Podcast
Questions and Answers
How does the myelination of an axon affect the speed of nerve impulse transmission, and what is the significance of the nodes of Ranvier in this process?
How does the myelination of an axon affect the speed of nerve impulse transmission, and what is the significance of the nodes of Ranvier in this process?
Myelination increases the speed of transmission through saltatory conduction, where the impulse effectively 'jumps' from one node of Ranvier to the next.
Explain the 'key-lock principle' in the context of neurotransmitter binding at a synapse. What determines whether a neurotransmitter will bind to a specific receptor?
Explain the 'key-lock principle' in the context of neurotransmitter binding at a synapse. What determines whether a neurotransmitter will bind to a specific receptor?
The 'key-lock principle' refers to the specific fit between a neurotransmitter (the 'key') and its receptor (the 'lock'). The shape and chemical properties of the neurotransmitter must match those of the receptor for binding to occur.
Compare and contrast the roles of sensory neurons, motor neurons, and interneurons in the nervous system. Provide an example of how these neurons work together to produce a coordinated response.
Compare and contrast the roles of sensory neurons, motor neurons, and interneurons in the nervous system. Provide an example of how these neurons work together to produce a coordinated response.
Sensory neurons transmit information from sensory organs to the central nervous system, motor neurons transmit signals from the central nervous system to muscles or glands, and interneurons process information and relay signals between sensory and motor neurons.
Describe the sequence of events that occurs when a nerve impulse reaches the axon terminal, leading to the release of neurotransmitters into the synaptic cleft.
Describe the sequence of events that occurs when a nerve impulse reaches the axon terminal, leading to the release of neurotransmitters into the synaptic cleft.
How does the resting membrane potential of a neuron contribute to its ability to respond to a stimulus, and what ions are primarily involved in establishing this potential?
How does the resting membrane potential of a neuron contribute to its ability to respond to a stimulus, and what ions are primarily involved in establishing this potential?
Explain how a stimulus can trigger an action potential in a neuron. What is the significance of the threshold potential in this process?
Explain how a stimulus can trigger an action potential in a neuron. What is the significance of the threshold potential in this process?
What are the main functions of the nervous system, and how do the peripheral and central nervous systems contribute to these functions?
What are the main functions of the nervous system, and how do the peripheral and central nervous systems contribute to these functions?
Describe how curare affects the synapses and how this leads to paralysis. What specific receptors does curare interact with, and what is the result of this interaction?
Describe how curare affects the synapses and how this leads to paralysis. What specific receptors does curare interact with, and what is the result of this interaction?
Contrast the 'falling dominoes' analogy for an action potential with the actual restoration of a neuron's resting potential after an impulse. What key mechanisms are involved in restoring the neuron and preparing it for the next impulse?
Contrast the 'falling dominoes' analogy for an action potential with the actual restoration of a neuron's resting potential after an impulse. What key mechanisms are involved in restoring the neuron and preparing it for the next impulse?
Describe how the opening of sodium ion ($Na^+$) channels in the membrane of a postsynaptic cell is able to make the postsynaptic cell more positive?
Describe how the opening of sodium ion ($Na^+$) channels in the membrane of a postsynaptic cell is able to make the postsynaptic cell more positive?
Flashcards
Synapse
Synapse
The junction where a nerve impulse passes from one neuron to another
Neurotransmitters
Neurotransmitters
Chemicals released at synapses to transmit signals
Synaptic Cleft
Synaptic Cleft
The gap between neurons where neurotransmitters diffuse
Peripheral Nervous System
Peripheral Nervous System
Signup and view all the flashcards
Central Nervous System
Central Nervous System
Signup and view all the flashcards
Sensory Neurons
Sensory Neurons
Signup and view all the flashcards
Motor Neurons
Motor Neurons
Signup and view all the flashcards
Interneurons
Interneurons
Signup and view all the flashcards
Resting Potential
Resting Potential
Signup and view all the flashcards
Moving Nerve Impulse
Moving Nerve Impulse
Signup and view all the flashcards
Study Notes
- Bio LEK - nervous system
Main Functions of the Nervous System
- Collects information about the body’s internal and external environment
- Processes that information
- Responds to it
Two Parts of the Nervous System
- Peripheral nervous system consists of nerves and supporting cells
- Peripheral nervous system gathers information and sends it to the central nervous system
- The central nervous system consists of the brain and spinal cord
- The central nervous system processes information and forms a response
Three Types of Neurons
- Sensory neurons carry impulses from sense organs (e.g., eyes) to the spinal cord and brain
- Motor neurons carry impulses from the brain and spinal cord to muscles and glands
- Interneurons process information from sensory neurons and send commands to other interneurons or motor neurons
Neuron Structure
- A neuron consists of a cell body, dendrites, axon, myelin sheath, axon hillock, and synaptic end bulbs
Parts of a Neuron
Cell Body
- Contains the nucleus and cytoplasm
- Largest part and carries genetic information
- Provides energy to drive activity
Dendrites
- Short, branched extensions that receive impulses from other neurons
- Carry impulses to the cell body
Axon
- Long fiber ending in a series of small swellings (axon terminals)
- Carries impulses away, usually only one axon
Myelin Sheath with Nodes
- Membrane that surrounds the axon in some neurons
- Impulse jumps from one node to the next, making it travel faster
- Contains many gaps where the axon membrane is exposed
Axon Hillock
- Lower end of soma
- Generates new impulses in the cell
How a Nerve Impulse is Transmitted
Resting Potential
- The inside of the neuron has a negative charge (-70 mV) compared to the outside
Stimulus
- Makes the inside of the neuron more positive
- If it exceeds the threshold (-55 mV), a nerve impulse/action potential is created
Action Potential
- An all-or-none phenomenon where the inside of the neuron becomes more positive (+40 mV)
The Moving Nerve Impulse
- Travels quickly down the axon towards axon terminals
- In myelinated axons, it skips from one node to the next
Resting Potential
- The inside of the neuron returns to its negative charge (-70 mV)
How a Nerve Impulse Crosses a Synapse
- Nerve impulse arrives at an axon terminal
- This causes the release of neurotransmitter into the synaptic cleft
- Neurotransmitter diffuses across the gap
- Neurotransmitter binds to receptors on the membrane of the receiving/postsynaptic cell (key-lock principle)
- Sodium ion (Na+) channels open in the membrane of the postsynaptic cell
- The postsynaptic cell becomes more positive
- If stimulation exceeds the cell’s threshold, a new impulse/action potential begins, or muscle contraction occurs
- Neurotransmitters are broken down by enzymes in the synaptic cleft and taken up by axon terminals
Visual Analogy of Nerve Impulse Transmission
- Standing dominos are like resting potential
- A push that causes the first domino to fall is like a threshold stimulus
- Falling dominoes are like action potential moving along the axon; once an action potential starts moving, it will not stop until it reaches the end
- Once an impulse passes, the neuron’s resting potential is restored, so the neuron is ready for the next action potential
- Fallen dominoes, however, are not automatically restored to a standing position
The Arrow Poison Curare
- Indigenous people used arrow poison (curare) to paralyze and thus kill their prey
How Curare Poisoning Causes Paralysis
- Curare blocks receptors in the postsynaptic cell, preventing neurotransmitters from binding, which causes paralysis
- Curare also affects the synapses of the heart muscle and the diaphragm
- Curare binds to and blocks the acetylcholine receptors of muscle fibers, according to the lock-and-key principle
- Unlike acetylcholine, curare does not trigger muscle contraction
- Skeletal muscles, as well as the diaphragm, are paralyzed
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
