Digestion Flashcards
(41 cards)
1
Q
Parts of Digestion
A
- Mechanical - breaking up food into small pieces
- Chemical - breakign down polymers with enzymes into small pieces
- Absorption - taking nutrients up into cells
2
Q
Alimentary canal
A
- path of food through the body
- mouth - pharynx - esophagus - stomach small intestine - large intestine - rectum
3
Q
Mouth
A
- 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
Q
Where does starch digestion begin?
A
5
Q
Peristalsis
A
- wavelike muscular action conducted by smooth msulce
- esophagus, stomach, small intestine, large intestine
- involuntary contractions
6
Q
salivary amylase
A
- pytalin
- breaks starch into maltose
7
Q
Esophagus
A
- 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
Q
Epiglottis
A
a flap of carilage in the back of the pharynx(throat)
9
Q
Pharynx
A
throat
10
Q
Stomach
A
- 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
Q
Hydrochloric Acid
A
- begins the breakdown of muscle(meat)
- activates the inactive enzyme pepsinogen to becom pepsin, which digests protein
*
12
Q
Pepsinogen
A
inactive enzyme activiated by hydrochloric acide to become pepsin, which breaks down protein
13
Q
Rennin
A
aids the digestion of the protein in milk
14
Q
Cardiac Sphincter
A
- at the top of the stomach
- keeps acidified food in the stomach from backing up into the esophagus and burning it
15
Q
Pyloric Sphincter
A
- bottom of stomach
- keeps food inthe stomach long enough to be digested
- Through it, Chyme enters the duodenum
16
Q
Where does protein digestion begin?
A
Stomach
17
Q
What does excessive acid do?
A
- cause an ulcer to form in the esophagus, stomach, or duodenum
- another common cause of ulcers is Heliobacter pylori, bacterium
18
Q
Duodenum
A
- 1st 10in of small intestine
- Chyme enters the duodenum through the pyloric sphincter
- All digestion is completed here
19
Q
Chyme
A
partially digested food in the stomach
20
Q
Small Intestine
A
- 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
Q
Villus(pl. Villi)
A
- 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
22
Q
Lacteal
A
Absorbs fatty acids and glycerol into the lymphatic system
23
Q
Nuclease
A
Hydrolyzes nucleic acids into nucleotides
24
Q
Lipase
A
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
