Digestion Flashcards
(90 cards)
1
Q
What is ingestion?
A
Taking in of nutrients
2
Q
What is digestion?
A
Breakdown of organic materials
3
Q
What is absorption?
A
Transport of digested nutrients into the blood stream
4
Q
What is egestion?
A
Removal of indigestible materials (feces)
5
Q
What is organic food material composed of?
A
Macromolecules
6
Q
What do macromolecules need to be broken down into?
A
Monomers
7
Q
What process is used to break bonds in macromolecules?
A
Enzymatic hydrolysis
8
Q
What are macromolecules broken down into and how?
A
They are broken down into component monomers by enzymatic hydrolysis.
9
Q
What are polysaccharides broken down into?
A
Monosaccharides
10
Q
What are proteins broken down into?
A
Amino acids
11
Q
What are lipids broken down into?
A
Fatty acids and glycerol
12
Q
List the accessory glands
A
Salivary glands
Pancreas
Liver
Gall bladder
13
Q
What (in general) do the accessory glands do?
A
Secrete juices into the alimentary canal
14
Q
List the layers of the alimentary canal from inside to outside
A
lumen, mucosa, submucosa, muscle layer, serosa
15
Q
What is the submucosa composed of?
A
connective tissue
16
Q
What are the purposes of the oral cavity?
A
mastication and lubrication
17
Q
What is formed in the oral cavity?
A
bolus
18
Q
What is peristalsis?
A
Waves of rhythmic contractions of smooth muscles that moves the bolus of food along the alimentary canal
19
Q
What initiates peristalsis?
A
swallowing
20
Q
What enzyme remains active as the bolus moves through the esophagus?
A
salivary amylase
21
Q
What happens to salivary amylase in the stomach and why?
A
It is denatured because of the acidity of the stomach.
22
Q
What is between the esophagus and stomach?
A
The gastro-esophageal junction, cardiac sphincter
23
Q
Where is the stomach?
A
Just below the diaphragm on LS of abdominal cavity.
24
Q
What happens in churning?
A
3 muscle layers of the stomach contract, mixing food
25
What are the layers of muscle involved in churning?
longitudinal
vertical
diagonal
26
How is chyme formed?
Churning, mixing, and addition of stomach acid forms a nutrient broth in the stomach.
27
What are the layers of cells in gastric pits?
Top: cells that secrete mucous
Bottom: cells that secrete acid (HCl)
Even Lower: pepsinogen-secreting cells
28
How are the insides of the duodenum and ileum/jejunum different?
The duodenum has folds, whereas the ileum and jejunum have villi and microvilli
29
What is the purpose of villi and microvilli?
To increase surface area for absorption
30
What are the functions of the mouth?
Voluntary control of eating and swallowing
Mechanical digestion of food by chewing and mixing with saliva (which contains lubricants and enzymes that start starch digestion)
31
What is the function of the esophagus
Movement of food by peristalsis from the mouth to the stomach
32
What are the functions of the stomach?
Churning and mixing with secreted water and acid, as well as initial stages of protein digestion
33
Why is there secreted water and acid in the stomach?
To kill foreign bacteria and other pathogens in food.
34
What are the functions of the small intestine?
Final stages of digestion of lipids, carbohydrates, proteins, and nucleic acids
Neutralizing stomach acid
Absorption of nutrients
35
What are the functions of the pancreas?
Secretion of surfactants in bile to break up lipid droplets
36
What are the functions of the gall bladder?
Storage and regulated release of bile
37
What are the functions of the large intestine?
Re-absorption of water
Further digestion especially of carbohydrates by symbiotic bacteria
Formation and storage of feces
38
How many types of gland tissue does the pancreas contain?
2
39
What hormones are secreted by the pancreas from small groups of cells?
insulin and glucagon
40
Where are digestive enzymes synthesized? Then where do they go?
In the pancreatic gland cells on ribosomes on the rough endoplasmic reticulum. They then are processed in the Golgi apparatus and secreted by exocytosis
41
Explain the structure and functions of ducts the pancreas
Ducts within the pancreas merge into larger ducts and finally form one pancreatic duct through which about a litre of pancreatic juice is secreted per day into the lumen of the small intestine
42
What enzymes are in pancreatic juice? What do each of them do?
Amylase digests starch
Lipases digest triglycerides and phospholipids
Proteases digest proteins and peptides
43
What does amylase do?
Digests starch to maltose
44
List the different salivary glands and how many of each there are
```
parotid glands (2)
submandibular glands (2)
sublingual gland (1)
```
45
What does lipase do?
Digests triglycerides to fatty acids and glycerol OR fatty acids and monoglycerides
46
What does phospholipase do?
Digests phospholipids to fatty acids, glycerol, and phosphate
47
What does protease do?
Digests proteins and polypeptides to shorter peptides
48
Give an example of something humans can't digest
Cellulose
49
What do nucleases do?
Digest DNA and RNA to nucleotides
50
What does maltase do?
Digests maltose to glucose
51
What does lactase do?
Digests lactose to glucose and galactose
52
What does sucrose do?
Digests sucrose to glucose and fructose
53
What are exopeptidases? How do they work?
Proteases that digest peptides by removing single amino acids either from the carboxy or amino terminal of the chain until only a dipeptide is left
54
What do dipeptidases do?
Digest dipeptides into amino acids.
55
What are monosaccharides? Give 3 examples
They are simple sugars
| ex. glucose, fructose, galactose
56
What forms can monosaccharides exist in?
linear or cyclic
57
Why do we need monosaccharides?
They are produced and metabolized for energy
58
What are disaccharides and how are they formed?
Two monosaccharides bonded together through dehydration synthesis.
59
How does dehydration synthesis work?
A water molecule is removed, breaking a bond.
60
Give three examples of disaccharides and how they are formed
glucose + fructose make sucrose
glucose + galactose make lactose
glucose + glucose make maltose
61
What is hydrolysis?
The opposite of dehydration synthesis. Requires the addition of water and is catalyzed by enzymes.
Part of chemical digestion of only carbohydrates
Occurs in the mouth and duodenum
62
What are polysaccharides?
Monosaccharides linked together in long chains.
63
Give three examples of polysaccharides and their function
Cellulose (structural for plants, can't be digested by humans)
Starch (glucose storage in plants)
Glycogen (animal storage for glucose)
64
What are the components of starch? Which is the primary component?
amylose *primary component
| amyloid pectin
65
What must happen for polysaccharides and disaccharides to release stored energy?
They must be hydrolyzed
66
What is the pH of the stomach?
2
67
What is secretin? What does it do and how and why?
A hormone that travels through the bloodstream to the pancreas, makes the pancreas add HCO3 1- to pancreatic juice so that the amylase is at the right pH (8-9 in the duodenum)
68
Where is the epithelium?
In the mucosa layer
69
What needs to be emulsified?
lipids
70
What are the two functional categories of lipids?
Storage lipids and membrane lipids
71
Explain the two functional categories of lipids
Storage lipids contain up to 6X more energy than glycogen (carbohydrates), are typically non-polar, and store energy.
Membrane lipids are usually packed into bilayers which have polar and non-polar regions.
72
What is the basic structure of a lipid?
3 fatty acids are covalently bonded to 1 glycerol to form a triglyceride.
73
List the types of lipids
```
Triglycerides
Phospholipids
Cholesterol (2 types) (building block for many hormones)
Steroids (also related to hormones)
Waxes
```
74
What are saturated fatty acids?
Fatty acids that have no double bonds between carbons. They stack together nicely and are solids and room temperature. Found in animal fats.
75
What are unsaturated fatty acids?
Fatty acids that have double bonds between Carbons, the higher % of double bonds, the healthier the fat is. They are liquid at room temperature and found in plants.
76
How are triglycerides formed?
Dehydration synthesis
77
Where are phospholipids found?
In membrane lipids
78
What is the basic structure of a phospholipid?
The third Carbon of the glycerol is occupied by a phosphate rather than a fatty acid (2 f.a.'s and a PO4-Alcohol all bonded to a glycerol backbone)
79
What is the structure of cholesterol/steroids?
4 linked carbon rings
80
Where are cholesterol and steroids found?
Animal cell membranes
81
Where are cholesterol and steroids synthesized?
In the liver from saturated fatty acids
82
What disease is associated with high concentration of cholesterol?
Atherosclerosis (when someone gets fat deposits of the vessels)
83
What is the goal for digestion of lipids?
End result of glycerol and fatty acids that can be absorbed into the body
84
Is there chemical digestion of lipids in the mouth or stomach? If so, what?
NOOOOOOOOO
85
What is the first step of digestion of lipids in the duodenum?
emulsification
86
What stimulates bile production by the liver?
Parasympathetic impulses along vagus nerves
87
What do fatty acids and amino acids in chyme stimulate when they enter the duodenum?
The secretion of cholecystokinin
| Acidic chyme entering the duodenum simulates the secretion of secretin into blood
88
What is the full name of CCK, what is it, what does it do, and how is its secretion stimulated?
CCK is cholecystokinin
It is a hormone
It causes the contraction of the gall bladder
It is stimulated by fatty acids and amino acids entering the duodenum
89
What does secretin do?
Enhances flow of bile rich in HCO3- from liver
90
What does bile do?
Emulsifies fats (mechanical digestion), resulting in a higher SA for lipase to work.
