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Organisation of cells animal tissues (view source)
Revision as of 16:45, 6 August 2014
, 16:45, 6 August 2014→Notes for teachers
http://www.nlm.nih.gov/medlineplus/ency/images/ency/fullsize/19089.jpg
http://www.nlm.nih.gov/medlineplus/ency/images/ency/fullsize/19089.jpg
'''Figure showing tendons and ligaments'''
'''Figure showing tendons and ligaments'''
'''Dense connective tissue'''
Connective tissue consisting of hard matrix called dense connective tissue.The cells are embedded in a dense matrix which is composed of calcium carbonate and calcium phosphate.<br>
Dense connective tissue is of two types:'''cartilage and bone'''<br>
'''Cartilage'''
Cartilage is a flexible connective tissue found in many areas in the bodies of humans and other animals, including the joints between bones, the rib cage, the ear, the nose, the bronchial tubes and the intervertebral discs. It is not as hard and rigid as bone but is stiffer and less flexible than muscle.<br>
Cartilage is composed of specialized cells called chondrocytes that produce a large amount of extracellular matrix composed of collagen fibers, abundant ground substance rich in proteoglycan, and elastin fibers. Cartilage is classified in three types, elastic cartilage, hyaline cartilage and fibrocartilage, which differ in the relative amounts of these three main components.Chondroblasts that get caught in the matrix are called chondrocytes. They lie in spaces called lacunae with up to eight chondrocytes per lacuna.<br>
Cartilage forms 'C' shaped rings in the trachea,bronchi.<br>
Cartilage present in larynx,epiglottis,wall of the eustachian tube and pinna contains elastic fibres in the matrix.It is called '''elastic cartilage'''.<br>
Cartilage found in between the vertebrae in the vertebral column chiefly contains collagen fibres.They are called '''fibrous cartilage'''.They bring about bending and stretching movements.<br>
'''Bone tissue'''
Bone tissue is a type of connective tissue that contains lots of calcium and phosphorous salts. About 25% of bone tissue is water, another 25% is made up of protein fibers like collagen. The other 50% of bone tissue is a mixture of mineral salts, primarily calcium and phosphorous.<br>
Bone tissue consists of cells embedded in a firm calcified matrix.The matrix chiefly consists of collagen fibres,protiens and inorganic salts like calcium phosphate,chlorides of potassium,sodium and magnesium.<br>
The long and strong bones of the limbs are filled with a fluid called '''bone marrow''',which consists of fat and blood vessels.It produces blood cells.<br>
The basic unit of Compact Bone is an '''osteon''', which is also known as a '''Haversian System'''. Each Haversian System has a cylindrical structure that consists of four parts:<br>
*A central tube called a '''Haversian Canal''', which contains blood vessels and nerves.The Haversian Canal is surrounded by alternate layers of:
*'''Lamellae'''(the word lamellae literally means "little plates") are concentric rings of a strong matrix formed from mineral salts including calcium and phosphates and collagen fibres. The mineral salts result in the hardness of the bone structure, while the collagen fibres contribute its strength.
*'''Lacunae''' are the small spaces between the lamellae in which contain the bone cells (called "osteocytes") are located.
*The lacunae are linked together by minute channels called '''canaliculi'''.The canaliculi provide routes by which nutrients can reach the osteocytes and waste products can leave them.<br>
The haversian canals of adjoining haversian systems are interconnected by transverse canals called '''volkmann's canal'''.
===Activities===
===Activities===