Mechanism of Synaptic Transmission

Voluntary Work in Suez

• This is a collaborative effort, not an individual project
• Participants are from the Suez medical community
• The project spans from 2020 to 2025

Mechanism of Synaptic Transmission

• Neurotransmitters are released through exocytosis
• Action potential travels down the axon, causing depolarization and calcium influx
• Calcium influx stimulates synaptic vesicles to migrate to the active zone
• Fusion between V-snare and T-snare occurs, releasing neurotransmitters
• Neurotransmitters diffuse into the synaptic cleft
• Neurotransmitters bind to specific receptors on the postsynaptic neuron
• Receptors are ligand-gated ion channels
• Influx of sodium or calcium causes depolarization, leading to excitatory postsynaptic potentials
• Influx of potassium or chloride causes hyperpolarization, generating inhibitory postsynaptic potentials
• Chemical transmitters are removed by diffusion, reuptake by the presynaptic knob, enzymatic degradation, or by microglial cells.

Drug of Choice for Absence Seizures

• Ethosuximide is the drug of choice for absence seizures.

Anterior Cerebral Artery Occlusion

• Anterior cerebral artery (ACA) supplies the medial surface of the cerebral hemisphere, excluding the occipital lobe and a portion of the lateral surface
• Smaller terminal branches
• Supplies the medial surface except the occipital lobe and upper inch on the lateral surface, and the medial half of the orbital surface of the frontal lobe.

Middle Cerebral Artery (MCA) Occlusion

• Runs over the insula in the lateral sulcus
• Larger terminal branches
• Supplies the lateral surface of the cerebral hemisphere, excluding the occipital lobe and a strip on the lateral surface of the temporal lobe near the inferior border

Posterior Cerebral Artery (PCA) Occlusion

• Runs in the anterior portion of the calcarine sulcus
• Supplies the tentorial surface, the occipital lobe, and a portion of the lower temporal lobe on the lateral surface.

Central Branches of the Arteries

• Pierce the anterior perforated substance and lamina terminalis
• Supply the anterior part of the corpus striatum and the anterior limb of the internal capsule

Arterial Supply of the Cingulate Gyrus

• Anterior cerebral artery

Neurotransmitter in Substantia Nigra

• Dopamine

Pain Modulation in the Brain

• Periaqueductal grey is a key component of the pain control system
• This area can suppress the transmission of pain signals to the brain
• Three major components: periaqueductal gray and periventricular areas, raphe magnus nucleus, and nucleus reticularis paragigantocellularis
• Signals pass through pain inhibitory complex located in the dorsal horns spinal cord before reaching brain
• This control system can block pain signals before they reach the brain

Toxicity of Alprazolam

• Flumazenil is a specific antagonist to benzodiazepines, including alprazolam.

Pilocytic Astrocytoma

• A type of glioma affecting children
• Well-circumscribed cerebellar cystic mass
• Microscopically: bipolar astrocytes, Rosenthal fibers, eosinophilic granular bodies, fibrillary background

Alzheimer's Disease

• Associated with deteriorating cognitive function

Microglia Functions

• Phagocytic cells within the nervous system

Peripheral Nervous System Cell Types

• Schwann cells: Myelin sheath formation around axons
• Neurons: Receive and transmit nerve signals, based on a variety of morphologies
• Astrocytes: Contribute to the blood-brain barrier.
• Oligodendrocytes: Myelin formation inside the central nervous system
• Ependymal cells: Secretion of cerebrospinal fluid
• Satellite cells: Support neurons

Opioid Overdose

• Naloxone blocks acute opioid overdose

Lateral Lemniscus

• Carries hearing impulses from both ears
• Spinal lemniscus: carries pain, temperature, and crude touch from opposite side of the body
• Trigeminal lemniscus: carries pain, temperature, touch and proprioception from the same side of the face.
• Medial lemniscus: carries fine touch and proprioception from opposite side of the body, below the face

Primary Motor Area

• Located in the precentral gyrus of the frontal lobe.
• Supplied by the MCA and ACA.
• Responsible for voluntary movements of the opposite side of the body (excluding the eye)
• Lesions result in contralateral hemiplegia.

Prefrontal Cortex

• Located in most of the medial frontal gyrus, orbital part of inferior surface, and rest of lateral frontal lobe
• Responsible for behavior, learning, and emotions
• Lesions result in disturbances of function.
• Frontal eye field (8): responsible for voluntary eye movements to the opposite side of the body

Broca's Area

• Located in the posterior inferior frontal gyrus
• Responsible for speech production
• Lesions result in motor aphasia

Primary Visual Cortex

• Located on each side of the calcarine sulcus
• Responsible for perception of visual stimuli
• Large lesion: result in contralateral homonymous hemianopsia

Secondary Visual Cortex

• Surrounds the primary visual cortex
• Responsible for understanding the meaning of visual information

Word Blindness

• Lesion to the middle of superior temporal gyrus
• Results in difficulty in recognizing words

Auditory Area

• Middle part of superior temporal gyrus
• Responsible for sound perception
• Lesion: unilateral or bilateral difficulty hearing

Wernicke's Area

• Located in posterior portion of superior and middle temporal gyri
• Responsible for comprehending language.
• Lesion: sensory aphasia

Primary Sensory Area

• Located in the postcentral gyrus, receiving sensory information from the opposite side of the body.
• Lesions affect sensations from the opposite side of the body.
• This section focuses on sensory areas and important details for understanding various diseases of the brain and their effects

Association Sensory Area

• Located in the superior parietal lobe

Tumor of the Interpeduncular Fossa

• Impacts the oculomotor nerve

Muscle Spindle Structure

• Nuclear bag: dynamic fibers
• Nuclear chain: static fibers

Ketolysis Regulation

• Bioavailability of oxaloacetate determines the regulation

Cerebellar Lesions

• Damage results in intention tremors

Classification of Drugs for CNS

• Monoamine reuptake inhibitors, monoamine oxidase inhibitors, and presynaptic inhibitors (alpha-2 blockers, 5-HT blockers)

Neurotransmitters of the CNS

• Glutamate

Symptoms of Cerebellar Diseases

• Ataxia and dysmetria are common symptoms.

Spinal Cord Hamisection

• Causes ipsilateral loss of tactile localization, vibration, and proprioception

Cranial Nerves in Upper Medulla

• Hypoglossal and vestibular nuclei are within open medulla

Myelinating Cell in Peripheral Nervous System

• Schwann cell

Toxin-Related Death

• Molecular death is the final stage

Diagnosis of Primary Amebic Meningoencephalitis

• Cerebrospinal fluid (CSF) sample

Important Medical Conditions

• Diabetic patient with heart attack, follow-up, quitting smoking, and lifestyle changes crucial

Types of Meningitis

• Group A and B Neisseria meningitides, Streptococcus pneumonia, and Listeria monocytogenes are common causes

Causes of Subacute Sclerosing Panencephalitis

• Measles

Location of Nerve Cells

• Ganglion: group of nerve cells outside CNS
• Nucleus: group of nerve cells inside CNS

Viral Infections

• Rabies: transmitted via peripheral nerves; mode of transmission: bite from a rabid animal or contact with the saliva of infected animals
• Poliomyelitis: transmitted through the fecal-oral route

Other details:

• Tolcapone: COMT inhibitor
• Rabies diagnosis: Negri bodies
• East African sleeping sickness: caused by Trypanosoma brucei rhodesiense
• Beriberi: vitamin B1 (thiamine) deficiency
• Mycotic aneurysms: due to subacute infectious endocarditis
• Alternative aspects and detailed explanations about different neurological topics.
• Meningiomas common characteristics
• Classification of different types of tumors and their locations and features
• Details on location of crucial parts of the brain, functions and nerves, and what happens if there is a disease in that region.

Types of Pain

• Fast pain: Neospinothalamic tract (glutamate)
• Slow pain: Paleospinothalamic tract (substance P)