Neuroglia is the interstitial tissue of the nervous system. In the brain and spinal cord the connective tissue is limited to the enveloping membranes the meninges and a slight amount accompanies the blood vessels. The supportive framework the interstitial tissue is formed by a special group of cells and fibers called neuroglia. In ordinary preparations of […]
Ganglia consist of aggregations of neurons situated outside the central nervous system. Each ganglion is surrounded by a connective tissue capsule which is continuous with the epineurium and perineurium of the peripheral nerve. Connective trabeculae extend from the capsule into the ganglion to form a framework. Within the ganglion the nerve cells are separated into
The relations between two neurons are of the nature of contact rather than complete structural continuity. This junction of two neurons is called a synapse. The synapse may be defined as a point of contact of the cell membrane (plasma membrane) of an axon terminal with the cell membrane of another neuron. The synapse may be
Muscle tendon spindle (Organ of Golgi) found at the junction of muscle and tendon spindle shaped composed of tendon bundles covered by a connective tissue capsule. Into this enter one or several afferent nerve fibres which terminate in arborization around bundles. Muscle spindles and muscle tendon spindles are proprioceptors of position and movement receiving stimuli
In voluntary muscle, sensory nerves end in end bulbs and Muscles spindles (Neuromuscular spindles). The muscle spindles, is a cylindrical elongated structure within which are one or several muscle fibres, connective tissue blood vessels and myelinated nerve fibres. The whole is enclosed in a connective tissue capsule, which is pierced, at various points by one
Receptors are of many kinds those concerned with general bodily sensibility or somesthetic sensibility, touch, pressure, heat, cold, paid, temperature, position, movement, and those which form organs of special senses (smell, sight, taste, hearing and head position and movement). They may also be classified as exteroceptors, the receptors, affected by external stimuli (touch light, pressure cutaneous pain
Visceral efferent fibers are myelinated fibers terminating in cardiac muscle, smooth muscle of viscera, blood vessels, hairs and glands. The nerve fibres form plexuses around the muscle bundles. From these plexuses fine fibres pass to individual muscle fibre. In glandular epithelium, the nerve fibers from plexus beneath the basement membrane through which fibers pass to
Motor end plate (Somatic efferent fibers) Nerve fibre outer perimysium and branch to pass to individual muscle fibres where they end in structures called motor end plate. At the end plate region the myelin is lost and endoneurium becomes continuous with endomysium of muscle fibre. The axon devoid of its sheath divides to fine terminations which
Axons which form peripheral fibers terminate in some peripheral structure to which or from which they convey nerve impulses. Efferent fibers terminate in tissues which are excited into activity by the nerve impulses somatic efferent fibers in voluntary striated muscle and visceral efferent in smooth muscle or secretory epithelium. These are called effector organs. Afferent
The nerve fibre is essentially a highly irritable conductor. Along it the dynamic nervous excitation propagates in waves, faster in large than in small axons. During the conduction of excitation the activity of one portion of the axon, serves as a stimulate activating the next portion, and so on. As the nerve fibres become active
