Final: Nutrition, Digestion, and Absorption Slides Flashcards

1
Q

Functions of digestive system (2)

A

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

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2
Q

Processes of digestive system (4)

A

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

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3
Q

What happens during motility?

A

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

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4
Q

Purpose of mixing food during motility

A

Promotes digestion and mixing with enzymes, and facilitates absorption

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5
Q

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

A

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

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6
Q

What happens during secretion in the digestive system?

A

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

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7
Q

What happens during process of digestion?

A

Food broken down into smaller pieces so it can be absorbed

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8
Q

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

A

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

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9
Q

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

A

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

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10
Q

Difference between main and accessory organs of the digestive system

A

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

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11
Q

Types of salivary glands and location (3)

A
  • Sublingual (under tongue)
  • Submandibular (under jaw)
  • Parotid (by ears)
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12
Q

What enzymes does saliva contain? What are their functions?

A

Salivary amylase: starts digestion of carbs

Lingual lipase: starts lipid breakdown (mostly insignificant effect)

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13
Q

Functions of saliva in the mouth (5)

A
  • 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)
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14
Q

Function of esophagus (and how it moves food)

A

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

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15
Q

Structure of esophagus

A
  • Upper esophageal sphincter is located proximally (beginning)
  • Lower esophageal sphincter is located distally (end)
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16
Q

Functions of stomach (3)

A
  • Starts digestion of proteins
  • Gastric mixing and gastric emptying
  • Temporary hold for food that is consumed
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17
Q

Structure of stomach

A
  • Gastroesophageal sphincter: opening from esophagus
  • Pyloric sphincter: gateway to small intestine
  • Rugae: folds that increase surface area
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18
Q

What happens during gastric emptying?

A

Pyloric sphincter open: peristaltic contractions move food into duodenum

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19
Q

What happens during gastric mixing?

A

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

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20
Q

What does the rugae of the stomach contain?

A

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

21
Q

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

A

Mucosa cells, chief cells, pareital cells

22
Q

Function of mucosa cells

A

Release mucous for lubrication

23
Q

Function of chief cells

A

Release pepsinogen (inactive enzyme)

24
Q

Function of parietal cells

A

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

25
Q

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

A

Activated by HCl; active form is pepsin

-Function of pepsin is to break down dietary proteins we consume into smaller peptide fragments

26
Q

What happens in the duodenum?

A

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

27
Q

From where does the duodenum receive input?

A

Pancreas, liver and gall bladder, stomach

28
Q

Structure of pancreas

A
  • Dual organ that contains endocrine (release hormones) and exocrine (release enzymes) tissue
  • Exocrine tissue contains acinar cells and duct cells
29
Q

Function of acinar cells of pancreas

A

Release pancreatic juice (mix of pancreatic enzymes)

30
Q

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

A
  • Proteolytic enzymes: trypsinogen, chymotrypsinogen, procarboxypeptidase
  • Pancreatic amylase
  • Pancreatic lipase
31
Q

Function of proteolytic enzymes released by pancreas

A

Break down proteins

32
Q

Function of pancreatic amylase and pancreatic lipase

A
  • Pancreatic amylase digests polysaccharides into disaccharides
  • Pancreatic lipase digests triglycerides into glycerol and fatty acids (requires bile from liver to do this)
33
Q

Function of pancreatic duct cells

A

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

34
Q

What triggers the pancreas to release its contents?

A

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

35
Q

Function of liver

A

Hepatocytes release bile salts that function in fat emulsification

36
Q

Function of gall bladder

A

Storage of bile salts

37
Q

Function of bile

A

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

38
Q

Pathway of food through digestive system main organs

A

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

39
Q

Parts of small intestine (3)

A

Duodenum, jejunum, ileum

40
Q

How does the small intestine increase its surface area?

A

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

41
Q

What are the brush border enzymes?

A

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

42
Q

Overview of carbohydrate digestion

A

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

43
Q

How are monosaccharides and amino acids absorbed into the blood?

A

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

44
Q

Overview of protein digestion

A

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

45
Q

Overview of lipid digestion

A

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

46
Q

How are lipids absorbed into the blood?

A

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

47
Q

Parts of large intestine

A

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

48
Q

What goes to the large intestine? (3)

A
  • 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
49
Q

Function of intestinal flora

A

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