The Digestive System Part 1 Flashcards
1
Q
What is the overall function of the digestive system?
A
To break down food into small molecules that can be absorbed and used by the body.
2
Q
What is the GI tract also called?
A
The alimentary canal.
3
Q
Where does the GI tract start and end?
A
It starts at the mouth and ends at the anus.
4
Q
What is the role of the GI tract?
A
To transport and process food during digestion.
5
Q
What are the named portions of the GI tract?
A
Esophagus, stomach, small intestine, large intestine, and rectum.
6
Q
How long is the GI tract?
A
Approximately 5-7 meters.
7
Q
What state are the muscles along the GI tract typically in?
A
A state of tonus (constant slight contraction).
8
Q
What is the role of GI tract muscles?
A
To help with the movement and breakdown of food.
9
Q
Are accessory organs part of the GI tract?
A
No, they are not part of the GI tract.
10
Q
What do accessory organs do?
A
Produce or store secretions that flow into the GI tract and aid in the chemical breakdown of food.
11
Q
What are examples of accessory organs?
A
Teeth, tongue, salivary glands, liver, gall bladder, and pancreas.
12
Q
Do accessory organs come into direct contact with food?
A
No, they never come into direct contact with food.
13
Q
What are the 6 basic processes involved in digestion (in order)?
A
Ingestion, secretion, motility, digestion, absorption, defecation.
“I Saw My Dog Always Dancing.”
14
Q
What happens during ingestion?
A
Foods and liquids are taken into the body.
15
Q
What is secretion in digestion?
A
The release of water, acid, buffers, and enzymes into the lumen of the GI tract.
16
Q
What is motility in digestion?
A
The mixing and propulsion of food and secretions through alternating muscle contractions and relaxation.
17
Q
What happens during digestion?
A
Ingested food is broken down into small molecules that the body can use.
18
Q
What is absorption in digestion?
A
Molecules move from the GI tract into blood or lymph vessels to be circulated through the body.
19
Q
What is defecation?
A
The removal of wastes, indigestible substances, bacteria, and unabsorbed materials.
20
Q
What are the four layers of the digestive canal (from deep to superficial)?
A
Mucosa, submucosa, muscular layer, and serosa/adventitia.
21
Q
Where in the digestive system do the four tissue layers exist?
A
From the lower esophagus to the anal canal.
22
Q
What are the three components of the mucosa layer?
A
Epithelium, lamina propria, and muscularis mucosae.
23
Q
What is the role of the epithelium in the mucosa?
A
It provides protection or supports secretion and absorption.
24
Q
What type of epithelium is found in the mouth, esophagus, and anal canal, and why?
A
Stratified squamous epithelium for protection.
25
Which type of epithelium is seen in the stomach and intestines, and what is its function?
Simple columnar epithelium for secretion and absorption.
26
What does the lamina propria in the mucosa contain?
Connective tissue with blood and lymph vessels, and MALT for immune protection.
27
What is the function of the muscularis mucosae in the mucosa?
It creates folds to increase surface area for digestion and absorption.
28
What does the submucosa connect, and what does it contain?
It connects the mucosa to the muscularis and contains blood vessels, lymphatics, glands, and the submucosal plexus.
29
What are the two types of muscles found in the muscularis layer, and where are they located?
Skeletal muscle is in the mouth, pharynx, esophagus, and anal canal for voluntary control. Smooth muscle is in most of the digestive canal for involuntary movement.
30
What is the purpose of the myenteric plexus in the muscularis layer?
It controls the muscle movements involved in digestion.
31
What is the serosa layer, and where is it found?
It is a serous membrane made of connective tissue and simple squamous epithelium, found in abdominal regions of the GI tract.
32
What is the esophagus's outermost layer called, and how does it differ from serosa?
The adventitia, which is a connective tissue layer providing structural support.
33
What is the Enteric Nervous System (ENS) often called?
The 'brain of the gut,' with about 100 million neurons.
34
Where does the ENS run?
From the esophagus to the anus.
35
What are the two main plexuses of the ENS?
The myenteric (Auerbach) plexus and the submucosal (Meissner) plexus.
36
Where is the myenteric plexus located, and what is its function?
Between the longitudinal and circular muscle layers of the muscularis, it controls motility, including the strength and frequency of muscle contractions.
37
Where is the submucosal plexus found, and what does it regulate?
Within the submucosa, it regulates secretions from digestive organs by controlling mucosal cells.
38
What types of neurons are included in the ENS?
Motor neurons (control muscles and secretions), interneurons (connect the plexuses), and sensory neurons (detect stimuli).
39
What do chemoreceptors in the ENS do?
Detect chemicals in food.
40
What do mechanoreceptors in the ENS detect?
The stretching of digestive canal walls as food moves through.
41
How does the parasympathetic system regulate digestion?
It increases digestion by enhancing secretion and motility using the vagus nerve and sacral spinal cord, which connect with the myenteric and submucosal plexuses.
42
What effect does the sympathetic system have on digestion?
It decreases digestion by reducing secretion and motility, often activated by stress, anger, or fear.
43
Where do sympathetic nerves regulating digestion originate from?
The thoracic and lumbar spinal cord.
44
How do interneurons in the ENS function?
They interconnect neurons of the myenteric and submucosal plexuses.
45
What does the myenteric plexus primarily control?
GI tract motility.
46
Where is the myenteric plexus located?
Between the longitudinal and circular layers of smooth muscle in the muscularis.
47
What do the motor neurons in the myenteric plexus regulate?
The strength and frequency of smooth muscle contractions for proper food mixing and movement.
48
What does the submucosal plexus primarily regulate?
The secretion of GI tract organs.
49
Where is the submucosal plexus found?
Within the submucosa.
50
What do the motor neurons of the submucosal plexus target?
Secretory cells of the mucosal epithelium, controlling enzyme, mucus, and secretion release.
51
How do the myenteric and submucosal plexuses coordinate their functions?
Through interneurons that connect and synchronize motility and secretion.
52
What types of sensory neurons are found in the ENS, and what do they detect?
Chemoreceptors: Monitor the chemical composition of food (e.g., acidity, nutrients). Mechanoreceptors: Detect stretching of the digestive canal walls.
53
What is the relationship between the ENS and the CNS?
The ENS operates independently but communicates with the autonomic nervous system (ANS) for regulation.
54
What effect does parasympathetic regulation have on digestion?
It enhances motility and secretion.
55
How does sympathetic regulation influence digestion?
It inhibits digestive activities.
56
What do GI reflex pathways regulate?
GI secretion and motility in response to stimuli within the GI tract.
57
What are the two types of sensory receptors involved in GI reflex pathways?
Chemoreceptors and stretch receptors.
58
What do chemoreceptors detect in the GI tract?
The chemical composition of contents, such as nutrients or acidity.
59
What do stretch receptors monitor?
The stretching of canal walls due to food.
60
Where do sensory neurons from the GI tract send signals?
To neurons in the Enteric Nervous System (ENS), Central Nervous System (CNS), or Autonomic Nervous System (ANS).
61
What information do sensory receptors relay to the nervous systems?
The nature of the contents and the degree of stretching in the GI tract.
62
How do the ENS, CNS, or ANS respond to sensory signals?
By activating or inhibiting digestive glands or smooth muscle.
63
What do digestive glands adjust in response to reflex pathways?
The secretion of enzymes, mucus, and other substances.
64
How do smooth muscles respond to GI reflex pathways?
They regulate motility to mix, move, or retain food contents as needed.
65
What is the peritoneum?
The body’s largest serous membrane.
66
What two tissues compose the peritoneum?
Simple squamous epithelium (mesothelium) and areolar connective tissue.
67
What are the two main layers of the peritoneum?
Parietal peritoneum and visceral peritoneum.
68
What does the parietal peritoneum line?
The walls of the abdominal cavity.
69
What does the visceral peritoneum cover?
The organs in the abdominal cavity; also called the organ's serosa.
70
What is the peritoneal cavity?
The slim space between the parietal and visceral layers.
71
What is the function of the serous fluid in the peritoneal cavity?
To reduce friction during organ movement.
72
What condition involves the accumulation of excess fluid in the peritoneal cavity?
Ascites, which can cause distension.
73
What are the primary roles of the peritoneum?
Protection, support, insulation, movement facilitation, and sensory regulation of abdominal organs.
74
How does the peritoneum support abdominal organs?
Its folds weave among the organs, coordinating their positions and keeping them in place.
75
What does the peritoneum bind together?
It binds organs to one another and to the abdominal cavity walls for stability.
76
What role does the peritoneal cavity play in movement?
It allows for organ movement during digestion or breathing.
77
What substance in the peritoneal folds helps insulate and protect abdominal organs?
Adipose tissue (fat).
78
What vessels and systems pass through the peritoneum?
Blood vessels, lymphatic vessels, and nerves.
79
What does the peritoneum supply to abdominal organs?
Nutrients, oxygen, immune defense, and neural regulation.
80
How does the peritoneum act as a barrier?
It provides protection from injury and prevents the spread of infection.
81
What sensory functions does the peritoneum provide?
It detects visceral pain, distension, pressure, and temperature.
82
Why is the peritoneum important for organ functionality?
It maintains the abdominal organs' position, allows movement, protects them, and regulates their environment.
83
What are the five major peritoneal folds?
Greater omentum, falciform ligament, lesser omentum, mesentery, and mesocolon.
84
Which is the largest peritoneal fold, and where is it located?
The greater omentum; it hangs in the anterior abdomen (double layer).
85
What type of tissue does the greater omentum contain in significant amounts?
Adipose tissue.
86
What does the falciform ligament attach?
The liver to the anterior abdominal wall and diaphragm.
87
What does the lesser omentum connect?
The stomach and duodenum to the liver.
88
What does the mesentery bind, and where does it attach?
The jejunum and ileum to the posterior abdominal wall (double layer).
89
What type of tissue is often present in the mesentery?
Adipose tissue.
90
What does the mesocolon bind, and where does it attach?
The transverse colon and sigmoid colon to the posterior abdominal wall.
91
What structures form the mouth?
The cheeks, hard and soft palates, and tongue.
92
Where are salivary glands located?
Outside the mouth, with ducts delivering saliva into the oral cavity.
93
What is the function of saliva?
It lubricates and starts chemical digestion.
94
How does the amount of saliva produced vary?
It increases when food is present to aid digestion.
95
How many pairs of salivary glands are there?
Three pairs.
96
Where are the parotid glands located?
Inferior and anterior to the ears, between the skin and the masseter muscle.
97
Where are the submandibular glands located?
On the floor of the mouth.
98
What are the three major salivary glands?
Parotid, submandibular, and sublingual glands.
99
Where are the parotid glands located, and what do they secrete?
In front of and below the ears; they produce watery saliva rich in salivary amylase.
100
What is the primary function of the parotid glands?
Enzyme production for early carbohydrate digestion.
101
Where are the submandibular glands located, and what do they secrete?
Beneath the jaw, in the floor of the mouth; they produce a thicker, mucus-like saliva with salivary amylase.
102
What is the primary function of the submandibular glands?
To balance lubrication for swallowing with enzyme activity for digestion.
103
Where are the sublingual glands located, and what do they secrete?
Beneath the tongue; they secrete a thicker, mucus-like saliva with very little amylase.
104
What is the primary function of the sublingual glands?
To provide lubrication and protection, especially for speech and swallowing.
105
What role does water in saliva play?
It keeps the mouth moist, aids in swallowing, and dissolves food molecules for taste.
106
What activates salivary amylase in saliva?
Chloride ions.
107
How do buffers in saliva protect the mouth?
They maintain a stable pH to protect tooth enamel and inhibit bacterial growth.
108
Which nervous system regulates saliva production dominantly?
The parasympathetic nervous system.
109
How does the parasympathetic system affect saliva production?
It increases saliva secretion, especially when eating, smelling, or thinking about food.
110
How does the sympathetic system affect saliva production?
It may reduce saliva secretion during stress, causing a 'dry mouth' sensation.
111
What does the tongue, along with its associated muscles, form?
The floor of the oral cavity.
112
How is the tongue divided?
Into two mirrored, separate compartments.
113
What type of muscle composes the tongue, and what covers it?
Skeletal muscle covered with a mucous membrane.
114
What actions do the extrinsic and intrinsic muscles of the tongue assist with?
Chewing, swallowing, and speech.
115
What covers the upper and lateral surfaces of the tongue?
Papillae, some of which contain taste buds.
116
What is the role of teeth in digestion?
They assist with mechanical digestion by breaking down food into smaller pieces.
117
What is mechanical digestion in the mouth?
The process of chewing (mastication), where food is manipulated by the tongue, ground by teeth, and mixed with saliva to form a soft bolus.
118
What role does saliva play in mechanical digestion?
It contains water that dissolves food molecules, enabling enzymes to act.
119
What is chemical digestion in the mouth?
The breakdown of food molecules by enzymes, salivary amylase, and lingual lipase.
120
What is the source of salivary amylase, and what does it digest?
Salivary glands secrete it to begin breaking down dietary starch (polysaccharides) into smaller sugars like maltose, maltotriose, and α-dextrins.
121
How long does salivary amylase act after swallowing?
About 1 hour, until stomach acid inactivates it.
122
What is the source of lingual lipase, and when is it activated?
Secreted by lingual glands in the tongue, it is activated in the acidic environment of the stomach.
123
What does lingual lipase break down?
It breaks down triglycerides (fats and oils) into fatty acids and diglycerides.
124
Why is mechanical digestion important for chemical digestion?
It prepares food by increasing surface area, making it easier for enzymes to act on the food.
125
What must polysaccharides be broken down into for absorption?
Monosaccharides (simple sugars).
126
Do some enzymes begin functioning only in the stomach?
Yes, lingual lipase starts working in the acidic environment of the stomach.
127
What is the pharynx, and where does it extend?
A funnel-shaped tube that extends from the internal nares to the esophagus posteriorly and the larynx anteriorly.
128
What is the pharynx composed of?
Skeletal muscle lined with a mucous membrane.
129
Where does swallowed food pass within the pharynx?
It moves into the oropharynx and then the laryngopharynx.
130
How is food moved through the pharynx?
By muscle contractions pushing food towards the esophagus.
131
What is the esophagus, and where is it located?
A collapsible, muscular tube lying posterior to the trachea, connecting the pharynx to the stomach.
132
How long is the esophagus?
Approximately 25 cm.
133
What regulates movement in and out of the esophagus?
Two sphincters.
134
What is swallowing (deglutition)?
The process of moving food from the mouth to the stomach, involving saliva, mucus, the mouth, pharynx, and esophagus.
135
What are the three stages of swallowing?
Voluntary stage, pharyngeal stage, and esophageal stage.
136
What happens in the voluntary stage of swallowing?
The bolus is pushed into the oropharynx.
137
What happens in the pharyngeal stage of swallowing?
The bolus moves involuntarily through the pharynx to the esophagus.
138
What happens in the esophageal stage of swallowing?
The bolus moves involuntarily through the esophagus into the stomach.
139
What shape is the stomach, and where is it located?
J-shaped, located below the diaphragm.
140
What does the stomach connect to?
The esophagus and the small intestine (duodenum).
141
Why is the stomach considered stretchy?
It can be small when empty but expand significantly when full.
142
What are the main functions of the stomach?
Acts as a holding tank for food.
Mixes food and releases it slowly into the small intestine.
Digests starches, fats (triglycerides), and begins protein digestion.
Converts solid food into chyme.
143
What is chyme?
A liquid form of partially digested food created in the stomach.
144
What changes about the stomach during breathing?
Its position moves slightly with breathing.
145
Why is the stomach special in terms of size?
It is the most expandable part of the digestive system.
146
What happens during the mechanical and chemical mixing in the stomach?
The stomach churns food together with saliva and gastric juice to form chyme—a thick liquid that is easier for the intestines to process.
147
Why is mixing food into chyme important?
It ensures that food is broken down mechanically and chemically, preparing it for efficient absorption in the intestines.
148
How does the stomach function as a reservoir for food?
It temporarily stores food, allowing for a steady and controlled release into the small intestine. The rate of release depends on the food’s composition—carbohydrates pass quickly while fats take longer.
149
What are the major components of gastric juice and their functions?
Hydrochloric Acid (HCl): Creates an acidic environment to aid digestion and kill bacteria.
Pepsin: Breaks down proteins into smaller peptides.
Intrinsic Factor: Essential for vitamin B12 absorption in the small intestine.
Gastric Lipase: Breaks down triglycerides into fatty acids and monoglycerides.
150
What role does the hormone gastrin play in stomach function?
Gastrin stimulates the secretion of more gastric juice and enhances stomach motility, helping to mix and churn the food. It also helps regulate the overall digestive process.
151
How is the anatomy of the stomach adapted for its digestive functions?
The stomach features four basic layers (mucosa, submucosa, muscularis, serosa) like the rest of the GI tract. Notably, its muscularis layer includes an extra oblique muscle layer for vigorous churning, and its mucosa contains specialized cells for secreting gastric juice and protecting the stomach lining from its own acid.
152
What are the four basic layers of the stomach wall?
Mucosa, submucosa, muscularis, and serosa.
153
What type of epithelial cells line the mucosa?
Simple columnar epithelial cells called surface mucous cells.
154
What is the function of surface mucous cells?
They secrete mucus to protect the stomach lining from acid.
155
What is the lamina propria, and what is its function?
It is areolar connective tissue in the mucosa that supports cells and facilitates blood and lymphatic flow.
156
What are gastric glands, and where are they located?
Secretory cells located at the base of gastric pits in the mucosa.
157
What flows through gastric pits into the stomach's lumen?
Secretions from gastric glands, such as enzymes and acid.
158
What is the submucosa composed of?
Connective tissue that provides support and supplies blood to the stomach wall.
159
How is the muscularis layer of the stomach unique?
It has three layers of smooth muscle (outer longitudinal, middle circular, and inner oblique), unlike the two layers found in most of the digestive tract.
160
What is the function of the muscularis layer?
To churn and mix food effectively.
161
What is the serosa, and what is its function?
The outermost layer made of connective tissue; it is part of the visceral peritoneum, which surrounds and protects the stomach.
162
What overall abilities do these structural features give the stomach?
Produce digestive juices for chemical digestion.
Mechanically mix food into chyme.
Protect itself from its acidic environment.
163
What are the two main groups of cells in the gastric glands?
Exocrine cells (which secrete directly into the stomach lumen) and enteroendocrine cells.
164
Which cells produce mucus to protect the stomach lining?
Surface mucous cells and mucous neck cells secrete mucus to protect the stomach lining from the acidic environment.
165
What are the secretions and functions of parietal cells?
Parietal cells secrete hydrochloric acid (HCl), which creates an acidic pH to activate digestive enzymes, and intrinsic factor, which is necessary for vitamin B12 absorption in the small intestine.
166
What are the main secretions produced by chief (zymogenic) cells and their roles?
Chief cells secrete pepsinogen, which is activated by HCl to form pepsin for breaking down proteins, and gastric lipase, which breaks down triglycerides into fatty acids and monoglycerides.
167
What is the combined secretion from exocrine cells known as and how much is produced daily?
Combined, these secretions form gastric juice, with approximately 2–3 liters produced per day.
168
What is the location and function of enteroendocrine (G) cells in the stomach?
G cells are primarily located in the pyloric antrum and release gastrin into the bloodstream, which stimulates HCl production by parietal cells and enhances stomach motility.
169
What are the four basic layers of the stomach wall?
The layers are the mucosa, submucosa, muscularis, and serosa.
170
How is the muscularis layer of the stomach specialized compared to other GI segments?
The stomach’s muscularis has three layers of smooth muscle—outer longitudinal, middle circular, and an additional inner oblique layer—which enhances its churning and mixing capabilities.
171
What does the submucosa provide in the stomach wall?
The submucosa is composed of areolar connective tissue that supports the mucosa and contains blood vessels.
172
How does the serosa contribute to the stomach’s anatomical structure?
The serosa, the outermost layer and part of the visceral peritoneum, extends along the lesser curvature as the lesser omentum to the liver, and along the greater curvature as the greater omentum that covers the intestines.
173
What are peristaltic waves in the stomach and how often do they occur?
Peristaltic waves are rhythmic muscular contractions that occur every 15–25 seconds, propelling stomach contents from the body of the stomach to the antrum.
174
What role does the pyloric sphincter play in the digestive process?
The pyloric sphincter is almost closed, permitting only small food particles to pass into the small intestine while larger particles are pushed back into the stomach for further mixing.
175
What is retropulsion in the stomach, and why is it important?
Retropulsion is the process by which large particles are pushed back into the body of the stomach for additional mixing, ensuring that only adequately broken-down food is forwarded for further digestion.
176
How does the cycle of propulsion and retropulsion contribute to digestion?
The alternating phases of propulsion and retropulsion mix the stomach’s contents with gastric juice effectively, forming a smooth, liquid mixture called chyme.
177
What is chyme and how is it formed in the stomach?
Chyme is a smooth, liquid mixture of well-mixed food and gastric juice that results from the mechanical churning and chemical digestion occurring in the stomach.
178
How does gastric emptying occur in terms of chyme particle size and volume?
Gastric emptying occurs when the food in the chyme is broken down into sufficiently small particles, with approximately 3 mL of chyme passing through the pyloric sphincter at a time into the small intestine.
179
Why is controlled emptying of chyme into the small intestine important for digestion?
Gradual, controlled emptying ensures that the small intestine receives chyme at a rate that optimizes further digestion and nutrient absorption.
180
How do mechanical and chemical digestion integrate in the stomach?
Mechanical digestion (via peristalsis, propulsion, and retropulsion) mixes food with gastric juice, while chemical digestion involves the action of enzymes – together they transform food into chyme ready for further processing in the small intestine.
181
Which specialized cells in the stomach secrete hydrochloric acid (HCl)?
Parietal cells secrete HCl into the stomach lumen.
182
What are the three main stimulators of HCl secretion and through which receptors do they act?
Acetylcholine (ACh) binds to cholinergic receptors, gastrin binds to gastrin receptors, and histamine binds to H2 receptors on parietal cells.
183
What is the role of histamine in regulating HCl secretion?
Histamine enhances the effects of ACh and gastrin, resulting in a synergistic increase in HCl secretion.
184
How does HCl contribute to protein digestion in the stomach?
HCl lowers the pH (to approximately 1–2), activating pepsinogen into pepsin, the enzyme that breaks down proteins into smaller peptides, while also denaturing proteins and killing bacteria.
185
What role do H2 receptors play in therapeutic interventions for acid-related conditions?
H2 receptors mediate the stimulatory effect of histamine on HCl secretion and are targeted by H2 blockers, such as ranitidine or famotidine, to reduce stomach acidity and treat conditions like acid reflux and ulcers.
186
What is the primary role of the stomach in digestion?
The stomach primarily digests food mechanically and chemically but absorbs only small amounts of water, ions, short-chain fatty acids, alcohol, and aspirin.
187
What do surface mucous and mucous neck cells secrete, and why?
They secrete mucus, which protects the stomach lining from being digested by its acid and enzymes.
188
What do parietal cells secrete, and what are their functions?
Intrinsic Factor: Required for vitamin B12 absorption in the small intestine (critical for red blood cell production).
HCl: Kills bacteria, activates pepsinogen into pepsin, and chemically breaks down food.
189
What do chief cells secrete, and what are their roles in digestion?
Pepsinogen: Converts into pepsin (with HCl), which digests proteins into smaller peptides.
Gastric Lipase: Breaks triglycerides (fats) into fatty acids and monoglycerides.
190
What hormone do G cells secrete, and what is its function?
G cells secrete gastrin, which stimulates parietal cells (for HCl), chief cells (for pepsinogen), enhances stomach motility, and helps regulate food movement out of the stomach.
191
What is the function of the muscularis layer in the stomach?
It mixes and churns food through peristaltic contractions, breaking food down mechanically and mixing it with gastric juice to form chyme.
192
What does the pyloric sphincter do?
It gradually releases chyme into the small intestine and prevents backflow of chyme into the stomach.
193
What is chyme, and how is it produced?
Chyme is a soupy liquid produced by mixing and churning food with gastric juice in the stomach.
194
Where does most nutrient absorption occur?
In the small intestine; the stomach absorbs only small amounts of water, alcohol, aspirin, and short-chain fatty acids.
195
What is the anatomical location of the pancreas?
It lies posterior to the stomach and is retroperitoneal.
196
What are the two main duct systems of the pancreas?
The pancreatic duct and the accessory duct, which join to form larger ducts that deliver pancreatic juice into the duodenum.
197
How are the digestive enzymes produced by the pancreas activated?
They are produced in an inactive form and are activated once they reach the small intestine.
198
What enzymes does the pancreas produce for carbohydrate digestion?
Pancreatic amylase.
199
Which pancreatic enzymes are involved in protein digestion?
Trypsin, chymotrypsin, carboxypeptidases, and elastase.
200
What enzyme is responsible for fat digestion in the pancreas?
Pancreatic lipase.
201
Which enzymes are secreted by the pancreas to digest nucleic acids?
Ribonuclease and deoxyribonuclease.
202
Apart from digestive enzymes, what substance does the pancreas secrete and what is its role?
Sodium bicarbonate, which buffers stomach acid in the duodenum.
203
What are the two functional portions of the pancreas?
The exocrine portion (acini that produce pancreatic juice) and the endocrine portion (pancreatic islets that produce hormones like glucagon, insulin, somatostatin, and pancreatic polypeptide).
204
How is pancreatic juice delivered to the duodenum?
It empties into the duodenum via the hepatopancreatic ampulla and the accessory duct.
