Lecture 17 - Gastrointestinal System Part II Flashcards
1
Q
a common passageway for food, liquid, and air, and has stratified squamous epithelium
A
the pharynx
2
Q
where does the pharynx end?
A
the proximal esophagus and trachea
3
Q
how is the pharynx innervated?
A
CN X
4
Q
what is the purpose of the palatal muscles in the pharynx?
A
elevates the soft palate during swallowing
5
Q
what is the purpose of the pharyngeal constrictors and suprahyoid muscles in the pharynx?
A
elevates the larynx and pushes the bolus towards the esophagus
6
Q
what is the bolus?
A
chewed food mixed with saliva
7
Q
propels the bolus along the length of the tube and occurs by coordination of circular and longitudinal muscles
A
peristalsis
8
Q
mechanical digestion where contents are churned and mixed by mainly circular muscles
A
segmentations
9
Q
type of muscle contraction along the gut tube where there is no movement in any particular direction
A
segmentation
10
Q
a hollow tube that is made of stratified squamous epithelium and leads to the stomach
A
esophagus
11
Q
how long is the esophagus?
A
~25cm long (C6-T7)
12
Q
what type of muscles are found in the esophagus?
A
skeletal and smooth muscles (flat when empty)
13
Q
what is the purpose of the extra glands in the submucosal layer of the esophagus?
A
to secrete mucus (allows for easy passage of the bolus)
14
Q
how is the esophagus innervated?
A
by CN X
15
Q
how does the esophagus prevent acid reflux and acid erosion?
A
- lower esophageal sphincter
- peristaltic clearance
- stratified squamous epithelium
- submucosal glands
- mucus glands from the stomach
16
Q
muscular sac that stores food temporarily and is the only place along the tube with chemical digestion
A
the stomach
17
Q
is the stomach intraperitoneal or retroperitoneal?
A
intraperitoneal
18
Q
where does the stomach get its vasculature from?
A
the celiac trunk
19
Q
what is the function of the stomach?
A
mechanically breaks down bolus of food, chemically and enzymatically digests food, and mixes the bolus and gastric juices to form chyme
20
Q
how does the stomach mechanically break down the food bolus?
A
through contractions of muscular wall
21
Q
how does the stomach chemically and enzymatically digest food?
A
through actions of secreted acid and enzymes
22
Q
what are the seven major components of the stomach?
A
- fundus
- cardia
- body
- greater curvature
- lesser curvature
- pyloric canal
- pyloric sphincter
23
Q
the stomach is lined with what type of tissue?
A
simple columnar epithelium
24
Q
what are the three layers of smooth muscle in the stomach?
A
- inner oblique
- middle circular
- outer longitudinal
25
the inner oblique muscles of the stomach form ____ which are capable of ____
rugae, stretching
26
what are the five types of secretory cells found in the stomach?
- surface mucus cells
- mucus neck cells
- parietal cells
- chief cells
- enteroendocrine cells
27
stomach cells which produce secretions that activate H+, Cl-, and enzymes (cells are a little more watery than surface mucus cells)
mucus neck cells
28
stomach cells which make acid in the form of H+ and Cl- ions
parietal cells
29
stomach cells that make enzymes like pepsin and lipase
chief cells
30
stomach acids and enzymes don't become active until:
they pass through the mucus neck cells
31
cells found in the fundus of the stomach which secrete gastrin
enteroendocrine cells
32
what is the function of gastrin?
stimulates parietal cells, chief cells, mucus neck cells, and mucus surface cells
33
the small and large intestines are lined by:
simple columnar epithelium
34
what are the three main parts of the small intestine?
duodenum, jejenum, and ileum
35
how long is the small intestine?
6-7m long
36
the longest part of the digestive tube
the small intestine
37
what is the function of the small intestine?
specialized for absorption
38
is the small intestine intraperitoneal or retroperitoneal
mostly intraperitoneal (exception: most of the duodenum)
39
25cm C-shaped segment of the tube located in the RUQ which is both intraperitoneal and retroperitoneal
duodenum
40
where does the duodenum receive secretions from?
the pancreas and the liver (via the gallbladder)
41
what is the function of the duodenum?
digestion of fat, proteins, and sugars
42
where does the duodenum receive its vasculature from?
anastamosis of the celiac trunk and SMA
43
provides abundant alkaline mucus to neutralize the acid contents entering the duodenum from the stomach (in addition to pancreatic buffers)
Brunner's glands
44
where are Brunner's glands found?
the submucosal layer of the duodenum
45
why is it that only structures before and after the stomach have submucosal glands?
because of the high acidity of the stomach
46
bile is secreted by the _____ and is stored in the _____ before being secreted into the duodenum
liver, gallbladder
47
what is the function of bile?
aids in digestions of lipids
48
secretes enzymes that aid in digestion of fats, proteins, and carbs, and secretes a bicarbonate buffer
the pancreas
49
chyme in the duodenum stimulates the mucosa to produce hormones by enteroendocrine cells in order to release:
pancreatic juice and bile
50
located posterior to the stomach, and between the duodenum and spleen
pancreas
51
is the pancreas intraperitoneal or retroperitoneal?
retroperitoneal (in the upper quadrants)
52
where does the pancreas get its vasculature from?
anastomosis of the celiac and SMA branches
53
what type of gland is the pancreas?
an endocrine and exocrine gland
54
what are the functions of the pancreas in the digestive system?
secretes digestive enzymes (digests food in the small intestines), and secretes bicarbonate buffer (neutralizes acidic chyme and establishes alkaline pH for pancreatic digestive enzymes)
55
the main pancreatic duct drains into the:
hepatopancreatic ampulla
56
the head of the pancreas is associated with:
the curvature of the duodenum
57
the tail of the pancreas touches the:
spleen
58
what is the path of venous drainage of the pancreas?
blood passes through the splenic vein to the hepatic portal vein
59
which pancreatic cells produce exocrine secretions?
pancreatic acini
60
what molecules are secreted by the pancreatic acini?
water, ions, digestive enzymes, and buffers (sodium bicarbonate)
61
what is the function of pancreatic exocrine secretions?
neutralize acidic chyme and break down ingested material
62
pancreatic cells which secrete digestive enzymes (amylase, lipase, and proteinase)
acinar cells
63
pancreatic cells which secrete bicarbonate buffer and regulate pre-enzyme release from acinar cells
centroacinar cells
64
digestive enzymes secreted by acinar cells are not activated until exposed to _____
centroacinar cells and chyme
65
the largest gland in the body
the liver
66
is the liver intraperitoneal or retroperitoneal?
intraperitoneal
67
where does the liver get its vasculature from?
the celiac trunk (hepatic artery) and hepatic portal vein
68
what are the three major functions of the liver?
- metabolic regulation
- hematological regulation
- synthesis and secretion of bile
69
how is the liver involved in metabolic regulation?
regulates circulating levels of all that is absorbed by the intestines, inactivates toxic compounds and metabolic wastes, and is involved in metabolism of carbs, proteins, and fat
70
how is the liver involved in hematological regulation?
destroys aged/damaged red bloods cells, cellular debris, and pathogens; and secretes plasma proteins into the blood
71
which vessels make up the portal triad?
- bile duct (flow out)
- hepatic artery proper (flow in)
- hepatic portal vein (flow in)
72
where is the portal triad located?
in the lesser omentum
73
oxygenated and deoxygenated nutrient-rich blood mix in the _____
liver
74
blood with appropriate levels of metabolites is carried from the liver to the ______ by the ______
inferior vena cava, left and right hepatic veins
75
large lipids delivered directly to the general circulation via the ______
lymphatic system
76
liver lobules are made up of ____
hepatocytes
77
cells which break down old/damaged red blood cells (act as macrophages)
Kupffer cells
78
what is the endocrine function of sinusoids in the liver?
take substances up from the blood and secretes substances into the blood
79
exocrine surfaces in the liver form small channels called _____, these exocrine cells secrete ______ into the ______
canaliculi, bile, canaliculi
80
bile from the liver is concentrated and stored in the _____
gallbladder
81
when the hepatopancreatic sphincter is closed, bile flows into the gallbladder via the:
cystic duct
82
when the hepatopancreatic sphincter is open, bile flows into the duodenum via the:
bile duct
83
the presence of chyme in the duodenum induces release of the hormone ______, which induces relaxation of the ______ and contraction of the ______
cholecystokinin (CCK), the hepatopancreatic sphincter, gallbladder
84
is it possible to have an accessory pancreatic duct in addition to the main pancreatic duct?
yes
85
- the second segment of the small intestine
- located in the upper abdominal quadrants
- intraperitoneal
- SMA and vein (midgut)
these are all characteristics of the:
jejenum
86
the majority of nutrient absorption in the digestive tube occurs in the:
jejenum
87
the jejenum begins at the:
duodenojejunal flexure
88
why is the jejenum redder than the ileum?
has more blood
89
contains large plicae circulares (folds) which are more numerous than in the ileum
jejenum
90
- final segment of the small intestine
- located in the lower quadrants of the abdomen
- intraperitoneal
- SMA and vein (midgut)
these are all characteristics of the:
ileum
91
what is the function of the ileum?
absorption of remaining nutrients
92
the ileum contains lymph nodules known as _____ which protects the small intestine from _____
Peyer's patches, colonic bacteria
93
with all of the folds and villi in the small intestine, the surface area increases by:
600x
94
what is the average length and diameter of the small intestine?
~5-6m long, and ~2.5-4cm wide
95
what are the 4 types of villar epithelial cells found in the small intestine?
- absorptive cells
- goblet cells
- enteroendocrine cells
- paneth cells
96
cells in the small intestine which produce mucus to lubricate the tube
goblet cells
97
cells in the small intestine which act as regulators by releasing many hormones
enteroendocrine cells
98
cells in the small intestine which provide immunity by killing some bacteria and determining gut flora (the microbiome)
paneth cells
99
monosaccharides and amino acids are absorbed by the villi and are brought into the:
hepatic portal circulation
100
fats are too big to travel through the hepatic portal circulation, and are deposited into the ______ which drains into the _____ before going to the ______
thoracic duct, heart, liver
101
horseshoe-shaped tube which is ~1.5m long and 7.5cm wide, located in all quadrants
the large intestine
102
is the large intestine intraperitoneal or retroperitoneal?
both!
intraperitoneal = cecum, transverse, and sigmoid
retroperitoneal = ascending, descending, and rectum
103
where does the large intestine receive its vasculature from?
the SMA and IMA (and their associated veins)
104
what are the three major functions of the large intestine?
- reabsorbs water and electrolytes
- absorbs important vitamins produced by colonic bacteria
- compacts and stores feces
105
true or false: the lage intestine has its own enteroendocrine cells
true
106
segments of the large intestine which can enlarge and contract, helps to package and move feces
haustrum (haustra)
107
3 strips of longitudinal smooth muscle which contract to push things along the large intestine
teniae coli
108
the ascending colon becomes the transverse colon at the:
right colic (hepatic) flexure
109
the transverse colon becomes the descending colon at the:
left colic (splenic) flexure
110
what types of epithelium are found in the large intestine?
absorptive cells and goblet cells
111
cells in the large intestine which absorbe water via osmosis
absorptive cells
112
cells in the large intestine produce lots of mucus to move waste towards the rectum
goblet cells
113
- made of simple columnar epithelium
- ~15cm long
- temporary storage for feces
- triggers the urge to defacate (stimulates internal anal sphincter)
these are all characteristics of the:
rectum
114
does the rectum contain absorptive cells?
no, just goblet cells
115
what type of epithelium is found in the anal canal?
stratified squamous epithelium
116
muscles that thicken and become the external anal sphincter
levator ani
117
the line between autonomic and somatic innervation in the anal canal
pectinate line
118
the anal column, sinus, and valve form the:
beginning of the anal canal
