DIRECTIONS FOB LABORATORY WORK 811 



septa. Sketch (367) several adjacent lobules. Note continuity of 

 medullary substance between adjacent lobules. Make h.p. sketch of a 

 lobule (3G8) ; also of a thymic corpuscle (concentric corpuscle of Has- 

 sall) (369). Where are the latter located ? Origin and function of the 

 thymic corpuscles? Is the thymus a lymphoid organ or an endocrin 

 (cryptorhetic) gland? Ontogenetic history of the thymus? From an 

 injected specimen of cat's thymus, sketch (370) the blood supply of a 

 lobule. 



(E) THE CAROTID GLAND. 



Location, origin and probable function of this gland? Sketch h.p. 

 (371) a small area. Compare with the Coccygeal Gland and the Para- 

 ganglia. Origin and function of the latter? 



(F) THE HYPOPHYSIS CEEEBRI (Pituitary Gland). 



In a stained sagittal section of the human hypophysis identify: a, 

 pars neuralis (posterior lobe) ; b, pars juxtaneuralis (intermediate por- 

 tion) ; c, residual lumen; d, pars distalis (anterior lobe). Make h.p. 

 sketches (372) of a small area from each of these portions. In the pars 

 distalis note the cords of central neutrophilic and parietal eosinophilic 

 cells. Significance of these two types? Over the periphery of the pars 

 distalis and lining the residual lumen note the basophilic cells. Signifi- 

 cance? What are the 'chromophobe' cells? 



Origin and probable function (normal and morbid) of this gland? 

 Blood and nerve supply? 



(G) THE EPIPHYSIS CEREBRI (Pineal Body). 



Study l.p. a stained sagittal section of the adult sheep's pineal body. 

 Note : pineal stalk with its pineal recess ; capsule, 'lobes', trabeculae, and 

 acervulus (brain sand). Compare with the human pineal body. Sketch 

 h.p. (373) a small area near the periphery. Note the two chief types 

 of cells: rieuroglia and 'interneurogliar'. Significance of the two types? 

 Note also the intercellular clumps of pigment, and the lamellated and 

 conglomerate types of acervulus, and the larger edematous areas. Com- 

 pare with a similar section of this gland from a young sheep. In the 

 latter note the intracellular pigment granules and the intercellular cysts. 

 Origin and probable function (normal and morbid) of this gland? 

 Blood and nerve supply? Significance of the melanic pigment? of the 

 cysts? of the brain sand? 



