BIOL 129 Lecture Notes - Lecture 10: Ankyloglossia, Amylase, Falciform Ligament
BIOL 129 // week 10
M** → homework due wed
**clicker → which structure absorbs large fat molecules + transports them to the liver? lacteal
1. gross anatomy of colon
a. consists of 4 parts: ascending, transverse, descending, sigmoid
b. makes 90 degree turns at the left + right colic flexures
c. the walls of the colon form pouches → haustra, which makes expansion &
elongation possible
2. histology of large intestine
a. mucosa layer is smooth → no villi or plica circularis
b. intestinal crypts → deeper than in small intestine, has goblet cells (mucus
producers)
c. muscularis layer → circular layer, 3 muscular bands, strong lengthwise
contractions cause the wall to pouch and make haustra. specialized longitudinal
layer → taenia coli
3. rectum + anal canal
a. rectum holds feces until defecation, rectal valves allow for passage of gas while
retaining feces
b. controlled by 2 sphincters, lined with goblet cells: internal (involuntary) + external
(voluntary)
c. mucosa produces extra mucus during defecation
d. hemorrhoids → pressure is too high in lamina propria + submucosa, which leads
to distension of veins. usually permanent, can have both internal and external
hemorrhoids. usually uncomfortably itchy and painful
4. digestive disorders
a. inguinal hernias are common → mesentery, small intestines, peritoneum, can
hang out of muscle wall + cause bowel obstructions. has to be surgically
repaired, 25x more likely in men
5. accessory structures
a. salivary glands → three main glands on each side of the face, all have ducts that
drain into the oral cavity
i. parotid → below the ear, inferior to zygomatic arch (25% of saliva
production)
ii. submandibular → in floor of mouth along inner surface of mandible (70%
of saliva production)
iii. sublingual → sits deep below the tongue in the floor of the mouth (5%
saliva production)
iv. cells are arranged in acini (sac-like clusters) that empty into the ducts. two
types of cells make up salivary glands:
1. serous secrete enzymes and watery fluid (stains dark)
2. mucus secrete slimy mucus (stains pale)
