[3-4] Muscle and Nervous Tisssue

• All muscles show similarities and differences, and are all composed of elongated cells called fibers.
• There are three types of muscle tissue: skeletal, cardiac, and smooth muscle.
• Saltatory conduction is a nerve impulse from one nerve to another.
• The Central Nervous System (CNS) part of the nervous system has glial cells known as Oligodendrocytes that produce the myelin sheath.
• Skeletal muscle is characterized by large, elongated multinucleated cells, multiple peripherally situated nuclei, voluntary muscle, innervated by alpha motor neurons, arranged in fascicles with endomysium, perimysium and epimysium, and have cross-striations due to organization of myofibrils.
• Muscle cytoplasm is called sarcoplasm, and the muscle cell membrane is sarcolemma.
• Schwann cells are found in the Peripheral Nervous System (PNS).
• Muscle fibers contain myofibrils made of contractile proteins.
• Smooth muscle is characterized by small fusiform cells, a single central nucleus, involuntary, autonomic innervation, surrounding network of collagen, no striations, myofibril meshwork anchored to dense bodies, and cells shorten and broaden on contraction.
• Cardiac muscle is characterized by elongated branching cells, a single central nucleus, involuntary muscle, spontaneously contractile, autonomic modulation, branching interconnected cells, functional syncytium, and have cross-striations due to organization of myofibrils.
• Axons are elongated processes of nerve that deliver impulses to the motor end plate, a cluster of synaptic knobs that attach to muscle fiber.
• Nodes of Ranvier allow transmission of nerve impulses and are process jumps from one nerve fiber to another.
• Synapse is a structure where synaptic knobs release acetylcholine neurotransmitter.
• Nervous tissue also contains glial cells, which are also known as neuroglia or glia.
• Motor nerve endings are attached to skeletal nerve muscles, which are striated muscles with bands of sarcomeres.
• Epineurium, the outer covering surrounding the entire nerves, is made of dense irregular connective tissues.
• The peripheral nerve also contains a perineurium which extends to fill the spaces between the fascicles.
• Endoneurium, which surrounds each nerve fiber, is a connective tissue surrounding individual nerve fibers.
• Axons are longer and covered by myelin, lipid layers.
• Connective tissue compartments of the nervous tissue include the epineurium, which is the outer covering surrounding the entire nerves, the perineurium, which divides each fascicle, and the endoneurium, which surrounds each nerve fiber.
• Axon Hillock is where action potentials arise.
• Nervous tissue contains two main types of processes that extend from each cell body: dendrite, usually many, and axon, usually one.
• Perineurium, which divides each fascicle, is a connective tissue that surrounds a bundle of nerve fibers.
• Nerve smear consists of two main kinds of cells: neurons or nerve cells and glial cells.
• Dendrites have one or more branched processes.
• Nervous tissue consists of peripheral nerves, which contain nerve fibers grouped into bundles to form the nerves, and also contains axons.
• Nerve bundles of axons are bound together by Schwann cells.