Exam 4 - Digestive System Flashcards
(170 cards)
1
Q
What are the five stages of digestion?
A
Ingestion, digestion, absorption, compaction, and defecation
2
Q
What is ingestion?
A
Selective intake of food
3
Q
What is digestion?
A
Mechanical and chemical breakdown of food into a form usable by the body
4
Q
What is absorption?
A
Uptake of nutrient molecules into the epithelial cells of the digestive tract and then into the blood and lymph
5
Q
What is compaction?
A
Absorbing water and consolidating the indigestible residue into feces
6
Q
What is defecation?
A
Elimination of feces
7
Q
What is mechanical digestion?
A
The physical breakdown of food into smaller particles
8
Q
What is chemical digestion?
A
a series of hydrolysis reactions that break dietary macromolecules into their monomers
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 fats broken down into?
A
Monoglycerides and fatty acid
12
Q
What are nucleic acids broken down into?
A
Nucleotides
13
Q
What is the digestive tract?
A
Mouth, pharynx, esophagus, stomach, small intestine, and large intestine
14
Q
What is the gastrointestinal tract?
A
Stomach and intestines
15
Q
What are accessory organs?
A
Teeth, tongue, salivary glands, liver, gallbladder, and pancreas
16
Q
What is the enteric nervous system?
A
Nervous network in esophagus, stomach, and intestines that regulates digestive tract motility, secretion, and blood flow
17
Q
What is mesenteries?
A
Connective tissue sheets that suspend stomach and intestines from abdominal wall
18
Q
What is the parietal peritoneum?
A
A serous membrane that lines the wall of the abdominal cavity
19
Q
What is the lesser omentum?
A
A ventral mesentery that extends from the lesser curvature of the stomach to the liver
20
Q
What is the greater omentum?
A
Hangs from the greater curvature of the stomach
21
Q
What is the mesocolon?
A
Extension of the mesentery that anchors the colon to the abdominal wall
22
Q
What is intraperitoneal?
A
When an organ is enclosed by mesentery on both sides
23
Q
What is retroperitoneal?
A
When an organ lies against the posterior body wall and is covered by peritoneum on its anterior side only
24
Q
What is the functions of the mouth?
A
Ingestion, taste and sensory responses to food, chewing and chemical digestion, swallowing, speech, and respiration
25
How many teeth does an adult have?
32
26
What are the different types of teeth?
3 incisors, 1 canine, 2 premolars, and 3 molars
27
What is salvia do?
Moistens mouth, begins starch and fat digestion, dissolves molecules, and inhibits bacterial growth
28
What is salivary amylase?
Enzyme that begins starch digestion in the mouth
29
What is lingual lipase?
Enzyme that is activated by stomach acid and digests fat after food is swallowed
30
What is mucus?
Binds and lubricates a mass of food and aids in swallowing
31
What is lysozyme?
Enzyme that kills bacteria
32
What is immunoglobulin A?
An antibody that inhibits bacterial growth
33
What is electrolytes?
Na, K, Cl, Phosphate, and bicarbonate
34
What are intrinsic salivary glands?
Small glands dispersed amid other oral tissues
35
What are extrinsic salivary glands?
Three pairs connected to oral cavity by ducts
36
What is a bolus?
Mass swallowed as a result of saliva binding food particles into a soft, slippery, easily swallowed mass
37
What is the pharynx?
Muscular funnel connecting oral cavity to esophagus and nasal cavity to larynx
38
What does the inferior constrictor do?
When not swallowing it remains contracted to exclude air from the esophagus
39
What is the esophagus?
Straight muscular tube that extends from pharynx to cardiac orifice of stomach
40
What is the stomach?
A muscular sac in upper left abdominal cavity immediately inferior to diaphragm
41
Where does most digestion occur?
Small intestines
42
What are the 4 regions of the stomach?
Cardia, fundus, body, and pyloric region
43
What is the pylorus?
Narrow passage to duodenum
44
What are stomach receives and what are they from?
Parasympathetic fibers from vagus
Sympathetic fibers from celiac ganglia
45
What are gastric pits?
Depressions in gastric mucosa
46
What are mucous cells?
Secrete mucus; mainly in cardiac and pyloric glands
47
What are regenerative cells?
Found in base of pit and in beck of gland
48
What are parietal cells?
Secrete HCl, Intrinsic factor ,and ghrelin
49
What are chief cells?
Most numerous; secrete gastric lipase and pepsinogen
50
What are enteroendocrine cells?
Concentrated at end of gland; secrete hormones and paracrine messengers
51
What are gastric juice?
Mixture of water, HCl, and pepsin; 2-3L per day
52
What does HCl do?
Activates pepsin and lingual lipase; breaks up connective tissue and plant cell wall; converts Fe3 to Fe2
53
What are zymogens?
Digestive enzymes secreted as inactive proteins
54
What is pepsinogen?
Zymogen secreted by chief cells
55
What does HCl do to pepsinogen?
Removes amino acid and forms pepsin
56
What is the autocatalytic effect of pepsinogen?
As some pepsin is formed, it converts more pepsinogen into more pepsin
57
What does pepsin do?
Digests dietary proteins into shorter peptides
58
What does gastric lipase do?
Produced by chief cells; digests 10-15% of dietary fats in stomach
59
What does intrinsic factor do?
Essential to absorption of vitamin B12 by the small intestines
60
What is the importance of vitamin B12?
It is needed to synthesize hemoglobin
61
What is the three ways the stomach is protected?
Mucous coat, tight junctions, and epithelial cell replacement
62
What is the mucous coat?
It is a thick, alkaline mucus resists action of acid and enzymes
63
What is tight junctions?
Between epithelial cells to prevent gastric juice from seeping through
64
What is epithelial cell replacement?
Cells live only 3-6 days and sloughed off into the chyme and digested with food
65
What happens if the methods of protecting the stomach are broken down?
It can cause inflammation and peptic ulcer
66
What causes most ulcers?
The acid resistance bacteria helicobacter pylori
67
What does the small intestines receive?
Chyme from stomach and secretions from liver and pancreas
68
Where is the liver and what is its function?
Inferior to the diaphragm and secretes bile which contributes to digestion
69
What are the 4 lobes of the liver?
Right, left, quadrate, and caudate
70
What does the falciform ligament do on the liver?
Separates the right lobe from the left lobe
71
What is the round ligament on the liver?
It is the fibrous remnant of umbilical vein
72
What is porta hepatis?
Irregular opening between quadrate and caudate lobes
73
What separates hepatic lobules?
Stroma
74
What is between lobules?
A hepatic triad of two vessels and bile ductule
75
What do hepatocytes do after a meal?
They are absorbed from the blood
76
What do hepatocytes do between meals?
Break down stored glycogen and release glucose, remove degrade, and secrete products into the blood
77
Where does the central vein lead to?
Right and left hepatic veins
78
What are bile canaliculi?
Narrow channels into which the liver secretes bile
79
What is the common hepatic duct?
Formed from convergence of right and left hepatic ducts on inferior side of the liver
80
What is the cysticduct?
From gallbladder and joins common hepatic duct
81
What is the bile duct?
Formed from union of cystic and common hepatic ducts
82
What is the purpose of the gallbladder?
To store and concentrate bile by absorbing water and electrocytes
83
Where does the neck of the gallbladder lead to?
The cystic duct
84
What is bile?
Yellow-green fluid that contains minerals, bile pigments, and bile acid
85
What is bilirubin?
Principal pigment derived from the decomposition of hemoglobin
86
What are bile acids?
Steroids synthesized from cholesterol
87
Where and how much bile acid are reabsorbed?
80% of bile acids are reabsorbed in the ileum and returned to the liver
88
What are the sections of the pancreas?
The head encircled by duodenum, a body, and a tail
89
What is the endocrine portion of the pancreas?
Pancreatic islets that secrete insulin and glucagon
90
What is the exocrine portion of the pancreas?
99% of pancreas that secretes 1.2L to 1.5L of pancreatic juice per day
91
Where is the pancreatic duct?
Runs lengthwise through middle of the gland
92
Where is the accessory pancreatic duct?
Smaller duct that branches from the main pancreatic duct
93
What is pancreatic juice?
Alkaline mixture of water, enzymes, zymogens, NaCO2, and other electrolytes
94
What are the pancreatic zymogens?
Trypsinogen, chymotrypsinogen, and procarboxypeptidase
95
What is trypsinogen?
Secreted into intestinal lumen and coverts to trypsin that is an autocatalytic
96
What is chymotrypsinogen?
Converted to chymotrypsin by trypsin
97
What is proarboxypeptidase?
Converted to carboxypeptidase by trypsin
98
What does pancreatic amylase do?
Digest starch
99
What does pancreatic lipase do?
Digest fat
100
What does the ribonuclease and deoxyribonuclease do?
Digest RNA and DNA respectively
101
What are the 3 stimuli responsible for the release of pancreatic juice and bile?
Acetylcholine, cholecystokinin, and secretin
102
Where is Acetylcholine from?
Vagus and enteric nerves
102
Where is cholecystokinin from?
Secreted by mucosa of duodenum in response to arrival of fats in small intestine
103
Where is secretin from?
Released from duodenum in response to acidic chyme arriving from the stomach
104
What does secretin do?
Stimulates ducts of liver and pancreas to secrete more sodium bicarbonate to raise pH level
105
What does cholecystokinin do?
Stimulates pancreatic acini to secrete enzymes
106
What does acetylcholine do?
Stimulates acini to secrete enzymes during cephalic phase
107
Where does most of the chemical digestion and nutrient absorption occur?
Small intestine
108
What is the duodenum?
A region of the small intestine, and begins at pyloric valve
109
What happens in the duodenum?
Fats are broken up by bile acids, pepsin is inactivated by increase pH, pancreatic enzymes perform chemical digestion
110
Where is the jejunum?
First 40% of small intestineW
111
What happens in the jejunum?
Most digestion and nutrient absorption
112
Where is the ileum?
Forms last 60% of small intestine
113
What does the ileum look like?
Thinner, less muscular and vascular
114
What are peyer patches?
Prominent lymphatic nodules in cluster on the slide opposite the mesenteric attachment
115
What are ileocecal junction?
End of small intestine
116
What is the ileocecal valve?
A sphincter formed by the thickened muscularis of the ileum
117
What are both the jejunum and ileum?
Intraperitoneal covered with serosa
118
What are circular folds?
Largest fold of intestinal wall that increase surface area to help with digestion and absorption
119
What are villi?
Little fingers-like projections that increase surface area by factor of 10
120
What are microvilli?
Villi on top of the villi (brush border) to increase surface area by a factor of 20
121
Where are the brush border enzymes?
Contained in plasma membrane of microvilli
122
What does the brush border enzyme do?
Final stages of enzymatic digestion
123
What are contact digestion?
Chyme must contact the brush border for digestion to occur
124
What is segmentation?
Movement in which stationary ring-like constriction appear in several places along the intestine
125
What does peristalsis do?
Move contents of small intestine toward colon
126
What are carbohydrates?
Sugar and starches
127
What are the different types of monosaccharides?
Glucose, galactose, and fructose
128
What are the different types of disaccharides?
Maltose, sucrose, and lactose
129
How is maltose formed?
Glucose + glucose
130
How is sucrose made?
Glucose + fructose
131
How is lactose made?
Glucose + galactose
132
What are polysaccharides?
Starch made from glucose
133
What is the most common startch?
amylose
134
How are the macromolecules absorbed?
They are all broken down into monosaccharides
135
How are protein made?
Amino acids linked by peptide bonds
136
What are the enzymes that digest proteins?
Proteases or peptidases
137
How are proteins absorbed?
Must be broken down into single amino acids
138
What are lipids?
Fatty acids, triglycerides, and monoglycerides
139
What digest lipids?
The enzyme lipase
140
What is the most digestible dietary carbohydrate?
Starch
141
What is starch first digested to?
Oligosaccharides
142
What are oligosaccharides digested to?
Disaccharide maltose
143
What are maltose digested to?
Glucose
144
What does salivary amylase do?
Hydrolyzes starch into oligosaccharides
145
What happens to people without lactase?
Lactose passes undigested into large intestine
146
What does lactose in large intestine do?
Increases osmolarity of intestinal contents and causes water retention
147
What does proteases do?
Enzymes that digest proteins
148
What are lipases?
Fat-digesting enzymes
149
What happens to vitamins?
They are absorbed unchanged
150
How much water is absorbed by small intestine
8 L
151
How much water is absorbed by large intestine?
0.8 L
152
What is diarrhea?
Occurs when large intestine absorbs too little water
153
What is constipation?
Occurs when feal movement is slow, too much water gets reabsorbed
154
Where does the large intestines form?
At the cecum
155
What is the rectum?
Portion ending at anal canal
156
What is the anal canal?
Final 3 cm of the large intestine
157
What are taenia coli?
Longitudinal fibers conc in three thickened, ribbon-like strips
158
What are haustra?
Pouches in the colon caused by the muscle tone of the taenia coli
159
What is internal anal sphincter?
Smooth muscle of muscularis externa
160
What is the external anal sphincter?
Skeletal muscle of pelvic diaphragm
161
What are feces consist of?
75% water and 25% solids
162
How often do haustral contractions occur?
every 30 mins
163
What happens to starch in the mouth?
The salivary amylase breaks it down into oligosaccharides and maltose
164
What happens to oligosaccharides in the small intestine?
Pancreatic amylase breaks it down into maltose
165
What happens to lactose in the small intestine?
It splits into fructose and galactose
166
What happens to protein in the stomach?
Pepsin breaks it into small peptides
167
what happens to small peptides in the small intestine?
Trypsin, chymotrypsin, carboxypeptidase break it down into dipeptides; turn into free amino acids
168
What happens to fats in the stomach?
The lingual lipase breaks it into free fatty acids
169
What happens to fats in small intestine?
Pancreatic lipase breaks it into monoglyceride and free fatty acids; they get turned into triglycerides
