lecture 7/8: the digestive system Flashcards
(332 cards)
1
Q
what are the basic functions of the digestive system
A
- Ingestion
- Secretion
- Mixing and propulsion
- Digestion
- Absorption
- Defecation
2
Q
what are the 4 layers f=if the GI tract
A
Mucosa
• Submucosa
• Muscularis
• Serosa
3
Q
arrange these from innermost to outmost: muscularis, serosa, mucosa, submucosa
A
mucosa
submucosa
muscularis
serosa
4
Q
which layer of the GI tract allows movement
A
serosa
5
Q
which anchors organs: serosa or adventia
A
adventia
6
Q
what is the only organ that has 3 muscularis layers
A
stomach
7
Q
what are the 3 layers of the mucosa of the GI tract
A
1) lining epithelium
2) lamina propria
3) muscularis mucosa
8
Q
what layer is in direct contact with the GI tract
A
lining of the epithelium
9
Q
epithelium in the mouth, pharynx, esophagus and anal canal serves what function
A
protective function (against highly acidic food)
10
Q
what is the function of the lining epithelium in the stomach and intestines
A
secretion and absorption
11
Q
every 5-7 days, what happens to epithelial cells
A
they are replaced by new ones
12
Q
within the absorptive epithelial cells, what are the 2 subsets of cells
A
exo and endocrine
13
Q
what is the function of the exocrine cells in the epithelium of GI tract
A
Exocrine cells which secrete mucous and fluid into the
lumen
14
Q
what is the function of endocrine cells in the epithelial cells of the GI tract
A
Endocrine cells which secrete hormones into the
bloodstream
15
Q
what is the function of lamina propria
A
Supports epithelium and binds it to the muscularis
mucosa
16
Q
what does lamina propria contain that serves a protective function
A
mucosa-associated lymph tissue (MALT)
17
Q
what is the function of muscularis mucosa
A
Increases the surface area for digestion and absorption
- Movement of muscle ensures that all absorptive cells
are fully exposed to the contents of the GI tract
18
Q
the subcosa of the GI tract contains what plexus
A
Meissner plexus
19
Q
what is the meissners plexus
A
a portion of the enteric nerve plexus (the brain of the gut)
20
Q
what does the Meissner plexus contain (neurons) and what is the function
A
- Contains sensory and motor enteric neurons and
parasympathetic and sympathetic postganglionic
fibers that innervate the mucosa and submucosa - Important in controlling secretions of the GI tract
21
Q
the Meissner’s plexus is only located in what layer of the GI
A
submucosa
22
Q
what areas contain skeletal muscle that produce voluntary swallowing
A
mouth
pahrynx and superior and meiddle parts of the esophagus
23
Q
skeletal muscles of the GI permit voluntary control of swallowing and what else
A
control of defecation
24
Q
throughout the GI tract, is it skeletal or smooth muscle
A
smooth
25
what are the 2 layers of muscular smooth in the muscularis muscle
outer longitudinal and inner circular
26
which is more outer in the muscularis of the Gi tract, longitudinal or circular
longitudinal
27
what is the function of involuntary contractions of the muscularis in the GI
Involuntary contractions help break down food physically, mix
it with digestive secretions and propel it along the tract
28
where is the myenteric nerve plexus location (in what layer)
muscularis
29
what plexus is located in the muscular layer of the GI
myenteric nerve plexus
30
what are the fibers found in the myenteric nerve plexus and what do they control
* Parasympathetic ganglia
* Sympathetic postganglionic fibers
* Controls primarily the frequency and strength of
contraction of the muscularis
31
what is the most superficial layer of the GI tract
serosa
32
what is another name of the serosa of the GI tract
Also called the visceral peritoneum on structures inferior to the
diaphragm
33
what is the peritoneum
envelope that surrounds the digestive organs
34
what does parietal peritoneum line
lines the walls of the abdominopelvic cavity
35
what does the visceral peritoneum cover
some organs in the cavity and form their serosa
36
what is the peritoneal cavity
thin space in between the parietal and visceral peritoneum (contain serous fluid)
37
be able to understand diagrams of the peritoneum
.
38
where is the greater omentum located
on greater curvature of stomach
39
what is the greater omentum made of
visceral peritoneum and fat
40
what is the largest peritoneal fold
greater omentum
41
where does the greater omentum hang
loosely over the transverse colon and coils over the SI
42
TRUE or false: the greater omentum is a double sheet that folds back onto itself
true
43
what does the falciform ligament attach
Attaches the liver to the anterior abdominal wall and diaphragm
44
true or false: the falciform ligament is an extension of visceral peritoneum
true
45
where is the falciform ligament located
anterior between right and left lobes
46
what does the lesser omentum suspend
suspends stomach and duodenum from liver
47
where is the lesser omentum located
on lesser curve of stomach
48
what does the lesser omentum arise as
arises as 2 folds in the serosa of the stomach and duodenum
49
what does the mesentery do
binds the SI to the posterior abdominal wall
50
what peritoneal folds are continuous with each other
mesentery and mesocolon
51
what is the mesocolon
fold of the peritoneum which binds the large Intestine to the posterior abdominal wall
52
what are 2 specific regions of the mesocolon
sigmoid and transverse
53
how are the Lips (labia) are attached to their corresponding gums
by a fold
| of mucous membrane called the labial frenulum
54
what is the hard palate formed by
maxilla and palatine bones
55
what is the soft palate
Muscular separation between oropharynx and nasopharynx
56
what is the uvula
• Uvula – muscular process hanging from the free border of the soft
palate
57
explain the movement of the soft palate and uvula during swallowing and what does that prevent
During swallowing, the soft palate and uvula are drawn superiorly
closing off the nasopharynx, preventing food and liquid from entering
the nasal cavity
58
where are the palatine tonsils location
stem between the arches in the oropharynx
59
where are the lingual tonsils location
at the base of the tongue
60
what are the fauces
opening between the oral cavity and the pharynx (throat)
61
without food, how much saliva do the salivary glands produce
Secrete just enough saliva to keep the mucous membrane of the mouth and
pharynx moist and to cleanse the mouth and teeth
62
when food enters the mouth, what happens to secretion
secretion increases and chemical breakdown of food begins
63
what are some small salivary glands
Labial, buccal, and palatal glands in the lips, cheeks and palate as well as
lingual glands in tongue
64
where are parotid glands located and what is their function
* Located inferior and anterior to the ears, between the skin and masseter muscle
* Secrete saliva into the oral cavity via the parotid (Stensen’s) duct
65
where does the facial nerve pass-through
parotid gland
66
where are the submandibular glands found
Found beneath the base of the tongue in the posterior part of the floor of the
mouth
67
Where do the submandibular ducts enter
the oral cavity lateral to the lingual frenulum
68
are the sublingual glands superior or inferior to submandibular glands
superior
69
what are the ducts of the sublingual glands and where do they open
Lesser sublingual (Rivinus’) ducts open into the floor of the mouth
70
true or false: the salivary glands receive both para and sympathetic innervation
true
71
what do sympathetic fibers of the salivary glands do
Sympathetic fibers initiate vasoconstriction which decreases saliva
production
72
what type of stimulation dominates the salivary glands during stress and what does that cause
sympathetic
| causes dry mouth, stops secrete of saliva to connserve h20
73
what do parasympathetic fibers of salivary glands do
Parasympathetic fibers of the glands produce vasodilation and increases the production of saliva
74
what is saliva mostly made by
water
75
what are the solutes in saliva
Solutes include mucous, lysozyme (a bacteriolytic enzyme), digestive enzymes
(salivary amylase and lingual lipase) and traces of salt, protein and other
organic compounds
76
what is salivary amylase
causes breakdown of carbs in the mouth but do not get activated until stomach
77
explain lingual lipase
Receptors for taste buds in the tongue are stimulated by
chemicals in food and convey impulses to two salivary nuclei
(sup. and inf.) in the brain stem resulting in an increase in saliva
secretion
• Smell, sight, sound, and/or thought of food may also stimulate
secretion of saliva
78
true or false: the tongue is a primary digestive organ
false, accessory
79
what is the tongue and what is is attached to
Composed of skeletal muscle covered by a mucous membrane
• Attached to the hyoid bone, styloid process and mandible
80
what are the extrinsic muscles fo the tongue and what do they do
hyoglossus, genioglossus and
styloglossus
• Move the tongue form side to side and in & out to maneuver food
81
explain the or/ins or intrinsic muscles of tongue and their function
Intrinsic muscles originate and insert into the connective
tissue within the tongue and alter its shape and size for speech
and swallowing
82
how is the tongue atached to the mandible
lingual frenulum
83
what is ankyloglossia
condition where a person's lingual frenulum is
| abnormally short or rigid impairing eating and speech
84
what are the dorsum and lateral surfaces of the tongue covered with
papillae
85
what are the 4 types of papillar
* Fungiform Papillae
* Filliform papilla
* Circumvallate
* folliate papilla
86
do the foliate papilla contain taste buds
yes
87
which papilla does not contain taste buds
filliform
88
where does the pharynx enter from and to
The pharynx extends from the internal nares to the esophagus
| and larynx
89
true or false: Oropharynx and laryngopharynx have digestive and respiratory
functions
true
90
what does the muscular content of the oropharynx and laryngopharynx help with
help
| propel the food into the esophagus and then into the stomach
91
what is deglutition
is the mechanism that moves food from the mouth
| to the stomach = swallowing
92
what is the esophagus
muscular tube that lies posterior to the trachea
93
does the esophagus lie anterior or posterior to trachea
posterior
94
does the esophagus stop at the diaphragm?
no it passes through the diaphragm at the esophageal hiatus
95
what is it called when a portion of the stomach protrudes through the esophageal
hiatal hernia
96
what are the 4 layers of the esophagus
adventia
muscularis
submusoa
mucosa
97
what is the difference between adventia and serosa in the esophagus.
Unlike the serosa, the connective tissue merges with the
connective tissue of surrounding structures of the
mediastinum attaching the esophagus to them
98
the superior 1/3 of the esophagus is made of what type of muscle
skeletal
99
the middle 1/3 of esophagus is made from what muscle
skeletal and smooth muscle
100
the inferior 1/3 of esophagus is made from
smooth muscle
101
what does the submucosa of the esophagus cotnain
Contains areolar connective tissue, blood vessels and
| mucous glands
102
the mucosa of the esophagus is near wher
near the stomach ,contain muucous gland
103
what is the function of mucosa of the esophaugus
Offers protection against abrasion and wear & tear from
food particles that are chewed, mixed with secretions and
swallowed
104
what is the function of the esophahus
Secretes mucous and transports food into the
| stomach
105
what does the upper esophageal sphinctor control
passage of food from laryngopharyngeal
106
what does the elevation of the larunx cause the upper esophanial sprincter todo
to relax and the bolus enters the esophagus
107
during exhalation, what is happening to the upper esophageal spnincter
it is relatxed
108
how is food pushed fhrough esophagus
peristatlsis
109
explain the profucess of moving food throug hesohagus
progression of involuntary contraction and relaxation of
the circular and longitudinal layers of the muscularis
• Controlled by the medulla oblongata
• Circular muscle contraction constricts the esophageal wall and
squeezes the bolus towards the stomach
• Longitudinal muscle fibers inferior to the bolus also contract
shortening the inferior section and pushing its wall outward so it
can receive the bolus
• Mucous secretes by esophageal glands lubricate the bolus and
reduces friction
110
what is another name for lower esophgeal spnincter
gastroesophageal/cardiac shincnter
111
what is the lwer esopheal spnincter
narrowing of the esophagus just superior to the diaphram
112
when does the loer esophageal relax
Relaxes during swallowing allowing the bolus to pass
| into the stomach
113
what is the position of the stormach in relation to the diaphram
inferior
114
whatt connects the esophagus to the duodenum
the stomach
115
what is the 1st part of the SI
dudodeum
116
what forces the food intto thte dudoenum
stromach
117
does the stomach force large or small quantities into tthe duodenum
small
118
explain the position of the stomach during inhalation and exhalation
The diaphragm pushes it inferior with each inspiration and pulls it up with
each expiration
119
when the stomach is empty ,what is the side a
large sausagee
120
true or false: digestion of starch starts in the stomach
false, starts in mout hwith saliva
121
where dos the digestion of protein and triglycerides begin
stomach
122
what happens to the semi bolus in hte stomach
gets converted to a liquid and certain substances are absrobed
123
what is it called when the bolus becomes liquid
chyme
124
what surrounds the superior opening of the stomach
cardia
125
what is the fundus of the stomach
rounded portion superior and to the L. of the
| cardia
126
is the fundus to the right or left of the cardia
to tthe left
127
in the body of tthe stomach inferior or superior to the fundus
inferior
128
the pylorus are thee regions that conenct to where
the duodenum
129
the pyloric antrum connects to where
the body of stomach
130
to pyloric canal leads to what
duodenum
131
what is the passageway from pyloris to duodenum called
pyloric sphincter
132
what is the pyloric sphincter made of
thickneing of the circular muscle
133
When the stomach is empty, the mucosa lies in large
| folds called what
Rugae
134
explain the lesser curvature
concave medial boder
135
what is the gerater curvative
concave lateral border
136
what is the artrerial supply to the stomach
Arterial supply: R / L gastric arteries ( form an
anastomoses along the lesser curvature) , R /L
gastroepiploic (form an anastomoses along the greater
curvature) and short gastric (supplies fundus)
137
R/L gastric ateries from an anastomoses along what
lesser curvature
138
R/L gastroepiploic form an anastomeses along where
greater curvature
139
what does the short gastric a suppy
funfus
140
what is the parasympathtic inenrvation of the stmach
vagus
141
what is the sympathteic inenrvatiton of the stoamch
celiac ganglia
142
the greater curvatture lies around what organ
against spleen
143
the lesser curvature lies close to what organ
liver
144
what region of the stomach is considered the "storage: region and why
fundus
| less muscle and curning
145
what are the 4 layers of the stomach (deep to superficial)
1) mucosa
2) submucosa
3) muscularis
4) serosa
146
what is the deepest layer of the stomach
mucuosa
147
what are the contents of the muscoa of stomach
lamina propria
muscularis mucosa
gastric glands
148
gastric galnds are located in what layer of the stomach
mucosa
149
where is the lamina located (what layer)
mucosa
150
gastric glands are what kind of cells
exocrine, secrete their products into the stomach lumen
151
what do the mucous neck cells secrete
mucous
| because gastric juices are very acidic
152
what do cheif cells in the stomach secrete
secrete pepsinogen and gastric lipase
153
what does gastric lipase inittiate
initiates breakdown of fat
154
what do the parietal cells in the gastric glands of the stoamch produce
HC1 and intrinsic factor (needed for absorption of b12)
155
what are the 3 exocrine cells found in the gastric galnds
mucous neck cells
cheif cells
parietal cells
156
what forms the gastric juice
secretions from the exocrine cells of the gastric galnds
157
give an example of the enteroendocrine cell i nthe mucosa layer of the stomach
g cell
158
where are g cells located
pyloric antrum
159
what does the g cell secrete
gastrin (hormone) into the blood stream 0
160
what is the function of gastrin secrete by G cells
• Stimulates growth of gastric glands and secretion of
large amounts of gastric juice
• Also strengthens contraction of the lower esophageal sphincter, increases mobility of stomach and relaxes
pyloric and ileocecal sphincter
161
what is submucosa of the stom
areolar connective tissue
162
how many layers of muscles are there in the muscularis muscle of the stomach
3
163
what are teh 3 layers of the staomch (outer to inner )
outer longitudinal
middle circualr
inner oblique
164
where are the smooth muscles of the stomach mostly located
in the body
165
true or false: in every organ, there are 3 layers of smooth muscle
false, only place there are 3 is in the stomach
166
what is the innermost muscualr layer (smooth) of the stomach
oblique
167
the serosa is the portion covering the stomach and is part of the BLANK
visceral peritoneum
168
• At lesser curvature, visceral peritoneum extends superior to what organ
liver
169
• At lesser curvature, visceral peritoneum extends superior to the liver - to form what
lesser omentum
170
• At greater curvature, the visceral peritoneum continues inferiorly as what
as the greater
| omentum and drapes over the intestines
171
the food mixes with the gastric juice reducing it to a liquid called BLANK
chyme
172
true or false: The pyloris remains partially closed and as food reaches it,
trtue
173
each wave/contraction of the stoamch forces what
forces several ml of chyme into the duodeum
174
digestion of proteins begins where
stomach
175
digestion of proteins is done mainly by what enxyme
pepsin
176
proteien chains of many amino acids can be broken down into what
peptides
177
pepsin can help in digestion of what types of proteins
milk
178
what is the function of gastric lipase
splots the short chain trsis (fats) found inmilk
=limited role in ttthe adult stomach
=rely more on pancreatic lipase
179
true or false: Within 2-9 hours after eating a meal, the stomach usually has
emptied its contents into the duodenum
false, 2-4
180
where does chyme pass after the stomach
into the duodenum of the small intenstine
181
what does chemical digestion in the SI depend on
activity of the pancrease, liver and gall bladder
182
the pancreas is considered what type of gland
retroperitoneal glands
183
where is the head of the pancrease
Head: expanded portion of the organ which lies near the
| duodenum
184
where is the body of the pancreas
Body: superior and to the left of the head
185
where is the tail of the pancreas
closer to the spleen, tapering of the body
186
what part of the pancreas is closer to the spleen
tail
187
pancreatic duct joints with what other duct
common bile duct
188
where does the pancreatic duct empty
in the greater duodenal papilla
189
where does the accessoru pancreatic duct empty
lesser duodonal papilla
190
the common bile duct and pancreastic duct meet up and empty where
greater duodenal papilla
191
what is the arterial supply of the pancreas
sup. and inf. pancreaticoduodenal aa, splenic artery, and superior
mesenteric aa.
192
the inferior pancreaticoduondal branches off what artery
supeerior mesenteric a
193
what is the innervation of the pancreas donee by
Celiac and superior mesenteric plexuses
194
true or false: innervation is the main controller of pancreatic secretion
Innervation is presumed to influence enzyme formation but pancreatic secretion is largely controlled by the hormones secretin and cholecystokinin (CCK) released by the small intestine.
195
pancreas is made up of small clusters of what types of ceells
glandular epithelial cells
196
what are 99% of the glandular epithelial cells in the pancreas called
acini
197
the acini clusters in the pancease make up what portion of the pancreas
exocrine
198
what do the acini cluster cells secrete in the pancrease
cells secrete a muxture of fluid and digestive enxymes called pancreatic juice
199
what cells in the pancreas make the pancreastic juice
acini
200
1% of the cluster glandular epithelial cells are what type
pancreastic islets
201
the pancreatic islets form what part of the pancreas
endocrine portion
202
what do pancreatic isletes secrete
secrete the following hormones: glucagon, insulin, somatostatin &
pancreatic polypeptide
203
what is pancreatic juice made from
Consists of water, salts, sodium bicarbonate and several digestive
enzymes
204
what gives the pancreatic juice a slighlty alkaline pH
sodium bicarbonate
205
what buffers the acidic juice in the chyme
pancrease
206
what stops the action of pepsin in the sotmach
pncrease
207
true or false: the pancreas Creates proper pH level for action of digestive enzymes in the S.I.
true
208
what is the Carbohydrate-digesting enzyme
• Pancreatic Amylase
209
what are the • Protein-digesting enzymes
• Trypsin, Chymotrypsin, Carboxypeptidase, Elastase
210
what is the • Triglyceride-digesting enzyme
• Pancreatic lipase
211
what are the• Nucleic-acid digesting enzymes
• Ribonuclease and Deoxyribonuclease
212
what is the heaevieset gland in the body
liver
213
what is the largest organ in the body
skin
214
what is the 2nd larger organ in the body
liver
215
what covres the liver
Almost completely covered by visceral peritoneum
and completely covered by a dense connective
tissue deep to the peritoneum
216
what are the right and left lobes of the liver divided by
falciform lig
217
what are the 4 lobes of the lvier
right
left
caudate
quadrate
218
what are the functional cells of the liver
hepatocytes
219
what is the function of hepatocytes
filttering
220
how are hepatocyes arranged
Arranged in irregular, interconnected plates around a central vein
221
what are the sinusoids of the liver
Sinusoids contain fixed phagocytes (stellate reticuloendothelial cells –
Kupffers cells) which destroy worn-out leukocytes and RBCs, bacteria,
and other foreign matter from the G.I. tract venous blood
222
what cells secrete bile in liver
hepatocytes
223
explain the pathway of bile
enters bile canaliculi which empty into small bile ductules
• the ductules pass bile into bile ducts
• eventually merge into the R/L hepatic ducts
• R/L hepatic ducts unite to form the common hepatic duct
• Common hepatic duct joins the cystic duct and they form
the common bile duct
224
where does bile first enter and where does that eempty
enters bile canaliculi which empty into the ductules
225
the bile ductules pass bile where
into bile ducts
226
bile ducts eventually merge into what
R/L hepattic ducts
227
RL hepattic ducts unite to form what
common hepatic duct
228
common hepattic duct joints the BLANK and they form the BLnk
• Common hepatic duct joins the cystic duct and they form
| the common bile duct
229
what does the falciform lig anchor
anchors to tliver tto tthe diaphragm
230
where is the round lig of the liver located
Located in the free border of the falciform ligament
231
what ligament isa remnant of the umbilical vein of the fetus
round lig
232
where does the round lig extend from
Extends from the liver to the umbilicus
233
what lig suspend the liver from the diaphragm
R/L coronary lig
234
what is the blood supply for the liver
hepatic artery and hepatic portal vein
235
branches from the hepatic artery and vein carry blood where
Branches from both the artery and vein carry blood into the sinusoids where O2, most nutrients and certain
toxins are taken by the hepatocytes
236
what tis the pathwat of Products manufactured by the hepatocytes & nutrients
needed by other cells are secreted back into the blood
(drained into central vein - hepatic vein - IVC)
237
what is the portal triad
hepatic portal vein, hepatic artery, and bile duct
238
what is the parasymp innervattion of the liver
vagus
239
what is the sympathetic innervation of the liver
celiac ganglia
240
where is the gall bladder located
located in a depression on the posterior surface of the liver
241
what is the most distal part of the gallbladder
fundus
242
which part of the gallbladder hangs inferiorly from liver
fundus
243
the portion where the body of the gallbladder narrows is called what
the neck
244
what is the function of the gall bladder
store and concentrate bile until it is needed by
| the S.I.
245
what is the blood supply for the gall bladder
cycstic artery
246
what is the innervation of the gall bladder
branches from the celiac plexus and Vagus
| nerve
247
does the gallbladder produce bile ?
no just stores and concetrates it
248
bile is mostly an ecretoru product but also partially a blank secretion
digestive
249
what plays a role in emulsification
bile salts
250
what happens to the greater duodenal pappila b/w meals
Between meals, the greater duodenal papilla closes off and bile
flows into the gall bladder for storage
251
• After a meal, parasympathetic impulses along the vagus nerve
stimulate the liver wjat
to increase bile production
252
Fatty acids and amino-acids in chyme stimulate duodenal
| enteroendocrine cells to secrete what
Cholecystokinin (CCK)
| in the blood
253
what are the functions of Cholecystokinin (CCK)
| in the blood
1) CCK causes the contraction of the gall bladder ,
squeezing stored bile into the cystic duct and through
the common bile duct
2) CCK also causes relaxation of the sphincter around the
greater duodenal papilla allowing bile to flow into the
duodenum
254
where does the majority of digestion and absorption occurs
small intesntie
255
what are the 3 regions fo the SI
duodenum
jejunum
illeum
256
what are the permanent ridges in the small intenstine mucosa called
circular folds
257
where do circular folds behing and end
Begin in the duodenum and end in the mid-portion of the ileum
258
what is the fucntion of circular folds in the SI
Enhance absorption by increasing the S.A. and causing chyme
| to spiral as it passes through the S.I.
259
what is the arterial supply of the SI
superior mesenteric and gastroduodenal
260
what is the innervation of teh SI
superior mesenteric plexus and vagus n.
261
two autonomic plexuses are found within the wall of the SI, what are they
1) myenteric plexus
| 2) meissners plexus
262
where is the myenteric plexus located
between muscle layers in the SI
263
where is the meissners plexus locatied
in submucosal layer of the IS
264
tthe myetneric and meissners plexus are associated with waht system
CNS (enteric)
265
the epithelium of tje mucosa of the SI is made up of what 4 cells
Absorptive cells
* Goblet cells
* Enteroendocrine cells
* Paneth cells
266
what is unqiue to the mucosa layer of the SI
contains villi
267
what is the function of th villi in the SI wall
Greatly increase the S.A. of the epithelium available for absorption and
digestion
268
each villi of the SI contrains a core called what
lamina propira
269
within each villi there is what
Within each is an arteriole, a venule, a blood capillary and a central
lacteal (lymph capillary)
270
Nutrients absorbed by the epithelial cells lining the villi in the SI pass through what
the wall of the capillary or central lacteal to enter the blood or lymph
271
what is teh function of the absorptive cells in the muscosa of SI
digeset and absorb
272
what is teh function of the globlet cells in the muscosa of SI
secrette musouc
273
what is teh function of the enteroendocrine cells in the muscosa of SI
secrete secretin , CCK or GIP (glucose dependanct insulinotrophic peptide)
274
what do panaeth ceells secrete
Secrete the bacterial enzyme lysozyme and has some
| phagocytotic functions
275
the lamina propria of the mucusa of the SI has many BLANK for immune support
has many mucosa associated lymphoid
| tissue (MALT):
276
what are two MALT
Solitary lymphatic nodules (mostly in distal ileum)
| • Peyers patches (also found mostly in distal ileum)
277
where are peyers patches located (what layers )
mucosa layer of SI
278
where are brunners galnds located (what layer)
submucosa of duodenum
279
what do brunners glands secrete
• Secrete an alkaline mucous which helps
| neutralize gastric acid in chyme
280
true or false: in the Si muscualris layer, we have oblique and circular smooth layers
false, longitinal and circular
281
what is the most superficial layer os the SI
serosa.
282
is intestinal juice alkaline or acidic
alkaline
283
what does intesntinal juice aid with
Aids with the absorption of substances as they come in contact
with the villi
284
Absorptive epithelial cells in the SI synthesize what
many digestive
enzymes (brush-border enzymes) and insert them into the
micovilli
285
what are the 2 types of movements taht occur inn the SI
Segmentation
• Migrating motility complex (a form of peristalsis)
286
segmentation mixes chyme with what
digestive juices
287
segmentation brings food particles in contact with what
in contact with the mucosa for absorption
288
explain segmentation in the SI
Starts with the contraction of circular muscle
* Constricts intestine into segments
* Segments divide again with the a second contraction of the muscle fibers lining each segment
• Finally, the muscles that initially contracted relax forming large segments
again
289
does segmentation occur after most of the meal is absorbed
no segnmentation stops and peristalsis begins
290
explain th migrating motility complex MMC
Begins in lower portion of stomach
• Pushes chyme forward into the S.I.
• The migrating motility complex (MMC) slowly migrates down the S.I.
• MMC reaches the end of the ileum in 90-120 minutes
Ø Then another MMC begins
291
when does absorption in the SI occur
Occurs once food has been changed into forms that can pass
through the epithelial cells lining the mucous into blood and
lymphatic vessels
292
most of the absorption (90%) occurs where
in SI
293
if 90% of digetion occurs in SI, 10% comes from where else
stomach and large intenstive
294
what is the terminal portion of the GI traction
the large intenstine
295
the large intenstine is divided into what 4 mainn regions
cecum
colon
rectum
anal cnaal
296
what is the function of the large intensine
Functions to complete absorption, produce certain vitamins,
| form feces, and expulse feces from the body
297
how is the large intestine attached to the posterior wall
by the mesocolon
298
where does the cecum lie
hangs from th ileocecal sphincter
299
the appendix is atatched to where
cecum
300
true or false: all 3 portions of the LI are considered retroperitoneal
false, only 2 (ascneding, descnedinng)
301
what is the right colic (hepatic) flexure
abrupt turn inferior to the liver
302
what is the lft colic splenic flexure
abrupt turn inferior to the spleen
303
what is the begininng and ending of the sigmoid colon
begins near L. iliac crest and ends at the level of
| 3rd sacral vertebrae
304
the rectum lies anterior to what
anterior to sacrum and oxxygic
305
what is the last part of the rectum called
anal canal
306
what is the anus guarded by
Guarded by an internal sphincter of smooth muscle (involuntary) and an
external sphincter of skeletal muscle (voluntary)
307
true or false: yhe anal sphincters are all voluntarility cotnrolled
false, Guarded by an internal sphincter of smooth muscle (involuntary) and an
external sphincter of skeletal muscle (voluntary)
308
what is the arterial supply fo the LI
sup. / inf. mesenteric aa.,
| sup. , middle, and inf., rectal aa.
309
what is the sympathetic innnervation of the LI
from the celiac, superior and inferior
| mesenteric ganglia
310
what is the parasymptethic inenrvation of the LI
from the vagus and pelvic
| splanchnic nerves
311
true or false; there are no villi or circualr folds in the mucosa of the LI
ttrue
312
what does the mucosa of the LI consist of
lamina propria and muscualris mucosa
313
what are the cells in the mucosa of the LI
```
Epithelium contains mostly absorptive cells (for water absorption) and
goblet cells (secrete mucous)
```
314
the mucosa of the LI contrains what types of nodules
Contains solitary lymph nodules
315
what are the muscularis layers of the LI
Consists of external longitudinal muscle layer and internal circular layer
316
what happens when the lonngitudinal muscle of the LI wall are thickened
forms 3 bands called the taenia coli
317
how is the taenia coli made
Some portions of the longitudinal muscle are thickened forming 3 bands
called the taenia coli
318
what forms the haustra
Tonic contractions of the bands (Tania coil) form a series of pouches called haustrae
319
Tonic contractions of the bands form a series of pouches called BLANK
haustrae
320
serosa layer of the LI is part of what
visceral peitoneum
321
Passage of chyme from the ileum into the cecum is controlled by WHAT
the ileocecal sphincter (slow process)
322
As food accumulates in the cecum and ascending colon,
| what begings
movement of the colon begins
323
when does movement of the colon begin
As food accumulates in the cecum and ascending colon,
| movement of the colon begins
324
true or false: haustra remain relaxed until they fill up
true
325
explain haustral churning
Ø Haustrae remain relaxed until they fill up
Ø After distension reaches a certain level, the wall contracts
and pushes the contents into the next haustrae
326
does peristalsis in the LI occur at a slow or fast rate
slow rate
327
explain mass peristalsis in the LI
Ø Strong peristaltic wave that begins in the middle of the transverse colon
and rapidly drives the contents into the rectum (3-4 times a day, during or
right after a meal)
328
how does the final stage of digestion occur
through the activity of
| bacteria in the lumen
329
what are the 4 functions of the LI
Ø Prepares chyme for elimination
Ø Fermentation of remaining carbohydrates, release of H+, CO2, methane gases
Ø Remaining protein are converted into indole, skatole, hydrogen sulfide, and fatty acids
Ø Absorbed and transported into the liver, excreted in urine
330
where are vit b and k absorbed
in the colon
331
after 3-10 hours, what happens to the chyme in the LI and why
chyme has become solid/semi-solid as a result
| of water absorption
332
true or false: Large intestine also absorbs electrolytes like Sodium and Chloride and some vitamins
true
