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Acute brain disorder 陳美嬌 108321110 (Mechanisms of Brain Injury (Abnormal…
Acute brain disorder
陳美嬌
108321110
Structure and Function of the Nervous System
peripheral nervous system (PNS)
autonomic nervous system (ANS)
nervous system (CNS)
skull and vertebral column, meninges, CSF, blood-brain barriers.
skull and vertebral column → brain and cord and protect them from external trauma
CSF and meninges provide buoyancy and shock-absorbing capacity.
Neuronal Structure and Function
glial cells
which provide supportive functions to neurons
but do not transmit action potentials
oligodendrocytes,寡突膠質細胞
寡樹突膠細胞，這種細胞的突起會包圍著神經元的軸突，形成如髓鞘般具有絕緣效果的皮膜，可加速傳遞的速度
microglia 微小膠質細胞
Microglia 微小膠質細胞來自單核細胞-巨噬細胞類型，並在CNS內提供吞噬功能，負責大腦的免疫功能。
ependymal cells室管膜細胞
Ependymal cells 室管細胞 :產生腦脊液並維持腦脊液屏障
astrocytes,星狀膠質細胞
星形膠質細胞是在神經膠細胞中最多的，且在中樞神經系統中起許多功能。
一些星形膠質細胞具有接觸大腦毛細血管的足突，並有助於維持血腦屏障的完整性，阻止有害物質通過血管，進入大腦
星狀細胞調節組織液的離子平衡，並可能影響營養從毛細血管向神經元的轉移。
參與神經系統信號傳導，並顯示出攝取和釋放可調節神經傳遞的分子
Neurons
the axon that generates and conducts action potentials
which generate and transmit nerve impulses
the dendrites that receive signals and conduct them to the cell body
the cell body containing cellular organelles
Neuronal Communication
primarily through the release of neuro transmitters into the synapses adjacent to target neurons.
Postsynaptic neurons have receptors for these neurotransmitters and respond by changing the flow of ions through channels in the cell membrane.
electrical synapses
去極化導致動作電位的產生，該動作電位將信號從神經元的一端快速傳遞到另一端。
到達軸突末端的動作電位打開電壓化的Ca2 +通道並刺激神經遞質釋放到突觸中
Mechanisms of Brain Injury
secondary injury
progress over days or weeks
preventing secondary damage have remained elusive
mortality and morbidity ↑
primary injury
Brain tissue necrosis
Cessation of blood flow - Stroke
Cytotoxic edema
Head trauma
Mechanisms of Brain Injury
Ischemia and Hypoxia
Excitatory Amino Acids
Reperfusion Injury
Cellular Energy Failure
Abnormal Autoregulation
Abnormal Autoregulation
Autoregulation is influenced →
carbon dioxide (Paco2) & oxygen (Pao2)
blood flow through brain tissue is controlled primarily by autoregulation
Cerebral perfusion pressure (CPP)
Blood flow is maintained rate → (MAP) from about 50 to 150 mm Hg
Ischemia/vascular damage / brain edema
Increased Intracranial Pressure
Etiology
increased ICP include stroke, trauma, and tumors.
These disorders have common features
volume of CSF, blood, or brain tissue
Increased Cerebrospinal Fluid Volume
Nonobstructive hydrocephalus
Obstructive hydrocephalus
Pseudotumor cerebri
Increased Blood Volume
Dural sinus thrombosis
Acidosis
High arterial Paco2
Increased Brain Tissue Volume
Infection
Cytotoxic edema
Tumor
Hemorrhage
Ischemia and necrosis
Vasogenic edema
IICP
As ICP rises to higher levels
consciousness decreases
pupil responsiveness to light becomes impaired.
exhibit altered respiratory patterns
unresponsive to stimulation
open the eyes
unable to move
verbalize
Manifestations
headache
Vomiting
altered level of consciousness (drowsiness)
blurry vision → edema of the optic disk (papilledema).
Brain Compression and Herniation
Neuronal Circuits
神經元突觸連接的模式稱為神經元迴路。 一個或多個迴路中特定組神經元的活動是神經系統功能的基礎：思想，記憶，感覺，運動和學習。
Cerebrovasscular Disease and Stroke
Ischemic Stroke
Thrombotic strokes
Emboli
Treatment:
The goals of therapy for acute ischemic stroke are to minimize infarct size and preserve neurologic function.
Aspirin
Thrombolytic therapy
戒菸 ,
lowering of serum lipid
Hemorrhagic Stroke
cerebral aneurysms
subarachnoid hemorrhage
arteriovenous malformations
Stroke Sequelae
Motor
decrease in or absence of muscle tone in the affected extremities
motor paralysis is contralateral to the side of the brain
Sensory Deficits
A lack of sensory information from the paralyzed side contributes to the phenomenon of neglect
Neglect is associated with a high risk for falls and other injuries.
Language Deficits
Broca aphasia
運動性失語
Wernicke aphasia
感覺性
聽覺性或接受性失語症
Anomic aphasia
有完整的理解力。 言語簡單
Cognitive Deficits
alert
remember/ reason
concentrate or attend to stimuli
Malformation
Cerebral aneurysms
arteriovenous malformations (AVMs)
Treatment:
Surgical
complications of cerebral vasospasm and hydrocephalus must be monitored and managed.
Central Nervous System Infection
meningitis
Treatment
supportive care
antibacterial drug therap
management of any complications.
Vaccination against
abscesses
Treatment
usually involves drainage or excision
intravenous antibiotics
encephalitis
Treatment
Supportive and symptomatic
Steroids control edema
anticonvulsants to prevent seizures
analgesics to relieve headaches
antipyretics to control hyperthermia.
Traumatic Brain Injury(TBI)
Concussion
but no evidence of brain damage on CT
alteration or loss ofconsciousness (<30 minutes)
mild traumatic brain injury (MTBI)
Contusion
Contusion is present when CT or MRI reveals an area of brain tissue damage (necrosis, laceration, bruising)
Intracranial hematoma
localized collection of blood within the cranium resulting from vascular damage.
Intracranial Hematomas
Subdural Hematoma,SDH
硬腦膜和蛛網膜外膜之間的空間形成硬膜下血腫
Subarachnoid Hemorrhage ,SAH
創傷性蛛網膜下腔出血是由於穿過間隙的橋接靜脈破裂所致，其方式類似於硬膜下出血。 儘管創傷是蛛網膜下腔出血的重要原因，但更常見的是與腦動脈瘤或動靜脈畸形（AVM）破裂相關
Epidural hematomas,EDH
顳骨骨折通常會破壞腦膜中動脈，導致急性硬膜外出血
Treatment:
surgical intervention
ICP monitors
CSF drainage devices.
雙極神經元只有一個從細胞體延伸的樹突和一個軸突 ，這些神經元普遍存在於視網膜，耳蝸和嗅覺結構中，
多極神經元具有從細胞體和一個軸突延伸出來的大量樹突 ，大多數神經元是這種類型的
單極神經元具有從細胞體突出的單個過程，該過程分裂形成樹突和軸突 ，普遍存在於體感神經中
Increased Intracranial Pressure
Brain Compression and Herniation
