Digestive system Flashcards
1
Q
List the organs of the alimentary canal
A
Mouth Pharynx Esophagus Stomach Small intestine Large intestine
2
Q
List the accessory digestive organs
A
Teeth Tongue Gallbladder Salivary glands Liver Pancreas
3
Q
List the 6 essential digestive processes
A
Ingestion Propulsion Mechanical digestion Chemical digestion Absorption Defecation
4
Q
Describe peristalsis
A
Waves of contraction/ relaxation of muscles
5
Q
Describe segmentation
A
Local constrictions of the intestines
6
Q
Describe chemical digestion
A
Catabolic breakdown of food
7
Q
Describe absorption
A
Movement of nutrients from GI Tract to blood/ lymph
8
Q
Where does chemical digestion take place
A
Mouth
Stomach
Small intestine
9
Q
What are the circulation systems to the digestive organs
A
Splanchnic circulation
Hepatic portal circulation
10
Q
Describe Splanchnic circulation
A
Aorta Celiac trunk Hepatic Splenic Left gastric Inferior/ superior mesenteric
11
Q
What is the function of the hepatic portal circulation
A
Collect nutrient rich blood
Deliver it to the liver for processing/ storage
12
Q
Name the 4 tunics of the alimentary Tract
A
Mucosa
Submucosa
Muscularis externa
Serosa
13
Q
Functions of mucosa
A
Secrete mucus
Absorption
Protection
14
Q
What are the layers of mucosa
A
Epithelium- simple columnar
Lamina propria- areolar and reticular
Muscularis mucosae- smooth miscle
15
Q
What do the mucosa of stomach and small intestine contain
A
Enzyme secreting cells
Hormone secreting cells
16
Q
What is the function of the mucosa lamina propria
A
Nourish the epithelium
Absorption
Contain MALT
17
Q
Where does the serosa get replaced by adventitia
A
Esophagus
18
Q
What does the submucosa contain
A
Elastic fibers Blood Lymph vessels Lymph nodes Nerves
19
Q
What does the enteric nervous system consist of
A
2 intrinsic nerve plexuses
- submucosal
- myenteric
20
Q
What does submucosal nerve plexus regulate
A
Glands
Smooth muscle of mucosa
21
Q
What does myenteric nerve plexus regulate
A
Control of GI mobility
22
Q
Function of the intrinsic tongue muscles
A
Change the shape
23
Q
Function of the extrinsic tongue muscles
A
Alter position
24
Q
What are the 3 types of tongue papillae
A
Filiform
Fungi form
Circumvallete
25
What makes the tongue rough
Filiform papillae
26
Gives tongue reddish hue
Fungiform papillae
27
In the back of the tongue
| v shaped row
Circumvallete papillae
28
Function of saliva
```
Clean mouth
Moisten food
Dissolve food
Bolus formation
Breakdown starch- amylase
Contain mucin, lysozyme, Defensins,IgA
```
29
Name an intrinsic salivary gland
| Function
Buccal gland
| Keep mouth moist
30
Name some extrinsic salivary glands
| Function
Parotid
Submandibular
Sublingual
Secrete enzyme rich saliva
31
What do extrinsic salivary glands respond to
Ingested food stimulating chemoreceptors and pressoreceptors
Thought of food
32
What inhibits salivation
Sympathetic stimulation
33
What is enamel made of
Acellular material
Calcium salts
Hydroxyapatite crystals
34
What is cementum
Calcified connective tissue that covers tooth root
| Attaches to periodontal ligament
35
What is Dentin
Forms bulk of tooth
| Bonelike material
36
What is pulp
Connective tissue
Blood vessels
Nerves
Inside of tooth
37
What are dental caries
Demineralization of enamel and Dentin by bacteria
| Acid produced by bacteria dissolves calcium salts
38
What happens to organic matter without calcium salts
Proteolytic enzymes digest organic material
39
Why is calculus bad
Disrupts seal between teeth an gingivae
40
What is periodontitis
gum disease
| Inflammation response
41
What are the 2 skeletal muscle layers of the pharynx
Inner longitudinal
| Outer pharyngeal constrictors
42
Where does the esophagus extent from and go to
From laryngopharynx to cardiac orifice
| Through the mediastinum/ diaphragm
43
What happens to mucosa from esophagus to stomach
Stratified squamous to simple columnar
44
What type of chemical digestion takes place in the mouth
Salivary amylase breakdown starch
45
What are the 2 phases of deglutination
Buccal phase
| Pharyngeal esophageal phase
46
Describe buccal phase
Bolus is voluntarily forced into oropharynx
47
Describe pharyngeal esophageal phase
Controlled by medulla/ pons
Close airways
Open digestive ways
48
What lets food enter stomach
Gastroesophogeal cardiac sphincter opening
49
Where is food converted to chyme
Stomach
50
What makes up the pyloric region of the stomach
Antrum and canal
| Terminate at pyloris
51
Describe mesentaries
Double layer of peritoneum fused
52
Where is lesser omentum
From liver to lesser curvature
53
Where is greater omentum
Greater curvature to small intestine
54
What type of mucus is in stomach from goblet cells
Thick alkaline mucus
| Traps bicarbonate rich fluid beneath it
55
Where are gastric glands
In gastric pits
56
What do the gastric glands secrete
Mucus
Gastric juice
Gastrin hormone
57
List the 4 types of cells in the stomach glands
Mucous neck cells
Parietal
Chief
Enteroendocrine
58
Mucous neck cells secrete
Thin Acid mucus
59
Parietal cells secrete
HCL
| Intrinsic factor
60
Chief cells secrete
Pepsinogen
61
Enteroendocrine cells secrete
Gastrin into lamina propria ( not lumen)
62
How is Pepsinogen activated
By HCL and pepsin
63
What keeps stomach from digesting itself
Bicarbonate rich mucus layer
Epithelium with tight junctions
Damaged cells replaced quickly
64
Functions of the stomach
```
Store food
Degrade food
Deliver chyme to small intestine
Enzymatic ally digest protein with pepsin
Secrete intrinsic factor
```
65
What regulates gastric secretion
Neural and hormonal controls
66
What are the 3 phases of gastric secretion regulation
Cephalic
Gastric
Intestinal
67
Function of the Cephalic phase
Prepares stomach for food
68
What occurs during Cephalic phase
Parasympathetic- vagus
Stimulate submucosal enteric plexus
Activate mucus, parietal, chief, and G cells
69
Function of gastric phase
Enhance secretions
Homogenize and acidify chyme
Initiate protein digestion by pepsin
70
What is the neural response of the gastric phase
Stretch/ chemoreceptors stimulate submucosal plexus as myenteric plexus
71
What is the hormonal response of gastric phase
Presence of peptides or caffeine stimulate Gastrin
| Gastrin stimulates parietal/ chief cells
72
What stimulates HCl secretion
Ach- neural
| Gastrin- hormonal
73
When is HCL release low
If only one ligand binds to a parietal cell
74
When is HCL release higher
If both Ligands bind to parietal cells
| Hormonal/ neural stimulation
75
What happens to Cl during HCL secretion
Cl transported into stomach lumen
| Maintain electrical balance
76
What happens to bicarbonate during HCL secretion
Bicarbonate ejected into capillary blood
77
What is the alkaline tide
Blood leaving the stomach is more alkaline than blood entering it
78
When does the intestinal phase begin
When chyme enters the small intestine
79
Describe what stimulates intestinal phase
```
Enterogastric reflex
Distension of duodenum
Acid- low ph
Lipids
Partially digested proteins
```
80
What occurs when the intestinal neural response is stimulated
Gastric contractions are inhibited
| Pyloric sphincters close
81
What occurs during hormonal response of the intestinal phase
Release of enterogastrones
| Inhibit gastric secretion
82
What are the enterogastrones
Cholecystokinin
Secretin
Vasoactive intestinal peptide
83
What is the rate of gastric contractions of peristalsis
3 per min Basic Electrical Rhythm
| Toward pyloric valve
84
What increases stomach contractions
Distension of stomach wall
| Activated chemoreceptors
85
What inhibits Gastrin and pepsin as chyme enters duodenum
Neural enterogastric reflex
| Hormonal mechanisms- enterogastrones
86
Where do the bike duct and main pancreatic duct join duodenum
Hepatopancreatic ampulla
| Controlled by Oddi
87
What do the villi of small intestine contain
Capillary bed
| Lacteals- lymph
88
What makes up the brush border
Microvilli and enzymes
89
What is small intestine mucosa made of
Absorptive columnar cells
Goblet cells
Enteroendocrine cells
90
What is another name for intestinal crypts
Crypts of lieberkuhn
91
What do intestinal crypts secrete
Intestinal juice
Enzyme poor watery mucus
rapidly dividing stem cells
92
What do brunners glass secrete
| Where are they
Alkaline mucus
| Duodenum
93
List the lobes of the liver
Right
Left
Caudate
Quadrate
94
What does the Falciform ligament do
Separate right/ left lobes
| Suspend liver from the diaphragm
95
Function of ligamentum teres( round)
Remnant of umbilical vein
| Along edge of Falciform ligament
96
Where do hepatic artery/ vein enter liver
Porta hepatis
97
Where does arterial/ venous blood mix in liver
Sinusoids
98
What forms the central vein
Sinusoids converging
99
What are lobules made of
Hepatocytes
100
What is the triad made of
Bike duct
Hepatic artery
Hepatic portal vein
101
Describe sinusoids
Leaky capillaries between hepatic plates
| House kupffer cells
102
Function of hepatocytes
Bile production
Processing blood borne nutrients/ toxins
Storage of fat soluble vitamins
103
Describe bile
Alkaline solution with bile salts and pigments
104
What do bile salts derive from
Cholesterol
105
What is the function of bile salts
Emulsify fat
Facilitate fat and cholesterol absorption
Help solublize cholesterol
106
How is bile recycled
Enterohepatic circulation
Absorbed in blood in the ilium
Return to liver via hepatic portal blood
107
What is main pigment in bile
Bilirubin
108
What causes release of bile
Acidic fatty chyme in duodenum - CCK and secretin Into blood
Bile salts and secretin stimulate bile production
109
What does CCK. Cause
Contractions of gallbladder
| Hepatopancreatic sphincter to relax
110
What does pancreatic juice consist of
Enzymes
| bicarbonate ions
111
What makes pancreatic juice
Acinar cells
112
What form are pancreatic enzymes released in
Inactive
| Activated in duodenum
113
What is the function of pancreatic water solution and HCO3
Neutralize acidic chyme
| Optimal ph for enzymes
114
Examples of inactive forms of pancreatic enzymes
Trypsinogen- trypsin
| Procarboxypeptidase- carboxypetidase
115
What enzymes does the pancreas secrete in active form
Amylase
Proteases
Lipase
Nuclease
116
What are zymogens
Inactive enzymes
117
What activates trypsinogen
Enterokinase in duodenum
| Then trypsin activates other enzymes
118
Example of proteases
Procarboxypeptidase
| Chymotrypsinogen
119
What regulates pancreatic secretions
Parasympathetic nervous system
| Local hormones
120
How does secretin regulate pancreas
Released in response to acid
Stimulates release of bicarbonate
Inhibits Gastrin
121
How does CCK regulate pancreatic secretion
Released in response to proteins/ fat
| Stimulates release of digestive enzymes
122
What condition is chyme that enters the duodenum in
Hypertonic
Low ph
Carbs/ protein partially digested
No fat digested
123
What initiates segmentation in small intestine
Cajal pacemaker cells
| Faster at duodenum
124
What is the migrating motility complex
Each wave of peristalsis is distal to the previous
125
What is function of large intestine
Absorb remaining water
| Elimination
126
What are teniae coli
3 bands of longitudinal smooth muscle in Muscularis externa of lg intestine
127
What are epiploic appendages
Fat filled pouches of visceral peritoneum
128
What is the difference in internal/ external anal sphincters
Smooth vs skeletal muscle
| Involuntary vs voluntary
129
How many valves does the rectum have
| Function
3 valves
| Prevent feces from passing with gas
130
What is large intestine lacking
Circular folds
Villi
Microvilli
131
What does large intestine have more of
Mucosa thickness
Crypts
Goblet cells
132
Function of anal sinuses
Excuse mucus
| Compress feces
133
What is associated with the anal canal
Superficial venous plexuses
134
What happens when superficial venous plexuses are inflamed
Itching
| Varicosities- hemorrhoids
135
Where do Colon bacteria come from
Survive through small intestine
| Trough anus
136
Function of enteric bacteria
Ferment indigestible carbs
Release gas and acid
Synth B/ K vitamins
Compete with pathogens
137
What 2 types of movements occur in the large intestine
Haustral contractions
| Mass movements
138
What stimulates haustral contractions
Distension
139
What stimulates mass movements
Gastrin
Slow powerful contraction
Just after eating
140
Describe defecation
Stretching of rectum- defecation reflex
Sensory nerves to spinal cord
Parasympathetic fibers relax internal sphincter
Voluntary control of external
141
Function of mesentery
Vascular and nerve supply to viscera
Hold organs in place
Store fat
142
What is another name for peritoneal organs
Mesocolons
143
List intraperitoneal organs
Small intestine
Transverse
Sigmoid colon
144
Where Does protein digestion begin
The stomach
Acid denatures
Pepsin converts proteins to peptides
145
Describe protein digestion in small intestine
Trypsin/ chymotrypsin- peptide fragments
| Carboxypeptidase- remove single amino acids from carboxy terminus
146
Describe the brush border
Aminopeptidase
Carboxypetidase
Dipeptidase- cleaves last 2 aminos
147
How are proteins absorbed
Single aminos transported into epithelial cells
Aminos enter blood capillaries if villi
Transported to liver
148
Where is carbohydrate digestion started
Mouth
| Amylase
149
What does amylase do
Starch into maltose
150
Describe carb digestion
Amylase- mouth/ sm intestine
| Maltase, sucrase, lactase- sm intestine
151
Maltase
Breaks maltose into 2 glucose
152
Sucrase
Sucrose into glucose and fructose
153
Lactase
Lactose into glucose and galactose
154
Describe carbohydrate absorption
Monosaccharides into epithelium
By transporters
Into capillary blood of villi
To liver
155
Where does lipid digestion begin
Stomach
156
Describe lipid digestion
Stomach- mechanical
Small intestine- bile salts emulsify
Pancreas- lipase
157
What does lipase do
Digest triglycerides Into fatty acid and monoglycerides - micelles
158
Lipid absorption
```
Fatty acids/ monoglycerides leave micelles
Diffuse across epithelium
SER triglycerides are reformed
Associated with protein
Endocytosed
Taken into lacteals
```
159
What is a chylomicron
Triglyceride with protein
160
How are nucleic acids absorbed
Active transport via membrane carriers
Villi
Liver
161
Where is most water reabsorbed
Small intestine
| By osmosis
162
Metabolism
All chemical reactions necessary for life
163
Anabolic
Synth larger from smaller
164
Catabolic
Hydrolysis of structures to smaller ones
165
Cellular respiration
Catabolic
| Glucose broken down to capture energy- ATP
166
3 major stages of metabolism
Digestion
Anabolism and formation of catabolic intermediates
Oxidative breakdown
167
Examples of oxidation
Rusting of iron
Burning of hydrogen
Oxides form
168
Example of reduction
Remove oxygen from metal oxide ores
169
Oxidation
Lose electrons
170
Reduction
Gain electrons
171
Reducing agent
Electron donor
Oxidized
Loses electrons
172
Oxidizing agent
Electron acceptor
Reduced
Gains
173
What happens to glucose and oxygen
Glucose oxidized
| Oxygen reduced
174
2 important coenzymes
Flavin adenine dinucleotide FAD
| Nicotinamide adenine dinucleotide NAD
175
What are the 3 carb metabolism pathways
Glycolysis
Krebs
ETC
Oxidative phosphorylation
176
Main points of glycolysis
Glucose oxidized into pyruvic acid
NAD to NADH
2 ATP
177
Where does the Krebs cycle take place
Mitochondrial matrix
178
What Are products of Krebs cycle
Co2 released
NAD to NADH
FADH
ATP
179
How many steps does Krebs have
8 steps
180
What occurs during Krebs
Acetyl coA is rearranged- keto acids
Decarboxylated
And oxidized
181
Where Is the ETC
Inner Mitochondrial membrane
182
How does oxidative phosphorylation work
H pumped into inner membrane space
| Diffuses back via ATP synthase
183
What type of process is oxidative phosphorylation
Chemiosmotic process
| Movement of substances across membrane couples reactions
184
What is glycogenesis
Formation of glycogen
| Excess glucose
185
What promotes glycogenesis
Insulin
| Through phosphorylation of glucose
186
What areas are most active in glycogenesis
Liver
| Muscle
187
What is glycogenolysis
Breakdown of glycogen to replenish glucose levels
188
Glycogenolysis promoted by
GH
| Glucagon
189
Glycogenolysis inhibited by
Insulin
190
What does glycogenolysis produce in most cells
| In liver
Cells- glucose6 phosphate trapped in cells
| Liver- free glucose
191
What is gluconeogenesis
Formation of sugar from noncarb molecules
192
What inhibits gluconeogenesis
Insulin
193
Promotes gluconeogenesis
Glucagon
| Glucocorticoids- cortisol
194
Where does gluconeogenesis occur
| Why
Liver
Protect brain
Ensure there is ATP
195
What is lipolysis
Catabolism of fat by 2 pathways
196
What 2 lipolysis pathways ate there
Glycerol
| Fatty acid pathway
197
Describe glycerol lipolysis
Glycerol converted to glyceraldehyde phosphate
Then acetyl coA
Krebs
198
Describe fatty acid lipolysis
Fatty acids undergo beta oxidation
Then 2 carbon acetic acetyl coA
Krebs
199
What must be present for fatty acids to enter Krebs
Oxaloacetic acid
200
What happens when carbs are deficient
Oxaloatic acid converted to glucose
201
What happens without Oxaloacetic acid
Acetyl coA is converted into ketones in liver
202
What happens from ketone accumulation
Ketosis
Ketones in urine
Metabolic acidosis
Breathing increases to blow off carbonic acid
203
What causes carbohydrate deficiency
DM
Starvation
Dieting
204
Describe lipogenesis
Excess dietary glycerol and fatty acid form triglycerides
205
Why is glucose easily converted to fat
Acetyl coA is a glucose catabolism intermediate
| Acetyl coA is start for synth of fatty acids
206
What type of cells synthesize phospholipids
All cells
207
What type of lipids are synthesized in the liver
Cholesterol
Lipoproteins for transport
Cholesterol from acetyl coA
Help form bile salts
208
What does excess dietary protein result in
Amino acids oxidized
| Converted to fat
209
What must happen to amino acids prior to oxidation
Deaminatation
210
What are deaminated amino acids converted into
Pyruvic acid
| Keto acid intermediate of Krebs
211
What happens to amine group during protein metabolism
Released as ammonia
Combined with CO2 in liver
Excreted as urea
212
What is the nutrient pool
Body's total supply of nutrients
| Can be interconverted
213
What is the absorptive state
Time during/ right after nutrient intake
214
What is post absorptive state
When GI tract is empty
| Energy supplied by body reserves
215
What occurs during absorptive state
Anabolism
Energy storage
Glucose is major fuel
Excess aminos are deaminated and used/ stored
216
Absorptive in muscle
Amino acid- protein
| Glucose to glycogen
217
Absorptive in liver
Amino acid- protein/ keto acid
| Glucose- glycogen/ fat
218
Absorptive in adipose
Glucose/ fat converted and stored
219
What stimulates insulin release
```
Increased blood glucose
Elevate amino acid levels
Gastrin
CCK
Secretin
```
220
What does insulin enhance
Active transport of amino acids into cells
| Facilitated diffusion of glucose into tissue
221
What occurs during post absorptive state
Catabolism
Replace fuel into blood
Glucose from glycogenolysis/ gluconeogenesis
Fatty acid/ ketones are major fuel supply
Amino acids converted to glucose in liver
222
Post absorptive in muscle
Protein broken into aminos
| Glycogen converted to ATP/ pyruvic acid
223
Post absorptive in liver
Amino, pyruvate, glycogen. Converted to glucose
| Fat into keto acids for ATP
224
Where can you get glucose from directly
Liver
| Not muscle
225
Why don't low carb meals cause hypoglycemia
Glucagon and insulin secreted together
226
What stimulates glucagon secretion
Decrease blood glucose
| Elevated aminos acid levels
227
Glucagon stimulates
Glycogenolysis
Gluconeogenesis
Fat breakdown from adipose
Glucose sparing
228
What does low plasma glucose stimulate
Epinephrine release
| Act on liver, muscle, adipose to promote glycogenolysis
