Podcast
Questions and Answers
What are the two main components of the nervous system?
What are the two main components of the nervous system?
Central nervous system (CNS) and peripheral nervous system (PNS)
What are the structural and functional units of the nervous system?
What are the structural and functional units of the nervous system?
Neurons
What are the three types of neurons based on their function?
What are the three types of neurons based on their function?
Sensory neurons, Motor neurons, and Association neurons (interneurons)
Neuron membrane is polarized due to the presence of a concentration gradient of sodium and potassium on either side of the plasma membrane.
Neuron membrane is polarized due to the presence of a concentration gradient of sodium and potassium on either side of the plasma membrane.
Signup and view all the answers
What is the resting potential of a neuron typically measured as?
What is the resting potential of a neuron typically measured as?
Signup and view all the answers
What is the brief change in membrane potential that propagates along a neuron called?
What is the brief change in membrane potential that propagates along a neuron called?
Signup and view all the answers
The action potential is dependent on the intensity of the electrical stimulation.
The action potential is dependent on the intensity of the electrical stimulation.
Signup and view all the answers
The all-or-none law states that once the threshold is reached, the action potential will always have the same magnitude regardless of the strength of the stimulus.
The all-or-none law states that once the threshold is reached, the action potential will always have the same magnitude regardless of the strength of the stimulus.
Signup and view all the answers
What are the two types of refractory periods that limit the frequency of action potential firing?
What are the two types of refractory periods that limit the frequency of action potential firing?
Signup and view all the answers
What are the two ways that synaptic integration can occur?
What are the two ways that synaptic integration can occur?
Signup and view all the answers
The velocity of nerve impulse conduction depends on the diameter of the axon.
The velocity of nerve impulse conduction depends on the diameter of the axon.
Signup and view all the answers
Myelination decreases the speed of nerve impulse conduction.
Myelination decreases the speed of nerve impulse conduction.
Signup and view all the answers
The propagation of nerve impulses is always unidirectional, moving from the presynaptic neuron to the postsynaptic neuron.
The propagation of nerve impulses is always unidirectional, moving from the presynaptic neuron to the postsynaptic neuron.
Signup and view all the answers
What are the two main types of synaptic transmission?
What are the two main types of synaptic transmission?
Signup and view all the answers
Synaptic transmission is essential for interneuronal communication.
Synaptic transmission is essential for interneuronal communication.
Signup and view all the answers
What is the junction between a motor neuron and a skeletal muscle cell called?
What is the junction between a motor neuron and a skeletal muscle cell called?
Signup and view all the answers
What are the three main components of a neuromuscular junction?
What are the three main components of a neuromuscular junction?
Signup and view all the answers
What is the primary neurotransmitter released at the neuromuscular junction?
What is the primary neurotransmitter released at the neuromuscular junction?
Signup and view all the answers
The presynaptic side of the neuromuscular junction contains vesicles filled with neurotransmitters.
The presynaptic side of the neuromuscular junction contains vesicles filled with neurotransmitters.
Signup and view all the answers
What are the two main types of postsynaptic potentials?
What are the two main types of postsynaptic potentials?
Signup and view all the answers
The release of neurotransmitters from the presynaptic neuron is triggered by the influx of calcium ions.
The release of neurotransmitters from the presynaptic neuron is triggered by the influx of calcium ions.
Signup and view all the answers
What are the main steps involved in neurotransmission?
What are the main steps involved in neurotransmission?
Signup and view all the answers
Study Notes
Introduction to Neurophysiology
- Nervous tissue is composed of neurons and neuroglia
- Nervous system is divided into central nervous system (CNS) and peripheral nervous system (PNS)
- CNS includes the brain and spinal cord
- PNS includes cranial and spinal nerves, including ganglia
- Autonomic nervous system innervates the viscera
Physiology of the Neuron
Structure of the Neuron
- Neurons are the structural and functional units of the nervous system (Figure 1)
- Neurons are excitable cells that communicate via neurotransmitters, neuromodulators, or neurohormones
- Excitation occurs via ion flow through protein channels in the neuronal plasma membrane.
- Neurons transmit signals to other neurons, muscles, or glands
- Neurons have dendrites, a cell body (soma), an axon hillock, and axons with terminal branches (axon)
Functional Classification of Neurons
- Sensory neurons carry impulses to the CNS (Figure 2)
- Somatic sensory neurons from skin, bones, muscles, and joints.
- Visceral sensory neurons from viscera.
- Motor neurons carry impulses from the CNS
- Somatic motor neurons to skeletal muscles
- Visceral motor neurons to cardiac muscle, smooth muscles, and glands
- Association neurons (interneurons) connect sensory neurons to motor neurons.
Membrane Potential
- Neuron membrane is polarized due to sodium and potassium concentration gradients
- Resting potential is -70mV, maintained by Na-K-ATPase pump
- Resting potential is negative because the inside of the membrane is more negative than the outside
- Ionic origin of resting potential: high permeability to K+ ions and low permeability to Na+ ions
- Action potential (AP) is a rapid change in membrane potential (depolarization) that propagates along the neuron.
- AP involves rapid Na+ influx and K+ efflux.
Neuron Excitability
- Excitation threshold is the minimum stimulus required to trigger an AP.
- Action potential properties: all-or-nothing law, refractory period
- Refractory period has absolute and relative refractory periods(Figure 2)
Law of Refractoriness (Refractory Period)
- Essential for unidirectional propagation of the action potential
- Absolute refractory period: the neuron cannot generate another AP.
- Relative refractory period: a stronger than normal stimulus is needed to generate an AP.
Synaptic Integration
- Spatial summation: multiple presynaptic neurons stimulate the postsynaptic neuron simultaneously.
- Temporal summation: one presynaptic neuron stimulates the postsynaptic neuron repeatedly within a short time.
Neuron Conductivity
- Propagation mechanism of action potential (Figure 2): Action potential starts from the axon hillock; travels through the axon; has stimulation; depolarization; repolarization; and hyperpolarization phases
- Velocity of conduction depends on axon diameter, myelin sheath, and nodes of Ranvier.
- Direction of propagation is unidirectional
Synaptic Transmission
- Synaptic transmission is the process of transferring signals between neurons or between a neuron and a muscle or gland cell
- Neurotransmitters are chemicals that transmit signals across synapses.
- Types of synapses: Chemical (the most common type) and Electrical
- Synapses have a presynaptic terminal, a synaptic cleft, and a postsynaptic membrane
Morphology of Synapses
- Synapses are characterized by the presence of synaptic vesicles and receptors.
- Synaptic transmission involves the release of the neurotransmitters from pre-synaptic vesicles into the synapse, triggering a response in the post-synaptic cell
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
This quiz covers the foundational concepts of neurophysiology, including the composition and divisions of the nervous system. Learn about the structure and function of neurons, their classification, and how they communicate within the body. Test your knowledge on the excitability and signal transmission of neurons.
