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Questions and Answers
What is the primary role of dendrites in a neuron?
What is the primary role of dendrites in a neuron?
Which type of neuron has multiple processes extending from the cell body?
Which type of neuron has multiple processes extending from the cell body?
What role do motor (efferent) neurons play in the nervous system?
What role do motor (efferent) neurons play in the nervous system?
Which component of the neuron contains the nucleus and surrounding cytoplasm?
Which component of the neuron contains the nucleus and surrounding cytoplasm?
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Which layer of connective tissue immediately surrounds a single axon?
Which layer of connective tissue immediately surrounds a single axon?
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What is the function of myelin sheath in motor neurons?
What is the function of myelin sheath in motor neurons?
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What is the primary function of the axon hillock in a nerve fiber?
What is the primary function of the axon hillock in a nerve fiber?
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What is the role of Schwann cells in the nervous system?
What is the role of Schwann cells in the nervous system?
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Which type of glial cell is most abundant and plays a key role in maintaining homeostasis?
Which type of glial cell is most abundant and plays a key role in maintaining homeostasis?
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What separates nerve cells from blood vessels in the brain?
What separates nerve cells from blood vessels in the brain?
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Study Notes
Nerve Tissue Composition
- Composed of neurons (nerve cells) and supporting cells.
- High capability to respond to stimuli and transmit impulses.
Neuron Structure
- Main functional unit of the nervous system, consisting of:
- Cell Body (Perikaryon/Soma): Contains the nucleus and cytoplasm.
- Dendrites: Numerous processes that receive stimuli.
- Axon: Single process that conducts nerve impulses to other cells.
Types of Neurons
- Multipolar Neurons: One axon and two or more dendrites; most common type in motor and interneurons.
- Bipolar Neurons: One axon and one dendrite; found in the retina, olfactory mucosa, and inner ear.
- Unipolar Neurons: Single process dividing into two branches; associated with spinal ganglia and cranial ganglia.
Functional Classification of Neurons
- Motor (Efferent) Neurons: Control effector organs, like muscles and glands.
- Sensory (Afferent) Neurons: Receive sensory stimuli from the environment and body.
- Interneurons: Connect motor and sensory neurons, forming a communication network.
Neuron Cell Body and Components
- Contains Nissl bodies (RER and ribosomes), visible as basophilic clumps under a microscope.
- The axon originates from the axon hillock, transitioning into the axon cylinder or nerve fiber.
Nerve Fiber (Axon) Characteristics
- Myelinated axons have a lipid-rich myelin sheath, segmented by nodes of Ranvier.
- Schwann Cells: Surround and form an insulating cover (neurolemma) around the axon.
Nerve Organization
- Endoneurium: Innermost connective tissue layer around a single axon.
- Perineurium: Connective tissue layer surrounding fascicles of axons.
- Epineurium: Outermost layer of dense connective tissue around the entire nerve.
Glial Cells (Neuroglia)
- Non-neuronal cells that maintain homeostasis, support, and protect neurons.
- Occupy space between neurons and separate them from blood vessels.
Functions of Glial Cells
- Support and stabilize neurons in place.
- Supply essential nutrients and oxygen.
- Insulate neurons from each other.
- Eliminate pathogens and dead neurons.
- Line brain ventricles and spinal cord's central canal.
Types of Glial Cells
- Astrocytes: Most abundant, play key roles in maintaining homeostasis and linking to blood vessels.
- Oligodendrocytes: Form myelin in the central nervous system.
- Microglia: Act as immune cells for the nervous system.
- Ependymal Cells: Line ventricles and central canal.
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Description
This quiz focuses on nerve tissue, specifically the microscopic differences between excitable and non-excitable cells in the nervous system. It will cover the composition of nerve tissue, including neurons and supporting cells. Test your understanding of how these cells respond to stimuli and transmit impulses.
