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Questions and Answers
What are the two main divisions of the Nervous System?
What are the two main divisions of the Nervous System?
What does the nervous system maintain for proper body functioning?
What does the nervous system maintain for proper body functioning?
homeostasis
What is the function of receptors in the nervous system?
What is the function of receptors in the nervous system?
sense stimuli
The central nervous system (CNS) includes the brain and ________.
The central nervous system (CNS) includes the brain and ________.
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Efferent neurons carry sensory input to the CNS.
Efferent neurons carry sensory input to the CNS.
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Which part of the nervous system contains ganglia?
Which part of the nervous system contains ganglia?
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What are the two divisions of the efferent neurons?
What are the two divisions of the efferent neurons?
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What is the primary role of neurofilaments in neurons?
What is the primary role of neurofilaments in neurons?
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What is the diameter range of neurofilaments?
What is the diameter range of neurofilaments?
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Which transport method is responsible for moving proteins and organelles along the axon?
Which transport method is responsible for moving proteins and organelles along the axon?
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What is the diameter of microtubules, which are involved in axoplasmic transport?
What is the diameter of microtubules, which are involved in axoplasmic transport?
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Neurofilaments work in conjunction with which other structural components of the neuron to maintain its shape?
Neurofilaments work in conjunction with which other structural components of the neuron to maintain its shape?
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Which motor protein is primarily responsible for orthograde transport from the nerve cell body to terminal boutons?
Which motor protein is primarily responsible for orthograde transport from the nerve cell body to terminal boutons?
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What is the role of mitochondria in neurons?
What is the role of mitochondria in neurons?
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Which statement about lipofuscin pigments is true?
Which statement about lipofuscin pigments is true?
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What best describes centriole's function in neurons?
What best describes centriole's function in neurons?
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What distinguishes dynein from kinesin in neuronal transport?
What distinguishes dynein from kinesin in neuronal transport?
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Study Notes
Divisions of the Nervous System
- The nervous system is composed of the central nervous system (CNS) and the peripheral nervous system (PNS).
- The CNS consists of the brain and spinal cord.
- The CNS serves as the integration center of the body, and directs actions and responses to various stimuli.
- The PNS is comprised of receptors and nerves found outside the CNS.
- The PNS houses ganglia, which are relay stations along nerve pathways.
- PNS receptors function to detect stimuli from both internal and external environments.
- Receptors convert stimuli into signals and transmit them to the CNS through afferent neurons.
- The CNS integrates the information and sends out signals through efferent neurons to create a response.
- Nerves found in the PNS are either afferent or efferent.
- Afferent neurons carry sensory input to the CNS.
- Efferent neurons carry motor output and innervate effectors.
Types of Efferent Neurons
- Efferent neurons are divided into the somatic nervous system and the autonomic nervous system.
- The somatic nervous system controls skeletal muscle activity.
- The autonomic nervous system regulates involuntary functions, including cardiac muscle, smooth muscle, and glands.
Features of Nervous Tissue
- Nervous tissue contains neurons with processes, which are either dendrites or axons.
- The number of nerve processes determines the classification of neurons.
Neurofilaments
- Neurofilaments are intermediate filaments found in neurons.
- Their diameter is 8-12 nm.
- They maintain the shape and rigidity of the neuron.
- They function as pathways for chemical and electrical signals.
Microtubules and Microfilaments
- These contribute to the neuron's cytoskeleton.
- They maintain cell shape and rigidity alongside neurofilaments.
- Microtubules are critical for axoplasmic transport, measuring at 24 nm in diameter.
- Microtubules are responsible for the movement of vesicles, proteins, and organelles.
- Neurofilaments allow for the passage of electrical signals.
Axonal Transport
- Axonal transport is the movement of proteins and organelles along axons.
- Transport can be anterograde or retrograde, both relying on microtubules.
- Anterograde transport moves substances from the cell body to the axon terminal.
- Retrograde transport moves substances from the axon terminal to the cell body.
- Motor proteins kinesin and dynein power axonal transport.
- Kinesin is involved in anterograde transport.
- Dynein is involved in retrograde transport.
- Slow axonal transport primarily involves protein monomers, while fast axonal transport involves organelles.
- Retrograde transport can allow harmful agents to reach the central nervous system.
Types of Neurons - Number of Processes
- Multipolar neurons have numerous processes, including one axon and multiple dendrites.
Types of Neurons - Function
- Sensory neurons convey sensory information from the periphery to the central nervous system.
- Motor neurons transmit signals from the central nervous system to effectors, such as muscles or glands.
- Interneurons connect various neurons within the central nervous system.
Nerve Endings/Receptors
- Structures that receive impulses from the internal or external environment are called receptors.
- Nerve endings convert stimuli into nerve impulses.
Main Types of Nerve Receptors - Interoceptors
- Detect changes in the visceral environment, such as pressure, temperature, and chemical stimuli.
- Examples include chemoreceptors and baroreceptors.
Main Types of Nerve Receptors - Proprioceptors
- Monitor skeletal muscle position, tension, and movement.
- Examples include neuromuscular spindles and Golgi tendon organs.
Main Types of Nerve Receptors - Exteroceptors
- Respond to stimuli from the external environment.
- Examples include free nerve endings and skin receptors (Merkel discs, Meissner's corpuscles, Ruffini's endings, and End bulbs of Krause).
Free Nerve Endings - General
- The most common type of nerve ending.
- Composed of sensory dendrites that can be stimulated by various stimuli.
- Each receptor monitors a specific area called a receptive field.
- Highly versatile - can detect various modalities, such as touch, thermal sense, and pain (nociceptors).
Free Nerve Endings - Nociceptors
- Free nerve endings that perceive pain.
Meissner's Corpuscles
- Found in the dermis of the skin.
- Fast-adapting receptors.
- Allow for discriminatory touch - identifying specific points of contact.
- Sensitive to low-frequency vibrations (10-50 Hz).
Vater-Pacinian Corpuscles
- Located in the hypodermis.
- Fast-adapting, meaning they respond quickly to stimuli and then adapt.
- Sensitive to rapid vibrations (200 Hz).
- Respond to deep pressure.
Ruffini's End Organs
- Found in the deep dermis.
- Detect tension in the skin.
- More commonly found in the soles of the feet.
End Bulbs of Krause
- Encapsulated receptors.
- Found in the oropharynx and conjunctiva.
- Detect cold temperatures.
Neuromuscular Spindles
- Specialized sensory organs found within skeletal muscle.
- Function as proprioceptors, reporting changes in muscle length and velocity.
- Essential in maintaining muscle tone and the knee-jerk reflex.
Spinal Cord - General
- Contains gray matter, primarily made up of nerve cell bodies, and white matter composed of myelinated nerve fibers.
Neuron - General
- The fundamental unit of the nervous system.
- Contains a cell body, dendrites, and an axon.
Meissner's Corpuscles - Micrograph
- Characterized by longitudinal laminations.
Pacinian Corpuscles - Micrograph
- Identified by concentric laminations.
Nerve Fascicles with Vasa Nervorum - Micrograph
- Bundles of nerve fibers with associated blood vessels.
Auerbach Plexus - Micrograph
- Located in the muscularis propria of the gastrointestinal tract.
- Component of the autonomic nervous system.
Dorsal Root Ganglion - Micrograph
- Contains the cell bodies of sensory neurons.
Slide Review
- These are the main structures you should be able to identify in prepared slides.
- Identify structures in both micrographs and drawings.
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Description
Explore the intricacies of the nervous system, including the central and peripheral components. Learn about the roles of afferent and efferent neurons, how stimuli are processed, and the function of ganglia within nerve pathways. This quiz is perfect for students studying human biology or health sciences.
