Test 2: Lecture 19, 20, 21: Digestive Flashcards
1
Q
3 layers of the GI tract
A
mucosa
submucosa
muscularis externa
2
Q
3 layers of mucosa
A
epithelium
lamina propria
muscularis mucosae
3
Q
carnivore stomachs have an extra layer in the mucosa called the
A
lamina subglandularis
4
Q
there is no ___ in the mouth/pharynx/part of the esophagus in a rumen
A
muscularis mucosae
5
Q
the lamina propria is ___ with lymphocytes and circulatory channels
A
loose connective tissue
6
Q
The muscularis mucosae is made of ___ usually only ___ layers thick
A
smooth muscle
a few cell
7
Q
what type of epithelium does the stomach, small intestine and large intestine have?
A
simple columnar epithelium (used for passive and active absorption)
8
Q
what part of the digestive tract have stratified squamous epithelium?
A
lips to cardiac stomach
anal canal
(protection)
9
Q
what part of the digestive tract have simple cuboidal epithelium
A
kidney
10
Q
ducts of GI have what type of epithelium?
A
pseudo stratified and stratified columnar
11
Q
submucosa is made of ___ tissue and contains __
A
dense irregular connective tissue
blood vessels
12
Q
where is the submucosal plexus found?
A
submucosa
13
Q
which layer of the GI tract is missing in the mouth?
A
submucosa
14
Q
A
15
Q
A
16
Q
muscularis externa are two layers of smooth muscle with a ___ in between
A
nerve plexus (myenteric plexus)
17
Q
layers of muscularis externa
A
a. Inner circular layer (smooth muscle): reduces gut diameter
b. Myenteric Plexus (enteric nervous system)
c. Outer longitudinal layer (smooth muscle): reduces gut length
18
Q
Adventitia
A
outermost layer of GI tract
loose CT
Inside the abdominal cavity (intraperitoneal), the adventitia is draped by serous membranes (mesothelium) and is renamed “serosa”
19
Q
Inside the abdominal cavity (intraperitoneal), the adventitia is draped by serous membranes (mesothelium) and is renamed ___
A
serosa
20
Q
A
21
Q
how is gut innervated?
A
autonomic innervation
parasympathetic
sympathetic
enteric
22
Q
parasympathetic innervation of the GI promotes
A
rest and digest
passage of food through GI
23
Q
Parasympathetic innervation to the upper g.i.: ___: innervation to mouth, pharynx, esophagus, stomach, duodenum, pancreas, liver, etc.
A
Vagus Nerve (cranial nerve X)
24
Q
Parasympathetic innervation to the lower g.i.: ___: particularly important for defecation.
A
Pelvic Nerve
25
autonomic sympathetic innervation of the GI promotes \_\_\_
fight or flight
inhibits digestion: closes sphincters, inhibits enteric motor neurons
26
Sympathetic innervation to the g.i. arises from ___ - preganglionic fibers arise from the celiac, cranial, caudal mesenteric ganglia.
T5 - L2 (splanchnic nerves)
27
what is the function of the ENS
enteric nervous system
controls g.i. movements, secretions, regional blood flow, fluid flow, etc.
activity of ENS can be regulated by autonomic nervous system ( parasympathetic= rest and digest)
28
what are the two plexi of the ENS
enteric nervous system
## Footnote
I. Outer plexus: Myenteric (Auerbach’s)
II. Inner plexus: Submucosal (Meissner’s)
29
outer plexus of the ENS
**Myenteric (Auerbach’s)**
a. Lies between the **inner circular and outer longitudinal layers of the muscularis externa.**
b. Controls the overall muscle tone of the gut as well as its rhythmic contractions (**peristalsis**).
c. **Peristalsis:** stimulated by distension of the gut. Inner circular layer of muscularis externa forms a contractile ring - squeezing around the gut. Outer longitudinal layer then contracts – pushing bolus caudally. At the same time, the distal gut relaxes, allowing food to enter.
d. **Anti-peristalsis:** regurgitation & vomiting.
30
myenteric plexus of ENS
31
what is 4
myenteric plexus of the ENS
32
Myenteric (Auerbach’s) controls ___ of the GI tract which \_\_\_
Peristalsis:
movement of food through the GI tract
33
Submucosal plexus of the ENS lies within the \_\_\_
submucosal layer
34
The inner plexus of the ENS oversees the \_\_\_
localized secretions and absorptions of the epithelium in the lumen, regulation of blood flow, etc.
35
\_\_\_ is responsible for localized contractions of the \_\_\_and the villi of the gut.
inner plexus, submucosal plexus, meissner's
muscularis mucosae
36
name for plexus of ENS within the 2nd layer of the GI
Inner plexus: Submucosal (Meissner’s)
37
38
the mouth is where food is chewed into a\_\_\_, partially digested, and lubricated by \_\_\_.
bolus
salivary glands
39
The oral cavity is lined by ___ epithelium which can have a range of keratinization based on diet.
stratified squamous epithelium
40
what is an easy way to determine oral vs aboral surface
aboral will have hair follicles and more keratinization (usually)
41
The tongue contains what type of glands
mucous and serous salivary glands
42
The core of the tongue is \_\_\_
Core of intrinsic **skeletal muscle,** arranged in three layers, all positioned at right angles to each other (*x*, *y*, and *z* planes).
43
44
Where are lingual papillae found
dorsal region of the tongue
45
what is the function of lingual papillae?
aid in retaining food and water, protection, and grooming.
46
\_\_\_ have a dermal core covered by stratified squamous epithelium (keratinized).
lingual papillae
47
3 types of lingual papillae that **lack** taste buds
filiform
conical
lenticular
48
Lingual Papillae *lacking* taste buds are used for \_\_\_
food/water acquisition, grooming, protection
49
Filiform lingual papillae are the ___ abundant type of papillae and are found on the ___ of the tongue
most
rostal ⅔ of the dorsal tongue
50
Filiform lingual papillae resemble small cones, apex points ___ and is highly ___ in cats
caudally
keratinized
51
Conical lingual papillae are found on the ___ of the tongue and are a subtype of \_\_\_
caudal ⅓
filiform
52
\_\_\_ type of lingual papillae are less abundant due to their large size
conical
53
\_\_\_ type of lingual papillae are only found in the oral cavity of a ruminant
lenticular
54
filliform papillae
55
filliform papillae of a cat
56
3 types of lingual papillae **with taste buds**
fungiform (mushroom)
circumvallate (dome)
foliate (rectangular blocks)
57
Fungiform lingual papillae are found where on the tongue?
lateral surface
mushroom shape (contain taste buds)
58
Curcumvallate lingual papillae are the ___ and form a __ shape that points __ on caudal ⅓ tongue
largest
“V” shape (apex pointing caudally) on caudal 1/3 tongue
59
\_\_\_ papillae are surrounded by a large circular trench
circumvallate (dome) (has taste buds)
60
\_\_\_ lingual papillae are common in rabbits and monkeys
foliate (rectangular blocks) (have taste buds)
61
filiform/ conical papillae
62
fungiform papillae
| (mushroom shape) (have taste buds)
63
Fungiform (mushroom): occupy lateral surfaces of tongue (have taste buds)
64
**Circumvallate** (dome): largest. Form a “V” shape (apex pointing caudally) on caudal 1/3 tongue. Each papillae surrounded by a large circular trench.
have **tastebuds**
65
foliate papillae rabbit (have tastebuds)
66
Taste Buds are ___ found on the sides of the lingual papillae and in other regions of mouth aside from the tongue.
specialized pores
67
taste buds consist of 50 - 150 cells, apical ends open into a \_\_\_
taste pore.
68
Each mature cell projects microvilli into the taste pore - these microvilli are in contact with the oral cavity and house ___ for chemical tastes
receptors
69
5 tastes
sweet, sour, salt, bitter, and *umami* (monosodium glutamate)
70
taste buds have 3 cell types
Taste Receptor Cells (“Gustatory”)
Immature / Supporting Cells
Basal Cells
71
In the cranial 2/3 of the tongue, the ___ (Cranial Nerve #7) is responsible for taste; while the sensations of touch, temperature, and pain are carried by the \_\_\_(Cranial Nerve #5).
facial nerve
trigeminal nerve
72
In the caudal 2/3 of the tongue, the ___ (Cranial Nerve #9), is responsible for both taste (primarily sweet and bitter) and overall sensation.
**glossopharyngeal nerve**
73
Tastebud
74
Salivary gland are compound ___ glands
exocrine
acinus (berry shape)
75
76
77
serous glands (\_\_\_) that produces \_\_\_
*Serous glands* (parotid / exocrine pancreas)
thin watery serous fluid containing numerous enzymatic & antimicrobial properties.
78
Secretory cells in serous glands store their secretions in \_\_\_
secretory granules
also called zymogen
(inactive precursors to digestive enzymes).
79
mucous glands produce \_\_\_
Produce **mucin,** a thick viscous fluid composed of glycoprotein.
Salivary mucin is similar to intestinal mucin, additionally has **antibacterial properties** in forming a protective film over the teeth.
80
The precursor of mucin is ___ and is stored in the ___ cells of the mucous glands
mucinogen
secretory
81
what are some functions of the salivary gland
lubrication of mouth and food
antimicrobial (serous glands mostly)
digestive component
buffering agent
tooth protection
82
what are some antimicrobials produced by the serous gland
**Lysozyme** (antibacterial agent)
**Lactoferrin** (antifungal, antiviral, and an antioxidant: binds up free iron)
**Salivary IgA** (neutralizes bacteria & yeast)
**Histitin** (inhibits fungal growth of *Candida albicans*)
83
How does salivary gland contribute to digestion
**Amylase (ptyalin)**: begins digestion of starches.
**Lingual lipase**: begins hydrolysis of fats.
84
How does salivary gland act as a buffering agent?
neutralizing acids & keeping pH neutral in oral cavity.
85
How does salivary gland act as a tooth protection
**mucins** and **salivary proteins** form a protective film on teeth: **pellicles**. Protects teeth from corrosive acids and bacteria
86
87
The serous demilune (half moon) morphology is not real-it’s an artifact caused by \_\_\_, driving mucinous cells to swell, pushing ___ cells to the outside.
formalin
serous
88
89
\_\_\_ cells are **e****pithelial** in origin, but have ___ properties usually associated w/ mesenchymal cells (eg, smooth muscle actin).
myoepthithelial cells
contractile
90
\_\_\_ aid in expulsion of acinar contents
myoepithelial cells
91
esophagus has two sphincters
Upper esophageal sphincter (proximal) : lies at the entranceway to the pharynx (cricopharyngeus muscle).
Lower esophageal sphincter (distal): relaxes to allow food to pass into stomach; constricts to prevent gastric reflux.
92
what muscle lies at the entranceway to the pharynx
cricopharyngeus muscle
upper esophageal sphincter (proximal)
93
\_\_ is a disorder when esophageal sphincter does not fully close
GERD
GERD (**_G_**astro- **_E_**sophageal **_R_**eflux **_D_**isease)
94
\_\_\_ are disorders when the esophageal sphincter does not open fully
Achalasia & megaesophagus
95
the mucosa layer of the esophagus is ___ epithelium
stratified squamous
96
Mucosa & submucosa organized into longitudinal folds in a \_\_\_esophagus. These folds disappear as \_\_\_passes through.
non-distended
food
97
the esophagus has two types of glands: ___ and \_\_\_. They produce ___ and help lubricate epithelial surfaces
mucosal glands (in lamina propria) and submucosal glands
mucus
98
muscularis externa in the esophagus is ___ between species
differnt
99
typically the composition of the muscularis externa of the esophagus is
Upper 1/3: both layers are striated
Middle 1/3: mix of striated and smooth
Lower 1/3: all smooth
100
how are ruminants and dog esophagus different?
the muscularis externa is striated throughout instead of the
typically it is:
Upper 1/3: both layers are striated
Middle 1/3: mix of striated and smooth
Lower 1/3: all smooth
101
what nerve innervates the esophageal musculature
vagus nerve (cranial nerve #10)
102
103
a ___ surrounds the esophagus only below the diaphragm
serosa
104
avian tongue
3. cartilage core
105
crop of avian upper GI
* diverticula of the esophagus
* subcutaneous
* lies in the thoracic inlet
* avian equivalent of “cheeks” (for food storage)
* Epithelial cells produce a “crop milk” in pigeons for feeding young
106
Epithelial cells of the ___ produce a “crop milk” in pigeons for feeding young
crop
107
avian esophagus
108
avian crop (no glands)
109
salivary glands are compound ___ glands that have mucous cells that secrete ___ and serous cells that secrete \_\_
tubuloacinar
mucin
thin fluid rich in amylase
110
esophagus
111
glandular regions of the stomach
cardiac
fundic
pyloric
112
monogastric stomach
columnar epithelium
glandular stomach (has glands)
113
The fore stomach of the rumen is ___ epithelium.
the last chamber of the ruminant stomach is ___ epithelium and has \_\_\_
non glandular, stratified squamous
columnar epithelium
glands
114
115
horses and ruminants have large ___ regions of the stomach
nonglandular
116
Ruminant stomach serves to breakdown cellulose through actions of microbiota, primarily bacteria, but also \_\_\_, yeast, and fungi.
protozoa
117
what are the four chambers of a rumen stomach
the rumen, the reticulum, the omasum and the abomasum.
118
the \_\_\_,\_\_\_ and ___ have non glandular squamous epithelium, compared to the ___ which has glandular columnar epithelium
the rumen, the reticulum, the omasum
abomasum
119
order of food through cow stomach
the rumen, the reticulum, the omasum and the abomasum.
120
the function of the first 3 chambers of the cow stomach are \_\_
The function of the last chamber of the cow stomach is \_\_\_
physical mechanical breakdown of food
chemical/ glandular breakdown of food
121
This is where saliva and ingesta mix to form cud, which is regurgitated, chewed, swallowed, etc. Here microbes break down cellulose.
Rumen and Reticulum
122
\_\_\_ is where microbes break down cellulose in ruminant
rumen and reticulum
123
\_\_\_ part of the cow stomach can absorb H20 and inorganic minerals
omasum
124
\_\_\_ part of the cow stomach is analogous to the monogastric stomach
abomasum
125
rumen
papillae with **keratinized** stratified squamous epithelium
no muscularis mucosa
no glands
126
the rumen has no ___ and no \_\_\_
muscularis mucosa
glands
127
\_\_\_ has folds with keratinized stratified squamous epithelium and core of lamina propria only or a mix of lamina propria, submucosa and muscularis interna. Also has no glands
reticulum (second chamber of cow stomach)
128
reticulum (second cow stomach chamber)
## Footnote
keratinized stratified squamous epithelium
core of lamina propria:
**short:** only LP
**long:** submusoca and muscle (long)
129
\_\_\_ has large folds (laminae omasi) with keratinized stratified squamous epithelium. It also has no glands and muscle core of large folds derived from muscularis submucosa and muscularis externa
omasum
130
the large folds of the omasum are called
laminae omasi
131
muscle core of the laminae omasi of the omasum are derived form ___ and \_\_\_
muscularis submucosa and muscularis externa
132
omasum
133
**omasum**
1. circular TM
2. longitudinal TM
3. Circular TM
LP lamina propria
134
what are two ways glandular stomach homogenizes and processes food?
**chemically** via enzymes and acids secreted by the mucosa
**mechanically** via muscular churning of the stomach wall.
135
Epithelium changes from ____ (esophagus/esophageal stomach/rumen) to \_\_\_(glandular stomach).
stratified squamous
simple columnar
136
Glandular stomach is lined by longitudinal folds, or ___ which disappear when the stomach distends.
rugae
137
gastric mucosal barrier
Mucous cells in epithelium secrete a protective gel layer that:
protects stomach lining from **auto-digestion**
Protects stomach from **abrasion** with food
138
what is the box?
fundus
box is rugae
139
Cats have additional layer, \_\_\_\_, between glands and muscularis mucosae. It contains a layer of fibroblasts and a layer of dense collagenous fibers
lamina subglandularis
140
The lamina subglandularis contains a layer of ___ and a layer of \_\_\_. Is found in \_\_\_
fibroblasts
dense collagenous fibers
cats (extra layer between glands and muscularis mucosae in the stomach)
141
Glands in the cardiac part of the stomach secrete ___ and are ___ in shape
secretes mucus
-simple, coiled, tubular. lined by surface mucosal cells, parietal and enteroendocrine cells may be seen
142
Glands in the gastric (fundus) part of the stomach secrete ___ and are ___ in shape
secretes mucus, HCl & pepsinogen
tubular, lined by mucous neck cells
143
Glands in the pyloric part of the stomach secrete ___ and are ___ in shape
secretes mucus/lysozyme
simple, tubular, lined by mucous neck cells
144
glands of the cardiac part of the stomach are lined by \_\_\_
surface mucosal cells, parietal and EE cells may be seen.
145
glands of the gastric and plyoric part of the stomach are lined by \_\_\_
mucous neck cells
146
cardiac stomach of a dog
147
pyloric glands
148
gastric( or fundic glands) are found where \_\_\_
fundus and body of a glandular stomach
149
Shape of gastric (or fundic glands)
long tubular glands, divided into a pit, neck, and branched body.
150
pit of gastric or fundic glands have \_\_\_
mucous cells (produce gastric mucosal barrier)
151
The neck of gastric or fundic glands have \_\_\_
mucous cells and stem cells
152
The body of gastric or fundic glands have 5 types of cells
mucous cells
chief cells (produce pepsinogen)
parietal cells (produce HCl)
stem cells
enteroendocrine cells (produce gastric hormones)
153
fundic region of glandular stomach
154
155
gastric gland of glandular stomach
156
\_\_\_ cells line gastric pit and neck of fundic gland cells and produce \_\_\_
mucous
mucins
157
\_\_\_ produce mucins (glycoproteins), which combine with water to form a protective gel that lines the surface of the stomach.
mucous cells
158
Mucous cells form the \_\_\_\_, traps bicarbonate ions (HCO3), the alkalinity of which offsets the acids secreted by the gastric gland and keeps the pH immediately around the epithelium at \_\_.
gastric mucosal barrier,
7.0
159
If the mucus layer is disrupted, peptic ___ and/or adenocarcinoma of the stomach can result
ulcers
160
\_\_\_ cells are found in the neck and upper ⅓ of the fundic gland
parietal (oxyntic cells)
161
partietal cells produce\_\_\_ and stain \_\_\_
HCl
bright pink (negative)
162
parietal cells produce HCl which lowers the stomachs pH to \_\_
1 - 2
163
What stimulate parietal cells to produce Hcl
enteroendocrine hormone gastrin.
164
\_\_\_ cells are found in the lower ⅓ of the fundic gland
chief
165
Chief cells hold zymogenic granules containing \_\_\_
proenzyme pepsinogen
166
What color do chief cells stain?
purple (basophilic cytoplasm)
167
When pepsinogen is released into the stomach, it interacts with HCl to form \_\_\_
pepsin
168
\_\_\_ is a proteolytic enzyme that digests proteins and is a product of HCl and pepsinogen interacting
pepsin
169
stomach mucosa
gastric gland
170
\_\_\_ cells are found in mucosa along the GI
enteroendocrine
171
enteroendocrine cells are \_\_\_.
monohormonal
172
Enteroendocrine cells produce hormones that are released into the ___ and act ___ or \_\_\_
lamina propria
locally
enter the bloodstream and affect target cells
173
What is the function of enteroendocrine cells?
involved in regulation of water, enzyme secretion, motility of the g.i., mucosal growth, etc.
174
2 examples of enteroendocrine cells
G cells (gastrin)
D cells (somatostatin)
175
G cells
G Cells (Gastrin) (makes stomach more acidic)
i. Peptide hormone produced by G cells in **pyloric antrum**
ii. Stimulated by s**tomach distension, vagus nerve**, or by partially digested foodstuffs (proteins)
iii. Gastrin stimulates **parietal cells** in the stomach’s body to **produce HCl** (along with acetylcholine [vagus n.] and histamine)
176
gastrin is a peptide hormone produced by ___ in the \_\_\_\_
G cell
pyloric antrum of the glandular stomach
177
G cells are stimulated by
stomach distension
vagus nerve
partially digested foodstuffs (proteins)
178
Gastrin stimulates ___ cells in the stomach’s body to produce \_\_\_
parietal
HCl
179
D cells are located next to \_\_\_
G cells in the pyloric antrum of the stomach
180
D cells produce ___ which \_\_\_
somatostatin
suppress gastrin release
181
pyloric stomach
P= pyloric gland pit
G= G cells, secretes gastrin
182
the avian stomach is broken into the
proventriculus (glandular)
ventriculus/gizzard (nonglandular)
183
\_\_\_ cells secrete both pepsinogen and Hcl in the avian stomach
oxynticopeptic cells
184
the gizzard is also called the ___ and is the ___ part of the avian stomach
ventriculus
nonglandular (second part)
185
the ventriculus of the avian stomach function is to \_\_\_
grind ingesta
## Footnote
contains grit, lined internally by a cuticle, and externally by a thick muscularis externa.
186
ventriculus gizzard of bird stomach
187
pancreas has both ___ and ___ functions
exocrine and endocrine
188
islets of langerhans are found in the ___ and secrete
pancreas
alpha cells → glucagon
beta cells → insulin
189
exocrine enzymes made in the pancreas drain into the ___ via ducts
duodenum (1st part of small intestine)
190
exocrine pancreas is similar to ___ glands.
salivary
191
exocrine pancreas only have __ acini
serous
192
acinar cells of the exocrine pancreas contain ___ granules: released into the lumen of the acinus, which leads to intercalated ducts.
zymogen
193
In the exocrine pancreas, center of acinus is ringed by ____ cells: these are an extension of the intercalated duct into the acinus.
centroacinar
194
In the exocrine pancreas, Intercalated ducts secrete water and ___ (as in salivary glands).
bicarbonate
195
exocrine pancreas
196
the exocrine pancreas has no ____ cells
myoepithelial
197
what does the exocrine pancreas secrete?
**Sodium bicarbonate**
**Pancreatic amylase**
**Pancreatic lipase**
**Cells house zymogens**: e.g. Trypsinogen & Chymotrypsinogen: precursors to Trypsin & Chymotrypsin: digests proteins
198
\_\_\_ neutralizes acidity from chyme entering duodenum from the stomach.
sodium bicarbonate
199
\_\_\_ hydrolyses starches and other sugars to form tri- and disaccharides.
pancreatic amylase
200
\_\_\_ hydrolyses fats (along with bile salts, which emulsifies the fats so they can be absorbed in the small intestine).
pancreatic lipase
201
secretion of exocrine pancreas is controlled by \_\_\_
**Acetylcholine** (vagus n., parasympathetic):
**Cholecystokinin** (CCK, enteroendocrine hormone):
**Secretin** (enteroendocrine hormone):
202
\_\_\_ stimulates intercalated duct to produce bicarbonate.
Secretin (enteroendocrine hormone):
203
\_\_\_ stimulates acinar cells (& gall bladder).
Cholecystokinin (CCK, enteroendocrine hormone)
204
\_\_\_ stimulates acinar cells
Acetylcholine (vagus n., parasympathetic):
205
islets of langerhans
endocrine pancreas
## Footnote
**Beta cells:** secrete insulin (facilitates uptake of glucose by cells)
**Alpha cells:** secrete glucagon (breaks down stored glycogen in liver into glucose)
206
Each ____ contains 2000-3000 cells surrounded by a fenestrated capillary bed.
islet of langerhans (endocrine pancreas)
207
pancreas
208
pancreas
209
liver cells are called
hepatocytes
210
two blood supplies to the liver are
**Hepatic artery** (aorta: 25%, oxygenated, nutrient poor)
**Portal vein** (gut: 75%, deoxygenated, nutrient rich)
211
Hepatocytes produce \_\_\_, which first drain into small bile canaliculi (ducts) adjacent to the hepatocytes. These collect into larger collecting bile ducts, ultimately draining into the common bile duct emptying to the \_\_\_.
bile
duodenum
212
The Hepatic Artery, Portal Vein, and Bile duct form the \_\_\_
portal triad
213
basic functions of the liver:
**Remove glucose from the bloodstream** and stores it as glycogen. Releases glucose back into the bloodstream when needed.
**Detoxifies** ingested drugs and toxins.
**Eliminates senescent blood cells** and foreign bodies (Kupffer cells: macrophages-not hepatocytes).
**Remove fat from the blood supply** and degrade them into fatty acids and glycerol.
Stores **Vitamin A, D, and B12.**
**Produce bile** to aid in digestion (stored in gall bladder)
214
macrophages in liver
kupffer cells
215
kupffer cells
eliminate senescent blood cells and foreign bodies
216
pig liver
217
liver
218
direction of blood in the liver
will travel through portal triad, into lobule of liver, be cleaned and then leave through the central vein in the center of liver lobule then leaves liver through the hepatic vein
219
direction of bile in liver
bile that is made as blood is cleaned will travel out of the liver lobule and back into the portal triad/tract to be stored in the gallbladder or released into the small intestine
220
221
the ___ is found in the connective tissue outside the lobule of the liver. This is the point where blood enters the lobule and lymph/bile exits
portal tract/triad
222
223
\_\_\_ contain blood cells, its walls are fenestrated so hepatocytes are in direct contact with blood as it passes by
sinusoids
224
what cells react to liver damage and make fibrous scars?
stellate cells
225
gall bladder stores ___ and concentrates it between meals
bile
226
Bile is transported from the liver via \_\_\_
cystic ducts
227
\_\_\_ causes contraction of the gall bladder wall, triggering release of its contents. It also causes the contraction of the smooth muscle sphincter at the base of the common bile duct where it opens into the duodenum
CCK
Cholecystokinin (CCK, enteroendocrine hormone)
228
What animals do not have a gallbladder?
horses and rats
229
bile from liver to small intestine
liver common hepatic duct
cystic duct
gallbladder
back out through cystic duct
common bile duct
ampulla
major duodenal papilla
small intestine
230
gallbladder
231
gallbladder has ___ epithelium but has no ___ or \_\_\_.
simple columnar
muscularis mucosae or submucosa
232
The ___ of the gallbladder does not have 2 distinct layers but has fibers interspersed
muscularis externa
233
three parts of the small intestine
duodenum, jejunum-ileum
234
ridges/folds in the intestinal wall
plicae circulares
235
plicae circulares are folds of \_\_\_\_encircling lumen of the small intestine, viewable grossly. Unlike rugae of stomach, plicae circulares are permanent folds
mucosa & submucosa
236
the lumen on the small intestines have plica circularis which have ___ along their edges
villi
237
Villi are fingerlike projections of ____ *only* into lumen of gut.
*mucosal layer*
238
Villi are lined by ____ epithelium
simple columnar
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. Enterocytes are surface absorptive cells which have ___ on their apical end
microvilli- form brush border
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Microvilli contain an\_\_\_ core, movement triggered by submucosal (Meissner’s) plexus.
actin
(micovilli are on the villi on the plica of the wall of the intestine)
increased surface area
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the villi of the small intestine are filled with lamina propria that house
lacteal, capillaries and muscularis mucosa
(lacteal- open ended lymph capillary)
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microvilli also contain enzymes such as lactase, maltase, and sucrase, involved in the terminal digestion of \_\_\_
carbohydrates and proteins.
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The brush border on enterocytes (\_\_\_) has two functions: increase surface area for absorption and increase surface area for ___ that perform final stages of extracellular digestion, preparing them for transport across the cell membrane.
(plica of the small intestine are lined with villi- enterocytes are one of the cell types that line the villi- have brush border)
enzymes
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villi are lined with \_\_\_, and project out into the lumen of the intestine.
single layer of columnar epithelial cells.
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villi in the small intestine are attached to the ___ that are imbedded within the lamina propria. These ___ have stem cells and produce enzymes used to keep intestinal bacteria at bay.
crypts
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an enterocyte- have brush border of micorvilli
a cell on the border of a villi on the plica of the intestinal wall
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Three types of cells found on the villi of the plica of the small intestine
enterocyte- absorption
goblet- mucus producing
enteroendocrine- secrete hormones basally (to base of the cell, not into the lumen)
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\_\_\_\_ produce a gel coat of mucus to protect the lumen from abrasion and bacterial invasion
Goblet cells:
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what can you find inside a villi in the small intestine
core of each villus (in the lamina propria):
1. Capillary plexus
2. Lacteal: blind-ended lymphatic vessel
3. Thin strands of muscularis mucosae
4. Lymphocytes, eosinophils, macrophages, etc.
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villi in small intestine
## Footnote
enterocyte- absorption
goblet- mucus producing
enteroendocrine- secrete hormones basally (to base of the cell, not into the lumen)
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enteroendocrine cell in the small intestine on the villi in the intestine
release hormones basely
252
intestinal crypts also called \_\_\_
crypts of lieberkuhn
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\_\_\_ are simple tubular glands in the intestine
crypt of lieberkuhn
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Crypts (aka crypts of Lieberkühn or intestinal glands) contain:
b. Stem cells - give rise to all intestinal cells.
c. Enteroendocrine cells.
d. **Paneth cells** at base (SI only): protect lining of gut from microorganisms such as bacteria & parasites (secrete lysozymes & defensins) (absent in some animals-*dogs, cats, pigs, racoons*)
e. sometimes Goblet cells
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\_\_\_\_ at base (SI only): protect lining of gut from microorganisms such as bacteria & parasites (secrete lysozymes & defensins) (absent in some animals-*dogs, cats, pigs, racoons*)
**Paneth cells**
256
Paneth cells protect the small intestine from ___ by producing lysozmes and defensins
microorganisms such as bacteria & parasites
257
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paneth cells found in the base of the crypts of the small intestine
## Footnote
Unlike enteroendocrine cells, secretions from Paneth cells enter lumen directly, they do not enter the bloodstream.
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Unlike enteroendocrine cells, secretions from Paneth cells enter ___ directly, they do not enter the bloodstream.
lumen
260
\_\_\_ can be used to see stem cells from the cyrpt changing/growing into enterocytes
BrdU
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where is this
small intestine
can see crypt and vili
paneth cells and stem cells alternating at base of the crypts
262
subepithelial telocytes line the \_\_\_
crypts of the small intestine
help with Wnt
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\_\_\_ are found in the duodenum and produce mucus and bicarbonate to offset the acidic chyme expelled from the stomach
brunner's glands
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brunner gland's are found where are make what?
submucosa of the duodenum
mucus and bicarbonate- offset the acid form the stomach
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the villi in the duodenum is \_\_\_
short, broad and leaf-like
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The serosal lining is incomplete (adventitia complete) in which part of the small intestine
duodenum
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the bile and pancreatic ducts are found \_\_\_
in the duodenum
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\_\_\_ cells are found in the base of crypts of Lieberkühn in the duodenum
paneth- protect lining of gut from microorganisms such as bacteria & parasites (secrete lysozymes & defensins)
## Footnote
Unlike enteroendocrine cells, secretions from Paneth cells enter lumen directly, they do not enter the bloodstream.
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what glands are found in the submucosa of the duodenum
brunner's gland- bicarbonate
270
gastric pits change into ___ in the duodenum
villi
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found in the submucosa of the duodenum- makes bicarbonate (ph9\_ to neutralize acidic chyme from the stomach
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duodenum- 3 cell type
enterocytes- with microvilli
goblet cells
enteroendocrine- hormones into base of cell
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which part of the intestine have the longest villi?
jejunum
274
how to tell you are in the jejunum
a. *Longest villi*
b. Abundant Paneth cells in of crypts of Lieberkühn
c. **No glands in submucosa** (no brunner's gland like in the duodenum)
275
where are we
jejunum
=no glands in the submucosa
276
how to tell ileum?
. Shorter villi
b. Paneth cells (not consistently present)
c. **Peyer’s patches in submucosa**.
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peyer's patch is found where?
ileum (last part of the small intestine)
278
ileum
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\_\_\_ cells are found in the ileum and transport antigens from the lumen into the peyers patch
M Cells
280
\_\_\_ are specialized lymphatic nodules found in the ileum
peyer's patch
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how does M cell work?
M ( = **_M_**icrofold) cells specialized epithelial cells that contain small microfolds on their lateral edges (viewable only under EM).
M cells sample and **trap antigens** from the lumen of the gut via endocytosis. **Antigen are then released beneath** M cells and taken up by antigen-presenting dendritic cells in the underlying dome. A**ntigens are then presented to T cells** to initiate an immune response.
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peyer's patch ileum
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peyer's patch of the ileum
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parts of the large intestine
cecum
colon
rectum
anus
285
function of the large intestine
***absorption of water, electrolytes (Na+,Cl-), vitamins, and minerals*****.**
Further digestion of any undigested carbohydrates via microbial fermentation. Formation of feces. Synthesized items include: various B vitamins, vitamin K+, Volatile Fatty Acids (VFAs), and mucus (bicarbonate)
286
\_\_\_ has no villi or folds
large intestine (colon)
287
epithelium of the colon is ___ and is composed of ___ cells
simple columnar
## Footnote
1) enterocytes (absorptive) with microvilli
2) goblet cells (secrete bicarbonate rich mucus)
3) enteroendocrine cells
4) stem cells at crypt base
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\_\_\_ serves to protect intestinal wall from excoriation, to hold fecal material together, and to protect intestinal wall from bacteria within feces.
Mucus
289
paneth cells are in the \_\_\_-
small intestine
should not be in the large intestine
290
taeniae coli
longitudinal smooth muscle bands (part of the muscularis externa: outer longitudinal) which generate the **haustra (sacculations)**. IE, muscle bands form bulges in colon.
291
. Taeniae coli: longitudinal smooth muscle bands (part of the \_\_\_: outer longitudinal) which generate the \_\_\_(sacculations).
muscularis externa
haustra
292
\_\_\_\_: aid in digesting cellulose & help form thiamine (B1), riboflavin (B2), cobalamin (B12), Vitamin K (blood clotting), & intestinal gas
Bacterial flora
293
large intestine
294
colon
crypts much deeper and no villi
lots of goblet cell- mucus producing cells
295
large inestine
outer layer (longitudinal) muscularis externa bunches into the taeniae coli and produces sacculations of the small intestine
296
difference between small and large intestine
duodenum- brunner's glands
jejunum- long villi- no glands in submucosa
ileum- peyers patch
large- no villi- very long crypts
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from rectum to anus: Epithelium abruptly changes from \_\_\_(rectum) to ___ at recto-anal junction.
simple columnar
stratified squamous
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At the recto-anal junction the outer longitudinal layer of muscularis externa \_\_\_at junction, and the *inner circular layer becomes \_\_\_*
ends
*the internal anal sphincter* (normally contracted, autonomic control)).
299
The external anal sphincter is ____ muscle (also normally contracted, voluntary control).
skeletal
300
\_\_\_\_ epithelum gives rise to cutaneous epithelium with hair follicles, sebacious and sweat glands at the mucocutanous junction
Stratified squamous
301
anus to rectum
abrupt change from columnar to stratified squamous
302
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how can you tell you went to outside of the body anus- cutaneous
hair follicle, sebacious and sweat glands
304
Three sets of glands near the anus
1. **Glands of the anal sac**: Scent & territorial markers.
2. **Anal glands**: located in the submucosa.
3. **Perianal/Circumanal glands**: the most caudal, sebaceous and nonsebaceous components-polygonal appearance of cells.
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\_\_\_\_/Circumanal glands: the most caudal, sebaceous and nonsebaceous components-polygonal appearance of cells.
Perianal
306
anal sac vs anal gland
anal glands produce secretions into the anal sacs
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