CNS Regulation Flashcards
Four functional brain areas
Cerebrum
Diencephalon
Brainstem
Cerebellum
Diencephalon components
Thalamus
Hypothalamus
Brainstem components
Midbrain
Pons
Medulla Oblongata
Cerebrum function
thinking, consciousness
sensory perception
movement, emotions, memory
Cerebellum function
balance, muscle coordination, posture
Diencephalon function
sensory relay, emotions, alert mechanism, regulation of body temp, fluid balance, sleep, appetite
Brainstem function
conduction pathway between PNS and CNS
cardiac, respiratory, vasomotor control (medulla/pons)
Intracranial Pressure
sum of pressure within the intracranial cavity
brain tissue + blood + CSF
Layers of the meninges
Dura mater
Arachnoid
Pia mater
Blood Brain Barrier components
endothelial cells with tight junctions
astrocytes
Where is CSF located
within the subarachnoid space
Normal ICP
0-15 mm Hg
Pathological ICP
sustained at > equal to 20 mm Hg
Anterior Cerebral Artery blood Supply
medial surface of cerebrum
frontal, parietal lobes + prefrontal cortex
Middle Cerebral Artery Blood Supply
lateral surface of cerebrum
frontal, parietal, temporal lobes + basal nuclei
broca’s & wernicke’s area
delivers 80% of blood to brain
Brain Cellular Metabolism
Brain cannot engage in anaerobic metabolism so it requires a constant supply of O2
otherwise, lactic acid/pyruvic acid builds up lowering pH
Factors causing cerebral vasodilation
Low O2
Decreased pH (increase in lactic/pyruvic acid)
Increased CO2
FAST
F = facial droop A = arm drift S = slurred speech T = time
Types of Stroke
Ischemic
Hemorrhagic
Hemiplegia
one sided paralysis
Posterior Cerebral Artery blood supply
posterior surface of cerebrum
occipital lobe + medial/inferior temporal lobe
Penumbra
ischemic brain tissue surrounding a central necrotic core
penumbra represents salvable brain tissue during the evolution of as stroke
Time period before infarction
3 minutes
Modifiable Risk Factors
Hypertension Diabetes Hyperlipidemia / Dyslipidemia Heart conditions (dysrhythmia, inflammation, heart failure) Atherosclerosis Obstructive sleep apnea Alcoholism Cocaine Smoking Hormone Replace Therapy Oral contraceptives Injury
Non-Modifiable Risk Factors
Age Gender Race (African-Americans) Family History/Genetics Stroke History
Common vessels of ischemic stroke
internal carotid arteries
vertebral arteries
basilar artery
Conditions for Thrombosis
Atrial fibrillation Valvular disorders Cardiogenic embolism Dilated left ventricle Atherosclerosis
Transient Ischemic Attacks
ischemic brain tissue without infarction
symptoms same as stroke without long-term damage
resolve within 24 hours
elevated risk of stroke for next 3 months
Agnosia
inability to recognize familiar persons/objects
Ataxia
uncoordinated muscle activity
Apraxia
inability to perform learned, motor tasks
Dysarthria
inarticulate/slurred speech due to neuromuscular impairment
Agraphria
inability to write
Alexia
inability to understand written words
Hemiplegia
one sided paralysis
Homonymous Hemianopia
loss of half of one’s vision field
Cerebral Perfusion Pressure equation
MAP - ICP
Medication management
anticoagulation
reperfusion
antiplatelet function
neuroprotective function
Primary Motor Cortex location
Frontal Lobe before central sulcus
Somatosensory Cortex Location
Parietal lobe behind central sulcus
Broca’s area
located in frontal lobe on the left side near motor cortex
involved in speech formation/articulation
Wernicke’s area
located in temporal lobe on left side near auditory cortex
involved in language comprehension
Visual cortex location
located in occipital lobe
Auditory cortex location
located in temporal lobe
Gustatory cortex location
located in the insular lobe
Middle Cerebral Artery Homunculus
hand, arm, face
Anterior Cerebral Artery Homunculus
feet, legs
prefrontal cortex
Prefrontal cortex Function
higher-order thinking
reasoning, planning, decision-making, problem-solving
Hemiparesis
one-sided weakness
Metabolic demand of brain
20% oxygen
15% CO
Adequate perfusion –> brain does not store glycogen or engage in anaerobic metabolism
Types of Ischemic Stroke
Thrombotic
Embolus (fat, air bubble, traveling blood clot)
Lacunar (very small strokes, small arteries)
Watershed
Stroke Medication Treatment
thrombolytics
antithrombotics
tPA
thrombolytic
aka tissue plasminogen activator
dissolves fibrin fibers of blood clots
used to treat ischemic strokes –> DO NOT USE for hemorrhagic stroke
tPA criteria
> 18 years old onset of stroke <4.5 hours ischemic stroke no bleeding conditions controlled HTN <185/110 normal glucose >50 mg/dL
Common causes of thrombi/emboli
cardiogenic emboli atrial fibrillation mitral valvular disease left ventricular thrombi carotid plaque right-left shunting polycythemia sickle cell disease
Alcohol and blood
risk factor for HTN
hypercoaguability of blood
decrease cerebral blood flow
increase risk of atrial fibrillation
Lacunar Stroke
<15 mm wide
affects smaller arteries
located in the subcortical region
Types of Hemorrhagic Stroke
Intracerebral
Subarachnoid
Hemostasis Stages
1) Vascular Spasm
2) Platelet plug
3) Coagulation
Plasmin
enzyme that dissolves blood clots by breaking up fibrin
Plasmin chemical equation
tissue plasminogen activator (tPA) + plasminogen –> plasmin
Antithrombotic classes
anticoagulants
antiplatelet
Factors increasing ICP
increase in SpCO2 (causes vasodilation)
Dysphagia Liquid Thickening
Thin
Mild (Nectar)
Moderate (Honey)
Extremely thick (Spoon)
Cushing’s Triad
late signs of ICP
bradycardia
decreased respiratory rate
increasing blood pressure
Frontal lobe function
emotional control center
personality
executive function, problem-solving, planning, behavior
Temporal lobe function
memory (hippocampus)
learning
hearing
managing emotions, recognizing faces
Parietal lobe function
somatosensory sensation
visuospatial processing
math, spelling, hand-eye coordination, fine motor movement
Occipital lobe function
vision
S/S of Increased ICP
nausea/vomiting headache blurred vision cushing's triad widened pulse pressure
Ischemic Stroke Treatment
thrombolytics
endovascular thrombectomy
Hemorrhage Stroke Treatment
surgery
manage ICP
NIHSS Stroke
lower the score the better
national stroke assessment tool
tPA drug info
Onset: 30 min
Peak: 60 min
Half life: 35 min
initial bolus dose then infusion
Hemorrhagic Stroke S/S
headache
vomiting d/t increased ICP
rapid onset
BP Management
extreme BP >220/120 should be treated by lowering 15% but not more than 25% over 24 hours
Hemorrhagic Stroke Diagnosis
CT scan
blood in CSF
How long can you prescribe antiplatelet and anticoagulants together
30 days
Antiplatelet drugs
aspirin
clopidogrel
Anticoagulant drugs
warfarin
apixaban (XA drugs)
heparin (prodrug)
Warfarin
anticoagulant
mechanism: interferes with vitamin K synthesis, interrupt clotting cascade
monitor for blooding
frequent INR checks
Ischemic Stroke & A-fib
Anticoagulant
Ischemic Stroke & No A-fib
Antiplatelet
Anticoagulant mechanism
interrupts the coagulation cascade to prevent the formation of clotting factors
Antiplatelet mechanism
prevents platelet aggregation by interrupting the enzymatic cascade
Coagulation pathways
intrinsic (ends at factor 10)
extrinsic (ends at factor 10)
common (factor 10 –> thrombin)
Impaired CNS Regulation Mechanisms
Reduced Perfusion Altered Neurotransmission Insufficient Glucose Infection Degeneration Neoplasm Developmental defects
Arteriovenous malformation
capillary bed fails to form between arterioles and venules
blood shunts from arteries (high pressure) –> venules (low pressure) causing venules to expand/weaken
Somatic Sensation
touch
pain
temperature
proprioception
Stroke Definition
brain tissue infarction secondary to ischemic or hemorrhagic damage. results in focal neurological deficits.
Virchow’s Triad
three factors that predispose clot formation
1) hypercoagulability
2) blood stasis
3) endothelial injury
INR
used to monitor anticoagulant therapy
measures intrinsic & common pathway of vitamin-k clotting factors
therapeutic range = 1.5-2.5x normal
Origin of Embolic Stroke
atherosclerotic plaques in the internal carotid artery
left side of heart
GCS Scores
Mild 13-14
Moderate 6-12
Severe 5-8
