Digestive System (Exam 3) Flashcards
1
Q
What are the 6 functions of the digestive system?
A
Ingestion Secretion Mixing/Propulsion Digestion Absorption Defecation
2
Q
What is digestion?
A
The actual breakdown of material
3
Q
What are the two types of digestion?
A
Mechanical digestion and Chemical digestion
4
Q
What is mechanical digestion?
A
The mashing up of food
5
Q
What are the two main groups of Digestive organs?
A
GI Tract organs and Accessory organs
6
Q
What are the organs of the GI Tract?
A
Stomach Anus Mouth Pharynx Large Intestine Esophagus Small intestine
SAMPLES (the “cavity” organs)
7
Q
What are the Accessory organs of the digestive system?
A
Teeth Tongue Salivary Glands Liver Gallbladder Pancreas
TTSLGP
8
Q
What are the GI Tract layers from inner to outer?
A
Mucosa
Submucosa
Muscularis
Serosa
9
Q
Mucosal layer is tissue that is open…
A
… to the environment.
10
Q
Is the mucosa well vascularized?
A
No
11
Q
What are the three layers of the Mucosal Lining?
A
Epithelium
Lamina propria
Muscularis Mucosae (smooth muscle)
12
Q
Does the tissue type of the mouth differ from the tissue type of the Intestines?
A
Yes
13
Q
As the GI Tract organs descend from the mouth to the intestines, what tissue change occurs?
A
In the mouth the epithelium of the mucosal tissue is stratified squamous which is thicker and offers mostly protection and by the time it descends to the intestines, the tissue is simple columnar epithelium which is thinner and offers mostly absorption.
14
Q
What is the thickness and purpose of stratified squamous epithelium?
A
Stratified squamous epithelium is very thick and offers protection
15
Q
What is the thickness of simple columnar epithelium and its purpose?
A
Simple columnar epithelium is comparatively thinner that stratified squamous epithelium and its purpose is absorption.
16
Q
What type of tissue is found in the mouth?
A
Stratified squamous epithelium
17
Q
What type of tissue is found in the intestines?
A
Simple columnar epithelium
18
Q
What type of tissue is the submucosal layer made of?
A
areolar connective tissue
19
Q
What is the muscularis layer made up of?
A
Higher up in the digestive system there is skeletal muscle, but mostly smooth muscle in the lower portions
20
Q
What is the muscularis layer responsible for?
A
Mixing and propulsion
21
Q
What is the serosa?
A
the visceral layer of the peritoneum
22
Q
The parietal layer of the peritoneum is located…
A
… on the abdominal wall
23
Q
How is the digestive system innervated?
A
via the enteric nervous system
24
Q
Is the enteric nervous system part of the autonomic nervous system?
A
Yes
25
The myenteric plexus is responsible for...
... mobility
26
Myo- means...
muscle
27
The submucosal plexus is responsible for...
stimulating the glands
28
The myenteric and submucosal plexus are connected by...
interneurons
29
The enteric nervous system is regulated by...
... the autonomic nervous system
30
Parasympathetic innervates or inhibits?
innervates
31
Sympathetic innervates or inhibits?
inhibits
32
What is the peritoneum?
It is the largest serous membrane that has five major folds and is parietal and visceral
33
Is the peritoneum all one structure?
yes
34
What are the five major folds of the peritoneum?
```
Greater omentum
Falciform ligament
Lesser omentum
Mesentery
Mesocolon
```
35
What is the purpose of the folds of the peritoneum?
the folds keep everything suspended in place rather than gravity causing everything to jumble up
36
What is the purpose of the greater omentum?
it's a big area for lymph nodes and collects adipose tissue
37
What is the purpose of the falciform ligament?
it attaches the liver to the diaphragm
38
What is the purpose of the lesser omentum?
To suspend the stomach and duodenum from the liver
39
What is the purpose of the mesentery?
to suspend the small intestine from the posterior wall
40
What major folds of the peritoneum has blood vessels and lymphatic organs/vessels running to and from it?
Mesentery and mesocolon
41
What is the purpose of the mesocolon?
It suspends the large intestine from the posterior wall; it is what the mesentery is to the small intestine
42
What are the 4 functions of the mouth?
Ingestion
Mastication
Beginning of chemical digestion
Movement of bolus to oropharynx
43
What is mastication?
Chewing
44
Where does starch begin to break down?
The mouth
45
Define bolus
a wad of food
46
What are the accessory organs of the mouth?
Salivary glands
Tongue
Teeth
47
What are the 3 salivary glands?
Parotid
Submandibular
Sublingual
48
What are the two major components of the tongue?
Papillae and lingual frenulum
49
What kind of muscle is the tongue made of?
Skeletal muscle
50
How many deciduous teeth are there?
20
51
How many permanent teeth are there?
32
52
What are the four types of teeth present on the upper and lower jaw?
Incisors
Canines
Bicuspid
Molars
53
How many incisors are there per jaw?
4
54
How many canines are there per jaw?
2
55
How many bicuspids are there per jaw?
4
56
How many molars are there per jaw?
4-6
57
Are mouth glands endocrine or exocrine glands?
Exocrine
58
What does exocrine mean as it relates to glands?
They are glands that have ducts which deliver fluid directly to the local area
59
Mechanical digestion is driven by...
... mastication
60
Mastication includes what structures/fluids?
Tongue
Teeth
Saliva
Creates a bolus
61
What are the enzymes released in the mouth?
Salivary amylase and Lingual lipase
62
What does salivary amylase do?
breaks down starches to disaccharides like maltose, alpha dextrins
63
Where is salivary amylase released and where is it active?
It is released in the mouth and active there as well
64
What does lingual lipase do?
It breaks down triglycerides to fatty acids and diglycerides; breaks down lipids
65
Where is lingual lipase released and where is it active?
Released in the mouth and activated in the stomach
66
What is gustation?
Taste
67
What are some other functions of saliva besides chemical digestion?
Destroy bacteria via Lysozyme, IgA
Lubricate food via mucus
Remove waste
Aid gustation (water)
68
The upper esophageal sphincter is made of what type of muscle?
Skeletal muscle
69
The lower esophageal sphincter is made of what type of muscle?
Smooth muscle
70
What structure does the bolus pass through via the diaphragm?
the esophageal hiatus
71
What is deglutition?
swallowing
72
What are the three stages of deglutition?
Voluntary stage
Pharyngeal stage
Esophageal stage
73
Define peristalsis
the symmetrical contraction and relaxation that propagates in a wave down a tube ie the esophagus
74
What kind of mechanical digestion occurs in the stomach?
Mixing waves that produce chyme and promote gastric emptying
75
What is chyme?
"paste-like" material
76
What is pepsin?
an enzyme activated by the acidic environment in the stomach that turns proteins into smaller peptides; pepsin is initially pepsinogen until activated by the HCl in the stomach
77
What is absorbed in the stomach?
Water
Ions
Fatty Acids
Some drugs and alcohol
78
What kind of glands are gastric glands?
exocrine glands
79
What do gastric glands do?
release gastric juice
80
What is gastric juice composed of?
HCl
Pepsin
Gastric lipase
Mucous
81
HCl in gastric juice serves what two purposes?
kills microbes
| converts pepsinogen to pepsin by providing an acidic environment
82
What does gastric lipase do?
breaks down triglycerides to fatty acids and monoglycerides
83
What does mucous in gastric juice do?
protects stomach lining from acids and digestive enzymes, etc
84
What type of gland is the pancreas?
Endocrine and exocrine, though only certain portions of the organ do one or the other
85
What two hormones do the pancreatic islets produce?
insulin and glucagon
86
What does insulin do?
lowers blood sugar
87
what does glucagon do?
increases blood sugar
88
What side of the pancreas produces insulin and glucagon
the endocrine side
89
what is the exocrine protion of the pancreas called?
acini
90
is the pancreas a critical organ?
yes
91
what is in pancreatic juice?
sodium bicarbonate and enzymes to digest all four macromolecule groups
92
is sodium bicarbonate acidic or basic?
very basic
93
What are the enzymes contained in pancreatic juice?
```
Pancreatic amylase
trypsin
chymotrypsin
carboxypeptidase
elastase
pancreatic lipase
ribonuclease
deoxyribonuclease
Other enzymes activated by trypsin formation from trypsinogen
```
94
what does amylase do?
breaks down starch
95
what do trypsin, chymotrypsin, carboxypeptidase, and elastase do?
all work on different aspects of protein breakdown
96
what does lipase do?
breaks down lipids
97
what does ribonuclease and deoxyribonuclease do?
breaks down RNA and DNA
98
What does tryspin do?
sets off a cascade reaction
99
what does bicarbonate do?
buffers gastric juice in chyme
100
Is the liver an essential organ?
yes
101
the lobes of the liver are divided into...
... hexagonal lobules
102
Hepatic refers to...
... the liver
103
Cells around the liver are referred to as...
... hepatocytes
104
what do the hepatocytes around the central vein do?
secrete bile and also metabolize a lot of different products such as alcohol, drugs, medicine, etc
105
what do the Kupffer cells do?
they clean; are essentially macrophages
106
What are sinusoids?
capillaries
107
what do sinusoids do?
sinusoids bring venous blood from the GI tract into the liver lobule
108
secretion of bile occurs in the ...
liver
109
bile is stored where?
the gallbladder
110
is storage of bile necessary?
no, which allows for the gallbladder to be removed
111
what is the liver used for?
excretion of bilirubin (remember hemoglobin)
emulsification of lipids by bile salts
easier absorption of lipids
excretion of drugs and hormones
glycogen storage and glucose release/production
lipid metabolism
protein metabolism
storage of vitamins and minerals
detoxification
phagocytosis of old blood cells and some bacteria
activation of vitamin D
112
is emulsification considered mechanical or chemical digestion?
mechanical
113
Where is bile produced?
the liver
114
What is the flow of bile from the bile canaliculi?
bile canaliculi > bile ductules > bile ducts > hepatic duct joins cystic duct and forms the common bile duct
115
What does glycogen do?
it allows for sugar to be stored; similar to a banking system or links to a chain
116
where is glycogen stored?
in the liver and muscles
117
What is the hepatic portal system?
System in which deoxygenated blood from the GI tract flows to the liver where hepatocytes absorb nutrients/toxins and secrete products that are then sent back into circulation from the central vein back to the hepatic vein
118
where does 90% of all absorption occur?
the small intestine
119
What is absorption aided by in regards to the small intestine?
Length (10 ft avg)
Villi (1mm)
Microvilli (1 um) - known as the "brush border")
120
What are villi and how do they help with absorption?
mucosa folds; they increase surface area into which things can be absorbed
121
What absorbs monomers in the small intestine?
capillaries or lacteals
122
What is the flow of the small intestine from the duodenum?
duodenum to jejunum to ileum
123
Finishing enzymes come from what glands?
intestinal glands
124
Do the duodenal glands secrete alkaline or acidic mucus and why
they secrete alkaline mucus which buffers stomach acid
125
What type of cell secretes mucus?
goblet cell
126
FYI
Pancreas (which releases digestive enzymes) ports into small intestine
127
FYI
Small intestine has circular folds that allow for better absorption
128
What three structures are the villi composed of?
Absorptive cells
capillaries/lacteals
microvilli
129
What are the two components of mechanical digestion in the small intestine?
Segmentations and peristalsis
130
Describe peristalsis in the small intestine
Occurs post segmentation and is a slow migration from stomach to ilium
131
Small intestine: Chem digestion: brush border enzymes: the -ase's : name and describe function
alpha dextrinase
maltase
sucrase
lactase
convert their input to monosaccharides (mostly glucose)
-Maltase works on maltose, sucrase on sucrose, etc
132
Small intestine: Chem digestion: brush border enzymes: the enzymes that work on peptides/proteins : name and describe function
aminopeptidase
dipeptidase
convert to amino acids; or catalyze the the cleavage of amino acids in petides/proteins
133
Purpose and location of nucleosides and phosphatases
take nucleotides and break them down into parts
located in small intestine
134
What are the three main components of chemical digestion in the small intestine?
Brush border enzymes
intestinal juices
pancreatic juice
135
FYI
Bile and intestinal juice work in combination with eachother
136
What are the three main components of mechanical digestion in the large intestine?
Haustral churning
Peristalsis
Mass peristalsis
137
What are Haustra and what is Haustral chruning?
Haustra are the pockets in the large intestine and Haustral churning is the contraction following distension
138
Describe chemical digestion in the large intestine
Bacteria is the large intestine consume the contents of the large intestine (not for our benefit), but their byproducsts are useful to us (and also create farts)
139
Where is the last stop for absorption of water, ions, and vitamins?
The large intestine
140
FYI
Diarrhea indicates that water is not being absorbed well in the large intestine
141
where are feces formed?
in the large intestine
142
What is feces composed of?
```
Water
inorganic salts
bacteria and their products
unabsorbed/indigestible material
epithelial cells
```
143
What are the five steps of the defecation reflex and are they voluntary or involuntary?
Rectum distends - involuntary
Stretch receptors are triggered from the spinal cord - involuntary
The parasympathetic nervous system causes contraction of colon and rectum - involuntary
Internal anal sphincter opens - involuntary
External anal sphincter is voluntarily relaxed - voluntary
144
What are the four macro molecules and subtypes, if any?
Carbohydrates - Mono- and polysaccharides
Proteins - Amino acids form polypeptides
Lipids - Simple, complex, steroids
Nucleic acids
145
What are the enzymes involved in the chemical digestion of carbs?
```
Salivary and pancreatic amylase
alpha dextrinase
sucrase
lactase
maltase
```
146
what do amylases do?
break down starch into maltose or alpha dextrins
147
what does alpha dextrinase do?
breaks down alpha dextrins to glucose or more accurately breaks down disaccharides into monosaccharides
148
Monosaccharides are absorbed where?
the small intestine
149
fructose travels via
facilitated diffusion
150
glucose and galactose travel via
secondary active transport
151
What are the enzymes involved in the chemical digestion of proteins?
```
pepsin
trypsin
chymotrypsin
elastase
carboxypeptidase
aminopeptidase
dipeptidase
```
152
what do pepsin, trypsin, chymotrypsin, and elastase do?
turn protein into peptides
153
what does carboxypeptidase do?
turns peptides into smaller peptides or amino acids
154
what do aminopeptidase and dipeptidase do?
turn peptides into amino acids
they are also known as the finishing enzymes
155
Where are amino acids, dipeptides, and tripeptides absorbed and via what transport method(s)
absorbed in the small intestine via active or secondary active transport
156
what are the enzymes involved in the chemical digestion of fats?
lingual lipase
gastric lipase
pancreatic lipase
bile salts
157
what is the purpose of the lipases?
they turn triglycerides into fatty acids or monoglycerides/diglycerides
158
what is the purpose of bile salts?
they ease the absorption of long-chain fatty acids and are used in emulsification
159
Through what transport method are lipids absorbed?
All lipids are absorbed by diffusion
160
Short chain fatty acids are carried via what type of vessel?
capillaries
161
long chain fatty acids are carried via what type of vessel?
lacteals
162
FYI
the longer the fatty acid, the more likely it is carried by the lacteals
163
What is beta oxidation as it applies to metabolism?
beta oxidation is when 2 carbons are removed from the fatty acid + CoA to create acetyl CoA which then leads in to the Krebs Cycle
164
Describe the 4 steps of deanimation as it applies to metabolism
The amino group is removed form the amino acid
NH3 is converted to urea by the liver which eventually becomes urine
The amino acid is converted to Krebs molecules and oxidized for ATP
Amino acid is is also converted to glucose and fatty acids
165
What are the enzymes involved in the chemical digestion of nucleic acids?
Ribonuclease
deoxyribonuclease
nucleosidases
phosphatases
166
what is the purpose of ribonuclease
breaks down RNA into nucleotides
167
what is the purpose of deoxyribonuclease
breaks down DNA to nucleotides
168
what is the purpose of nucleosidases and phosphatases
break down nucleotides into 3 parts
169
through what transport method are the parts of nucleic acid absorbed?
absorbed via active transport
170
what is the pH of saliva?
6.5 (acidic)
171
what is the pH of gastric juice?
2 (acidic)
172
what is the pH of pancreatic juice?
7.1 - 8.2
173
what is the pH of intestinal juice?
7.6
174
pH is adjusted by what type of feedback and what are some examples?
adjusted by negative feedback, examples include buffers and hormone release
175
what are the three hormones involved in digestion?
Gastrin
Cholecystokinen
Secretin
176
what is the purpose of gastrin?
triggers an increase in gastric juice which leads to the cascading effect of increased gastric emptying and sphinter control
177
what is the purpose of cholecystokinen?
triggers an increase in pacreatic juice which leads to the cascading effect of increased bile release leading to increased gastric emptying and satiation
178
what is the purpose of secretin?
triggers an increase in pancreatic juice which leads to a decrease in gastric juice
179
Where is it released? Where is it active? What is its job?
Salivary amylase
Release by salivary glands in mouth
active in the mouth
job is to break down starch to maltose and dextrins
180
Where is it released? Where is it active? What is its job?
Pancreatic amylase
released by pancreas
active in small intestine
job is to break down starch to maltose and and dextrins
181
Where is it released? Where is it active? What is its job?
Alpha dextrinase
released by brush border of small intestine
active in small intestine
job is to break down starch/glycogen to glucose
182
Where is it released? Where is it active? What is its job?
Sucrase
released by brush border of small intestine
active in small intestine
job is to convert sucrose to glucose
183
Where is it released? Where is it active? What is its job?
Lactase
released by brush border of small intestine
active in small intestine
job is to convert lactose into glucose
184
Where is it released? Where is it active? What is its job?
Maltase
released by brush border of small intestine
active in small intestine
job is to convert maltose into glucose
185
Where is it released? Where is it active? What is its job?
Lingual Lipase
released by salivary glands in mouth
active in small intestine
job is to break down triglycerides to fatty acids and diglycerides
186
Where is it released? Where is it active? What is its job?
Gastric Lipase
released in stomach
active in stomach and small intestine
job is to break down triglycerides to fatty acids and diglycerides
187
Where is it released? Where is it active? What is its job?
Pancreatic lipase
released in pancreas
active in small intestine
job is to break down triglycerides to fatty acids and diglycerides
188
Where is it released? Where is it active? What is its job?
Pepsin
released by chief cells in stomach
active in stomach
job is to break down proteins into polypeptides
189
Where is it released? Where is it active? What is its job?
Trypsin
released by pancreas
active in small intestine
job is to break down polypeptides into small peptides
190
Where is it released? Where is it active? What is its job?
Chymotrypsin
released by pancreas
active in small intestine
job is to break down proteins into polypeptides
191
Where is it released? Where is it active? What is its job?
Elastase
released by pancreas
active in small intestine (activated by trypsin)
job is to break down proteins into polypeptides
192
Where is it released? Where is it active? What is its job?
Carboxypeptidase
released by pancreas
active in small intestine
job is to break down proteins into polypeptides
193
Where is it released? Where is it active? What is its job?
Aminopeptidase
released by brush border of small intestine
active in small intestine
job is to break down protein, specifically removing the amino portion
194
Where is it released? Where is it active? What is its job?
Dipeptidase
released by brush border of small intestine
active in small intestine
job is to break down protein to convert to amino acids
195
Where is it released? Where is it active? What is its job?
ribonuclease
released by pancreas
active in small intestine
job is to break down RNA to nucleotides
196
Where is it released? Where is it active? What is its job?
deoxyribonuclease
released by pancreas
active in small intestine
job is to break down DNA to nucleotides
197
Where is it released? Where is it active? What is its job?
nucleosidases
released by brush border enzymes
active in small intestine
job is to break down nucleosides
198
Where is it released? Where is it active? What is its job?
phosphatases
released by liver
active in liver
job is to break down nucleotides into 3 parts
199
Gastrin: Where is it produced? Where is it active? What triggers it? What does it do?
produced in stomach by gastric glands
active in stomach
triggered by the smell or sight of food
causes gastric juice increase which leads to increase of gastric emptying
200
Cholecystokinen: Where is it released? What does it do?
Released in the small intestine
causes increase in pancreatic juice which leads to increase in bile release which leads to increased gastric emptying and satiation
201
Secretin: Where is it released? What does it do?
Released by the small intestine
| Causes increase in pancreatic juice which leads to decrease in gastric juice
