Specialized organs of digestive system

Question 1

Mammilian digestive system consists of

Answer 1

alimentary canal, and accessory glands that secrete digestive juices through ducts

Question 2

Oral cavity

Answer 2

• Mechanical digestion with teeth occurs here
• Salivary glands deliver saliva to lubricate food, exposes food to amylase which initiates breakdown of glucose polymers
• Saliva contains mucus (mix of water, salts, cells, and glycoproteins)
• Tongue shapes food into bolus

Question 3

Esophagus

Answer 3

• Pharynx is junction that opens to both the esophagus and trachea
• Esophagus connects to the stomach
• Conducts food to the stomach through peristalsis
• Swallowing causes the epiglottis to block the entry to the trachea and the larynx guides the bolus
• Striated and smooth muscle

Question 4

Stomach

Answer 4

• Stores food and begins digestion of proteins

- Stomach secretes gastric juice (HCl and pepsin) which converts a meal to chyme

Question 5

Cells of gastric glands of stomach

Answer 5

1. Muscous cells
2. Cheif cells
3. Parietal cells

Question 6

Mucous cells

Answer 6

Secrete mucus, protection, lining

Protects the stomach lining from gastric juice

Question 7

Cheif cells

Answer 7

Secrete inactive pepsinogen which is activated to pepsin when mixed with HCl in stomach

Question 8

Parietal cells

Answer 8

Secrete hydrogen and chloride ions separately into the lumen of the stomach

Question 9

Gastric juice

Answer 9

• Low pH of about 2
• Kills bacteria and denatures proteins
• HCl and pepsin
• Pepsin is a protease (protein digestive enzyme), cleaves proteins into smaller peptides (works best at acidic pH)

Question 10

Small intestine

Answer 10

Longest compartment of the alimentary canal. Most enzymatic hydrolysis of macromolecules from food occurs here

Question 11

First portion of small intestine

Answer 11

Duodenum, where chyme from stomach mixes with digestive juices from the pancreas, liver, gallbladder, and small intestine itself.
Neutralizes acids with juices with pH of 8

Question 12

Bile

Answer 12

In small intestine, aids in digestion and absorption of fats

• Made in the liver out of bile salts and stored in the gallbladder
• Destroys nonfunctional RBC

Question 13

Absorption

Answer 13

Large surface area because of villi and microvilli (finger like projections) increases the rate of nutrient absorption
Transport across the epithelial cells can be passive or active depending on nutrient

Question 14

Pancreas

Answer 14

Produces proteases trypsin and chymotrypsin that are activated in the lumen of the duodenum. The solution is alkaline (with bicarbonate and enzymes) and neutralizes the acidic chyme (buffer)

Question 15

Large intestine

Answer 15

Colon of the large intestine is connected to the small intestine. Completes the reabsorption of water started in small intestine
-Cecum aids in fermentation of plant material and connects where small and large intestines meet

Question 16

Appendix

Answer 16

Extension of the cecum, plays a small role in immunity

Question 17

Rectum

Answer 17

Feces are stored here until they are eliminated through the anus. Two sphincters between the rectum and anus control bowel movements