University:
Texas A&M University
Course:
BIOL 319 | Integrated Human Anatomy and Physiology I
Academic year:

2021
Views:

395

Pages:

33
Author:

Lamghari6kx

Histo 07 NERVOUS TISSUE Part 1 Objectives Part 1 • Describe the components of a neuron. • Distinguish between neurons and glial cells. • Identify the components of the meninges, grey and white matter. Part 2 • Recognize peripheral nerves and identity their structural components (in longitudinal and transverse sections); understand the structural and functional differences between myelinated and unmyelinated fibers with both light microscopy and electron micrographs. Four Basic Types of Tissues in the Body ----------------------------------------------Epithelium (90% of tumors) Muscular Tissue Connective Tissue Four Basic Types of Tissues in the Body ----------------------------------------------Epithelium (90% of tumors) Muscular Tissue Connective Tissue Nervous Tissue Nerve is like Epithelium Origin of nerve is ectoderm like epidermis (epithelium) of skin Nervous Tissue Functions: specialized for the transmission, reception, and integration of electrical impulses Distinguishing features: Neurons – very large excitable cells with long processes called axons and dendrites. The axons make contact with other neurons or muscle cells at a specialization called a synapse where the impulses are either electrically or chemically transmitted to other neurons or various target cells (e.g., muscle). Others secrete hormones. Nervous tissue Distribution: comprise the central nervous system. Individual peripheral nerves are found throughout the body. Individual neurons and clusters of neurons (called ganglia) are found in most organs. Function of the Nervous System is Communication Dependent upon special signaling properties of neurons Long processes of neurons (e.g., 1 meter motor neuraxon) Function of the Nervous System is Communication Characteristics of neurons Irritability - protoplasm capable to react to various physical and chemical agents Conductivity - ability to transmit the resulting excitation from one locality to another Activity of the Nervous System Information • Receive: receptors afferent pathway • Process: CNS (centralization is paramount) • Transmit: efferent pathways  effect Voluntary (conscious ) = somatic Involuntary = autonomic • Sympathetic - fight or flight • Parasympathetic - vegetative CNS & PNS divisions • Central Nervous System (CNS) • Brain and spinal cord • Grey matter (neuron’s somas and some processes) • White matter (myelinated and unmyelinated axons) • Myelination is from oligodendrocytes • Glial cells: • Astrocytes • Microglial cells Part of the blood-brain barrier (BBB) • Peripheral Nervous System (PNS) • Nerves, sensory ganglia, and autonomic ganglia (or plexus) • Schwann cells: myelin producing glial cells of the PNS  Axon hillock Nervous system & neuron All images copyright McGraw-Hill Companies Slide 3: Cerebral cortex (Luxol fast blue) Grey matter White matter Neuropil Neuron with large nucleus containing a large nucleolus Neuroglia support cell Slide 3: Cerebral cortex (Luxol fast blue) Gray matter White matter Neuropil = felt-work of a complex and highly ordered meshwork of dendritic, axonal, and glial processes whose entanglements facilitate an ordered activity important in the communications function of the nervous system. The neuropil provides an enormous region for synaptic contact and functional interactions among nerve cell processes. Neuropil Slide DHD100: Fibrous Astrocytes Cajal staining method • Used to visualize: the numerous stellate processes of fibrous astrocytes and neurons INTERMEDIATE FILAMENTS of cells FIVE CLASSES (not conserved) KERATIN - INSOLUBLE SUBSTANCE, EPITHELIUM INTERMEDIATE FILAMENTS of cells FIVE CLASSES (not conserved) KERATIN - INSOLUBLE SUBSTANCE, EPITHELIUM INTERMEDIATE FILAMENTS of cells FIVE CLASSES (not conserved) KERATIN - INSOLUBLE SUBSTANCE, EPITHELIUM DESMIN – CYTOSKELETON IN MUSCLE VIMENTIN - NUCLEAR ENVELOPE FOR MECHANICAL SUPPORT AND STABILITY OF ITS LOCATION IN CELL, MESENCHYMAL CELL INTERMEDIATE FILAMENTS of cells FIVE CLASSES (not conserved) KERATIN - INSOLUBLE SUBSTANCE, EPITHELIUM DESMIN – CYTOSKELETON IN MUSCLE INTERMEDIATE FILAMENTS of cells FIVE CLASSES (not conserved) KERATIN - INSOLUBLE SUBSTANCE, EPITHELIUM DESMIN – CYTOSKELETON IN MUSCLE VIMENTIN - NUCLEAR ENVELOPE FOR MECHANICAL SUPPORT AND STABILITY OF ITS LOCATION IN CELL, MESENCHYMAL CELL INTERMEDIATE FILAMENTS FIVE CLASSES con’t NEUROFILAMENTS • DENDRITES AND AXONS OF NERVE CELLS • INTERNAL SUPPORT - GELATED STATE OF CYTOPLASM INTERMEDIATE FILAMENTS FIVE CLASSES con’t NEUROFILAMENTS • DENDRITES AND AXONS OF NERVE CELLS • INTERNAL SUPPORT - GELATED STATE OF CYTOPLASM GLIAL FILAMENTS - ASTROCYTES INTERMEDIATE FILAMENTS IMMUNOFLUORESCENCE DETECTION - TOOL IN DISTINGUISHING CELL TYPE OF ORIGIN OF MALIGNANT TUMORS Astrocytes GLIAL FILAMENTS - ASTROCYTES Intermediate filaments of GFAP (glial fibrillary acidic proteins) filament is used clinically to identify astrocytes as in the diagnostic classification of a tumor as an astrocytoma Spinal cord - Slide 4, 17, 18: Spinal Cord and Meninges Central “H” shaped grey matter White matter Central canal lined by ependymal cells The ependymal cells have microvilli and can have cilia. Cerebral spinal fluid (CSF) surrounds the brain and spinal cord and acts as a cushion, protecting the brain and spine from injury. The fluid is clear normally, and the pressure in the spinal fluid is important too. Slide 4, 17, 18: Spinal Cord and Meninges Ventral horn (motor) Dorsal horn (sensory) Glial cells Motor neuron in ventral horn Nissl bodies 17 Nissl bodies = rough endoplasmic reticulum and free ribosomes(polyribosomes or polysomes for short) Slide 4, 17, 18: Spinal Cord and Meninges Grey matter White matter White matter Axons surrounded by dissolved myelin sheath Axonal tracts Grey matter Slide 4, 17, 18: Spinal Cord and Meninges Dura mater Subdural space Arachnoid matter Spinal nerve Subarachnoid space Pia mater Slide 4, 17, 18: Spinal Cord and Meninges Histo 18 Dura mater Subdural space Arachnoid matter Spinal nerve Subarachnoid space Slide 17 Spinal Cord and dorsal root ganglia Dorsal root ganglia Given pseudounipolar neurons found in the dorsal root ganglia reach from the sensory detection to the spinal cord, there are no synapses of these sensory neurons in the dorsal root ganglia. THE NERVOUS SYSTEM CENTRAL NERVOUS SYSTEM (CNS) • BRAIN AND SPINAL CORD • NEURONS AND SUPPORT NEUROGLIA

Nervous Tissue Part 1

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