Digestive System Flashcards
(115 cards)
1
Q
Swallowing
A
Begins with voluntary muscle action but finishes with involuntary peristalsis.
Upper one-third of the esophagus, the muscularis is exclusively skeletal muscle
The middle portion of the esophagus has a combination of skeletal and smooth muscle fibers
The lower third the muscularis is exclusively smooth muscle
2
Q
Esophagus layers
A
The four layers of the GI tract are present. The esophageal mucosa has nonkeratinized stratified squamous epithelium.
Innermost: Mucosa
Submucosa
Muscularis
Outermost: Serosa
3
Q
Esophageal glands
A
Small mucus-secreting glands in the submucosa which lubricate and protect the mucosa.
4
Q
Stomach functions
A
Functions:
To continue the digestion of carbohydrates initiated by the amylase of
saliva,
To add an acidic fluid to the ingested food and mixing its contents into a viscous mass called chyme by the churning activity of the muscularis
To begin digestion of triglycerides by a secreted lipase
To promote the initial digestion of proteins with the enzyme pepsin.
5
Q
Stomach regions
A
The wall in all regions of the stomach is made up of all four major layers of the GI tract.
Cardia, pylorus, fundus, and body
6
Q
Cardia
A
A narrow transitional zone, 1.5-3 cm wide, between the
esophagus and the stomach
7
Q
Pylorus
A
The funnel-shaped region that opens into the small intestine. Both regions produce mucus and are similar histologically.
8
Q
Fundus and body
A
The much larger fundus and body regions are identical in structure and are the sites of gastric glands releasing acidic gastric juice.
9
Q
Rugae
A
The mucosa and submucosa of the stomach have large, longitudinally
directed folds called rugae, which flatten when the stomach fills with food.
10
Q
Mucosal surface
A
A simple columnar
epithelium that invaginates deeply into the lamina propria. The invaginations form millions of gastric pits.
11
Q
Gastric glands
A
The gastric pits of the mucosal surface lead to long, branched, tubular gastric glands. In
the fundus and body the gastric glands themselves fill most of the mucosa.
12
Q
Secretory cells of the gastric glands
A
Mucous neck cells
Parietal (oxyntic) cells
Chief (zymogenic) cells
Enteroendocrine cells
13
Q
Mucous neck cells
A
Secretes acidic fluid containing mucin
14
Q
Parietal (oxyntic) cells
A
Produces hydrochloric acid (HCl).
15
Q
Chief (zymogenic) cells
A
Has all the characteristics of active protein-secreting cells. They produce pepsins, which starts the breakdown of protein, and gastric lipase, which starts the breakdown of lipids.
16
Q
Enteroendocrine cells
A
Scattered epithelial cells with endocrine or
paracrine functions. Some secrete serotonin and others produce the peptide gastrin.
17
Q
Gastric and duodenal ulcers
A
Painful erosive lesions of the mucosa that may extend to deeper layers.
Can occur anywhere between the lower
esophagus and the jejunum.
Causes:
Bacterial infections with Helicobacter pylori.
Effects of nonsteroidal anti-inflammatory drugs
Overproduction of HCl or pepsin.
Lowered production or secretion of mucus or
bicarbonate.
18
Q
Small Intestine
A
The site where the digestive processes are completed and where the nutrients are absorbed.
Same four layers as other parts of the GI tract
Mucosa (inner), submucosa, muscularis, serosa, outer mesentery
19
Q
Small Intestine segments
A
Duodenum (first), jejunum, and ileum
20
Q
Mucosa of small intestine
A
Densely covering the entire mucosa of the small intestine are short mucosal outgrowths called villi that project into the lumen.
21
Q
Villi of small intestine
A
finger- or leaflike mucosal projections covered by a
simple columnar epithelium of absorptive cells called
enterocytes, with many interspersed goblet cells that produce mucus.
22
Q
plicae circulares
A
The mucosa and
submucosa form circular
folds or plicae circulares,
which increase the
absorptive area.
23
Q
Small Intestine Cell Types in Mucosa
A
Enterocytes
Goblet cells
Paneth cells
Enteroendocrine cells
24
Q
Enterocytes
A
The absorptive cells, are tall columnar cells. The
apical end of each enterocyte displays a striated (or brush) border, which is a layer of densely packed microvilli through
which nutrients are taken into the cells.
25
Goblet cells
Secrete mucus to protect and lubricate the lining of
the intestine.
26
Paneth cells
For innate immunity. They release lysozyme and
other peptides that break down membranes of microorganisms.
27
Celiac disease (celiac sprue)
A disorder of the small
intestine mucosa that causes malabsorption and can lead to damage or destruction of the villi.
An immune reaction
against gluten or other proteins in wheat. The resulting inflammation affects the enterocytes, leading to reduced nutrient absorption.
28
Crohn disease
A chronic inflammatory bowel disease in
the ileum or colon; its cause is not understood. a
combination of immune, environmental, and genetic factors.
29
Large Intestine
Absorbs water and electrolytes and forms
indigestible material into feces, has the following regions: the short cecum,
with the ileocecal valve and the appendix; the ascending, transverse,
descending, and sigmoid colon; and the rectum, where feces is stored prior to evacuation.
30
Mucosa of the large intestine
The mucosa lacks villi and except in the rectum has no major folds.
Cell types:
Goblet cells
Enterocyte
Enteroendocrine cells
Colonocytes
31
Colonocytes
Have irregular microvilli and dilated intercellular spaces indicating active water absorption.
32
Lymphoid tissue of the large intestine
The richness in MALT (lymphatic nodules) is related to the large bacterial population of the large intestine.
33
Muscularis of the colon
The fibers of the outer layer gathered in three
separate longitudinal bands called teniae coli.
34
Colorectal cancer
An adenocarcinoma that
develops initially from benign adenomatous polyps in the mucosal epithelium.
35
Rectoanal junction
At the rectoanal junction the simple columnar
epithelium is replaced by stratified squamous
epithelium, typical of the epidermis.
36
Hemorrhoids
Swollen blood vessels in the mucosa or submucosa
of the anal canal
Results from a low-
fiber diet, constipation, prolonged sitting, or straining at defecation, conditions that produce increased pressure on these blood vessels.
37
Functions of salivary glands
(1) to moisten and lubricate ingested food and the oral mucosa
(2) to initiate the digestion of carbohydrates and lipids with amylase and
lipase, respectively.
(3) to secrete innate immune components such as lysozyme.
38
Three epithelial cell types of salivary glands
Serous cells
Mucous cells
Myoepithelial cells
39
Serous cells
Protein-secreting cells (enzymes and other proteins).
40
Mucous cells
Contain apical granules with mucins that provide lubricating properties in saliva.
41
Myoepithelial cells
have contractile processes around the secretory unit
or duct that move secretory products into and through the ducts.
42
Parasympathetic stimulation of salivary glands
Usually elicited through the smell or taste of
food, provokes a copious watery secretion with relatively little organic content.
43
Sympathetic stimulation of salivary glands
Inhibits such secretion and produces dry mouth
often associated with anxiety
44
Pancreas
A mixed exocrine-endocrine gland that produces both digestive
enzymes and hormones.
45
Pancreas exocrine
The digestive enzymes are produced by cells of serous acini in the larger exocrine portion. This somewhat resembles the parotid gland histologically.
Secretes alkaline pancreatic juice into duodenum where bicarbonate ions neutralize the acidic chyme from the stomach
46
Pancreas endocrine
Involves primarily smaller cells located in clusters called the pancreatic islets (islets of Langerhans)
47
Pancreatic cancer
Usually a carcinoma of
duct cells, occurs most often in the head of the
organ.
48
Liver
The largest internal organ, in adults
Main digestive function is production of bile, needed for the emulsification, hydrolysis, and uptake of fats in the duodenum.
Major interface between the digestive system and the blood.
49
Hepatocytes
Liver cells
Functions:
Secretion of bile
Endocrine secretion into the blood of the major plasma proteins, including albumins, fibrinogen, and
many others
Conversion of amino acids into glucose
Breakdown (detoxification) and conjugation of ingested toxins, including many drugs
Amino acid deamination, producing urea removed from blood in kidneys
Storage of glucose in glycogen granules and triglycerides in small lipid droplets
Storage of vitamin A and other fat-soluble vitamins
Removal of erythrocytes (by specialized macrophages, or Kupffer cells)'
Storage of iron in protein complexes.
50
Liver: Arteries and Veins
Hepatic portal vein brings blood laden with nutrients and waste from intestines, and into the liver for processing.
Hepatic vein collects processed blood from liver and brings it to the inferior vena cava.
51
Bile
Bile acts as a surfactant, helping to emulsify the lipids in the duodenum, promoting their digestion and absorption.
Bile canaliculi form a complex network of channels.
Hepatocytes secrete bile into the canaliculi
52
Bilirubin
A pigmented breakdown product of heme (an
iron-containing molecule). It is released into the
duodenum and is converted by intestinal bacteria into
other pigmented products. These give feces and urine
their characteristic brownish and yellowish colors.
53
Liver cirrhosis
Occurs late in chronic liver disease, fibrosis and proliferation of fibroblasts and hepatic stellate cells occur beyond the portal areas. The excessive connective tissue may disrupt the normal hepatic architecture and interfere with liver function.
54
Gall Bladder
A saclike structure that stores and concentrates bile, and releases it into the duodenum after a meal.
55
Cholangiocytes
The cuboidal or low
columnar epithelial cells lining the gallbladder have microvilli and large intercellular spaces; these cells actively transport water, in this case for
concentrating bile.
56
Cholecystokinin (CCK)
Released from enteroendocrine cells of
the small intestine, causes contraction of the gallbladder muscularis layer to move bile into the duodenum.
57
Cholelithiasis
Reabsorption of water from bile in the gallbladder is involved in the formation
of gallstones in the gallbladder or biliary ducts, a condition called
cholelithiasis.
58
The portal lobule is a functional component of the liver that is primarily concerned with the
Flow of bile from hepatocytes into the bile duct
59
# Reversed prompt
Begins with voluntary muscle action but finishes with involuntary peristalsis.
Upper one-third of the esophagus, the muscularis is exclusively skeletal muscle
The middle portion of the esophagus has a combination of skeletal and smooth muscle fibers
The lower third the muscularis is exclusively smooth muscle
Swallowing
60
# Reversed prompt
The four layers of the GI tract are present. The esophageal mucosa has nonkeratinized stratified squamous epithelium.
Innermost: Mucosa
Submucosa
Muscularis
Outermost: Serosa
Esophagus layers
61
# Reversed prompt
Small mucus-secreting glands in the submucosa which lubricate and protect the mucosa.
Esophageal glands
62
# Reversed prompt
Functions:
To continue the digestion of carbohydrates initiated by the amylase of
saliva,
To add an acidic fluid to the ingested food and mixing its contents into a viscous mass called chyme by the churning activity of the muscularis
To begin digestion of triglycerides by a secreted lipase
To promote the initial digestion of proteins with the enzyme pepsin.
Stomach functions
63
# Reversed prompt
The wall in all regions of the stomach is made up of all four major layers of the GI tract.
Cardia, pylorus, fundus, and body
Stomach regions
64
# Reversed prompt
A narrow transitional zone, 1.5-3 cm wide, between the
esophagus and the stomach
Cardia
65
# Reversed prompt
The funnel-shaped region that opens into the small intestine. Both regions produce mucus and are similar histologically.
Pylorus
66
# Reversed prompt
The much larger fundus and body regions are identical in structure and are the sites of gastric glands releasing acidic gastric juice.
Fundus and body
67
# Reversed prompt
The mucosa and submucosa of the stomach have large, longitudinally
directed folds called rugae, which flatten when the stomach fills with food.
Rugae
68
# Reversed prompt
A simple columnar
epithelium that invaginates deeply into the lamina propria. The invaginations form millions of gastric pits.
Mucosal surface
69
# Reversed prompt
The gastric pits of the mucosal surface lead to long, branched, tubular gastric glands. In
the fundus and body the gastric glands themselves fill most of the mucosa.
Gastric glands
70
# Reversed prompt
Mucous neck cells
Parietal (oxyntic) cells
Chief (zymogenic) cells
Enteroendocrine cells
Secretory cells of the gastric glands
71
# Reversed prompt
Secretes acidic fluid containing mucin
Mucous neck cells
72
# Reversed prompt
Produces hydrochloric acid (HCl).
Parietal (oxyntic) cells
73
# Reversed prompt
Has all the characteristics of active protein-secreting cells. They produce pepsins, which starts the breakdown of protein, and gastric lipase, which starts the breakdown of lipids.
Chief (zymogenic) cells
74
# Reversed prompt
Scattered epithelial cells with endocrine or
paracrine functions. Some secrete serotonin and others produce the peptide gastrin.
Enteroendocrine cells
75
# Reversed prompt
Painful erosive lesions of the mucosa that may extend to deeper layers.
Can occur anywhere between the lower
esophagus and the jejunum.
Causes:
Bacterial infections with Helicobacter pylori.
Effects of nonsteroidal anti-inflammatory drugs
Overproduction of HCl or pepsin.
Lowered production or secretion of mucus or
bicarbonate.
Gastric and duodenal ulcers
76
# Reversed prompt
The site where the digestive processes are completed and where the nutrients are absorbed.
Same four layers as other parts of the GI tract
Mucosa (inner), submucosa, muscularis, serosa, outer mesentery
Small Intestine
77
# Reversed prompt
Duodenum (first), jejunum, and ileum
Small Intestine segments
78
# Reversed prompt
Densely covering the entire mucosa of the small intestine are short mucosal outgrowths called villi that project into the lumen.
Mucosa of small intestine
79
# Reversed prompt
finger- or leaflike mucosal projections covered by a
simple columnar epithelium of absorptive cells called
enterocytes, with many interspersed goblet cells that produce mucus.
Villi of small intestine
80
# Reversed prompt
The mucosa and
submucosa form circular
folds or plicae circulares,
which increase the
absorptive area.
plicae circulares
81
# Reversed prompt
Enterocytes
Goblet cells
Paneth cells
Enteroendocrine cells
Small Intestine Cell Types in Mucosa
82
# Reversed prompt
The absorptive cells, are tall columnar cells. The
apical end of each enterocyte displays a striated (or brush) border, which is a layer of densely packed microvilli through
which nutrients are taken into the cells.
Enterocytes
83
# Reversed prompt
Secrete mucus to protect and lubricate the lining of
the intestine.
Goblet cells
84
# Reversed prompt
For innate immunity. They release lysozyme and
other peptides that break down membranes of microorganisms.
Paneth cells
85
# Reversed prompt
A disorder of the small
intestine mucosa that causes malabsorption and can lead to damage or destruction of the villi.
An immune reaction
against gluten or other proteins in wheat. The resulting inflammation affects the enterocytes, leading to reduced nutrient absorption.
Celiac disease (celiac sprue)
86
# Reversed prompt
A chronic inflammatory bowel disease in
the ileum or colon; its cause is not understood. a
combination of immune, environmental, and genetic factors.
Crohn disease
87
# Reversed prompt
Absorbs water and electrolytes and forms
indigestible material into feces, has the following regions: the short cecum,
with the ileocecal valve and the appendix; the ascending, transverse,
descending, and sigmoid colon; and the rectum, where feces is stored prior to evacuation.
Large Intestine
88
# Reversed prompt
The mucosa lacks villi and except in the rectum has no major folds.
Cell types:
Goblet cells
Enterocyte
Enteroendocrine cells
Colonocytes
Mucosa of the large intestine
89
# Reversed prompt
Have irregular microvilli and dilated intercellular spaces indicating active water absorption.
Colonocytes
90
# Reversed prompt
The richness in MALT (lymphatic nodules) is related to the large bacterial population of the large intestine.
Lymphoid tissue of the large intestine
91
# Reversed prompt
The fibers of the outer layer gathered in three
separate longitudinal bands called teniae coli.
Muscularis of the colon
92
# Reversed prompt
An adenocarcinoma that
develops initially from benign adenomatous polyps in the mucosal epithelium.
Colorectal cancer
93
# Reversed prompt
At the rectoanal junction the simple columnar
epithelium is replaced by stratified squamous
epithelium, typical of the epidermis.
Rectoanal junction
94
# Reversed prompt
Swollen blood vessels in the mucosa or submucosa
of the anal canal
Results from a low-
fiber diet, constipation, prolonged sitting, or straining at defecation, conditions that produce increased pressure on these blood vessels.
Hemorrhoids
95
# Reversed prompt
(1) to moisten and lubricate ingested food and the oral mucosa
(2) to initiate the digestion of carbohydrates and lipids with amylase and
lipase, respectively.
(3) to secrete innate immune components such as lysozyme.
Functions of salivary glands
96
# Reversed prompt
Serous cells
Mucous cells
Myoepithelial cells
Three epithelial cell types of salivary glands
97
# Reversed prompt
Protein-secreting cells (enzymes and other proteins).
Serous cells
98
# Reversed prompt
Contain apical granules with mucins that provide lubricating properties in saliva.
Mucous cells
99
# Reversed prompt
have contractile processes around the secretory unit
or duct that move secretory products into and through the ducts.
Myoepithelial cells
100
# Reversed prompt
Usually elicited through the smell or taste of
food, provokes a copious watery secretion with relatively little organic content.
Parasympathetic stimulation of salivary glands
101
# Reversed prompt
Inhibits such secretion and produces dry mouth
often associated with anxiety
Sympathetic stimulation of salivary glands
102
# Reversed prompt
A mixed exocrine-endocrine gland that produces both digestive
enzymes and hormones.
Pancreas
103
# Reversed prompt
The digestive enzymes are produced by cells of serous acini in the larger exocrine portion. This somewhat resembles the parotid gland histologically.
Secretes alkaline pancreatic juice into duodenum where bicarbonate ions neutralize the acidic chyme from the stomach
Pancreas exocrine
104
# Reversed prompt
Involves primarily smaller cells located in clusters called the pancreatic islets (islets of Langerhans)
Pancreas endocrine
105
# Reversed prompt
Usually a carcinoma of
duct cells, occurs most often in the head of the
organ.
Pancreatic cancer
106
# Reversed prompt
The largest internal organ, in adults
Main digestive function is production of bile, needed for the emulsification, hydrolysis, and uptake of fats in the duodenum.
Major interface between the digestive system and the blood.
Liver
107
# Reversed prompt
Liver cells
Functions:
Secretion of bile
Endocrine secretion into the blood of the major plasma proteins, including albumins, fibrinogen, and
many others
Conversion of amino acids into glucose
Breakdown (detoxification) and conjugation of ingested toxins, including many drugs
Amino acid deamination, producing urea removed from blood in kidneys
Storage of glucose in glycogen granules and triglycerides in small lipid droplets
Storage of vitamin A and other fat-soluble vitamins
Removal of erythrocytes (by specialized macrophages, or Kupffer cells)'
Storage of iron in protein complexes.
Hepatocytes
108
# Reversed prompt
Hepatic portal vein brings blood laden with nutrients and waste from intestines, and into the liver for processing.
Hepatic vein collects processed blood from liver and brings it to the inferior vena cava.
Liver: Arteries and Veins
109
# Reversed prompt
Bile acts as a surfactant, helping to emulsify the lipids in the duodenum, promoting their digestion and absorption.
Bile canaliculi form a complex network of channels.
Hepatocytes secrete bile into the canaliculi
Bile
110
# Reversed prompt
A pigmented breakdown product of heme (an
iron-containing molecule). It is released into the
duodenum and is converted by intestinal bacteria into
other pigmented products. These give feces and urine
their characteristic brownish and yellowish colors.
Bilirubin
111
# Reversed prompt
Occurs late in chronic liver disease, fibrosis and proliferation of fibroblasts and hepatic stellate cells occur beyond the portal areas. The excessive connective tissue may disrupt the normal hepatic architecture and interfere with liver function.
Liver cirrhosis
112
# Reversed prompt
A saclike structure that stores and concentrates bile, and releases it into the duodenum after a meal.
Gall Bladder
113
# Reversed prompt
The cuboidal or low
columnar epithelial cells lining the gallbladder have microvilli and large intercellular spaces; these cells actively transport water, in this case for
concentrating bile.
Cholangiocytes
114
# Reversed prompt
Released from enteroendocrine cells of
the small intestine, causes contraction of the gallbladder muscularis layer to move bile into the duodenum.
Cholecystokinin (CCK)
115
# Reversed prompt
Reabsorption of water from bile in the gallbladder is involved in the formation
of gallstones in the gallbladder or biliary ducts, a condition called
cholelithiasis.
Cholelithiasis
