Nervous System Organisation Part IV: Synapse
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Questions and Answers

What is the primary cause of symptoms in Alzheimer's Disease?

  • Severe vitamin deficiencies
  • Beta-amyloid protein binding to nerve cells (correct)
  • Increased levels of dopamine
  • Destruction of myelin sheaths

    • Which symptom is NOT typically associated with Multiple Sclerosis?

  • Severe memory loss (correct)
  • Slurred speech
  • Numbness
  • Blurred vision

    • Which treatment option is commonly used to manage seizures in epilepsy patients?

  • Cognitive behavioral therapy
  • Anticonvulsants (correct)
  • Radiation therapy
  • Physical therapy

    • In which disease is the destruction of myelin sheaths primarily responsible for symptoms?

    <p>Multiple Sclerosis</p> Signup and view all the answers

    What is a characteristic feature of Parkinson's Disease?

    <p>Tremors in hands and head</p> Signup and view all the answers

    What happens to the tremors in Parkinson's Disease as the condition worsens?

    <p>They worsen and lead to loss of movement</p> Signup and view all the answers

    What is the treatment outlook for Multiple Sclerosis?

    <p>It is treatable but currently incurable</p> Signup and view all the answers

    What aspect of epilepsy distinguishes it from other neurological disorders?

    <p>Patients experience repeated, unpredictable seizures</p> Signup and view all the answers

    Which cognitive decline symptom is NOT typically associated with Alzheimer's Disease?

    <p>Slurred speech</p> Signup and view all the answers

    What causes cell death in the brain for Alzheimer's patients?

    <p>Accumulation of beta-amyloid protein</p> Signup and view all the answers

    What is the function of calcium ions at the synapse?

    <p>To facilitate the fusion of synaptic vesicles with the cell membrane</p> Signup and view all the answers

    What distinguishes neurotransmitters from other chemical messengers?

    <p>They bind to specific receptors on post-synaptic neurons</p> Signup and view all the answers

    Which of the following describes the role of neuroreceptors?

    <p>To provide specific binding sites for neurotransmitters on the post-synaptic membrane</p> Signup and view all the answers

    What occurs immediately after neurotransmitters bind to sodium channels in the post-synaptic membrane?

    <p>The post-synaptic cell membrane depolarizes, possibly triggering action potential</p> Signup and view all the answers

    What is the role of synaptic vesicles in neurotransmission?

    <p>To store neurotransmitters until they are released</p> Signup and view all the answers

    How is an action potential generated in the post-synaptic neuron?

    <p>By the influx of sodium ions following neurotransmitter binding</p> Signup and view all the answers

    What happens to the neurotransmitter acetylcholine after it has performed its function?

    <p>It is degraded by the enzyme, acetylcholinesterase</p> Signup and view all the answers

    What is the synaptic cleft?

    <p>The gap between the synaptic knob and the postsynaptic membrane</p> Signup and view all the answers

    Which of the following is NOT a part of the synapse mechanism?

    <p>Voltage-gated sodium channels opening in the presynaptic neuron</p> Signup and view all the answers

    What process allows the breakdown products to be absorbed by the pre-synaptic neuron?

    <p>Endocytosis</p> Signup and view all the answers

    How does cocaine affect the dopamine transporter in the presynaptic neuron?

    <p>It blocks endocytosis of dopamine.</p> Signup and view all the answers

    What is one of the consequences of prolonged cocaine use on the brain's reward circuit?

    <p>Decreased efficiency in dopamine receptor function.</p> Signup and view all the answers

    What happens to the synapse if neurotransmitters are not re-synthesized?

    <p>The synapse permanently remains on.</p> Signup and view all the answers

    What effect does cocaine have on neurotransmitter levels in the synaptic cleft?

    <p>It causes neurotransmitters to accumulate.</p> Signup and view all the answers

    Among the following, which condition is associated with accelerated brain aging due to cocaine use?

    <p>Loss of grey matter</p> Signup and view all the answers

    What motivates individuals to take stronger doses of cocaine over time?

    <p>Desire for sustained high effects</p> Signup and view all the answers

    Which of the following diseases is NOT listed as a common brain disease?

    <p>Amyotrophic Lateral Sclerosis</p> Signup and view all the answers

    What primary energy source do mitochondria provide for neurotransmitter re-synthesis?

    <p>ATP</p> Signup and view all the answers

    What psychological effects are associated with cocaine use when dopamine builds up in the synapse?

    <p>Euphoria and increased energy</p> Signup and view all the answers

    What type of disorder is characterized by repeated, unpredictable seizures?

    <p>Epilepsy</p> Signup and view all the answers

    Which symptom is typically seen as an early manifestation of Alzheimer's Disease?

    <p>Irritability</p> Signup and view all the answers

    In which neurological disorder is the destruction of myelin sheaths most directly responsible for the symptoms?

    <p>Multiple Sclerosis</p> Signup and view all the answers

    What is a treatment option that may reduce the frequency of seizures in epilepsy patients?

    <p>Anticonvulsants</p> Signup and view all the answers

    What neurotransmitter deficiency is primarily associated with Parkinson’s Disease?

    <p>Dopamine</p> Signup and view all the answers

    What is a common effect as Multiple Sclerosis progresses?

    <p>Temporary paralysis</p> Signup and view all the answers

    Which of the following is a potential treatment for seizure symptoms due to specific brain conditions?

    <p>Surgical removal of tumors</p> Signup and view all the answers

    What is the typical progression of tremors in Parkinson’s Disease?

    <p>Worsening over time</p> Signup and view all the answers

    In Alzheimer's Disease, what cognitive function is primarily affected as the disease progresses?

    <p>Memory recall</p> Signup and view all the answers

    What symptom is commonly associated with Multiple Sclerosis that affects daily life?

    <p>Difficulty controlling urination</p> Signup and view all the answers

    What sequence of events occurs first at the synapse when an action potential reaches it?

    <p>Calcium ions enter the pre-synaptic neuron</p> Signup and view all the answers

    Which component of the synapse is responsible for carrying the nerve impulse across the synaptic cleft?

    <p>Neurotransmitters</p> Signup and view all the answers

    What occurs after neurotransmitters bind to their receptors on the post-synaptic neuron?

    <p>Sodium channels open, leading to depolarization</p> Signup and view all the answers

    Which of the following processes directly follows the entry of calcium ions into the pre-synaptic neuron?

    <p>Release of neurotransmitters by exocytosis</p> Signup and view all the answers

    What is the role of the enzyme acetylcholinesterase in neurotransmission?

    <p>Breaks down acetylcholine in the synaptic cleft</p> Signup and view all the answers

    Which part of the synapse ensures that the neurotransmitter can bind to the post-synaptic neuron?

    <p>Chemical-gated ion channels</p> Signup and view all the answers

    At which location would you find neuroreceptors in the synaptic transmission process?

    <p>On the post-synaptic neuron's membrane</p> Signup and view all the answers

    Which statement is true regarding the difference between impulse transmission at the synapse and along the axon?

    <p>Transmission at the synapse uses neurotransmitters, while along the axon does not.</p> Signup and view all the answers

    What might occur if there is an inhibition of acetylcholinesterase activity at the synapse?

    <p>Prolonged action of acetylcholine</p> Signup and view all the answers

    Which of the following components is NOT directly involved in the release of neurotransmitters?

    <p>Action potentials in the post-synaptic neuron</p> Signup and view all the answers

    How does cocaine impact the re-entry of dopamine into the pre-synaptic neuron?

    <p>It blocks the dopamine transporter.</p> Signup and view all the answers

    What primary function do mitochondria serve in the context of neurotransmitter re-synthesis?

    <p>They provide energy for the re-synthesis process.</p> Signup and view all the answers

    What consequence does prolonged cocaine use have on brain structure?

    <p>It leads to accelerated loss of gray matter.</p> Signup and view all the answers

    What is one psychological effect experienced by users when dopamine levels build up due to cocaine use?

    <p>Heightened sense of well-being or euphoria.</p> Signup and view all the answers

    What adaptation occurs within the brain's reward circuits as cocaine use continues?

    <p>Decreased effectiveness of the reward circuit.</p> Signup and view all the answers

    What mechanism prevents the synapse from being permanently activated after neurotransmitter release?

    <p>Absorption of breakdown products by pre-synaptic neurons.</p> Signup and view all the answers

    Which of the following is NOT a consequence of cocaine use on the brain?

    <p>Increased neuronal plasticity.</p> Signup and view all the answers

    What initial effect does cocaine have on neurotransmitter levels in the synaptic cleft?

    <p>It causes a temporary increase in neurotransmitter levels.</p> Signup and view all the answers

    What behavior is commonly observed as individuals attempt to maintain the same effects from cocaine?

    <p>Increased dosage and frequency of use.</p> Signup and view all the answers

    Which neurotransmitter is specifically affected by cocaine in relation to its transporter?

    <p>Dopamine.</p> Signup and view all the answers

    Study Notes

    Nervous System Organisation (Part IV)

    • Previous parts covered the spinal cord, spinal and cranial nerves, somatic vs autonomic systems, action potential, and transmission along axons.
    • This section focuses on the synapse, neurotransmitters, and diseases of the brain.

    Synapse

    • Nerve impulses travel between neurons across a small gap called a synapse.
    • Synapses occur between two neurons, a neuron and an effector, or a sensory receptor and a sensory neuron.
    • A synaptic knob is a bulge at the end of a presynaptic neuron's axon terminal. It contains vesicles with neurotransmitters.
    • The synaptic cleft is the space between the synaptic knob and the postsynaptic neuron.

    The Synapse (Detailed)

    • A single neuron can have thousands of synaptic junctions on its dendrites and cell body.
    • Synaptic knobs contain mitochondria and synaptic vesicles, which contain neurotransmitters.
    • The pre-synaptic membrane is adjacent to the synaptic cleft and post-synaptic membrane, which has receptors for the neurotransmitters.

    Synapse Function

    • An action potential cannot cross the synaptic cleft directly.
    • Neurotransmitters carry the impulse across the cleft.
    • Neurotransmitters are produced by the presynaptic neuron and stored in synaptic vesicles.
    • The neurotransmitters are released by exocytosis when calcium ions enter the presynaptic neuron following an action potential.
    • Neurotransmitters diffuse across the synaptic cleft.
    • The neurotransmitter binds to the neuroreceptors on the postsynaptic membrane.
    • This binding opens ion channels, often leading to a change in the postsynaptic neuron's electrical potential.

    Synaptic Events

    • Voltage-gated calcium channels in the pre-synaptic neuron open when an action potential arrives. This allows calcium ions to enter the neuron.
    • Calcium influx triggers the fusion of synaptic vesicles with the membrane, releasing neurotransmitters into the synaptic cleft.
    • Neurotransmitters diffuse across the cleft and bind to receptors on the postsynaptic membrane.
    • Receptor binding initiates a response in the postsynaptic cell.

    Synapse Function (concluded)

    • The neurotransmitter is broken down by enzymes in the synaptic cleft.
    • The breakdown products are reabsorbed by the presynaptic neuron for reuse.
    • This process prevents the synapse from being permanently active.

    Neurotransmitters

    • Various neurotransmitters exist, each with specific functions and locations in the brain and body.
    • Examples like acetylcholine, serotonin, histamine, dopamine, epinephrine, norepinephrine, glutamate, GABA, and glycine are mentioned.
    • Acetylcholine is involved in memory, while Serotonin and Histamine affect moods and sleep. Dopamine and Epinephrine are involved in emotions/moods and motor control.

    Effects of Drugs on Synapses

    • Drugs can affect neurotransmitter function at the synapse.
    • Cocaine blocks the reuptake of dopamine, leading to higher levels in the synaptic cleft.
    • This can have various effects, including euphoria and increased energy and arousal, but can also lead to a dopamine imbalance and addiction.
    • Cocaine's impact on the aging of the brain is also noted.

    Comparison of Axon and Synaptic Transmission

    Feature Axon Transmission Synaptic Transmission
    Nature Electrical Chemical
    Conduction Travels along one neuron Involves two adjacent neurons
    Calcium No Yes (required for neurotransmitter release)
    Depolarization Only excitatory Both excitatory and inhibitory
    Time Immediate Synaptic delay (due to neurotransmitter release)
    Action Potential All-or-none response Summation of action potentials may be needed
    Recovery Due to potassium efflux; sodium-potassium pump Due to enzyme breakdown of neurotransmitters
    Speed Affected by axon diameter and myelin Affected by drugs like curare
    Transmission Bi-directional Unidirectional, from presynaptic to postsynaptic
    Information transmission Over a distance of 1 meter Over a distance of 20 nanometers

    Diseases of the Brain

    • Four common brain diseases are discussed: Alzheimer's disease, Parkinson's disease, multiple sclerosis, and epilepsy.

    Alzheimer's Disease

    • Progressive loss of mental function (loss of memory and confusion in older individuals).
    • Gradual onset with symptoms like forgetfulness, irritability, lack of initiative, and inability to recognize loved ones.
    • Cause is unknown, but likely involves damage caused by the protein beta-amyloid, which binds to nerve cells and causes cell death.

    Multiple Sclerosis

    • Caused by the destruction of myelin sheaths around nerve cells in the CNS.
    • Leads to nerve cell death causing numbness, slurred speech, paralysis, temporary weakness, blurred vision, and difficulty controlling urination.
    • Treatable but incurable.

    Epilepsy

    • Brain disorder characterized by repeated, unpredictable seizures or episodes of abnormal brain activity.
    • Epilepsy can result from known medical conditions, brain injuries, or unknown causes.
    • Seizures can often be treated with medication (anticonvulsants).

    Parkinson's Disease

    • Neurological disorder caused by a lack of dopamine in specific brain regions.
    • Leads to progressive deterioration controlling movement, particularly involuntary movements like tremors in the hands and head.
    • Treatable with drugs like levodopa, but the effects of the treatment may diminish over time.

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    Description

    This quiz delves into the organization of the nervous system, focusing on the synapse, neurotransmitters, and related brain diseases. Explore the structure and function of synapses, including the role of synaptic knobs and the transmission of nerve impulses between neurons.

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