Final: Nutrition, Digestion, and Absorption Slides

Question 1

Functions of digestive system (2)

Answer 1

-Chemically breaks down food we eat
-Absorbs the food to transfer it to cells
(making nutrients in food accessible to cells)

Question 2

Processes of digestive system (4)

Answer 2

Motility, secretion, digestion, absorption (in that order)

Question 3

What happens during motility?

Answer 3

Food moves through organs at appropriate speed (propulsive), and food is mixed

Question 4

Purpose of mixing food during motility

Answer 4

Promotes digestion and mixing with enzymes, and facilitates absorption

Question 5

What are proteins, carbohydrates, and lipids broken down into?

Answer 5

Proteins: amino acids
Carbs: glucose, fructose, galactose (monomers)
Lipids: fatty acids

Question 6

What happens during secretion in the digestive system?

Answer 6

Digestive organs release many substances (enzymes, lubricants, etc.)

Question 7

What happens during process of digestion?

Answer 7

Food broken down into smaller pieces so it can be absorbed

Question 8

What are the main organs of the digestive system? (7)

Answer 8

Mouth, pharynx, esophagus, stomach, small intestine, large intestine, anus

Question 9

What are the accessory organs of the digestive system? (4)

Answer 9

Salivary glands (3), liver, gall bladder, pancreas

Question 10

Difference between main and accessory organs of the digestive system

Answer 10

Food only physically passes through the main organs, while accessory organs release substances into the main organs

Question 11

Types of salivary glands and location (3)

Answer 11

• Sublingual (under tongue)
• Submandibular (under jaw)
• Parotid (by ears)

Question 12

What enzymes does saliva contain? What are their functions?

Answer 12

Salivary amylase: starts digestion of carbs

Lingual lipase: starts lipid breakdown (mostly insignificant effect)

Question 13

Functions of saliva in the mouth (5)

Answer 13

• Facilitates swallowing by lubricating food particles
• Provides antibacterial action by releasing lysozymes (break down bacteria)
• Saliva dissolves food particles to stimulate taste buds
• Aids in speech
• Neutralizes ingested acid (saliva usually basic)

Question 14

Function of esophagus (and how it moves food)

Answer 14

Muscular tube (smooth muscle) that connects pharynx and stomach; peristaltic waves push food down (no actual digestion occurs)

Question 15

Structure of esophagus

Answer 15

• Upper esophageal sphincter is located proximally (beginning)
• Lower esophageal sphincter is located distally (end)

Question 16

Functions of stomach (3)

Answer 16

• Starts digestion of proteins
• Gastric mixing and gastric emptying
• Temporary hold for food that is consumed

Question 17

Structure of stomach

Answer 17

• Gastroesophageal sphincter: opening from esophagus
• Pyloric sphincter: gateway to small intestine
• Rugae: folds that increase surface area

Question 18

What happens during gastric emptying?

Answer 18

Pyloric sphincter open: peristaltic contractions move food into duodenum

Question 19

What happens during gastric mixing?

Answer 19

Pyloric sphincter closed: food mixed inside stomach, cannot enter duodenum

Question 20

What does the rugae of the stomach contain?

Answer 20

Gastric mucosa (has gastric pits, comprised of many different cell types)

Question 21

What types of cells comprise the gastric mucosa? (3)

Answer 21

Mucosa cells, chief cells, pareital cells

Question 22

Function of mucosa cells

Answer 22

Release mucous for lubrication

Question 23

Function of chief cells

Answer 23

Release pepsinogen (inactive enzyme)

Question 24

Function of parietal cells

Answer 24

Release HCl and intrinsic factor (helps absorption of Vitamin B12, needed for red blood cell synthesis)

Question 25

How is pepsinogen activated and what is its function? What is the active form called?

Answer 25

Activated by HCl; active form is pepsin | -Function of pepsin is to break down dietary proteins we consume into smaller peptide fragments

Question 26

What happens in the duodenum?

Answer 26

Food broken down into final digestible form (amino acids, fatty acids, etc.)

Question 27

From where does the duodenum receive input?

Answer 27

Pancreas, liver and gall bladder, stomach

Question 28

Structure of pancreas

Answer 28

- Dual organ that contains endocrine (release hormones) and exocrine (release enzymes) tissue - Exocrine tissue contains acinar cells and duct cells

Question 29

Function of acinar cells of pancreas

Answer 29

Release pancreatic juice (mix of pancreatic enzymes)

Question 30

What classes of enzymes do acinar cells release into the duodenal lumen?

Answer 30

- Proteolytic enzymes: trypsinogen, chymotrypsinogen, procarboxypeptidase - Pancreatic amylase - Pancreatic lipase

Question 31

Function of proteolytic enzymes released by pancreas

Answer 31

Break down proteins

Question 32

Function of pancreatic amylase and pancreatic lipase

Answer 32

- Pancreatic amylase digests polysaccharides into disaccharides - Pancreatic lipase digests triglycerides into glycerol and fatty acids (requires bile from liver to do this)

Question 33

Function of pancreatic duct cells

Answer 33

Release bicarbonate (HCO3-), which neutralizes acidic food mixture coming from stomach

Question 34

What triggers the pancreas to release its contents?

Answer 34

Small intestine (duodenum) releases two hormones: secretin acts on duct cells, and cholecystokinin (CCK) acts on acinar cells

Question 35

Function of liver

Answer 35

Hepatocytes release bile salts that function in fat emulsification

Question 36

Function of gall bladder

Answer 36

Storage of bile salts

Question 37

Function of bile

Answer 37

Emulsification: break down large fat globules into smaller fat droplets (increased solubility)

Question 38

Pathway of food through digestive system main organs

Answer 38

Mouth - esophagus - stomach - small intestine - large intestine - anus

Question 39

Parts of small intestine (3)

Answer 39

Duodenum, jejunum, ileum

Question 40

How does the small intestine increase its surface area?

Answer 40

Has circular folds that contain villi (fingerlike projections), and each villus has many epithelial cells that have their own folds (microvilli, or brush border)

Question 41

What are the brush border enzymes?

Answer 41

Additional enzymes in the small intestine: enterokinase (activate trypsinogen), disaccharidases (break down disaccharides), and aminopeptidases (hydrolyze peptide fragments to amino acids)

Question 42

Overview of carbohydrate digestion

Answer 42

Dietary carbohydrates - SALIVARY AMYLASE - smaller polysaccharides - (no digestion in stomach) - PANCREATIC AMYLASE - disaccharides - DISACCHARIDASES - monosaccharides

Question 43

How are monosaccharides and amino acids absorbed into the blood?

Answer 43

Enter duodenal lining through secondary active transport and leave through facilitated diffusion

Question 44

Overview of protein digestion

Answer 44

Dietary proteins - PEPSIN (in stomach) - small polypeptides - PANCREATIC TRYPSINOGEN AND CHYMOTRYPSINOGEN - very small peptides and amino acids - AMINOPEPTIDASES - amino acids

Question 45

Overview of lipid digestion

Answer 45

Dietary lipids - LINGUAL LIPASE - fat globules - BILE SALTS - fat droplets - PANCREATIC LIPASE - glycerol, fatty acids, monoglycerides

Question 46

How are lipids absorbed into the blood?

Answer 46

Glycerol and fatty acids contained in micelles (vesicles) enter epithelial cell lining through diffusion, are resynthesized into triglycerides, packaged, and exocytose in chylomicrons (vesicles) to enter lymphatic vessels

Question 47

Parts of large intestine

Answer 47

Cecum, colon (ascending, transverse, descending, sigmoid), rectum

Question 48

What goes to the large intestine? (3)

Answer 48

- Stuff that's indigestible; these waste products are excreted from the body as feces - Houses helpful bacteria in colon (intestinal flora) - Some absorption of water and electrolytes

Question 49

Function of intestinal flora

Answer 49

Symbiotic relationship: they help us produce Vitamin K, we give them an unlimited food source (but they must stay contained in the large intestine)