Colon, anatomy

Joo JS, Ehrenpreis ED, Gonzalez L, Kaye M, Breno S, Wexner SD et al. Alterations in colonic anatomy in-dnced by chronic stimulant laxatives the cathartic colon revisited. J Clin Gastroenterol 1998 26(4) 283-6. 

Despite recent developments, effectiveness of chemotherapy is still rather limited for most types of cancer, including tumors of the colon, lung, kidney, pancreas, and liver. Why some cancers respond better than others may be explained by factors relating to the anatomy and physiology of the cancer-ridden organ or... 

FIGURE 88-1. Colon and rectum anatomy. (From DiPiroJT, Talbert... 

The anatomy of the distal colon, with its thick muscular walls, suggests a predominantly propulsive activity. Studies with single administrations of pellets or Pulsincap devices suggested that the distal part of the transverse colon area is difficult to treat since this area and the descending colon function as a conduit. Steady-state measurements confirm this assertion (48) and Weitschies group have also reported data showing mass movements propel objects quickly through the distal transverse colon. 

More important possibly from the standpoint of function is the diversity of the anatomy of the pelvic colon itself. Figure 5 shows the various types of anatomical structures and the percentage occurrence of each. These percentages should be taken as indicative rather than accurate since they are based upon examination of only 210 specimens. If these percentages were accurate for the whole population of the United States, each of the least common forms (represented at the bottom of Figure 5) would exist in about 600,000 persons. It seems obvious that with this array of different types of pelvic colons (as well as transverse colons), people should differ tremendously (as they do) with respect to their problems of elimination. It is interesting to note in this connection that healthy newborn ba-... 

Pelvic colon. Variation in form and position. Diagrammatic. Major types (I to IX) are illustrated, together with varieties (A to C, etc.) within the more inclusive categories. The percentage occurrence of each type and subtype is recorded, as determined from an examination of 210 specimens. From Barry J. Anson, Atlas of Human Anatomy, p. 349. 

Haeberlin, B., and Friend, D.R., Anatomy and physiology of the gastrointestinal tract. In Oral Colon-Specific Drug Delivery (D.R. Friend, ed.), CRC Press, Boca Raton, 1992, pp. 1-43. 

Q1 Describe the anatomy of the colon and outline the absorptive function of this structure. 

Tarin, D. and Price, J. E. (1981). Influence of microenvironment and vascular anatomy on metastatic colonization potential of mammary tumors. Cancer Res. 41, 3604-3609. 

---