased production of Reactive Oxygen Species (ROS)
What is ROS and what causes it?
Reactive Oxygen Species which can lead to DNA damage, protein admage and lipid abnormalities
ROS levels increase during times of environmental stress
How do the innate and adaptive immune systems communicate?
Chemical communication via Cytokines
What are some physical changes in the brain of someone with Alzheimer’s?
Brain Atrophies
Gyri get narrower
Sulci get wider
Ventricles enlarge
What is a Gene?
A segment of DNA that codes for the production of specific proteins
LMNs can pass through either ______ or ______ nerves
Spinal Nerves - control muscles of limbs and trunk
Cranial Nerves - control muscles of head and neck
What is the biggest risk Factor in Alzheimer’s?
Age - 50% of cases over 85, only 1% over 65
What is Immune Privilege?
Sites of the body are able to tolerate introduction of foreign substance without eliciting inflammatory response
Brain is not immune privileged due to interaction with peripheral immune system
Saltatory Conduction
Depolarization along axon leaps from node to node
Steps for an Action Potential
- Depolarization → Threshold of -55mv reached → Na+ ions rush into cell → membrane potential rises to +30mv
- Repolarization → At +30mv, Na+ channels close and K+ channels open → K+ rushes OUT → Cell becomes more negative
- Hyperpolarization → too much K+ leaves and mebrane potential drops below -70mv → Na/K+ pumps reset concentrations
What are the most common causes of a hemorrhagic stroke and what is the mortality rate?
High blood pressure and aging blood vessels
35% mortality rate
Mild Cognitive Impairment
Memory problems greater than expected for age, but no daily functional impairments observed
What is an Allele?
A variant (alternative form) of a gene
Following neuronal death and removal of dead tissue after a stroke, nearby, undamaged neurons can _______ to affected area and take over some lost _______
Migrate
Functions
27 genes for HD have been uncovered so far, usually they cause abnormal ______ production which can lead to protein ______
Protein
Aggregates
A concussion resulting in altered neurological function most likely affected which brain regions?
Corpus Callosum
Anterior Commissure
How does Ca2+ effect the brain after a stroke?
Excess Ca2+ (Calcium), as a result of neuronal depolarization, results in production of ROS - in turn Mitochondria can’t deal with this stress and release signals to induce apoptosis
Deposits of _______ in the arteries (Atherosclerosis), which forms plaques, can lead to what? (which can cause a stroke)
Chloresterol
Narrowing of the arteries in the neck or brain
Glutamate
Excitatory Neurotransmitter
When it binds to Post-synaptic receptors it causes an influx of positive ions
What are common sensory disturbances faced by stroke victims?
Damage to sensory pathways can lead to tingling, numbness, and chronic neuropathic pain
Stressor
Stimuli that challenge the body’s homeostasis and trigger a response
Hormones - 5 Principles of Action
- Act in gradual fashion
- Change probability or intensity of behavior
- Have reciprocal relationship with behavior
- May have multiple effects
- Often show pulsatile pattern of release
Hormones vs Neurons
Neurons → Hormones
Local → Distant
Fast → Slow
Voluntary → Involuntary
Precise → Imprecise
Both: Produced and stored in neurons or glands and released upon stimulation, bind to receptors to stimulate target cells
In a stroke how does Necrosis occur?
Lack of oxygen → switch to anaerobic glucose metabolism → Acid build-up (acidosis) → decreased membrane permeability → Ions and water rush in → cell swells and ruptures
What codon does HD Gene have a section containing a repeat for?
CAG
What are some Emotional symptoms in HD?
Depression/Apathy
Anti-social behaviour
Aggression
How is GABA involved in HD?
Upregulated in early stages of disease followed by marked reduction
Might be initially upregulated to deal with excess Glu
In ALS what does degeneration of UMNs lead to?
Spasms, increased muscle tone, abnormal reflexes
Pituitary
Master Gland
Anterior releases stimulating hormones (ACTH, TSH)
Posterior releases vasopressing and oxytocin
What are some environmental/experiental factors which can cause a stroke?
What are the common link between all of them?
High BP, smoking, obesity, inactivity, trauma, or alcoholism
Increased inflammation of vessel walls
How do leukocytes (white blood cells) infilitrate the BBB and what effects do they have on the brain? (Stroke)
Due to the weakened BBB → reperfusion brings leukocytes with it
They release even more inflamamtory molecules, futher compromising stability and impeding recovery
What is Glutamic Acid Decarboxylase (GAD)?
Precursor for GABA, found in BG of HD patients
What are Lower Motor Neurons?
Motor Neurons which originate in the brainstem or spinal cord
Axons leave the CNS and synapse onto muscles at the Neuromuscular Junction
Receive signls from UMNs and tell muscles to contract
Metabotropic Receptor
NT bind to receptor which causes a G-Protein to activate an ion channel elsewhere in the cell
What are two forms of Endogenous repair (regrowth) after a stroke?
Axonal Sprouting - new connections from surviving neurons
Angiogenesis - vascular growth, restores flow of nutrients to affected area
What is the main circuit involved in HD?
Basal Ganglia-Thalamo-Cortical Circuit
What is a subarachnoid hemorrhage? What is the most common cause and the mortality rate?
Bleeding in subarachnoid space
Brain Aneurysm (blood-filled bulge in weakened blood vessel wall)
40-50% mortality rate
HPA Axis
- Stress stimulates Hypothalamus which releases CRH
- CRH stimulates Anterior Pituitary which releases ACTH
- ACTH stimulates Adrenal Cortex which releases Cortisol
- Cortisol induces metabolic changes
- Negative feedback tells hypothalamus to shut off stress response
HD Pathology is a result of ______ mutant htt function and ______ of WT htt function
Increased
Loss
What is reperfusion?
When blood flow resumes after a stroke
LMN damage results in no contraction of muscles leading to ______ and ______
Flaccidity
Atrophy
In HD, increased unregulated ______ activity + dysfunctional ______ activity in corticostriatal circuit = disruption of integrative processes by ______
GABA
Glu
MSNs
How does the Blood Brain Barrier get damaged in a stroke, and how does this effect the immune response?
Ischemia → epithelial cells weakened (due to hypoxia and resulting acidosis) → reperfusion, peripheral immune cells leak through → exacerbate immune response and inflammation
90-95% of cases of Alzheimer’s are ______ (late onset) and causes are not understood, while only 5-10% of cases are ______ (early onset) involving a dominant gene that speeds up progression of disease
Sporadic
Familial
What is Chronic Traumatic Encephalopathy (CTE)?
A progressive degenerative disease found in individuals with a history of multiple concussions
Where do symptoms start in ALS?
Weakness in the arms and legs
Loss of arm function usually occurs first with sporadic forms of ALS, while loss of leg function ususally occurs first with familial forms of ALS
Lack of Oxygen (Hypoxia) in TBI as a result of decreased blood flow causes a switch to _______ glucose metabolism which can lead to overproduction of _______ _______ (acidosis) which damages BBB
Anaerobic
Lactic Acid
What are the effects of TBI in the Temporal Lobe?
Problems with short and long-term memory
What is the result of a multitude of CAG repeats?
Many Gln residues linked together (polyglutamine residues) which cause conformational changes in the htt protein reulting in misfolding and toxic protein aggregates in cells
Infarction
Ischemia-induced cell death
What type of pattern of inheritance does HD follow?
Autosomal-Dominant (only need one HD allele)
What is Acquired Brain Injury (ABI)?
Any brain injury that occurs after birth and is not hereditary, congenital, or degenerative
A TIA leads to a more severe ischemic stroke in _______% of patients
15-30%
ATP is required to make and use _______
_______ is required to make ATP
Glucose
Glucose
What is the treatment for a TIA?
Anti-coagulants (blood thinners) to help prevent blood clotting and larger stroke
What is Neuroplasticity?
The ability of the brain to reorganize and form new connections
DNA can be _______ which allows for cell division and _______
Copied
Reproduction
How many repeats of CAG result in an increased risk of HD, and how many repeats guarantee HD will develop during a normal life span?
36-40 repeats = increased risk of HD
>40 repeats = HD will develop - result in mutant htt
What is the core of a stroke and how is it affected?
Area directly fed by occluded vessel
Receives less than 20% of normal blood vessel
Results in Necrosis and Apoptosis
How does Diffuse Axonal Injury (DAI) occur?
Twisting and shearing forces cause axons to be torn from cell bodies (axotomy)
What is the Circle of Willis
A communication circle at the base of the brain formed by the common carotid and vertebral arteries