Nerve Tissue Histology Mind Map PDF

Endoneurium: Surrounds individual axons A single nerve is composed of bundles of nerve Perineurium: Encloses fascicles...

Endoneurium: Surrounds individual axons A single nerve is composed of bundles of nerve Perineurium: Encloses fascicles fibers (fascicles) and connective tissue layers Epineurium: Encases the entire nerve Nerve structure ganglia sensorial Sensory Nerves: Transmit sensory data (e.g., Excitability: Ability of neurons to respond to stimuli touch, temperature) from the periphery to the CNS Conductivity: Propagation of electrical impulses **Key terms** (action potentials) across their membrane Motor Nerves: Carry motor commands from the Nerve Types CNS to muscles or glands Specialization: Neurons are morphologically and functionally specialized for transmitting information rapidly and accurately Mixed Nerves: Contain both sensory and motor Nerve Tissue fibers. Body of neurons and glial cells in grey matter Neurons Functional units of the nervous system Surrounded by epineurium and perineurium Axons with myelin shape in white matter PNS **Components of nerve tissue** Contain adipocytes for insulation and Components Neuroglia (Glial cells)  Supporting cells that maintain homeostasis, form myelin, protection and provide support and protection for neurons Axons may be myelinated (insulated by Schwann cells) or unmyelinated Peripheral nerves Sensory Input: Detects environmental changes Produced by Schwann Cells in the PNS via receptors (e.g., touch, temperature, light) Myelin Sheath: Unmyelinated axons are still supported by Features Schwann Cell Nuclei and allows Integration: Processes and interprets the sensory Schwann cells efficient signal conduction data in the CNS (central nervous sytem), making decisions about appropriate responses Functions of Nerve Tissue Neurons: Predominantly pseudounipolar neurons specialized for rapid signal transmission Motor Output: Transmits signals to effectors (muscles or glands) for voluntary or involuntary actions Ganglion Cell Nuclei: Located centrally in Spinal and cranial sensory ganglia large ganglionic neurons. Higher Functions: Cognition, emotion, memory,  and learning. Associated Cells: Satellite Cell Nuclei: Support cells surrounding neuron cell bodies for metabolic and structural support. Cerebrum: Responsible for higher cognitive functions, Center = white matter sensory interpretation, and voluntary motor activities peripherie= grey mater Outer protective layer of the head Scalp Center = white matter Brain Cerebellum: Coordinates movement and balance peripherie= grey mater Dense irregular connective tissue covering the Periosteum Brainstem: Controls vital involuntary functions Center = grey matter bone **Central Nervous System (CNS)** (e.g., heart rate, respiration) peripherie= White mater Provides structural protection for the brain. Bone of skull Center = grey matter (in H shape Spinal Cord: Acts as a relay between the brain and the with a central canal of the spinal Tough outermost layer Dura Mater Layers of the skull body, mediating reflex arcs and signal transmission cord with the cerebral spiral fluid) peripherie= White mater Meninges (Protective membranes) Nervous System Overview Web-like middle layer Arachnoid mater Nerves: Axon bundles that relay sensory and motor Includes Arachnoid Villus: Structures involved signals between the CNS and the rest of the body in cerebrospinal fluid (CSF) reabsorption Ganglia: Clusters of neuronal cell bodies Thin innermost layer closely adhering to **Peripheral Nervous System (PNS)** outside the CNS (e.g., dorsal root ganglia) Pia matter the brain's surface Somatic Nervous System (SNS): Voluntary Meninges control over skeletal muscles Functional Divisions: Contains a central canal filled with cerebrospinal fluid Sympathetic: "Fight or flight." H-shaped Gray Matter: Autonomic Nervous System (ANS): Involuntary (CSF) for nutrient exchange and cushioning Spinal cord control of smooth muscle, glands, and internal organs We can see ependymal cells Parasympathetic: "Rest and digest."  Venules: Blood vessels aiding nutrient exchange Choroid plexus (Specialized Pia Connective Tissue: Structural support Components: structure producing CSF) Contains the nucleus and organelles, **Cell Body (Soma)** synthesizes neurotransmitters Ependymal Cells: Specialized epithelial cells lining the choroid plexus and central canal CNS Nerve Tissue **Dendrites**: Branching processes that receive Sparse neurons Histology Mind Map input from other neurons or sensory stimuli Molecular Layer (I) Axon Hillock: Region where action potentials are initiated Dense network of synaptic connections **Axon** Long projection that transmits Grey Matter electrical impulses away from the soma Axon Terminals: Release neurotransmitters to target cells Contains granular cells receiving cortical input Outer Granular Layer (II) Neurofilaments: Provide structural support Composed of myelinated axons for signal and maintain the shape of the neuron transmission Neuron Structure white matter layer Multiple Layers of the CNS Microtubules: Facilitate axonal transport of Purkinje Cells: Large neurons located between **Cytoskeleton** organelles and vesicles the white matter and granular layer Microfilaments (Actin): Support dynamic In between white and granular layer With purkinji cells changes in the neuronal structure Molecular Layer (I): Nissl Bodies: Specialized rough endoplasmic reticulum, vital for synthesizing proteins like neurotransmitter precursors Outer Granular Layer (II): **Organelles** Mitochondria: Abundant in neurons, meeting high energy demands Outer Pyramidal Layer (III): Cerebral Cortex Layers (from superficial to Melanin: Found in regions like substantia nigra. deep): Inner Granular Layer (IV) Inclusions: Lipofuscin: Pigment accumulation indicating  Ganglion Layer (V cellular aging Multiform Layer (VI) Electrical Synapse: Direct current flow via gap junctions; found in reflex pathways for rapid responses **Types** Alzheimer’s: Characterized by amyloid plaques and neurofibrillary tangles Chemical Synapse: Mediated by neurotransmitters. **Neurodegenerative Diseases** Parkinson’s:Loss of dopaminergic neurons in the Presynaptic Terminal: Releases substantia nigra neurotransmitters stored in vesicles Multiple Sclerosis: Autoimmune destruction of Synaptic Cleft: Space between the CNS myelin. Synapse **Key Components** presynaptic and postsynaptic membranes. **Demyelinating Diseases** Pathologies Guillain-Barré Syndrome: PNS myelin damage. Postsynaptic Membrane: Contains receptors for neurotransmitters, initiating a response Axonal Regeneration: More effective in PNS due to Schwann cell activity Excitatory: Glutamate, Acetylcholine. **Injuries** **Neurotransmitters** CNS Damage: CNS damage often results in Inhibitory: GABA.  permanent loss due to the inhibitory environment created by glial scar formation Astrocytes: Regulate the blood-brain barrier, maintain ion balance, and repair tissue **Function**: Insulates axons for faster signal conduction. Oligodendrocytes: Form the myelin sheath for multiple axons, enhancing signal speed CNS: Oligodendrocytes. **CNS Glial Cells** Myelin sheath: Lipid-rich layer produced by Myelination Microglia: Immune cells that phagocytose PNS: Schwann Cells. debris and pathogens Gaps in myelin sheath. Neuroglia Ependymal Cells: Produce cerebrospinal fluid (CSF). **Nodes of Ranvier** Gaps in the myelin sheath where action potentials regenerate, enabling saltatory  Schwann Cells: Myelinate single axons. conduction (faster signal transmission) **PNS (peripheral nervous system) Glial Cells** Satellite Cells: Support neurons in ganglia. 