That Means That Underlying the Cells That Are the Cellular Component of the Epithelial Tissue
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That means that underlying the cells that are the cellular component of the epithelial tissue, there is a layer of acellular ("a-" means not, so "acellular" means not cellular) material. Cells within this tissue readily divide to make more cells.
Functions of Epithelial Tissue
Protection Epithelial cells from the skin protect underlying tissue from mechanical injury, harmful chemicals, invading bacteria and from excessive loss of water.
Sensation Sensory stimuli penetrate specialised epithelial cells. Specialised epithelial tissue containing sensory nerve endings is found in the skin, eyes, ears, nose and on the tongue.
Secretion In glands, epithelial tissue is specialised to secrete specific chemical substances such as enzymes, hormones and lubricating fluids.
Absorption Certain epithelial cells lining the small intestine absorb nutrients from the digestion of food.
The essential characteristic that separates connective tissue from the other three tissue types is the presence of an abundant amount of extracellular matrix or material between its cells.
FUNCTIONS OF CONNECTIVE TISSUE
Structural support
The connective tissues serve several functions, of which the most prominent function is structural support to enable maintenance of anatomical form of organs and organ systems. Examples include the connective tissue capsules surrounding organs (such as the kidney, lymph nodes). The loose connective tissue acts to fill the spaces between organs. The tendons (connecting muscles to bone) and the elastic ligaments (connecting bones to bones) are examples of specialized orderly forms of connective tissue. The skeletal tissues (cartilage and bone) are special forms of connective tissue.
Metabolic functions
The connective tissues serve a nutritive role. All the metabolites from the blood pass from capillary beds and diffuse through the adjacent connective tissue to cells and tissues. Similarly waste metabolites from the cells and tissues diffuse through the loose connective tissue before returning to the blood capillaries. The adipose tissue (especially that of the hypodermis) serves as an energy store and also provides thermal insulation. Surplus calories can be converted into lipid and stored in adipocytes.
Blood components and blood vessels
The hematopoietic tissues (blood-forming tissues) are a further specialized form of connective tissue. These include the myeloid tissue(bone marrow) and the lymphoid (lymphatic) tissue. The lining of the blood and lymphatic vessels (endothelial cells) as well as the peripheral blood, are also specialized forms of connective tissue.
Defensive functions
Various components of the connective tissue play roles in the defense or protection of the body including many of the components of the vascular and immune systems (plasma cells, lymphocytes, neutrophils, eosinophils, basophils, mast cells). The various macrophages of the body are also categorized as connective tissue cells. These all develop from monocytes and are grouped as part of the Mononuclear Phagocyte System of the body. Macrophages are important in tissue repair as well as defense against bacterial invasion. The fibroblasts of connective tissue proliferate in response to injury of organs and migrate to and deposit abundant new collagen fibers, resulting in the formation of fibrous scar tissue.
Nervous tissue is the main component of the nervous system - the brain, spinal cord, and nerves-which regulates and controls body functions.
Functions of Nerve Tissue
Nervous tissue allows an organism to sense stimuli in both the internal and external environment. The stimuli are analysed and integrated to provide appropriate, co-ordinated responses in various organs.
The afferent or sensory neurons conduct nerve impulses from the sense organs and receptors to the central nervous system. Internuncial or connector neurons supply the connection between the afferent and efferent neurons as well as different parts of the central nervous system. Efferent or somatic motor neurons transmit the impulse from the central nervous system to a muscle (the effector organ) which then react to the initial stimulus. Autonomic motor or efferent neurons transmit impulses to the involuntary muscles and glands.
There are three types of muscle tissues- smooth, skeletal and cardiac. Smooth tissues regulate the blood pressure and flow of blood in arteries. Also found in the digestive system in the stomach and intestines to cause the peristalsis movement. Skeletal muscles bring about movement of bones and is invovled in the breathing process. Cardiac muscles are found in the heart and causes the rhythmical beating of the heart and thus bring about oxygen to the entire body.
Read more: http://wiki.answers.com/Q/Function_of_muscle_tissue#ixzz1X57XCJoc
Functions of Epithelial Tissue
Protection Epithelial cells from the skin protect underlying tissue from mechanical injury, harmful chemicals, invading bacteria and from excessive loss of water.
Sensation Sensory stimuli penetrate specialised epithelial cells. Specialised epithelial tissue containing sensory nerve endings is found in the skin, eyes, ears, nose and on the tongue.
Secretion In glands, epithelial tissue is specialised to secrete specific chemical substances such as enzymes, hormones and lubricating fluids.
Absorption Certain epithelial cells lining the small intestine absorb nutrients from the digestion of food.
The essential characteristic that separates connective tissue from the other three tissue types is the presence of an abundant amount of extracellular matrix or material between its cells.
FUNCTIONS OF CONNECTIVE TISSUE
Structural support
The connective tissues serve several functions, of which the most prominent function is structural support to enable maintenance of anatomical form of organs and organ systems. Examples include the connective tissue capsules surrounding organs (such as the kidney, lymph nodes). The loose connective tissue acts to fill the spaces between organs. The tendons (connecting muscles to bone) and the elastic ligaments (connecting bones to bones) are examples of specialized orderly forms of connective tissue. The skeletal tissues (cartilage and bone) are special forms of connective tissue.
Metabolic functions
The connective tissues serve a nutritive role. All the metabolites from the blood pass from capillary beds and diffuse through the adjacent connective tissue to cells and tissues. Similarly waste metabolites from the cells and tissues diffuse through the loose connective tissue before returning to the blood capillaries. The adipose tissue (especially that of the hypodermis) serves as an energy store and also provides thermal insulation. Surplus calories can be converted into lipid and stored in adipocytes.
Blood components and blood vessels
The hematopoietic tissues (blood-forming tissues) are a further specialized form of connective tissue. These include the myeloid tissue(bone marrow) and the lymphoid (lymphatic) tissue. The lining of the blood and lymphatic vessels (endothelial cells) as well as the peripheral blood, are also specialized forms of connective tissue.
Defensive functions
Various components of the connective tissue play roles in the defense or protection of the body including many of the components of the vascular and immune systems (plasma cells, lymphocytes, neutrophils, eosinophils, basophils, mast cells). The various macrophages of the body are also categorized as connective tissue cells. These all develop from monocytes and are grouped as part of the Mononuclear Phagocyte System of the body. Macrophages are important in tissue repair as well as defense against bacterial invasion. The fibroblasts of connective tissue proliferate in response to injury of organs and migrate to and deposit abundant new collagen fibers, resulting in the formation of fibrous scar tissue.
Nervous tissue is the main component of the nervous system - the brain, spinal cord, and nerves-which regulates and controls body functions.
Functions of Nerve Tissue
Nervous tissue allows an organism to sense stimuli in both the internal and external environment. The stimuli are analysed and integrated to provide appropriate, co-ordinated responses in various organs.
The afferent or sensory neurons conduct nerve impulses from the sense organs and receptors to the central nervous system. Internuncial or connector neurons supply the connection between the afferent and efferent neurons as well as different parts of the central nervous system. Efferent or somatic motor neurons transmit the impulse from the central nervous system to a muscle (the effector organ) which then react to the initial stimulus. Autonomic motor or efferent neurons transmit impulses to the involuntary muscles and glands.
There are three types of muscle tissues- smooth, skeletal and cardiac. Smooth tissues regulate the blood pressure and flow of blood in arteries. Also found in the digestive system in the stomach and intestines to cause the peristalsis movement. Skeletal muscles bring about movement of bones and is invovled in the breathing process. Cardiac muscles are found in the heart and causes the rhythmical beating of the heart and thus bring about oxygen to the entire body.
Read more: http://wiki.answers.com/Q/Function_of_muscle_tissue#ixzz1X57XCJoc
