Topic 6B – Nervous Coordination Flashcards
What is a neuron?
A neuron is a specialized cell that transmits electrical impulses throughout the body to facilitate communication between the brain, spinal cord, and other organs.
What are the main parts of a neuron?
The main parts of a neuron are the cell body, dendrites, axon, and axon terminals.
What is the function of dendrites?
Dendrites are branched extensions that receive electrical impulses from other neurons and carry them toward the cell body.
What is the function of the axon?
The axon is a long extension of a neuron that transmits electrical impulses away from the cell body to other neurons, muscles, or glands.
What is the role of the myelin sheath?
The myelin sheath is a fatty layer that surrounds the axon, increasing the speed of electrical impulse transmission by insulating the neuron.
What is the node of Ranvier?
The node of Ranvier is a gap in the myelin sheath where ion channels are concentrated, allowing saltatory conduction (jumping of action potentials) to speed up nerve signal transmission.
What is synaptic transmission?
Synaptic transmission is the process by which a nerve impulse is transmitted from one neuron to another through a synapse using chemical signals called neurotransmitters.
What is a synapse?
A synapse is the junction between two neurons or between a neuron and a target cell (like a muscle or gland), where neurotransmitters are released to transmit signals.
What are neurotransmitters?
Neurotransmitters are chemicals released from the presynaptic neuron into the synapse, which then bind to receptors on the postsynaptic neuron or other target cells, facilitating signal transmission.
How does an action potential cross the synapse?
When an action potential reaches the axon terminal, it causes the release of neurotransmitters into the synaptic cleft, which bind to receptors on the postsynaptic neuron, initiating a new action potential.
What happens to neurotransmitters after they have acted on the postsynaptic receptors?
After neurotransmitters have bound to postsynaptic receptors, they are either broken down by enzymes or taken back into the presynaptic neuron by reuptake to terminate the signal.
What is muscle contraction?
When muscle fibers shorten and generate force, leading to movement. It is triggered by action potentials from motor neurons
What is the sliding filament theory?
Explains how muscle contraction occurs. It states that actin (thin) filaments slide over myosin (thick) filaments, shortening the sarcomere and causing the muscle to contract.
What role does calcium play in muscle contraction?
Calcium ions bind to troponin on the actin filaments, causing a conformational change that exposes binding sites for myosin, allowing the cross-bridge cycle to occur and muscle contraction to take place.
What is the role of ATP in muscle contraction?
ATP provides the energy needed for the myosin heads to attach to actin, pull, and detach during the contraction cycle. ATP also actively pumps calcium ions back into the sarcoplasmic reticulum to end the contraction.
What is the neuromuscular junction?
The synapse between a motor neuron and a muscle fiber, where neurotransmitters (acetylcholine) are released to initiate muscle contraction.
What is an axon?
A long, slender extension of a neuron that transmits electrical impulses away from the cell body to other neurons, muscles, or glands.
What is the myelin sheath?
A fatty layer that insulates the axon of a neuron, increasing the speed of electrical impulse transmission.
What is an action potential?
An electrical impulse that travels along the axon, triggering neurotransmitter release at the synapse.
What are calcium ions?
Ions that bind to troponin on actin filaments during muscle contraction, exposing binding sites for myosin to initiate the contraction process.
What is role of ATP in muscle contraction?
The energy source used for myosin-actin interaction, as well as calcium ion pumping during muscle relaxation.
