Question

1. Name the specializations of the small intestine from largest to smallest structure. What is their purpose?

2. Name the subdivisions of the small and large intestines in the complete and correct sequence.

3. Draw and label the parts of the uriniferous tubule. Include all parts of the nephron and the collecting duct. List the sequence of filtrate moving through the nephron to collecting duct in the correct sequence.

Answer 1

1. The specializations of small intestine are

• long, narrow, folded or coiled anatomy that accomodates the 6.7 to 7.6 m length that gives enough time and area for the absorption of nutrients during passage of food through the small intestine.
• The plicae circulares are the permanent ridges in the mucosa of the small intestine.This causes the spiral motion of the food and helping in mixing of the chyme with the digestive juices.
• Villi are fingerlike projections on the surface of the mucosa. They increase the surface area for absorption. The spaces between adjacent villi forms crypts of Lieberkuhn to where the intestinal glands empty.
• Microvilli are microscopic extensions seen on the surface of each villi. They are mase up of brush bordered cells that increases the absorptive surface area.

2. The sub divisions of SMALL INTESTINE are

1. duodenum
2. jejunum
3. Ileum

The subdivisions of large intestine are

1. caecum (appendix is a blind sac arising from the caceum)
2. ascending colon
3. transverse colon
4. Descending colon
5. rectum
6. Anal canal