Chapter 23 Digestive System Flashcards
1
Q
What does the alimentary canal or the gastrointestinal tract do?
A
digests and absorbs food
2
Q
The alimentary canal is what parts of the body?
A
the mouth, pharynx, esophagus, stomach, small intestine, and large intestine
3
Q
The accessory digestive organs are?
A
teeth, tongue, gallbladder, salivary glands, liver, and pancreas
4
Q
The GI tract is a ___________line.
A
disassembly line
5
Q
Along the (GI Tract) disassembly line the nutrients become
A
move available to the body in each step
6
Q
There are six essential activities:
A
Ingestion, propulsion, and mechanical digestion
Chemical digestion, absorption, and defecation
7
Q
Ingestion
A
taking food into the digestive tract
8
Q
Propulsion
A
swallowing and peristalsis
9
Q
Peristalsis
A
waves of contraction and relaxation of muscles in the organ walls
10
Q
Mechanical digestion
A
chewing, mixing, and churning food
11
Q
Peritoneum
A
the serous membrane of the abdominal cavity
12
Q
The peritoneum has ___ layers
A
two; visceral and parietal
13
Q
Visceral
A
covers the external surface of most digestive organs
14
Q
Parietal
A
lines the body wall
15
Q
Peritoneal cavity
A
lubricates digestive organs and allows them to slide across one another
16
Q
Mesentery-double layer of peritoneum that provides:
A
- Vascular and nerve supplies to the viscera
* Hold digestive organs in place and store fat
17
Q
Retroperitoneal organs
A
organs outside the peritoneum
18
Q
Peritoneal organs (intra-peritoneal)-
A
organs surrounded by peritoneum
19
Q
Chemical digestion
A
catabolic breakdown of food
20
Q
Absorption
A
movement of nutrients from the GI tract to the blood or lymph
21
Q
Defecation
A
elimination of indigestible solid wastes
22
Q
Histology–From esophagus to the anal canal the walls of the GI tract has the same ______ tunics
A
four
23
Q
Histology–from the lumen outward they are the _______,_______, ________, and ______.
A
musosa, submucosa, muscularis externa, and serosa
24
Q
Histology–Each tunic has a predominant tissue type and a specific ____________.
A
digestive function.
25
Mucosa
moist epithelial layer that lines the lumen of the alimentary canal
26
Three major functions of the mucosa:
* secretion of mucus
* absorption of end products of digestion
* protection against infectious disease
27
The mucosa consists of three layers:
a lining epithelium, lamina propria, and muscularis mucosae
28
Mucosa :Lamina Propria
* loose areolar and reticular connective tissue
* nourishes the epithelium and absorbs nutrients
* contains lymph nodes (part of MALT) importance in defense against bacteria
29
Mucosa: Muscularis Mucosae
smooth muscle cells that produce local movements of the mucosa
30
Mucosa: Epithelial Lining
*Simple columnar epithelium and mucus-secreting goblet cells
*Mucus secretions:
*Protect digestive organs from digesting themselves
*Ease food along the tract
*Stomach and small intestine mucosa contain:
*Enzyme-secreting cells
*Hormone-secreting cells (making them endocrine
and digestive organs)
31
Mucosa: Other Sublayers
Submucosa, Muscularis Externa and Serosa
32
Submucosa
dense connective tissue containing elastic fibers, blood and lymphatic vessels, lymph nodes, and nerves
33
Muscularis Externa
responsible for segmentation and peristalsis
34
Serosa
the protective visceral peritoneum
* replaced by the fibrous adventitia in the esophagus
* retroperitoneal organs have both an adventitia and serosa
35
Oral or buccal cavity
* is bounded by lips, cheeks, palate, and tongue
* has the oral orifice as its anterior opening
* is continuous with the oropharynx posteriorly
36
To withstand abrasions:
* the mouth is lined with stratified squamous epithelium
| * the gums, hard palate, and dorsum of tongue are slightly keratinized
37
Lips and cheeks have a core of
skeletal muscles.
* Lips: orbicularis oris
* Cheeks: buccinators
38
Vestibule
bounded by the lips and cheeks externally, and teeth and gums internally
39
Oral cavity proper
the area that lies within the teeth and gums
40
Labial frenulum
median fold that joins the internal aspect of each lip to the gum
41
Hard palate
underlain by palatine bones and palatine bones and palatine processes of the maxillae
* Assists the tongue in chewing
* Slightly corrugated on either side of the raphe (midline ridge)
42
Soft palate
mobile fold formed mostly of skeletal muscle
* Closes off the nasopharynx during swallowing
* Uvula projects downward from its free edge
43
Palatoglossal and palatopharyngeal arches form the
borders of the fauces
44
tongue
occupies the floor of the mouth and fills the oral cavity when the mouth is closed
45
Functions of the tongue:
* gripping and repositioning food during chewing
* mixing food with saliva and forming the bolus
* initiation of swallowing, and speech
46
Intrinsic muscles change the
shape of the tongue
47
Extrinsic muscles alter the
tongue's position
48
Lingual frenulum secures the
tongue to the floor of the mouth
49
The tongues superior surface bears three types of papillae
Filiform, Fungiform, and Circumvallate
50
Filiform
give the tongue roughness and provide friction
51
Fungiform
scattered widely over the tongue and give it a reddish hue
52
Circumvallate
V-shaped row in back of tongue
53
Sulcus terminalis
groove that separates the tongue into two areas:
* Anterior 2/3 residing in the oral cavity
* Posterior third residing in the oropharynx
54
Salivary glands
produce and secrete saliva that:
* cleanses the mouth
* moisten and dissolves food chemicals
* aid in bolus formation
* contains enzymes that break down startch
55
Parotid
lies anterior to the ear between the masseter muscle and skin
*Parotid duct opens into the vestibuluar next to second upper molar
56
Submandibular
lies along the medial aspect of the mandibular body
| *its ducts open at the base of the lingual frenulum
57
Sublingual
lies anterior to the submandibular gland under the tongue
| *it opens via 10-12 ducts into the floor of the mouth
58
Teeth
there are primary and permanent dentitions have formed by age 21
59
Primary teeth
20 deciduous teeth that erupt at intervals between 6 and 24 months
60
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 have erupted by the end of adolescence
* Usually 32 permanent teeth
61
Teeth are classified according to their ____ and ____.
shape and function
62
Incisors
chisel-shaped teeth for cutting or nipping
63
Canines
fanglike teeth that tear or pierce
64
Premolars (bicuspids) and molars
have broad crowns with rounded tips; best suited for grinding or crushing
65
During chewing, upper and lower molars
lock together generating crushing force
66
Periodontal ligament
* anchors the tooth in the alveolus of the jaw
| * forms the fibrous joint called a gomaphosis
67
Gingival sulcus
depression where the gingiva borders the tooth
68
Dentin
bonelike material deep to the enamel cap that forms the bulk of the tooth
69
Pulp Cavity
cavity surrounded by dentin that contains pulp
70
Pulp
connective tissue, blood vessels, and nerves
71
Root Canal
the portion of the pulp cavity that extends into the root
72
Apical foramen
proximal opening to the root canal
73
Odontoblasts
secrete and maintain dentin throughout life
74
The tooth has two main regions
crown and the root
75
Crown
the exposed part of the tooth above the gingiva
76
Enamel
acellular, brittle material composed of calcium salts and hydroxyapatite crystals; the hardest substance in the body
*encapsules the crown of the tooth
77
Root
the portion of the tooth embedded in the jawbone
78
Neck
constriction where the crown and root come together
79
Cementum
calcified connective tissue
* covers the root
* attaches it to the periodontal ligament
80
Pharynx
from the mouth, the oro- and laryngopharynx allow passage or:
* Food and fluids to the esophagus
* Air to the trachea
81
The pharynx is lined with
stratified squamous epithelium and mucus glands
82
The pharynx has two skeletal muscle layers
* Inner longitudinal
| * Outer pharyngeal constrictors
83
Deglutition (Swallowing)
Coordinated activity of the tongue, soft palate, pharynx, esophagus, and 22 separate muscle groups
84
Buccal phase
bolus is forced into the oropharynx
85
Pharyngeal-esophageal phase
controlled by the medulla and lower pons
| *all routes except into the digestive tract are sealed off
86
Peristalsis moves food through the
pharynx to the esophagus
87
Esophagus
* muscular tube going from the laryngopharynx to the stomach
* travels through the mediastinum and pierces the diaphragm
* joins the stomach at the cardiac orifice
88
Digestive Processes in the Mouth
* Food is ingested
* Mechanical digestion begins (chewing)
* Propulsion is initiated by swallowing
* Salivary amylase begins chemical breakdown of starch
* The pharynx and esophagus serve as conduits to pass food from the mouth to the stomach
89
Stomach
chemical breakdown of proteins begins and good is converted to chime (the pulpy acidic fluid that passes from the stomach to the small intestine, consisting of gastric juices and partly digested food)
90
Cardiac region
surrounds the cardiac orifice
91
Fundus
dome-shaped region beneath the diaphragm (superior side)
92
Body
midportion of the stomach
93
Pyloric region
made up of the antrum and canal which terminates at the pylorus
94
Pylorus
is continuous with the duodenum through the pyloric sphincter
95
Small Intestine: Gross Anatomy
* runs from pyloric sphincter to the ileocecal valve
* has three subdivisions:
duodenum, jejunum, and ileum
96
the bile duct (from the gallbladder) and main pancreatic duct:
* Join the duodenum at the hepatopancreatic ampulla
| * Are controlled by the sphincter of Oddi
97
The jejunum extends
from the duodenum to the ileum
98
The ileum joins the
large intestine at the ileocecal valve
99
The stomach:
* Holds ingested food
* Degrades this food both physically and chemically
* Delivers chyme to the small intestine
* Enzymatically digests proteins with pepsin
* Secretes intrinsic factor required for the absorption of vitamin B12
100
Liver
the largest gland in the body
101
The liver superficially has four lobes
right, left, caudate, and quadrate
102
The falciform ligament
* separates the right and left lobes anteriorly
| * suspends the liver from the diaphragm and anterior abdominal wall
103
the ligamentum teres
* is a remnant of the fetal umbilical vein
| * runs along the free edge of the falciform ligament
104
The gallbladder
* thin-walled, green muscular sac on the ventral (underside) 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
105
Liver; Associated Structures
* the lesser omentum anchors the liver to the stomach
* the hepatic blood vessels enter the liver at the porta hepatis
* the gallbladder rests in a recess on the inferior surface of the right lobe
106
composition of bile
*a yellow-green, alkaline solution containing bile salts, bile pigments, cholesterol , neutral fats, phospholipids, and electrolytes
107
Bile salts are cholesterol derivatives that:
* Emulsify fat
* facilitate fat and cholesterol absorption
* help solubilize cholesterol
108
Enterohepatic circulation recycles
bile salts
109
the chief bile pigment is
bilirubin, a waste product of heme
110
Liver produces
bile
111
Pancreas Location
* lies deep to the greater curvature of the stomach
| * the head is encircled by the duodenum and the tall abuts (next to or to touch/lean upon) the spleen
112
Pancreas Exocrine Function
* secretes pancreatic juice which breaks down all categories of foodstuff
* Acini (clusters of secretory cells) contain zymogen granules with digestive enzymes
113
Pancreas Endocrine Function
release of insulin and glucagon
114
Digestion in Small Intestine-As chyme enters the duodenum
* carbohydrates and proteins are only partially digested
| * no fat digestion has taken place
115
Digestion continues in the small intestine
* Chyme is released slowly into the duodenum
* Because it is hypertonic and has low pH, mixing is required for proper digestion
* Required substances needed are supplied by the liver
* Virtually all nutrient absorption takes place in the small intestine
116
Large Intestine has three unique features:
Teniae coli, haustra, and epiploic appendages
117
Teniae coli
three bands of longitudinal smooth muscle in its muscularis
118
Haustra
pocketlike sacs caused by the tone of the tenia coli
119
Epiploic appendages
fat-filled ouches of visceral peritoneum
120
The large intestine is subdivided into the
cecum, appendix, colon, rectum, and anal canal
121
The saclike cecum
* lies below the ileocecal valve in the right iliac fossa
| * contains a wormlike vermiform appendix
122
The color has distinct regions:
ascending colon, hepatic flexure, transverse colon, splenic flexure, descending colon and sigmoid colon
123
The transverse and sigmoid portions of the colon are anchored
via mesenteries called mesocolons
124
The sigmoid colon joins the
rectum
125
The anal canal, the last segment of the large intestine, opens
to the exterior at the anus
126
Three valves of the rectum stop feces from being passed with
gas
127
The anus has two sphincters
* Internal anal sphincter composed of smooth muscle
| * External anal sphincter composed of skeletal muscle
128
The sphincters are closed except during
defecation
129
Stomach and colon cancers rarely have
early signs or symptoms
130
Metastasized colon cancers frequently cause
secondary liver cancer
131
Prevention of stomach or colon cancer is by
regular dental and medical examinations
132
Colon cancer is the 2nd largest cause of cancer deaths in
males (lung cancer is 1st)
133
Forms from benign mucosal tumors called polyps whose formations
increase with age
134
Regular colon examinations should be done for all
those over 50
