Finals - Digestive system Flashcards
(130 cards)
1
Q
digestive system provides the body with
A
nutrients, water and electrolytes essential for health
2
Q
the organs of the digestive system function
A
ingest, digest, and absorb food and
eliminate the undigested remains as feces
3
Q
digestive system consists of
A
a hollow tube (alimentary
canal) extending from the mouth to the anus, into which various
accessory organs or glands empty their secretions.
4
Q
digestive organ system are divided into two groups
A
- alimentary canal
2. accessory digestive organs
5
Q
alimentary canal
A
-Mouth, pharynx, and
esophagus
-Stomach, small intestine, and
large intestine (colon)
6
Q
accessory digestive organs
A
-Teeth and tongue
-Gallbladder, salivary glands,
liver, and pancreas
7
Q
the digestive processes of digestive system
A
- Ingestion
- Propulsion
- Mechanical digestion
- Chemical digestion
- Absorption
- Defecation
8
Q
• The walls of the ventral body cavity and the outer surfaces of the
organs it contains are covered with
A
h an thin, double-layered membrane
called the serosa (serous membrane)
9
Q
parietal serosa
A
: the part of the
membrane lining the cavity walls
10
Q
viceral serosa
A
: the part of the
membrane covering the external surface
of the organs within the cavit
11
Q
function of serosa
A
produce a thin
lubricating fluid that allows the viceral
organs to slide over one another or to rub
against the cavity wall without friction.
• They also compartmentalize the various
organs so that infection of one organ is
prevented from spreading to others
12
Q
peritoneum
A
: the serosa lining the the abdominopelvic cavity and
covering its organs.
13
Q
visceral peritoneum
A
surrounds digestive organs
14
Q
parietal peritoneum
A
lines the body wall
15
Q
peritoneal cavity
A
space between the visceral and parietal peritoneum that contains a lubricating serous fluid
16
Q
mesentery
A
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.
17
Q
mesentery function
A
Holds organs in place
-Sites of fat storage
-Provides a route for circulatory vessels and nerves
Dorsal mesenteries > ventral mesenteries
18
Q
the two ventral mesenteries are?
A
falciform ligament
lesser omentum
19
Q
falciform ligament
A
binds the anterior aspect of the liver to the
anterior abdominal wall and diaphragm
20
Q
lesser omentum
A
runs from the liver to the stomach and
duodenum.
21
Q
the dorsal mesenteries are
A
greater omentum
mesentery (proper)
transverse mesocolon
sigmoid mesocolon
22
Q
greater omentum
A
connects the greater curvature of the stomach
to the posterior abdominal wall
23
Q
mesentery (proper)
A
sheet that fans
interiorly from the posterior
abdominal to support the jejunum and
ileum.
24
Q
transverse mesocolon
A
holds
transverse colon to posterior
abdominal wall
25
sigmoid mesocolon
connects
| sigmoid colon to posterior pelvic wal
26
the four tissue layers of the alimentary canal
Mucosa → Submucosa → Muscularis externa → Serosa
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mucosa (mucous membrane)
innermost layer containing three
sublayers: a) a lining epithelium, b) a lamina propria, and c) a
muscularis mucosae
28
mucosa
lining epithelium
lamina propria
muscularis mucosae
29
lining epithelium
: abuts the lumen of the alimentary canal and
| functions to absorb nutrients and secrete mucus
30
lamina propria
a: a loose areolar or reticular C.T. that nourishes the
lining epithelium and absorb digested nutrients.
- Contains MALT
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muscularis mucosae
a thin
layer of smooth muscle that
produces local movements of
the mucosa
32
muscularis mucosae function
-Dislodges food particles
that become embedded in
the mucosa
33
submucosa
: a layer of C.T. containing major blood and lymphatic
| vessels and nerve fibers
34
the vascular network of submucosa
sends branches to all other layers of the wall
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the C.T of submucosa
is a “moderately dense” C.T….an intermediate between loose
| areolar and dense irregular C.T.
36
muscularis externa (muscularis) consists of
of two layers of smooth
| muscle that are responsible for peristalsis
37
the two layers of muscularis externa
a) inner circular layer: squeezes the gut tube
| b) outer longitudinal layer: shortens the gut tube
38
-In some places, the circular layer thickens to form sphincters that act
as
valves to prevent the backflow of food from one organ to the next.
39
serosa
(visceral peritoneum): the protective outermost layer;
| areolar C.T. covered by single layer of squamous epithelial cells
40
mouth (oral cavity)
where food enters the alimentary canal and is
chewed, manipulated by the tongue, and moistened with saliva.
Mouth
- Mucosa-lined cavity bounded
by the lips, cheeks, palate, and the
tongue.
41
oral orifice
anterior opening
42
poseteriorly the mouth borders?
the fauces of the oropharynx
43
the mouth is divided into?
where food enters the alimentary canal and is
chewed, manipulated by the tongue, and moistened with saliva.
Mouth
- Mucosa-lined cavity bounded
by the lips, cheeks, palate, and the
tongue.
44
vestibule
: the slit between the
| teeth and the cheeks (or lips)
45
oral cavity proper
the region
of the mouth that lies internal to
the teeth.
46
Lips (labia) and cheek
h help keep food inside the mouth
during chewing, are composed of a core of skeletal muscle covered
by skin
47
lips
: thick flaps extending
from the inferior boundary of the
nose to the superior boundary of
the chin
48
red margin
in: the region of the lip
where lipstick is applied…a
transition zone where the skin
meets the oral mucosa
49
labia frenulum
a median fold
that connects the internal aspect
of each lip to the gum
50
palate
the roof of the mouth; has two distinct parts…
1. hard palate
2. soft palate
51
hard palate
the anterior bony
part that forms a rigid surface
against which the tongue forces
food during chewing
52
soft palate
the posterior
muscular part that is a mobile flap
that rises to close off the
nasopharynx during swallowing
53
uvula
projects downward from
| the free edge of the soft palate
54
the soft palate is anchored to?
the tongue by the palatoglossal
arches and to the wall of the oropharynx by the palatopharyngeal
arches.
55
tongue constructed of
f interlacing fascicles of skeletal muscle
| fibers.
56
functions of tongue
```
- Grips food and constantly repositions
it between the teeth.
- Mixes the food with salvia and form
it into a compact mass called a bolus.
- During swallowing…the tongue
moves posteriorly to push the bolus
into the pharynx.
- Houses most of the tastebuds
- In speech, the tongue helps form
some consonants (k, d, t, and l)
```
57
lingual frenulum
a fold of mucosa on the undersurface of the
tongue that both secures the tongue` to the floor of the mouth and limits
its posterior movements.
58
three major types of peglike
| projections that the mucosa of the superior surface of the tongue bears
filiform papillae
fungiform papilae
circumvallate papillae
59
filiform papillae
: give the tongue roughness and provide friction
60
fungiform papillae
: scattered widely over the tongue and give it a
| reddish hue, contains taste buds
61
circumvallate papillae
V-shaped row in back of tongue, contains
| taste buds
62
the teeth (denitions)
) tear and grind the food, breaking it into
smaller fragments.
• Humans have two sets of teeth…
63
primary denition (deciduous teeth)
20 total that erupt at
intervals between 6 and 24
months
64
permanent teeth
```
enlarge and
develop causing the root of
deciduous teeth to be resorbed
and fall out between the ages of
6 and 12 years; all but the third
molars (“wisdom teeth”) have
erupted by the end of
adolescence; there are usually 32
permanent teeth
```
65
teeth are classifed according to ?
their shape and function
1. incisors
2. canines
3. premolars (bicuspid and molars
66
incisors
: chisel-shaped teeth adapted for cutting or nipping
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canines
conical or fanglike teeth that tear or pierce
68
c) Premolars (bicuspids) and molars
have broad crowns with
| rounded tips and are best suited for grinding or crushing
69
during chewing (mastication)
upper and lower premolars and
| molars lock together generating crushing force
70
saliva
a mixture of water, mucus, and enzymes
71
function of saliva
a) moisten, dissolves food, binds food together (bolus)
b) aids in digestion of starch
c) prevents tooth decay by neutralizing acids
d) contains bactericidal enzymes, antiviral substances, and
antibodies to kill harmful oral microorganisms
e) contains proteins to help growth of beneficial bacteria
72
all salivary glands are
```
are compound (branched ducts) tubuloalveolar
(secretory unit shape) glands:
```
73
intrinsic salivary glands
s: scattered within mucosa of tongue,
| palate, lips, and cheeks; keep mouth moist at all times
74
extrinsic salivary glands
: lie external to the mouth but have ducts
| that open to the mouth
75
parotid glands
exterior
to ear, between masseter
and skin
76
submandibular jglands
at medial surface of
mandible, anterior to
mandibular angle
77
sublingual glands
in
floor of oral cavity,
inferior to tongue
78
• From the mouth, the oropharynx and laryngopharynx allow passage
of
f food and fluids to the esophagus and air to the trachea.
79
the pharynx is lined with
- Lined with stratified squamous epithelium and mucus glands
| - Has two skeletal muscle layers; Inner longitudinal and outer pharyngeal constrictors
80
esophagus
```
Muscular tube (~10
inches) that joins the laryngopharynx
to the stomach; travels through the
mediastinum and pierces the
diaphragm; joins the stomach at the
cardiac orifice
-The empty esophagus is folded
longitudinally and flattened
```
81
esophagus glands and muscularis
```
Glands secrete mucus as a bolus
moves through the esophagus
-Muscularis changes from skeletal
(superiorly) to smooth muscle
(inferiorly)
```
82
stomach
```
Site where food is
churned into chyme (the liquid
substance found in the stomach;
consists of partially digested food,
water, hydrochloric acid, and various
digestive enzymes). ~4 hours
```
83
stomach functions
-Protein digestion begins (Secretes
pepsin)…functions under acidic
conditions
-Hydrochloric acid: a strong acid
that destroys many harmful bacteria
in the food
84
location of the stomach, cardiac region (cardia), fundus, Body
stomach: lies in upper left quadrant of peritoneal cavity
- Cardiac region (cardia): surrounds the cardiac orifice at the junction
with the esophagus
Fundus: dome-shaped region immediately inferior to diaphragm
85
body
- Body: midportion of the
| stomach
86
pyloric region
made up of
the antrum (cave) and canal
which terminates at the
pylorus
87
pylorus
is continuous
with the duodenum (1st part
small intestine) through the
pyloric sphincter
88
rugae
greater curvature
lesser curvature
- Rugae: longitudinal folds of mucosa; allow distension
- Greater curvature: entire extent of the convex lateral surface
- Lesser curvature: concave medial surface
89
small intestine
```
Longest
portion of the alimentary canal
(short people: 2.7-5 meters, tall
people: 6-7 meters).
-Site of most enzymatic
digestion and absorption
```
90
three subdivision of small intestine
: duodenum
(5%), jejunum (40%), and
ileum (55%)
91
duodenum
chyme passes through the pyloric valve and enters the
duodenum (~10 inches long).
-Receives digestive enzymes from the pancreas and bile from the liver
and gallbladder
92
main pancreatic duct and common bile duct enter the wall of the duodenum where they form a bulb called
hepatopancreatic
| ampulla.
93
The ampulla opens into the duodenum via a mound called
| the
major duodenal papilla.
94
The wall of the small intestine has three structural modifications that
amplify its absorptive surface
) Circular folds (plicae circulares)
b) Villi
c) microvilli
95
a) Circular folds (plicae circulares):
1cm tall transverse ridges of the
mucosa and submucosa.
-Force the chyme to spiral through the intestinal lumen…slowing its
movement.
96
billi
1 mm tall fingerlike projections of the mucosa that are
covered by a simple columnar epithelium made up primarily of
absorptive cells (enterocytes) specialized for absorbing digested
nutrients.
-Contains lacteals and blood capillaries
97
microvilli
tiny projections of absorptive cell’s at the apical surface
that contain enzymes
Total surface area of small intestine = 200 m
98
absorptive cells
uptake digested nutrients…contain many
mitochondria.
- Contain an abundant amount of endoplasmic reticulum…assembles
newly absorbed lipid molecules into lipid-protein complexes called
chylomicrons, which enter the lacteal capillaries
99
goblet cells
secrete mucus that lubricates chyme and forms a
protective barrier that prevents enzymatic digestion of the intestinal
wall
100
Enteroendocrine cell
cells of the
duodenum that secrete hormones:
a) Cholecystokinin
b) secretin
101
cholecystokinin
signals the
gallbladder to release stored bile and the
pancrease to secrete its digestive
enzymes
102
secretin
signals the pancreatic ducts
to secrete a bicarbonate-rich juice to
neutralize the acidic chyme entering the
duodenum
103
Intestinal crypts
mucosa between the
villi that contain epithelial cells that
secrete intestinal juice…a watery liquid
that mixes with chyme
104
epithelial stem cells divide in and renew ?
- Epithelial stem cells divide in the crypts and renew the mucosal
epithelium by moving continuously into the villi.
105
large intestine main function
```
: absorb water
and electrolytes (~12-24 hours).
-Digested residue contains few
nutrients
-Small amount of digestion by
bacteria
-Mass peristaltic movements
force feces toward the rectum
```
106
• Large intestine: 1.5 meters
| -Subdivided into:
- Cecum,
- appendix,
- colon,
- rectum,
- anal canal
107
The large intestine exhibits three special features:
teniae coli
haustra
epiploic appendages
108
teniae coli
three longitudinal strips, spaced at equal intervals
around the circumference of the cecum and colon.
-Thickenings of the longitudinal layer of the muscularis externa
109
haustra
puckered sacs of the large intestine
110
epiploic appendages
fat-filled pouches of visceral peritoneum that
| hang from the intestine…no known function.
111
cecum
a pouch connected to the ileum and the ascending colon of
| the large intestine
112
ileocecal valve
```
a sphincter muscle situated at the junction of the
small intestine (ileum) and the large intestine.
-It regulates the flow of chyme into the bowels
```
113
vermiform appendix
tube connected to the cecum; neutralizes
pathogens.
-Removed: the appendix is a vestigial structure with no absolute
purpose
114
colon
A storage tube for solid wastes. The main function of the
colon appears to be extraction of water and salts from feces.
-Divided into distinct segments: Ascending, transverse, descending,
and sigmoid colon
115
rectum
the final straight portion of the large intestine, terminating
at the anus
116
anal canal
the last subdivision of the large intestine. The external
| opening of the rectum
117
liver
Largest gland in the
body (~3 lbs)
-Performs over 500 functions
118
functions of liver
```
: It plays
a major role in…
metabolism,
glycogen storage,
decomposition of red blood
cells,
plasma protein synthesis,
and detoxification.
```
119
liver digestive function
…produces bile; an alkaline compound
| which aids in digestion, via the emulsification of lipids.
120
most of the liver is covered with a?
a layer of visceral peritoneum…
however the superior part (bare area) is fused to the diaphragm and is
devoid of peritoneum.
121
the liver has four lobes
left, right, caudate, quadrate lobes.
122
falciform ligament
mesentery that separates the right and left lobes
| anteriorly and binds the liver to the anterior abdominal wall.
123
porta hepatis
area near the center of the visceral surface where most
of the major vessels and nerves enter and leave the liver.
-Enter via the porta hepatis:
124
-Enter via the porta hepatis:
```
a) The right and left branches
of the hepatic portal vein,
which carry nutrient-rich
blood from the stomach and
intestines
b) The right and left branches
of the hepatic artery carrying
oxygen-rich blood to the liver
```
125
-Exit via the porta hepatis:
a) The right and left hepatic ducts, which carry bile from the
respective lobes exit and fuse to form the common hepatic duct
126
gallbladder
rests in a recess on the inferior surface of the right lobe
and is the storage place for bile
-Thin-walled, green muscular sac on the ventral surface of the liver,
stores and concentrates bile by absorbing its water and ions, releases
bile via the cystic duct, which flows into the bile duct
127
Cystic duct, hepatic duct, and common bile duct:
-Bile, which is synthesized in the liver, is carried to the right and left
hepatic ducts, which converge to form the common hepatic duct.
There it enters the superior end of the common bile duct and either
empties into the second part of the duodenum, or enters the cystic
duct to be stored in the gallbladder.
128
Pancreas:
| -Exocrine function:
```
Acinar cells make, store,
and secrete pancreatic
enzymes which are activated
in the duodenum and breaks
down food.
```
129
pancreas
| -Endocrine function:
produces the hormones
insulin and glucagon which
regulates blood sugar
130
• Pancreas: Pancreatic duct
-A duct joining the pancreas to the common bile duct to supply
pancreatic juices which aid in digestion provided by the "exocrine
pancreas".
