Digestion Flashcards Preview

SAT II BIOLOGY > Digestion > Flashcards

Flashcards in Digestion Deck (41):
1

Parts of Digestion

  1. Mechanical - breaking up food into small pieces
  2. Chemical - breakign down polymers with enzymes into small pieces
  3. Absorption - taking nutrients up into cells

2

Alimentary canal

  • path of food through the body
  • mouth - pharynx - esophagus - stomach small intestine - large intestine - rectum

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3

Mouth

  • Mechanical and chemical digestion begins here
  • the enzyme salivary amylase in saliva begins starch digestion
  • tongue and teeth break down food mechanically
  • incisors for cutting, canines for tearing, molars for grinding
  •  

4

Where does starch digestion begin?

5

Peristalsis

  • wavelike muscular action conducted by smooth msulce 
  • esophagus, stomach, small intestine, large intestine
  • involuntary contractions 

6

salivary amylase

  • pytalin
  • breaks starch into maltose

7

Esophagus

  • NO digestion occurs here
  • transports food from throat to stomach
  • peristalsis
  • foods is directed away from the windpipe by the epiglottis, a flap of cartilage in the back of the pharynx(throat)

8

Epiglottis

a flap of carilage in the back of the pharynx(throat)

9

Pharynx

throat

10

Stomach

  • Mechanical and chemical digestion
  • Protein digestion begins here
  • thick, muscular wall churns food mechanically
  • gastric glands produce hydrochloric acid and the enzyme pepsin
  • acidic, low pH(2-3) necessary from pepsin; destroys ingested microoragnisms

11

Hydrochloric Acid

  • begins the breakdown of muscle(meat)
  • activates the inactive enzyme pepsinogen to becom pepsin, which digests protein
  •  

12

Pepsinogen

inactive enzyme activiated by hydrochloric acide to become pepsin, which breaks down protein

13

Rennin

aids the digestion of the protein in milk

14

Cardiac Sphincter

  • at the top of the stomach
  • keeps acidified food in the stomach from backing up into the esophagus and burning it

15

Pyloric Sphincter

  • bottom of stomach
  • keeps food inthe stomach long enough to be digested
  • Through it, Chyme enters the duodenum

16

Where does protein digestion begin?

Stomach

17

What does excessive acid do?

  • cause an ulcer to form in the esophagus, stomach, or duodenum
  • another common cause of ulcers is Heliobacter pylori, bacterium

18

Duodenum

  • 1st 10in of small intestine
  • Chyme enters the duodenum through the pyloric sphincter
  • All digestion is completed here

19

Chyme

partially digested food in the stomach

20

Small Intestine

  • All digestion is completed(duodenum) and nutrients are absorbed here
  • pH - 8
  • intestinal enzymes are amylases, proteases, lipases, nucleases
  • Pancreatic amylases are secreted in here
  • glands produce aminopeptidases for polypeptide digestion and disaccharidases
  • Peptidases(ex/ trypsin, chymotrypsin) continue to break down proteins
  • Millions of villi line the small intestine and absorb all the nutrients from digested food

21

Villus(pl. Villi)

  • fingerlike projections that line the small intestine and absorb all nutrients from digested food
  • each contains:
    • Capillaires - absorbs amino acids, vitamins, monosaccharides directly into the bloodstream
    • lacteal - absorbs fatty acids and glycerol into the lymphatic system
  • have microscopic appendages called microvilli that further enhance the rate of absorption
  • epithelial cells

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22

Lacteal

Absorbs fatty acids and glycerol into the lymphatic system

23

Nuclease

Hydrolyzes nucleic acids into nucleotides

 

24

Lipase

breaks down fats

25

Pancreas

  • Secretes Peptidases, protein-digesting enzymes, into small intestine
  • Pancreatic proteases are stored in inactive froms called zymogens
    • prevents damage to pancreatic tissues that occurs if proteases are prematurely active
  • Produces amylas, trypsin, chymotrypsin
  • Alkaline range pH; bicarbonate ion neutralizes acidity of the chyme 

26

Peptidases/Proteases

Pepsin

Trypsin

Chymotrypsin

27

Amylase

breaks down starch

28

Liver

  • Produces bile
  • Sends bile to the gallbladder until its release into the small intestine
  • Breaks down and recycles red blood cells
  • Detoxifies blood - removes alcohol and drugs
  • Produces cholesterol for structure of cell membranes
  • Produces urea from protein metabolism
  • Strorage of iron and vitamin B
  • Regulate blood glucose levels

29

erythrocytes

Red blood cells

30

Hepatic Portal Vein

Delivers glucose and other monosaccharides absorbed in the small intestine during digestion to liver

31

Gluconeogenesis

  • When liver syntesizes glucose from noncarbohydrate precurors when blood glucose levels are low

32

What processes glucose-rich blood?

  • Liver converts excess glucose to glycogen for storage in the liver

33

What happens when blood has a low glucose concentration?

  • liver converts glycogen into glucose and releases it into the blood, restorign blood glucose levels to normal
  • gluconeogenesis

34

Zymogens

  • Pancreatic proteases in inactive forms
  • activated after secretion when they are cleaved by another protease
  • prevetns dame to the pancreatic tissues that occurs if proteases are prematurely active

35

Bile

  • Produced in liver; Stored in gallbladder
  • emulsifies fats in small intestine
  • pH 11; neutralizes chyme entering the small intestine

36

Gallbladder

  • Stores bile
  • Can function without

37

Large Intestine/Colon

  • No digestion
  • Egestion 
  • Vitamin production - bacteria symbionts livign in the colon produce the B vitamins, vitamin K, and folic acid
  • Reabsorption of water
    • Constipation
    • Diarrhea

38

Egestion

  • Large intestine
  • removal of undigested waste

39

Constipation

Too much water is reabsorbed from large intestine into body

40

Diarrhea

Too little water absorbed back into body

41

Rectum

  • Egestion
  • last 7-8 inches of the gastrointestinal tract
  • Stores feces until release through anus