Digestive System

Question 1

List four types of digestion that occur within the body.

Answer 1

1. Intracellular
2. Extracellular
3. Mechanical
4. Chemical

Question 2

Intracellular Digestion vs. Extracellular Digestion

Answer 2

1. Intracellular: Involves oxidation of glucose and fatty acids of energy. (In the cell)
2. Extracellular: Process of obtaining nutrients from food. Occurs within Lumen of alimentary canal.

Question 3

Mechanical Digestion

Answer 3

Physical Breakdown of food into smaller particles. Does not involve breaking of chemical bonds

Question 4

Enzymatic cleavage of chemical bonds

Answer 4

Chemical Digestion

Question 5

Describe overall pathway which food travels when moving down the alimentary canal

Answer 5

1. Mouth
2. Pharynx
3. Esphagus
4. Stomach
5. Small Intestine
6. Large Intestine
7. Rectum
8. Anus

Question 6

What are accessory organs? List all accessory organs of digestive system within the human body.

Answer 6

Help to provide enzymes and lubrication necessary for the digestion of food.

• Salivary Glands
• Liver
• Pancreas
• Gallbladder

Question 8

Part of the nervous system that control peristalisis in the wall of the alimentary canal.

Answer 8

Enterc Nervous System

• Upregulated by PSN System
• Downregulated by SNS

Question 9

What do ADH and Aldosterone promote in regards to feeding behavior?

Answer 9

Thirst (to influence fluid consumption)

Question 10

What does Glucagon and Ghrelin promote?

Answer 10

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Glucagon is release by pancreas

Ghrelin is release by the pancreas and stomach

Question 11

What do leptin and cholecstokinin stimulate?

Answer 11

Feelings of satiety.

Question 12

Explain what happens during chemical and physical digestion of food within the mouth.

Answer 12

1. Physical
   
   1. Mastication
      
      1. Involves physical breakdown of food to increase SA of food for enzymatic digestion as it passes through the gut
      2. Moderates size of food entering gut
   2. Moistening/Lubrication of food via saliva (realeased by salivary glands which are controlled by PSN System)
2. Chemical Breakdown
   
   1. W/i saliva there is
      
      1. Lipase (hydrolyzes lipids)
      2. Amylase (hydrolizes carbs into smaller sugars)
3. Food is formed into a “bolus” and swallowed

Question 13

What happens to food from the pharynx to the stomach?

Answer 13

1. Swallowing is initiated at the upper esophageal sphincter
2. Esophagus propels food down to stomach via peristalsis
3. Food enters stomach via lower esophageal sphincter

It is important to note that not much chemical or physical digestion takes place during this phase.

Question 14

Where is the stomach located in the abdomen and what is it comprised of?

Answer 14

1. Location: LUQ, under the diaphragm
2. Part of the Stomach (In order)
   
   1. Body
   2. Fundus
   3. Pylorus
   4. Antrum
3. Additional Features
   
   1. Lesser and Greater Curvature
   2. Rugae (inner foldings)

Question 15

What are the two types of glands in the stomach?

Answer 15

1. Gastric
2. Pyloric

Question 16

The gastric gland releases enzymes in the stomach in response to the vagus vagus nerve of the PSN System. What is the vagus nerve activated by?

Answer 16

sight, smell, and taste of food.

Question 17

What are the major enzymes secreted by the gastric gland of the stomach?

Answer 17

1. Mucous cells
2. Chief Cells
3. Parietal Cells

Question 18

Cells in the stomach that produce mucous that lines the stomach (also helps to prevent autodiegstion via mucous)

Answer 18

mucous cells

Question 19

What do the chief cells do?

Answer 19

1. Secrete Pepsinogen
   
   1. Zymogen form of Pepsin
   2. Pepsin: Hydrolytic enzyme that help break proteins into polypeptides (activated by increasing levels of HCL)

Question 20

What do the parietal Cells of the stomach secrete?

Answer 20

1. HCL
2. Intrinsic Factor: glycoprotein involved in absorption of B12.

Question 21

What is the major cell of the pyloric gland?

Answer 21

G-Cell: Secrete Gastrin

• Induces parietal cells to secrete more HCL
• Induces the contraction of the stomach muscles to mix stomach contents, which eventually becomes chyme

Question 22

Sphincter which chyme passes to enter duodenum.

Answer 22

Pyloric Sphincter

Question 23

What are the major structures of the small intesine?

Answer 23

1. Duodenum
2. Jejunum
3. Ileum

Question 24

What is the major role of the Duodenum of the stomach and what are its major enzymes?

Answer 24

Further Chemical Digestion

1. Brush Border Enzymes
2. Enteropeptidase
3. Secretin and CCK

Question 25

What are brush-border enzymes and what types exist within the duodenum?

Answer 25

Enzymes that line the lumenal surface the duodenum and further hydrolyze sugars (disiccharidses) and peptides (protein) 1. Disaccharidases Hydrolyzes into monosaccharides 1. Maltose 2. Isomaltose 3. Lactose 4. Sucrose 2. Peptidases Hydrolyzes Proteins into Peptides 1. Aminopeptidases 2. Dipeptidasis

Question 26

Removes N-terminal AA from peptide

Answer 26

Aminopeptidases

Question 27

Hydrolyzes peptide bond between two AA to release free AA.

Answer 27

Dipeptidasis

Question 28

Activates the release of other digestive enzymes from accessory digestive system organs.

Answer 28

Enteropeptidase

Question 29

What enzymes do enteropeptidase activate?

Answer 29

1. Trypsinogen 1. Enteropeptidases activates the transformation of Trypsinogen to Trypsin, which initiates activation cascade 2. Procarboxypeptidase A and B into toehir active forms

Question 30

What are the purposes of secretin?

Answer 30

1. Stimulate the acinar cells in the pancrease to release contents nessary for neutralizing the acidic contents of chyme. 2. Slow motility (enterogastrone) 1. allow increased time for digestive enzymes to act on chyme.

Question 31

What is the purpose of CCK?

Answer 31

1. Stimulate the gallbladder to contract and release stored bile into small intestine (important for emulsification of facts) 2. Release Pacreatic Juices 3. Increase Satiety

Question 32

What is the main purpose of bile?

Answer 32

1. Help with emulsification of fats by getting fats into solution and increasing their SA by placing them into micelles

Question 33

What importance do pancreatic juices play in digestion? (3)

Answer 33

1. Neutralize acidic chyme with bicarbonate and H2O 2. Provide an ideal working environment for digestive enzymes 3. Contains enzymes that digest lipids, carbs, and proteins

Question 34

The pancreas has endocrine and excrine fuctions. What is the exocrine function? What enzymes are released by the pancreas?

Answer 34

The pancreas is activated by the enteropeptidase (which converts trypsinogen to Trypsin) to release contents and enzymes to the stomach during digetion. 1. Acinar cells: produce bicarbonate/H2O rich pancreatic juices that contain enzymes for digestion. 2. Enzymes include 1. Pancreatic Amylase 2. Pancreatic Peptidase (Trypsin and Chymotrypson) 3. Pancreatic Lypase 3. All contents are released to the stomach via the pancreatic duct

Question 35

What are the two unique structures of the liver when communicating with the digestive system?

Answer 35

1. Bile Duct (releases contents to the gall bladder and stomach) 2. Hepatic Portal Vein

Question 36

What are the major functions of the liver?

Answer 36

1. Make Bile 2. Receives and stores nutrients after receiving nutrient rich blood from hepatic portal vein. 1. Stores these nutrients (i.e. glycogen and triacylglycerols) 2. Can also reverse the store process to release lipids and sugars when necassar 3. (i.e. glycogenesis /glycogenolysis /gluconeogensis 3. Detoxification 4. Synthesis of proteins (i.e. albumin and clotting factors) for proper body function

Question 37

Main function of the gallbladder.

Answer 37

1. Store and concentrate bile

Question 38

What are the main structure for absorption in the small intestine? What is the main structure that helps with absorption?

Answer 38

1. Jejunum and Illeum 2. Microvilla: finger-like projections on the lining of the lumen of the small intestine that increase SA for absorption

Question 39

Lymphatic System that takes up fats for transport into the lymphatic system, located in the small Jejunum and illem of the small intestine

Answer 39

Lacteal

Question 40

Fat soluble compounds in the samm intestine enter the \_\_\_\_\_\_\_\_, while water soluble compounds enter the \_\_\_\_\_\_\_\_\_.

Answer 40

1. Lacteal 2. Capillary bed

Question 41

From the large intestine, how does stool get to the rectum, where it eventually exits the body through the anus?

Answer 41

1. Enters the cecum from the small intestine through the illeoceal valve 2. Passes the the colon (large intesine) 1. Ascending, Transverse, Descending, and Sigmoid Colon 3. Rectum

Question 42

What are the primary purposes of the large intestine?

Answer 42

1. Reabsorption of H2O. 2. Electrolyte Absorption 3. Houses e. Coli

Question 43

What do e. coli produce?

Answer 43

1. Vit K 2. B12 3. Thiamine 4. Riboflavin