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Questions and Answers
What is the primary function of the neuro muscular junction (NMJ)?
What is the gap between the presynaptic terminal and muscle fiber called?
What is the name of the autoimmune disorder where the immune system attacks ACh receptors?
What is released from the synaptic vesicles into the synaptic cleft?
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What is the result of the binding of ACh to nicotinic ACh receptors on the postsynaptic membrane?
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What is the name of the bacterial toxin that inhibits ACh release, leading to muscle weakness and paralysis?
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Study Notes
Neuro Muscular Junction (NMJ)
Definition
- Site where motor neuron terminals release neurotransmitters to stimulate muscle contraction
- Also known as neuromuscular synapse or myoneural junction
Structure
-
Presynaptic Terminal: Motor neuron terminal that releases neurotransmitters
- Contains synaptic vesicles filled with acetylcholine (ACh)
- Synaptic Cleft: Small gap (20-30 nm) between presynaptic terminal and muscle fiber
- Postsynaptic Membrane: Muscle fiber membrane with ACh receptors
Neurotransmission
- Release of Neurotransmitters: ACh is released from synaptic vesicles into synaptic cleft
- Binding of ACh: ACh binds to nicotinic ACh receptors on postsynaptic membrane
- Muscle Contraction: Binding of ACh triggers muscle contraction through muscle action potential
Functions
- Muscle Contraction: NMJ enables muscle contraction in response to neural stimulation
- Motor Control: NMJ plays a crucial role in motor control and coordination
Diseases and Disorders
- Myasthenia Gravis: Autoimmune disorder where immune system attacks ACh receptors
- Lambert-Eaton Syndrome: Autoimmune disorder where immune system attacks presynaptic terminal proteins
- Botulism: Bacterial toxin that inhibits ACh release, leading to muscle weakness and paralysis
Neuro Muscular Junction (NMJ)
Definition
- The site where motor neuron terminals release neurotransmitters to stimulate muscle contraction
- Also known as neuromuscular synapse or myoneural junction
Structure
- The presynaptic terminal contains synaptic vesicles filled with acetylcholine (ACh)
- The synaptic cleft is a small gap (20-30 nm) between the presynaptic terminal and the muscle fiber
- The postsynaptic membrane has ACh receptors on the muscle fiber membrane
Neurotransmission
- ACh is released from synaptic vesicles into the synaptic cleft through exocytosis
- ACh binds to nicotinic ACh receptors on the postsynaptic membrane, causing a conformational change
- The binding of ACh triggers muscle contraction through muscle action potential
Functions
- The NMJ enables muscle contraction in response to neural stimulation
- The NMJ plays a crucial role in motor control and coordination
Diseases and Disorders
- Myasthenia Gravis is an autoimmune disorder where the immune system attacks ACh receptors, leading to muscle weakness and fatigue
- Lambert-Eaton Syndrome is an autoimmune disorder where the immune system attacks presynaptic terminal proteins, leading to muscle weakness and fatigue
- Botulism is a bacterial toxin that inhibits ACh release, leading to muscle weakness and paralysis
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Description
Test your knowledge of the Neuro Muscular Junction, where motor neurons stimulate muscle contraction, including its structure and function.
