The cell junctions called tight, adhering and gap junctions are found in
Goblet glands are
Areolar connective tissue joins
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Solution
Areolar connective tissue has rich supply of nerve fibres and blood vessels. It joins skin epithelia with muscles,nerves & blood vessels. Binding of body parts together is the main function of areolar connective tissue.
Which of the following substances, if introduced into the bloodstream, would cause coagulation of blood at the site of its introduction?
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Solution
Fibrinogen, prothrombin, throm- boplastin are respectively clotting factors I, II and III.Thromboplastin released from injured plateletsor injured tissue. This converts prothrombin into thrombin in the presence of calcium ions. The thrombin converts fibrinogen into fibrin and the latter forms the clot.
The epithelium of air sacs of lungs and the walls of blood vessels is
Mast cells of connective tissue contain
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Solution
Mast cells are granulated wandering leucocyte cells.Their granules contain histamine which is vasodilator and heparin (anticoagulant).These take part in body defence and allergic reaction. Vasopressin is released by posterior lobe of pituitary. Relaxin is released by placenta. Calcitonin is released by thyroid. Serotonin and melanin are released by intermediate lobe of pituitary gland.
Which one of the following contains the largest quantity of extra cellular material?
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Solution
Areolar tissue is the least specialized connective tissue.It has a large amount of ground substance (extra cellular material) and possesses rich blood and nerve supplies.It spreads extensively throughout the body, under the skin and epithelia, in between and around muscles,nerves and blood vessels and in the submucosa of respiratory and gastrointestinal tract.
Which cells do not form layer and remain structurally separate?
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Solution
Only nerve cells do not form layers. These also remain structurally separate from each other. Nerve cells or neurons are the cells specialized to conduct an electrochemical current. Nerve tissue is made up of these cells and supporting cells. Epithelial tissue is made of one or a few layers of compactly arranged cells overlying a basement membrane. Glands are epithelial cells specialized to elaborate and release chemicals for use in the body. Muscle tissue is made of elongated and contractile cells called myocytes.
A piece of bone such as femur of frog if kept in dilute HCl for about a week will
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Solution
When a bone is kept in dilute acids like HCl for a few days, the Ca salts get dissolved leaving only the soft and flexible organic matrix. This process is called Decalcification. If a bone is kept in KOH it remains unaffected and only the surrounding muscles and connective tissues get dissolved so that the bone now appears clean.
Out of the four basic types of tissues, which is not the one ?