GIT 🍫ℹ️ Flashcards
(215 cards)
1
Q
The organs of the digestive system fall into two main groups ..
A
1) the alimentary canal
2) accessory digestive organs
2
Q
The alimentary canal, also called ..
A
gastrointestinal (GI) tract or gut.
3
Q
The alimentary canal ..
A
Continuous muscular tube span through the body from the mouth to the anus.
4
Q
The alimentary canal function ?
A
Digestion & absorption
5
Q
The organs of the alimentary canal
A
Mouth —> pharynx —> esophagus —> stomach —> small intestine —> large intestines
6
Q
The accessory digestive organs are ..
A
Teeth, tongue, gall bladder
& secretory large glands —-> liver, pancreas, salivary glands
7
Q
The accessory digestive organs are functions ..
A
Secrete digestion substances ..
8
Q
The processing of food by the digestive system involves six essential activities ..
A
- Ingestion
- Propeulsion
- Mechanical breakdown
- Digestion
- Absorption
- Defecation
9
Q
Ingestion ..
A
taking food into the digestive tract (eating).
10
Q
Propulsion ..
A
moves food through the alimentary canal.
includes swallowing, voluntarily, and peristalsis an involuntary process.
11
Q
Mechanical breakdown ..
A
increases the surface area of ingested food, physically preparing it for digestion by enzymes.
12
Q
Mechanical processes include ..
A
chewing
mixing food with saliva
churning food in the stomach
segmentation (rhythmic local constrictions of the small intestine)
13
Q
Segmentation function?
A
mixes food with digestive juices and makes absorption more efficient
14
Q
Digestion ..
A
catabolic steps in which enzymes secreted to break down complex food.
15
Q
Absorption ..
A
the passage of digested end products from the GI tract through the mucosal cells by active or passive transport into the blood or lymph.
16
Q
Defecation ..
A
eliminates indigestible substances from the body via the anus in the form of feces.
17
Q
The peritoneum of the abdominopelvic cavity is the most extensive serous membrane.
T/F
A
True
18
Q
The visceral peritoneum
A
covers the external surfaces of most digestive organs and is continuous with the parietal peritoneum that lines the body wall.
19
Q
parietal peritoneum ..
A
Lines body wall
20
Q
Between the two peritoneums is the ..
A
peritoneal cavity, a slitlike potential space containing a slippery fluid secreted by the serous membranes.
21
Q
The serous fluid allows ..
A
the mobile digestive organs to glide easily
22
Q
mesentery ..
A
double layer of peritoneum— a sheet of two serous membranes fused back to back—that extends to the digestive organs from the body wall.
23
Q
Mesenteries provide ..
A
routes for ..
blood vessels
lymphatics
nerves
hold organs in place
store fat
24
Q
retroperitoneal
A
organs that lose their mesentery and come to lie posterior to the peritoneum.
include most of the pancreas and duodenum and parts of the large intestine,
25
intraperitoneal or peritoneal organs.
digestive organs (like the stomach) that keep their mesentery and remain in the peritoneal cavity
26
From the esophagus to the anal canal, the walls of the alimen- tary canal have the same four basic layers
mucosa
submucosa
muscularis externa
serosa
27
The Mucosa ..
innermost layer which is moist epithelial membrane that lines the alimentary canal lumen from mouth to anus.
28
The Mucosa functions are ..
Secrete mucus, digestive enzymes, and hormones
Absorb the end products of digestion into the blood
Protect against infectious disease
29
typical digestive mucosa consists of three sublayers ..
(1) a lining epithelium
(2) a lamina propria
(3) a muscularis mucosae.
30
mouth, esophagus, and anus where the epithelium is ..
stratified squamous
31
the epithelium of the mucosa is ..
simple columnar epithelium, rich in mucus-secreting cells.
The slippery mucus it produces protects digestive organs from being digested
32
stomach and small intestine, the mucosa also contains both enzyme-synthesizing and hormone-secreting cells.
T/F
True
33
The lamina propria ..
(proprius = one’s own)
underlies the epithelium
is loose areolar connective tissue.
Its capillaries nourish the epithelium and absorb digested nutrients.
34
External to the lamina propria is the
muscularis mucosae ..
a scant layer of smooth muscle cells that produces movements for the mucosa that can enhance absorption and secretion.
35
submucosa ..
just external to the mucosa ..
areolar connective tissue
containing a rich supply of blood and lymphatic vessels, lymphoid follicles, and nerve fibers which supply the surrounding tissues of the GI tract wall
36
Submucosal is abundant of elastic fibers enabling the stomach to ..
regain its normal shape after temporarily storing a large meal.
37
The Muscularis Externa
Surrounding the submucosa is the muscularis externa, or muscularis.
It is responsible for segmentation and peristalsis.
It typically has an inner circular layer and an outer longitudinal layer of smooth muscle cells
38
In several places along the tract, the circular layer thickens, forming sphincters that act as valves to ..
control food passage from one organ to the next and prevent backflow.
39
The serosa ..
the outermost layer of the intraperitoneal organs, is the visceral peritoneum.
40
The serosa formed of ..
areolar connective tissue covered with mesothelium, a single layer of squamous epithelial cells.
41
esophagus, the serosa is replaced by an ..
adventitia, ordinary dense connective tissue that binds the esophagus to surrounding structures.
42
Retroperitoneal organs have both an adventitia (on the side facing the dorsal body wall) and a serosa (on the side facing the peritoneal cavity).
T/F
True
43
The splanchnic circulation includes ..
the arteries that branch off the abdominal aorta to serve the digestive organs
the hepatic portal circulation.
44
arterial supply of the splanchnic circulation are ?
the branches of the celiac trunk that serve
🥩 the spleen
🍕 liver
🌭 stomach
🍦 and the mesenteric arteries that serve the small and large intestines
45
hepatic portal circulation ..
collects nutrient-rich venous blood draining from the digestive viscera and delivers it to the liver.
46
enteric nervous system or the gut brain ..
The great regulator of the GI tract which consists of over 100 million neurons.
47
The enteric nervous system ..
is the in-house nerve supply of the alimentary canal.
It is staffed by enteric neurons
48
The enteric nervous system is staffed by ..
enteric neurons that communicate widely with one another to regulate diges- tive system activity
49
intrinsic nerve plexuses are composed of ..
ganglia interconnected by unmyelinated fiber tracts
50
two major intrinsic nerve plexuses found in the walls of the alimentary canal are ..
the submucosal
the myenteric nerve
51
The submucosal nerve plexus occupies the ..
submucosa
52
the large myenteric nerve plexus lies ..
between the circular and longitudinal muscle layers of the muscularis externa ..
53
submucosal nerve plexus and the large myenteric nerve plexus of the Enteric neurons provide ..
major nerve supply to the GI tract wall.
control GI tract motility (motion).
54
Short reflexes ..
mediated entirely by enteric nervous sys- tem plexuses in response to stimuli within the GI tract.
55
Control of the patterns of segmentation and peristalsis is largely ___________, involving ..
Automatic, involving pacemaker cells and reflex arcs between enteric neurons in the same or different organs.
56
Long reflexes ..
involve CNS integration centers and extrinsic autonomic nerves.
57
The enteric nervous system sends information to the central nervous system via ..
afferent visceral fibers.
58
ENS receives sympathetic and parasympathetic branches (motor fibers) of the autonomic nervous system that enter ..
the intestinal wall to synapse with neurons in the intrinsic plexuses
59
Long reflexes can be initiated by stimuli arising inside or outside of the GI tract.
T/F
True
60
parasympathetic inputs enhance _________ and sympathetic inpulses __________ .
Digestive activities, inhibit them respectively.
61
The mouth is also called ..
the oral cavity, or buccal cavity.
62
Mouth boundaries are ..
🦷 anterior opening is the **oral orifice**
🦷 the lips anteriorly
🦷 cheeks laterally
🦷 palate superiorly
🦷 tongue inferiorly
🦷 Posteriorly is continuous with the oropharynx.
63
The walls of the mouth are lined with ..
a thick stratified squamous epithelium ..
64
thick stratified squamous epithelium function in the mouth ..
withstands considerable friction.
65
The epithelium is slightly keratinized in ? And why ?
on the gums, hard palate, and dorsum of the tongue.
for extra protection against abrasion during eating.
66
The lips (labia) and the cheeks function?
help keep food between the teeth when we chew
67
The lips (labia) and the cheeks, are composed of ..
a core of skeletal muscle covered externally by skin.
68
the fleshy lips are formed by which muscle ?
The orbicularis oris muscle
69
the cheeks are formed largely by which muscle?
the buccinators.
70
oral vestibule is ..
The recess bounded externally by the lips and cheeks and internally by the gums and teeth.
71
The oral cavity proper ..
area that lies within the teeth and gums ..
72
The labial frenulum ..
is a median fold that joins the internal aspect of each lip to the gum.
73
The palate forming ..
the roof of the mouth.
74
The palate has two distinct parts:
hard palate anteriorly and the soft palate posteriorly
75
The hard palate is underlain by ..
the palatine bones and the palatine processes of the maxillae.
76
The hard palate forms ..
a rigid surface against which the tongue forces food during chewing.
77
The raphe ..
a midline ridge
78
The mucosa on either side of its raphe ..
is slightly corrugated, which helps create friction.
79
The soft palate ..
is a mobile fold formed mostly of skeletal muscle that rises reflexively to close off the nasopharynx when we swallow.
80
the soft palate is anchored to the tongue by the ..
palatoglossal arches
81
the soft palate is anchored to the wall of the oropharynx by ..
the more posterior palatopharyngeal arches.
82
fauces ( fauc = throat ) ..
palatoglossal arches and palatopharyngeal arches. This pair of folds form the boundaries of the fauces
the arched area of the oropharynx that contains the palatine tonsils.
83
uvula ..
Projecting downward from the free edge of the soft palate which looks a fingerlike ..
84
The tongue occupies ..
the floor of the mouth.
85
The tongue is composed of ..
interlacing bundles of skeletal muscle fibers.
86
Tongue functions ..
during chewing, it grips the food and constantly repositions it between the teeth.
mixes food with saliva, forming it into a compact mass called a bolus
initiates swallowing by pushing the bolus posteriorly into the pharynx.
helps us form consonants (k, d, t, and so on) when we speak.
87
What types of skeletal muscle fibers does the tongue has ?
The intrinsic muscles
The extrinsic muscles
88
The intrinsic muscles
confined in the tongue and are not attached to bone.
*allow the tongue to change its shape (but not its position)
*becoming thicker, thinner, longer, or shorter as needed for speech and swallowing.
89
The extrinsic muscles ..
extend to the tongue from their points of origin on bones of the skull or the soft palate.
alter the tongue’s position. They protrude it, retract it, and move it from side to side.
90
lingual frenulum
A fold of mucosa secures the tongue to the floor of the mouth and limits its posterior movements.
91
median septum
connective tissue, and each half contains identical muscle groups.
92
The conical filiform papillae ..
roughen the tongue surface
helping us lick semisolid foods (such as ice cream)
providing friction for manipulating foods.
93
the smallest and most numerous type papillae ..
The conical filiform papillae
94
The conical filiform papillae align ..
in parallel rows on the tongue dorsum.
95
The conical filiform papillae contains ..
keratin, which stiffens them and gives the tongue its whitish appearance.
96
The mushroom-shaped fungiform papillae are ..
scattered widely over the tongue surface. Each has a vascular core that gives it a reddish hue.
97
Eight to twelve large vallate papillae are located in ..
V-shaped row at the back of the tongue.
98
vallate papillae resemble ..
the fungiform papillae but have an additional surrounding furrow.
99
Pleatlike foliate papillae ..
located on the lateral aspects of the posterior tongue.
100
the terminal sulcus location ..
Immediately posterior to the vallate papillae
101
the terminal sulcus ..
a groove that distinguishes the portion of the tongue that lies in the oral cavity (its body) from its posterior portion in the oropharynx (its root).
102
The mucosa covering the root of the tongue lacks ..
papillae, but it is still bumpy because of the nodular lingual tonsil, which lies just deep to its mucosa
103
The salivary glands ..
A number of glands associated with the oral cavity secrete saliva
104
Saliva functions ..
Cleanses the mouth
Dissolves food chemicals so they can be tasted
Moistens food and helps compact it into a bolus
Contains the enzyme amylase that begins the digestion of starchy foods
105
Most saliva is produced by ..
the major or extrinsic salivary glands that lie outside the oral cavity and empty their secretions.
Minor or intrinsic salivary glands (buccal glands and others) scattered throughout the oral cavity mucosa augment the output slightly.
106
The major salivary glands are ..
paired compound tubuloalveolar glands that develop from the oral mucosa and remain connected to it by ducts
107
parotid gland
large, roughly triangular gland, lies anterior to the ear between the masseter muscle and the skin.
108
parotid gland prominent duct ..
parallels the zygomatic arch, pierces
the buccinator muscle, and opens into the vestibule next to the second upper molar.
109
the submandibular gland lies ..
along the medial aspect of the mandibular body.
110
the submandibular gland duct runs ..
beneath the mucosa of the oral cavity floor and opens at the base of the lingual frenulum
111
sublingual gland ..
small, almond-shaped gland lies anterior to the submandibular gland under the tongue and opens via 10–20 ducts into the floor of the mouth
112
The salivary glands are composed of two types of secretory cells:
serous and mucous
113
Serous cells
produce a watery secretion containing enzymes, ions, and a tiny bit of mucin.
114
mucous cells
produce mucus, a stringy, viscous solution.
115
The parotid and submandibular glands contain mostly _________ cells.
serous
116
Buccal glands have approximately equal numbers of ____________ cells.
serous and mucous
117
The sublingual glands contain mostly ____________.
mucous cells
118
Composition of Saliva ..
Electrolytes (Na+, K+, Cl−, PO43−, and HCO3−)
The digestive enzymes salivary amylase and lingual lipase
The proteins mucin, lysozyme, and IgA
Metabolic wastes (urea and uric acid)
119
Describe the saliva ..
largely water—97 to 99.5%—and therefore is hypoosmotic.
saliva is slightly acidic (pH 6.75 to 7.00), but its pH may vary.
120
Saliva osmolarity depends on ?
Its osmolarity depends on the specific glands that are active and the stimulus for salivation.
121
The teeth ..
lie in sockets (alveoli) in the gum-covered margins of the mandible and maxilla.
122
We masticate, or chew, by ..
opening and closing our jaws and moving them from side to side while using our tongue to move the food between our teeth.
123
Ordinarily by age 21, two sets of teeth ..
the primary and per- manent dentitions.
124
The primary dentition consists of
the deciduous teeth, also called milk or baby teeth.
125
From the mouth, food passes **posteriorly** into ..
the oropharynx and then the laryngopharynx.
126
The mucosa of the pharynx contains ..
friction-resistant stratified squamous epithelium well supplied with mucus-producing glands.
127
The external muscle layer of the pharynx consists of ..
two skeletal muscle layers.
128
The esophagus ..
is a muscular tube about 25 cm (10 inches) long and is collapsed when not involved in food propulsion ..
129
the esophagus pierces the diaphragm at the ..
esophageal hiatus
130
the esophagus joins the stomach at the ..
cardial orifice within the abdominal cavity.
131
The cardial orifice is surrounded by ..
the gastroesophageal or cardiac sphincter ..
132
The muscular diaphragm, which surrounds the cardiac sphincter, helps ..
helps keep it closed when food is not being swallowed
133
Mucous cells on both sides of the cardiac sphincter help ..
protect the esophagus from reflux of stomach acid.
134
the stomach continues the demolition job begun in the oral cavity by ..
further degrading food both physically and chemically.
135
chyme
the product of the stomach activity.
136
The stomach then delivers chyme into ..
the small intestine.
137
Protein digestion begins in the _______ and is the main type of enzymatic breakdown that occurs there.
Stomach.
138
The most important protein-digesting enzyme produced by the gastric mucosa is ..
pepsin.
139
In infants, the stomach glands also secrete ..
rennin
140
rennin
an enzyme that acts on milk protein (casein), converting it to a curdy substance that looks like soured milk.
141
Fat digestion occurs primarily in ..
the small intestine
142
the only stomach function essential to life is ..
secretion of intrinsic factor.
143
Intrinsic factor is ..
required for intestinal absorption of vitamin B12
144
B12 vitamin needed to ..
produce mature erythrocytes. In its absence, pernicious anemia results.
145
The liver’s digestive system function is to ..
produce bile for export to the duodenum
146
Bile is ..
a fat emulsifier that breaks fats into tiny particles to make them more readily digestible.
147
The gallbladder is chiefly ..
A storage organ for bile.
148
The pancreas ..
supplies most of the enzymes that digest chyme as well as bicarbonate that neutralizes stomach acid.
149
liver ..
The ruddy, blood-rich, the largest gland in the body, weighing about 1.4 kg in the average adult. Shaped like a wedge.
150
The liver’s location ..
Occupies most of the right hypochondriac and epigastric regions.
extending farther to the right of the body midline than to the left.
Located under the diaphragm, the liver lies almost entirely within the rib cage, which provides some protection
151
The liver has four primary lobes ..
the right lobe
the left lobe
caudate lobe
quadrate lobe
152
The right lobe ..
The largest, is visible on all liver surfaces and separated from the smaller left lobe by a deep fissure
153
caudate lobe and the quadrate lobe
The posteriormost, which lies inferior to the left lobe, are visible in an inferior view of the liver
154
the falciform ligament ..
A mesentery, separates the right and left lobes anteriorly and suspends the liver from the diaphragm and anterior abdominal wall
155
the round ligament, or ligamentum teres ..
Running along the inferior edge of the falciform ligament, a fibrous remnant of the fetal umbilical vein.
156
the bare area ..
the superiormost liver area, which touches the diaphragm
157
entire liver is enclosed by ..
the visceral peritoneum, Except for the bare area.
158
The lesser omentum anchors the liver to ..
the lesser curvature of the stomach
159
The vessels that enter the liver at the **porta hepatis** ..
The hepatic artery proper and the hepatic portal vein
160
the common hepatic duct, which runs ..
inferiorly from the liver
161
The gallbladder rests in ..
a recess on the inferior surface of the right liver lobe.
162
Bile leaves the liver lobes through ..
the right and left hepatic ducts.
163
the right and left hepatic ducts fuse to form ..
the large common hepatic duct, which travels downward toward the duodenum.
164
Along the course of the large common hepatic duct, it fuses with the ..
the cystic duct draining the gallbladder to form the bile duct
165
liver lobules ..
sesame seed–sized structural and functional units of the liver.
166
liver lobules ..
Each lobule is a roughly hexagonal structure consisting of plates of liver cells, or hepatocytes ..
167
The hepatocyte plates radiate out- ward from ..
a central vein running in the longitudinal axis of the lobule.
168
At each of the six corners of a lobule is ..
a portal triad (portal tract region).
169
a portal triad (portal tract region), so named because it contains three basic structures:
A branch of the hepatic artery proper (supplying oxygen-rich arterial blood to the liver)
A branch of the hepatic portal vein (carrying venous blood laden with nutrients from the digestive viscera)
A bile duct
170
Between the hepatocyte plates are enlarged, heavily fenestrated structure ..
liver sinusoids.
171
Blood from both the hepatic portal vein and the hepatic artery proper percolates from ..
the triad regions through liver sinusoids sinusoids and empties into the central vein.
172
From the central veins of the liver blood eventually enters ..
the hepatic veins, which drain the liver, and empties into the inferior vena cava.
173
star-shaped stellate macrophages, also called hepatic macrophages ..
They remove debris such as bacteria and worn-out blood cells from the blood as it flows past.
174
The versatile hepatocytes have large amounts of both ..
rough and smooth ER
Golgi apparatus
peroxisomes
mitochondria.
175
hepatocytes can:
Secrete some 900 ml of bile daily
Process bloodborne nutrients in various ways (e.g., they store glucose as glycogen and use amino acids to make plasma proteins)
Store fat-soluble vitamins
Play important roles in detoxification, such as ridding the blood of ammonia by converting it to urea
176
Secreted bile flows through tiny canals ..
bile canaliculi, that run between adjacent hepatocytes toward the bile duct branches in the portal triads
177
that blood and bile flow in opposite directions in the liver lobule.
T/F
True
178
Bile entering the bile ducts eventually leaves the liver via ..
the common hepatic duct to travel toward the duodenum.
179
The gallbladder ..
is a thin-walled green muscular sac about 10 cm (4 inches) long.
The size of a kiwi fruit.
it snuggles in a shallow fossa on the inferior surface of the liver.
180
The gallbladder stores ..
bile that is not immediately needed for digestion and concentrates it by absorbing some of its water and ions.
181
Gallbladder muscular wall contracts to expel bile into the ..
cystic duct.
182
cystic duct ..
From there bile flows into the bile duct.
183
The gallbladder, is covered by ..
visceral peritoneum.
184
The pancreas is important to the digestive process because ..
it produces enzymes that break down all categories of foodstuffs.
185
The pancreas is ..
a soft, tadpole-shaped gland that extends across the abdomen from its tail (next to the spleen) to its head, which is encircled by the C-shaped duodenum.
186
Most of the pancreas is ..
retroperitoneal and lies deep to the greater curvature of the stomach.
187
The pancreas contains ..
exocrine and endocrine parts.
188
The exocrine part of the pancreas produces ..
pancreatic juice
189
pancreatic juice consists of ..
Acini.
Acini are clusters of secretory acinar cells that produce the enzyme-rich component of pancreatic juice.
Ducts.
A system of ducts transports the secretions of the aci- nar cells.
190
The endocrine part of the pancreas is a scattering of miniendocrine glands called ..
pancreatic islets.
191
The pharynx and esophagus single digestive system function is food propulsion, accomplished by ..
deglutition or swallowing.
192
two major phases involved in deglutition ..
The buccal phase
The pharyngeal-esophageal phase
193
The pharyngeal-esophageal phase ..
involuntary and is controlled by the swallowing center in the brain stem (medulla and lower pons).
Once food enters the pharynx, respiration is momentarily inhibited and all routes except the desired one into the digestive tract are blocked off.
194
The buccal phase ..
occurs in the mouth and is voluntary. It ends when a food bolus leaves the mouth and stimulates tactile receptors in the posterior pharynx
195
the stomach ..
A bag where chemical breakdown of proteins begins and food is converted to a paste.
196
In the stomach, food is converted to a paste called ..
Chyme
197
rugae ..
large, longitudinal folds within the stomach.
198
The small cardial part, or cardia ..
surrounds the cardial orifice through which food enters the stomach from the esophagus.
199
The fundus of the stomach ..
is the stomach’s dome-shaped part, tucked beneath the diaphragm, that bulges superolaterally to the cardia.
200
the pylorus ..
is continuous with the duodenum through the pyloric sphincter or valve
201
the pyloric sphincter or valve ..
controls stomach emptying (pylorus = gatekeeper).
202
The convex lateral surface of the stomach is its ..
greater curvature
203
concave medial surface of the stomach is its
lesser curvature.
204
omenta ..
two mesenteries, that help tether the stomach to other digestive organs and the body wall
205
The lesser omentum ..
runs from the liver to the lesser curvature of the stomach, where it becomes continuous with the visceral peritoneum covering the stomach.
206
The greater omentum ..
drapes inferiorly from the greater curvature of the stomach to cover the coils of the small intestine.
runs dorsally and superiorly, wrapping the spleen and the transverse portion of the large intestine
207
mesocolon ..
mesentery that secures the large intestine to the parietal peritoneum of the posterior abdominal wall.
208
The small intestine ..
convoluted tube extending from the pyloric sphincter to the ileocecal valve (sphincter) where it joins the large intestine.
209
The small intestine has three subdivisions ..
the duodenum, which is mostly retroperitoneal, and the jejunum and ileum
210
The arterial supply of the small intestine is primarily from ..
the superior mesenteric artery
211
The small intestinal veins parallel the arteries and typically drain into the ..
superior mesenteric vein.
212
the nutrient-rich venous blood from the small intestine drains into ..
the hepatic portal vein, which carries it to the liver.
213
Nerve fibers serving the small intestine include parasympathetics from ..
the vagus
214
Nerve fibers serving the small intestine include sympathetic from the ..
thoracic splanchnic nerves
215
Nerve fibers serving the small intestine include parasympathetics and sympathetics both relayed through the ..
superior mesenteric (and celiac) plexus.
