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Which branch of the autonomic nervous system is responsible for the 'fight or flight' response?
What type of muscles does the somatic nervous system primarily control?
What role do neuroglia play in the nervous system?
Which of the following is NOT a characteristic of neuroglia?
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What is the primary function of the parasympathetic branch of the autonomic nervous system?
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What is the primary role of astrocytes in the central nervous system?
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What distinguishes protoplasmic astrocytes from fibrous astrocytes?
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What is a characteristic feature of oligodendroglia in the central nervous system?
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Which cells are responsible for producing myelin in the peripheral nervous system?
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What is the primary function of microglia in the central nervous system?
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What is the role of satellite cells in the peripheral nervous system?
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What are the uncoated areas on axons called that aid in signal propagation?
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What type of cells line the cavities of the brain and spinal cord?
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What is the primary function of ependymal cells in the central nervous system?
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Which type of cell is responsible for the formation of the myelin sheath in the central nervous system?
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What characterizes the function of microglia in the central nervous system?
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What does the term 'efferent' refer to in the context of neural processes?
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In the context of neuronal firing, what occurs when an impulse is created?
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How is signaling between neurons primarily characterized?
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What happens to neurons affected by Alzheimer's dementia?
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Which of the following best describes the concept of a gyrus?
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What primarily maintains the resting potential of a neuron?
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What happens when a neuron is stimulated by a weak impulse?
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What is synaptic transmission primarily responsible for?
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What is the role of excitatory postsynaptic potential (EPSP)?
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Which type of synapse connects an axon directly to another axon?
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What effect do inhibitory postsynaptic potentials (IPSPs) have on a neuron's membrane potential?
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What integral role does the semi-permeable membrane play in a neuron's function?
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What is the potential outcome if the stimulus to a neuron is strong enough?
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What is the primary function of the sodium-potassium pump in a neuron?
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What characterizes the intracellular fluid in a neuron?
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Which of the following accurately describes the polarization of a neuron?
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During the resting state of a neuron, what is the typical membrane potential measurement?
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What is the effect of concentration gradients and charge gradients on neuronal function?
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What will happen if the sodium-potassium pump fails to function properly?
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Which ions are in higher concentration outside a neuron compared to the inside?
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What triggers the action potential in a neuron?
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Study Notes
Peripheral Nervous System (PNS)
- PNS is divided into two main systems: Somatic and Autonomic.
- Somatic System: Controls voluntary muscles (striated).
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Autonomic System: Controls involuntary muscles (smooth), further divided into:
- Sympathetic Branch: Triggers "fight or flight" response; increases heart rate, dilates pupils, alters saliva production during arousal events (fear, drugs).
- Parasympathetic Branch: Responsible for maintenance of routine activities and calming the body post-arousal.
Neurons and Neuroglia
- Neurons are supported by non-excitable cells called neuroglia, which outnumber neurons by 5-10 times.
- Neuroglia regulate ionic concentration in the extracellular fluid and do not generate nerve impulses.
Types of Neuroglia
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Astrocytes:
- Most common in CNS; nourish neurons and support their structures.
- Part of the blood-brain barrier, restricting blood substance movement.
- Types include:
- Protoplasmic: Found in gray matter.
- Fibrous: Found in white matter.
- Oligodendroglia: Myelinate multiple axons in the CNS.
- Schwann Cells: Myelinate single axons in the PNS.
- Microglia: Act as immune defenders, removing pathogens through phagocytosis.
- Ependymal Cells: Line CNS cavities and regulate cerebrospinal fluid (CSF) flow.
Neuronal Communication
- Neurons communicate through electrical and chemical processes involving action potentials.
- Efferent signals are motor (top-down), and afferent signals are sensory (bottom-up).
- Synaptic transmission involves neurotransmitters facilitating communication across synapses.
Neuronal Firing Dynamics
- Neurons are constantly active, firing when impulses trigger membrane permeability changes.
- Resting potential ranges from -50 to -70 mV, maintained by the sodium-potassium pump.
- Action potential occurs when a neuron is sufficiently stimulated, resulting in an electrical impulse that propagates along the axon.
Synapse Functionality
- Synapses connect neurons for signal transmission, allowing communication with muscles or glands.
- Neurotransmitters mediate transmission; they may excite (EPSP) or inhibit (IPSP) subsequent action potentials.
- Different synapse types:
- Dendrodendritic: Dendrite to dendrite.
- Axodendritic: Axon to dendrite (most common).
- Axosomatic: Axon to cell body.
- Axoaxonic: Axon to axon.
Electrical Activity of Neurons
- Changes in ionic concentrations create a gradient critical for neuronal activity.
- Intracellular fluid contains high potassium levels, while extracellular fluid is rich in sodium.
- Proper ion balance is essential for maintaining resting potential and during action potentials.
Neurological Disorders
- Disorders often stem from dysfunction in neuronal cellular and molecular activities.
- For instance, Alzheimer’s dementia is linked to neuronal entanglement leading to impaired synaptic transmission.
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Description
Explore the Peripheral Nervous System (PNS) with a focus on its main divisions: the Somatic and Autonomic systems. Understand how each system functions, the role of neurons, and the types of neuroglia that support neuronal activities. This quiz will test your knowledge of these essential concepts in neuroscience.
