Lecture 10 – Digestion
1. How many are true:
a. Proteins produce more energy than fat
b. Direticulum of the two way gut increases the surface area
c. Cnidarians have two kinds of cells, enzymatic and nutritive cells
d. Increase in the surface area of the gut is one of the evolutionary examples
A is incorrect. Fat produces twice the energy of protein.
B is correct
C is correct
D is correct
2. How many are true;
a. The brush border of the intestine is made from microfilaments
b. Ceca increases the surface area of the gut as well as house microbes such as protozoans
c. Crop is found in chickens and birds, and it is an extension of the esophagus which stored
d. Humans can only cleave the beta 1,4 bond in starch while bacterium can cleave the
alpha 1,4 cellulose bond
D is incorrect. It should be the opposite. Humans can cleave the alpha 1,4 bind in
3. How many are true,
a. Cows have a digastric stomach which consists of rumen and the reticulum, and the
omasum and the abomasum
b. Fermented bacteria is housed on the omasum and the abomasum
c. Salivary glands of humans consists of parotid, mandibular, orbital and sublingual.
d. Salivary glands consists of serous and mucous cells which secretes mucus and enzymes
Fermented bacteris is in the rumen and reticulum not in the omasum and
abomasum. Abomasum consists of the acidic region
Humans lacks the orbital gland
Serous cells secrete enzynmes, mucous cells secrete, well…mucous. Opposite. 4. What is true
a. While chief cells are found within the stomach, enteroendocrine cells are found in the
small intestine as well as the stomach
b. G cells are found within enteroendocrine cells and secretes gastrin enzyme
c. Enterochrmaffin cells secrete histidine
Not gastrin enzyme, gastrin hormone
Not histidine, histiamine
5. What is true about bile;
a. Bile is important in getting rid of waste such as bilirubin because bilirubin is hydrophobic
and difficult to dissolve in the blood
b. Bile helps in digesting lipds by increasing the surface area pancreatic lipase can work on
by emulsifying it, pancreatic lipase breaks it down into triglycerides and monoglycerides.
c. Bile is stored in the liver, but produced in the gallbladder
d. Bile is composed of waste, salts and phospholipases
Pancreatic lipase breaks lipids into fatty acids and monoglycerides
Bile is made in the liver, stored in the gall bladder
6. What is true about the following enzymes;
a. Pancreases produces lipases, amylases, nucleases and proteases
b. The proteases- pepsin, trypsin, and Carboxypeptidase is produced in the pancreas and
secreted as pro enzymes
c. Membrane bound enterokinase producing trypsin cleaves trypsinogen into trypsin and
this creates a positive feedback.
d. Trypsinogen is cleaved first which then cleaves chymotrysinogen and Carboxypeptidase.
Pepsin is produced in the stomach 7. How many are true;
a. peptide YY, and leptin acts on the arcuate nucleus in the hypothalamus and suppress
appetite and ghrelin stimulates appetite
b. neuropeptide Y is an enzyme which stimulates appetite, as well as agouti related
peptide and GABA
c. leptin has a positive stimulation on NPY releasing neurons and a negative stimulation on
POMC releasing hormones (alpha MHS).
d. Ghrelin positively stimulates NPY releasing hormones.
e. Ghrelin and peptide Y controls feeding between meals, while leptin is long term
controlling the amount in the adipose tissue
f. Peptide YY and ghrelin antagonizes each other.
Neuropeptide Y is an appetite stimulant. POMC is an appetite inhibitor. Leptin is an
inhibitor. It has a negative effect on NPY and a positive effect on POMC.
E is true too. Leptin is long term controller. Ghrelin and peptide YY controls feeding
F is true too.
8. How many are true;
a. Gastrin stimulates the release of histamine, acid and pepsinogen from ECF cells, parietal
cells and chief cells in the stomach.
b. Chemoreceptors stimulates the release of gastrin via enteric nervous system
c. Bicarbonate is important in the parietal cells in supplying protons and maintaining
chloride concentration in the cell
d. Drugs for acid reflux inhibits the histamine production from enterchromafin cells.
e. Control of gastric secretions are done by parasympathetic nerves, enteric nerves and
chemo and mechano receptors while intestinal secretions are stimulated by acid and
v. 5 9. How many are true;
a. Acid stimulates the intestine cells to secrete secretin and vasoactive intestinal peptides
b. Secretin stimulates the release of bile from gall bladder while CCK stimulates the
production and release of bile from the liver
c. CCK stimulates smooth muscle cells to release bile from the pancrease
d. CCK stimulates the release of proteases from the pancreas
e. Vasoactive intestinal peptide is the only contributor towards increasing the pH in
A is true.