80 



HUMAN TISSUES 



ticity build those parts of the body, such as the ear and voice box, 

 that require strength combined with some elasticity. The inter- 

 cellular substance of cartilage is a secretion of the cells. 



fimWfWK7*''QH^ '^^^ proper growth of 



^pC^^^^^^^^Q t^^^'^'^^:^^^ bone depends upon suffi- 



cient lime salts in the food 

 and the presence of certain 

 bone- ceU valuable growth promoters 



oone, . found in food, called vita- 



cancil mms, which stnnulate the 



proper use of the lime salts 



Bone cells, with their irregular projections of proto- ^y ^"^ "^^^^^ CClls. It DOUC 

 plasm, deposit calcium compounds which they obtain (JqCS liot deVCloD UrODCrlv 

 from blood. An individual bone cell is also shown. ^ ^ ^ • ' 



skeletal deformities, like 

 bowlegs, may occur. This will later be discussed in connection 

 with vitamins. 



Problem. Study of other supporting tissues. 



I. Place a prepared slide of fibrous tissue under the inicroscope. 



A. Note the large deposits of wavy white fibers with cells scattered 

 among them. The white fibers are the intercellular material which was 

 secreted bv the cells. 



B. Draw a few cells with the surrounding fibers enlarged five times. 

 Label the cells and intercellular fibers. 



II. Place a prepared slide of fat or adipose tissue under the microscope. The 

 large space filling the center of each cell is a vacuole filled with stored oil. 

 The cytoplasm lies just within the wall, crowded there by the enlarged vacu- 

 ole. The nucleus can be noticed wathin the cytoplasm. 



A. Describe the adaptation of adipose cells for fat storage. 



B. Draw a group of adipose cells. Label cell membrane, nucleus, cyto- 

 plasm, and vacuole. 



Fibrous, elastic, and adipose tissues. The white fibrous tissue is 

 made strong and flexible by the intercellular fibers which are prob- 

 ably secreted by the cells. It builds ligaments, strong flexible bands, 



