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Questions and Answers
What is the primary function of the filum terminale?
What is the primary function of the filum terminale?
What is the total number of pairs of spinal nerves in the human body?
What is the total number of pairs of spinal nerves in the human body?
Which layer of the meninges is tightly bound to the surface of the spinal cord?
Which layer of the meninges is tightly bound to the surface of the spinal cord?
What type of neurons are primarily found in the cerebral cortex?
What type of neurons are primarily found in the cerebral cortex?
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Where are anesthetics typically injected in relation to the spinal cord?
Where are anesthetics typically injected in relation to the spinal cord?
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Why is there one additional cervical nerve compared to cervical vertebrae?
Why is there one additional cervical nerve compared to cervical vertebrae?
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Which function do efferent fibers serve in the nervous system?
Which function do efferent fibers serve in the nervous system?
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Identify the components of the gray matter in the spinal cord.
Identify the components of the gray matter in the spinal cord.
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What are the two roots that connect spinal nerves to the spinal cord?
What are the two roots that connect spinal nerves to the spinal cord?
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Which part of the spinal cord contains myelinated axons?
Which part of the spinal cord contains myelinated axons?
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How many cranial nerves are there in the human body?
How many cranial nerves are there in the human body?
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What separates the left and right halves of the spinal cord?
What separates the left and right halves of the spinal cord?
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Which type of glial cells are primarily responsible for supporting neurons?
Which type of glial cells are primarily responsible for supporting neurons?
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What fills the subarachnoid space?
What fills the subarachnoid space?
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Which structure connects the spinal cord to the dura mater?
Which structure connects the spinal cord to the dura mater?
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Which region of the vertebral column has 5 associated spinal nerves?
Which region of the vertebral column has 5 associated spinal nerves?
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What structure is formed from the entoderm layer during development?
What structure is formed from the entoderm layer during development?
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What is the role of the neural crest during development?
What is the role of the neural crest during development?
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When does neural tube closure typically complete?
When does neural tube closure typically complete?
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What forms from the mesoderm during embryonic development?
What forms from the mesoderm during embryonic development?
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What is the primary function of the axons in the peripheral nerves?
What is the primary function of the axons in the peripheral nerves?
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Which layer thickens to form the neural plate during the third week of development?
Which layer thickens to form the neural plate during the third week of development?
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What component surrounds individual axons within the peripheral nerve?
What component surrounds individual axons within the peripheral nerve?
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What is true about the anterior and posterior neuropores during neural tube formation?
What is true about the anterior and posterior neuropores during neural tube formation?
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Which layer of connective tissue is the outermost in a peripheral nerve?
Which layer of connective tissue is the outermost in a peripheral nerve?
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What is the significance of the Nodes of Ranvier in nerve conduction?
What is the significance of the Nodes of Ranvier in nerve conduction?
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Which of the following does NOT arise from the ectoderm layer?
Which of the following does NOT arise from the ectoderm layer?
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What type of neurons are primarily found in the dorsal root ganglia?
What type of neurons are primarily found in the dorsal root ganglia?
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What happens to the cells on the lateral margin of the neural plate during invagination?
What happens to the cells on the lateral margin of the neural plate during invagination?
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What is the role of Schwann cells in peripheral nerves?
What is the role of Schwann cells in peripheral nerves?
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What is found within the irregular connective tissue layer enclosing each dorsal root ganglion?
What is found within the irregular connective tissue layer enclosing each dorsal root ganglion?
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What is neurokeratin associated with in peripheral nerves?
What is neurokeratin associated with in peripheral nerves?
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What is the primary function of microglial cells in the central nervous system (CNS)?
What is the primary function of microglial cells in the central nervous system (CNS)?
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Which type of cell is responsible for myelination in the central nervous system?
Which type of cell is responsible for myelination in the central nervous system?
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Where are ependymal cells primarily located within the central nervous system?
Where are ependymal cells primarily located within the central nervous system?
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Which of the following statements is true regarding glial cells in the peripheral nervous system (PNS)?
Which of the following statements is true regarding glial cells in the peripheral nervous system (PNS)?
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What distinguishes oligodendrocytes from Schwann cells?
What distinguishes oligodendrocytes from Schwann cells?
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What is the most significant characteristic of microglial cells?
What is the most significant characteristic of microglial cells?
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Cranial nerves arise from where in the nervous system?
Cranial nerves arise from where in the nervous system?
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Which option best describes the function of the cilia on ependymal cells?
Which option best describes the function of the cilia on ependymal cells?
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What does the myelencephalon develop into?
What does the myelencephalon develop into?
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Which primary brain vesicle differentiates into the mesencephalon?
Which primary brain vesicle differentiates into the mesencephalon?
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What structures are derived from the telencephalon?
What structures are derived from the telencephalon?
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During which week do secondary swellings develop in the prosencephalon and rhombencephalon?
During which week do secondary swellings develop in the prosencephalon and rhombencephalon?
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Which structure is NOT formed from the diencephalon?
Which structure is NOT formed from the diencephalon?
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What is the role of the prosencephalon in brain development?
What is the role of the prosencephalon in brain development?
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Which of the following structures represents a part of the hindbrain vesicle?
Which of the following structures represents a part of the hindbrain vesicle?
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What is formed from the metencephalon during brain development?
What is formed from the metencephalon during brain development?
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What components are included in the Central Nervous System (CNS)?
What components are included in the Central Nervous System (CNS)?
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Which part of the autonomic nervous system is responsible for preparing the body for emergencies?
Which part of the autonomic nervous system is responsible for preparing the body for emergencies?
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What is the primary function of neuroglia in the CNS?
What is the primary function of neuroglia in the CNS?
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Which structure is associated with the distribution of involuntary nervous functions?
Which structure is associated with the distribution of involuntary nervous functions?
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Which type of cell in the nervous system is typically excitable and capable of transmitting impulses?
Which type of cell in the nervous system is typically excitable and capable of transmitting impulses?
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What is the role of the peripheral nervous system (PNS)?
What is the role of the peripheral nervous system (PNS)?
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Which of the following accurately describes the primary functions of the two parts of the autonomic nervous system?
Which of the following accurately describes the primary functions of the two parts of the autonomic nervous system?
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What are the major divisions of the Central Nervous System?
What are the major divisions of the Central Nervous System?
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What is the primary function of myelin sheaths in neuron communication?
What is the primary function of myelin sheaths in neuron communication?
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Which neuron type is responsible for transmitting information from sensory organs to the spinal cord?
Which neuron type is responsible for transmitting information from sensory organs to the spinal cord?
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What occurs at the axon hillock in a neuron?
What occurs at the axon hillock in a neuron?
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How does the presence of myelin affect action potential conduction?
How does the presence of myelin affect action potential conduction?
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Which cells are responsible for myelinating axons in the peripheral nervous system?
Which cells are responsible for myelinating axons in the peripheral nervous system?
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What structural feature of dendrites enhances their ability to form synapses?
What structural feature of dendrites enhances their ability to form synapses?
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What role do interneurons play in the central nervous system?
What role do interneurons play in the central nervous system?
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What role do nodes of Ranvier play in nerve impulse propagation?
What role do nodes of Ranvier play in nerve impulse propagation?
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What is the primary characteristic of Purkinje cells in the cerebellar cortex?
What is the primary characteristic of Purkinje cells in the cerebellar cortex?
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Which layer of the cerebellar cortex has the highest density of neurons?
Which layer of the cerebellar cortex has the highest density of neurons?
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What is the function of Nissl substance found in multipolar motor neurons?
What is the function of Nissl substance found in multipolar motor neurons?
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What characterizes the anterior gray horn of the spinal cord?
What characterizes the anterior gray horn of the spinal cord?
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What does silver staining reveal in the context of motor neurons?
What does silver staining reveal in the context of motor neurons?
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Which type of neurons are primarily found in the inner granular layer of the cerebellar cortex?
Which type of neurons are primarily found in the inner granular layer of the cerebellar cortex?
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How do dendrites relate to Nissl substance in motor neurons?
How do dendrites relate to Nissl substance in motor neurons?
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What structural feature distinguishes the cerebellar white matter?
What structural feature distinguishes the cerebellar white matter?
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What is the primary role of acetylcholine (ACh) at the neuromuscular junction?
What is the primary role of acetylcholine (ACh) at the neuromuscular junction?
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Which enzyme is responsible for inactivating acetylcholine (ACh) at the neuromuscular junction?
Which enzyme is responsible for inactivating acetylcholine (ACh) at the neuromuscular junction?
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What happens to acetylcholine (ACh) after it is released into the synaptic cleft?
What happens to acetylcholine (ACh) after it is released into the synaptic cleft?
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What is the function of the synaptic vesicles at the axon terminal?
What is the function of the synaptic vesicles at the axon terminal?
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Which process occurs when a nerve impulse arrives at the axon terminal?
Which process occurs when a nerve impulse arrives at the axon terminal?
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What effect does acetylcholinesterase (AChE) have on acetylcholine (ACh) at the neuromuscular junction?
What effect does acetylcholinesterase (AChE) have on acetylcholine (ACh) at the neuromuscular junction?
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Which statement best describes the interaction between ACh and muscle fibers?
Which statement best describes the interaction between ACh and muscle fibers?
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What is the significance of the staining of acetylcholinesterase (AChE) in neuromuscular junctions?
What is the significance of the staining of acetylcholinesterase (AChE) in neuromuscular junctions?
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Study Notes
Spinal Cord Anatomy
- Filum terminale anchors spinal cord to coccyx.
- Meninges consist of three layers:
- Dura mater: outermost, continuous with epineurium of spinal nerves.
- Arachnoid mater: in the middle layer.
- Pia mater: inner layer, tightly bound to the spinal cord surface.
- Forms denticulate ligaments attaching the spinal cord to the dura.
Meningeal Spaces
- Epidural space: external to the dura, fat-filled; site for anesthetic injections.
- Subdural space: located between dura and arachnoid, contains serous fluid.
- Subarachnoid space: between pia and arachnoid, filled with cerebrospinal fluid (CSF); lumbar puncture typically performed at L3-L4 or L4-L5.
Spinal Cord Structure
- Anterior median fissure and posterior median sulcus create deep clefts dividing the spinal cord.
- Gray matter houses neuron cell bodies; organized into:
- Posterior (dorsal) horn
- Anterior (ventral) horn
- Lateral horn
- White matter consists of myelinated axons, divided into three columns (funiculi):
- Ventral, dorsal, and lateral, each containing sensory or motor tracts.
- Commissures connect left and right halves, with the central canal in the gray matter center.
Peripheral Nervous System (PNS)
- PNS includes 12 pairs of cranial nerves and 31 pairs of spinal nerves:
- 8 cervical
- 12 thoracic
- 5 lumbar
- 5 sacral
- 1 coccygeal nerve
- Unique: 8 cervical nerves correspond to only 7 cervical vertebrae, and 1 coccygeal nerve for 4 coccygeal vertebrae.
- Each spinal nerve connects to the spinal cord via anterior (efferent) and posterior (afferent) roots.
Brain Development
- Three embryonic layers:
- Entoderm: forms gastrointestinal tract, lungs, liver.
- Mesoderm: develops muscles, connective tissues, vascular system.
- Ectoderm: gives rise to skin and nervous system.
- Neural plate forms in the 3rd week; narrows into a neural groove, which fuses to create the neural tube.
- Neural crest originates between the neural tube and ectoderm, forming various neural structures (e.g., ganglia).
Microglial Cells
- Part of the CNS phagocyte system, originating from bone marrow.
- Irregular shape, small nucleus; migrate to sites of damage to remove dead tissue.
Oligodendrocytes and Ependymal Cells
- Oligodendrocytes: small cells in gray and white matter, create myelin sheaths around multiple axons.
- Ependymal cells: line brain ventricles and central canal, ciliated to facilitate CSF movement.
Peripheral Nerve Structure
- Composed of neurons, glial cells (like Schwann cells), and axons outside the CNS.
- Nerve fascicles are surrounded by connective tissue:
- Epineurium (outer layer)
- Perineurium (encircles fascicles)
- Endoneurium (surrounds individual axons).
- Dorsal root ganglia contain unipolar sensory neurons, enclosed by connective tissue with small satellite cells providing metabolic support.
Overview of the Nervous System
- Composed of specialized cells that process sensory stimuli and transmit responses to effector organs.
- Higher species' nervous systems can store sensory information from past experiences.
Nervous System Division
- Central Nervous System (CNS): Includes the brain and spinal cord.
- Peripheral Nervous System (PNS): Comprises cranial and spinal nerves and associated ganglia.
Autonomic Nervous System
- Involuntary structures innervated by the autonomic nervous system (e.g., heart, smooth muscles, glands).
- Divided into:
- Sympathetic part: Activates the fight-or-flight response.
- Parasympathetic part: Focuses on energy conservation and restoration.
CNS Organization
- CNS has protective layers known as meninges and contains cerebrospinal fluid.
- Comprised of white matter (myelinated axons) and gray matter (neuron cell bodies).
- Major divisions include forebrain (prosencephalon), midbrain (mesencephalon), and hindbrain (rhombencephalon).
Brain Development
- Brain vesicle formation begins three weeks after neural tube closure into three primary vesicles.
- Secondary vesicle development at the fifth week creates five distinct structures: telencephalon, diencephalon, mesencephalon, metencephalon, myelencephalon.
- Each structure develops into various brain components:
- Telencephalon: Cerebral hemispheres, cortex, corpus striatum.
- Diencephalon: Thalamus, hypothalamus, subthalamus, epithalamus.
- Mesencephalon: Midbrain and its structures.
- Metencephalon: Pons and cerebellum.
- Myelencephalon: Medulla oblongata.
Neurons and Neuroglia
- Neurons: Excitable cells with a cell body (soma), dendrites, and a single axon.
- Neuroglia: Supportive cells that maintain the environment around neurons.
Types of Neurons
- Sensory Neurons: Detect environmental stimuli and relay signals to CNS.
- Motor Neurons: Transmit signals from CNS to muscles and glands.
- Interneurons: Connect various neurons within the CNS.
Axon Structure and Function
- Axons originate from the axon hillock and are responsible for conducting impulses via action potentials.
- The conduction rate of impulses is influenced by axon diameter and myelination.
Myelination
- Myelin sheath, comprising lipids and proteins, insulates axons and speeds up impulse propagation.
- Nodes of Ranvier allow for saltatory conduction, enhancing nerve signal speed.
- Oligodendrocytes in CNS and Schwann cells in PNS are responsible for myelination.
Spinal Cord
- Contains anterior gray horns with multipolar motor neurons displaying prominent nuclei and Nissl substances for protein synthesis.
- Fine neurofibrils are distributed within gray matter and motor neurons, visible through silver staining techniques.
Neuromuscular Junctions
- Axon terminals release acetylcholine (ACh) into the synaptic cleft upon the arrival of nerve impulses.
- Acetylcholinesterase (AChE) breaks down ACh to prevent continuous stimulation of muscle fibers until the next impulse arises.
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Description
Test your knowledge on the anatomy of the spinal cord, including its protective coverings known as meninges. This quiz will cover the layers of the meninges, such as dura mater, arachnoid mater, and pia mater, along with the function of the filum terminale. Expand your understanding of spinal cord structure and its anchoring mechanisms.
