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Questions and Answers
What are the main functions of the nervous system?
What are the main functions of the nervous system?
Which part of the nervous system is composed of nerves and ganglia?
Which part of the nervous system is composed of nerves and ganglia?
In the nervous system's motor division, what type of signals are sent to skeletal muscles?
In the nervous system's motor division, what type of signals are sent to skeletal muscles?
Which property of neurons allows them to respond to stimuli?
Which property of neurons allows them to respond to stimuli?
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What is the main role of interneurons in the nervous system?
What is the main role of interneurons in the nervous system?
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What anatomical structure of a neuron is primarily responsible for receiving signals?
What anatomical structure of a neuron is primarily responsible for receiving signals?
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What is the primary function of neuroglia in the nervous system?
What is the primary function of neuroglia in the nervous system?
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Which division of the peripheral nervous system is responsible for arousing the body?
Which division of the peripheral nervous system is responsible for arousing the body?
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What is the primary function of oligodendrocytes in the CNS?
What is the primary function of oligodendrocytes in the CNS?
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Which type of glial cell is most abundant in the CNS and provides structural support?
Which type of glial cell is most abundant in the CNS and provides structural support?
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What characterizes the nodes of Ranvier in myelinated nerve fibers?
What characterizes the nodes of Ranvier in myelinated nerve fibers?
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What is the primary mode of communication at a chemical synapse?
What is the primary mode of communication at a chemical synapse?
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Which neurotransmitter is classified as inhibitory?
Which neurotransmitter is classified as inhibitory?
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What distinguishes an electrical synapse from a chemical synapse?
What distinguishes an electrical synapse from a chemical synapse?
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Which structure at a chemical synapse contains packets of neurotransmitters?
Which structure at a chemical synapse contains packets of neurotransmitters?
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What is the primary function of ependymal cells in the CNS?
What is the primary function of ependymal cells in the CNS?
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Study Notes
Nervous System Overview
- Neurobiology is the study of the nervous system, encompassing neuroanatomy and neurophysiology.
- The nervous system's functions include sensory perception (organization and interpretation), integration (combining information), and motor planning (output).
- The central nervous system (CNS) comprises the brain and spinal cord.
- The peripheral nervous system (PNS) consists of nerves and ganglia.
Peripheral Nervous System
- The sensory division transmits signals from receptors to the CNS. This includes the somatic division (signals from skin, muscles, bones, and joints) and the visceral division (signals from the thoracic and abdominal cavities).
- The motor division transmits signals from the CNS to glands and muscles. This includes the somatic division (signals to skeletal muscles) and the visceral division (signals to glands, cardiac, and smooth muscle). The visceral motor division is further divided into the sympathetic (arousing) and parasympathetic (energy intake and conservation) systems.
Neurons
- Neurons are nerve cells.
- Fundamental properties of neurons include excitability (responding to stimuli), conductivity (sending signals quickly to distant locations), and secretion (releasing neurotransmitters).
Functional Classes of Neurons
- Sensory (afferent) neurons detect stimuli.
- Interneurons (association neurons) receive signals and process responses.
- Motor (efferent) neurons send signals to muscles to cause a response.
Structure of a Neuron
- The neurosoma (soma or cell body) is the neuron's control center.
- Nissl bodies are compartments of rough endoplasmic reticulum within the neurosoma.
- Dendrites receive signals.
- Axons send action potentials.
- The synaptic knob (terminal button) is the axon's ending, communicating with other cells.
Neuroglia (“glial cells”)
- Neuroglia outnumber neurons 10 to 1.
- They are support cells that protect and aid in neuronal function.
- Glia means "glue," reflecting their role in binding neurons together.
Types of Neuroglia (CNS)
- Oligodendrocytes myelinate CNS axons, aiding conduction. They have multiple arm-like processes, each spiraling around a nerve fiber.
- Ependymal cells line brain and spinal cord cavities, secreting and circulating cerebrospinal fluid.
- Microglia are small macrophages involved in defense and debris/pathogen disposal.
- Astrocytes, the most abundant glia, provide structural support, form the blood-brain barrier, and provide nourishment.
Myelination of the CNS
- Myelin acts like insulation on a wire, speeding up signal transmission.
- Oligodendrocytes produce the fatty white matter of the CNS.
- Internodes are myelin-covered segments of a nerve fiber.
- Nodes of Ranvier are gaps in the myelin sheath between internodes.
Synapses
- A synapse is the junction between a neuron and another cell.
- Communication can be chemical (neurotransmitters) or electrical (ions).
Chemical Synapse
- The presynaptic neuron releases neurotransmitters to the postsynaptic cell.
- Neurotransmitters are messenger molecules; some are excitatory, others inhibitory. Examples include acetylcholine (neuromuscular junction), norepinephrine (sympathetic nervous system), glutamate & aspartate (excitatory), GABA & glycine (inhibitory), and many others (dopamine, serotonin, histamine etc.).
Chemical Synapse Structures
- Synaptic knobs contain synaptic vesicles (packets of neurotransmitters) on the presynaptic neuron.
- The synaptic cleft separates the pre- and postsynaptic cells.
- Neurotransmitter receptors are located on the postsynaptic cell.
Electrical Synapse
- Electrical synapses connect neurons, neuroglia, and cardiac/smooth muscle cells.
- Adjacent cells are joined by gap junctions allowing ion diffusion.
- Transmission is rapid, with no delay for neurotransmitter release and binding.
- There's no integration or decision-making process in electrical synapses.
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Description
Explore the intricate workings of the nervous system in this quiz. Understand the divisions of the nervous system, including the central and peripheral components, along with their functions. Test your knowledge on neuroanatomy and neurophysiology with various questions.
