Definition of tissue
Tissue. In biology, the tissues are those materials constituted by an organized set of cells, with their respective organoid equal or of a few types of differences between differentiated cells in a certain way, ordered regularly, with a Coordinated physiological behavior and a common embryonic origin. It is called histology to study these organic tissues.
The cells that make up a certain tissue can and are usually different in terms of their morphological characteristics, such as appearance and size, and in terms of their specific function; However, what characterizes a tissue is that each of the types of cells that compose it plays an indispensable role for that one, together, can perform its own function.
It’s made up of cells, fibers and substances. It forms generally flat structures, totally or partially covered by a fibrous membrane called pericardium. In this membrane are elongated cells, collagen and elastic fibers, vascular and nervous elements.
The fibers are continued in the intercellular substance of the cartilage. In the fetus and the child forms a large part of the skeleton, which will then be reemplazadodo by bone tissue.
In Adult man cartilage covers the articular surfaces of the bones and forms the sole support of the larynx, trachea, bronchi and other structures.
The cartilages are used to accommodate the surfaces of the femoral condyles to the glenoideas cavities of the tibia, in order to cushion the strokes and jumps, to prevent friction wasting and to allow movement of the joint. It is a support structure and gives some mobility to the joints.
Types of cartilaginous tissue:
Fetal cartilage: May contain blood vessels. The abundant rounded or even stared spindle cartilaginous cells are evenly distributed. No Condrones are formed.
Hyaline cartilage: Formed mainly by type II collagen fibrils. It possesses chondrocytes arranged in groups. There is pericondus.
It is the most abundant of the body. It has a bluish whitish appearance. It is found in the nasal skeleton, larynx, trachea, bronchi, the rib arches (ribs) and the articular ends of the bones, is avascular, nourished from synovial fluid. of few fibers and is located in the nasal cartilage, trachea and bronchi.
Fibrous or fibrocartilage cartilage: it is a form of transition between dense connective tissue and hyaline cartilage, with type I collagen fibers. It is found in the intervertebral discs, articular edges, articular discs and Menisci, as well as in the insertion sites of the ligaments and tendons, lacks of pericondus (layer of dense collagen connective tissue). It possesses both groups Isógenos.
Elastic cartilage: Formed by type II collagen, has elastic fibers. There is pericondus. It forms the epiglottis, corniculado cartilage or of Santorini, cuneiform or of Wrisberg, in the larynx, the external ear (acoustic meatus) and in the walls of the external auditory canal and the Eustachian tube. It is yellowish and has greater elasticity and flexibility than hyaline. Its main difference with the latter is that the matrix presents a dense weaving of fine elastic fibers that are basophilic and stained with Hematoxylin and eosin, as well as Orcein. It forms the pinna. It possesses more groups axial Isógenos and Porifero
The muscular tissue is composed of numerous specialized cells, known as muscular fibers, that are characterized by their power of contraction and their property to transmit the conduction of the nerve impulses. The muscle fibers are thin, elongated, cylindrical or needle-shaped cards that can measure up to 30 cm. Long and are surrounded by a layer of connective tissue, whose function is to provide support to muscle tissue.
The three types of muscle derive from the mesoderm. The cardiac muscle has its origin in the Splanchnic mesoderm, most of the smooth muscle in the splanchnic and somatic mesoderm and almost all skeletal muscles in the somatic mesoderm. The muscular tissue consists of three basic elements:
The muscular fibers, which are usually placed in bundles or fascicles.
An abundant capillary network.
Fibrous connective tissue of support with fibroblasts and collagen and elastic fibers.
Its main function is the movement that can be of three types:
Movement of all internal structures: It consists of smooth muscular tissue and will be found with vessels, visceral walls and glands.
External movement: characterized by manipulation and gait in our environment. It is characterized by being formed by striated muscle.
Automatic movement: It works by itself, it’s the cardiac muscle. striated muscular tissue.
Nervous tissue – definition of tissue
It is composed basically of two types of cells: neurons and glia cells or neurology.
The neuron: It is a very specialized cell which is only formed in the development of the embryonic phase of the human; From there its number remains stable, estimated that in the adult there are 16 million of this type of cells; It also has no ability to divide.
It comes into contact with its peers through synapses. Two types of prolongations emerge from your cell or pericarion body; Some very branched short, receive the nervous impulse and call themselves the Dentritas; Another one with few ramifications emerging at right angles (collateral) is responsible for driving the nerve impulse away from the pericarion, called axon or Neurite cilindroeje.
The final ramifications end in globose widening (terminal buttons). They present a large nucleus, abundant neurofibrils and bodies or granules of NISSL (Atigrada substance) It has been proven that the latter corresponds to cisterns of granular endoplasmatic reticulum and free polyribosomes. According to the number of extensions emitted by pericarion, neurons can be classified in: unipolar (a single prolongation) pseudounipolar (an extension is divided into two right-angled branches) bipolar (two extensions being born in opposite poles) and Multipolar (an axon and several dentritas, are the Títpicas).
Glia or Neorología: are nerve cells that in addition to serving as a filler and support of neurons, intervene in their nutrition and defense of the nervous system by each neuron are calculated that there are 10 cells of Glia, although they occupy by their size half the volume of the T Ejido. Astrocytes, Digodentrocitos, micrologic and Epidenmarias cells are distinguished. The first two are encompassed in geology. The nanites have numerous ramifications that can be dilated at their ends in contact with the blood capillaries (basoculares feet) being probably the alimentary route to the neurons, as other extensions contact them. The Oligodentrocitos have short and scarce extensions, are located in the vicinity of the cell bodies (satellite cells) in the Central nervous system there are no Schwann cells, being produced the whitish-colored myelin that Contrasts with the grayish hue of the neuronal bodies. Epedimarias cells cover the cavities of the brain and spinal cord, being bathed by the cerebrospinal fluid that occupies them. They are cylindrical with a sharp end that can be branched in long extensions that penetrate inside the nervous system