M5 U1 Digestive System Flashcards
1
Q
The primary function of the digestive system
A
bring essential nutrients into the internal
environment
2
Q
the process of altering the chemical and
physical composition of food
A
Digestion
3
Q
The process of digestion depends on
A
-endocrine and exocrine secretions
-controlled movement of ingested food
4
Q
The process of complex foods taken in
A
INGESTION
5
Q
Complex nutrients are broken down into simpler nutrients
From the breakdown of large chunks of food into smaller bits, and move it along the gastrointestinal tract
A
DIGESTION
6
Q
Movement by the muscular components of the digestive tube
A
MOTILITY
7
Q
- Release of digestive enzymes to breakdown large molecules into small molecules in the gastrointestinal tract
A
SECRETION
8
Q
Movement of nutrients through the mucosa into the internal environment
A
ABSORPTION
9
Q
The material not absorbed must then be excreted to make room for more material
A
ELIMINATION
10
Q
gastrointestinal tract is also known as
A
alimentary tract (alimentary canal)
11
Q
tube open at both ends formed by the main
organs of the digestive system
A
GASTROINTESTINAL TRACT
12
Q
provides the body with a continual supply of water, electrolytes, vitamins, and nutrients.
A
GASTROINTESTINAL TRACT
13
Q
parts of the mouth
A
Lips
Cheeks
Tongue
Teeth
Uvula
Gums
Hard and soft palate
Salivary glands
14
Q
Food material is ingested into the oral (buccal)
cavity and is reduced by
A
chewing/mastication
15
Q
anterior teeth (incisors) provide
A
strong cutting action
16
Q
posterior teeth (molars) provide
A
grinding
17
Q
serve to mix food with saliva in preparation of swallowing
A
chewing movements/ mastication
18
Q
rate of digestion is dependent on the
A
total surface area exposed to the digestive secretions
19
Q
located inferior and anterior to the ears, between the skin and the masseter muscle
A
Parotid gland
20
Q
found in the floor of the mouth; they are medial and partly inferior to the body of the mandible.
A
Submandibular gland
21
Q
Beneath the tongue and superior to the submandibular glands.
A
Sublingual gland
22
Q
THREE MAJOR SALIVARY GLANDS
A
Parotid gland
Submandibular gland
Sublingual gland
23
Q
Secreted by the salivary glands
A
Salivary amylase
24
Q
Initiates the breakdown of starch
A
Salivary amylase
25
secreted by lingual glands in the tongue
Lingual lipase
26
becomes activated in the acidic environment of the stomach and thus starts to work after food is swallowed
Lingual lipase
27
It breaks down dietary triglycerides (fats and oils) into fatty acids and diglycerides
Lingual lipase
28
serves as an air passageway that propels mucus
Nasopharynx
29
Nasopharynx is lined with
pseudostratified ciliated columnar epithelium
30
serves as a passageway for both air and swallowed food
Oropharynx
31
Oropharynx is lined with
nonkeratinized stratified squamous epithelium
32
opens into the esophagus (food tube) posteriorly, and the larynx (voice box) anteriorly
Laryngopharynx
33
Laryngopharynx is lined with
nonkeratinized stratified squamous
epithelium
34
The process of swallowing
DEGLUTITION
35
three stages of deglutition
Oral stage
Pharyngeal stage
Esophageal stage
36
esophagus to stomach
Esophageal stage
37
oropharynx to esophagus
Pharyngeal stage
38
mouth to oropharynx
Oral stage
39
From here on, swallowing becomes entirely – or almost entirely – automatic and ordinarily cannot be stopped
ORAL STAGE
40
functions primarily to conduct food
rapidly from the pharynx to the stomach
esophagus
41
lubricates the bolus and reduces friction.
Mucus secreted by esophageal glands
42
The movement of food bolus down the esophagus is accomplished through
peristalsis
43
A long tube that extends from the oropharynx into the stomach.
ESOPHAGUS
44
prevents food and secretions from leaking into the windpipe. Also prevents air from entering during respiration.
Upper esophageal sphincter
45
help prevent significant reflux of stomach contents into the esophagus
Lower esophageal sphincter (cardiac sphincter)
46
A progression of coordinated contractions and
relaxations of the circular and longitudinal layers of the muscularis
Occurs in the esophagus, stomach, small and large intestine.
PERISTALSIS
47
The backward flow of stomach acid up through the LES and into the lower esophagus.
ACID REFLUX
48
chronic, more severe form of acid reflux.
Gastroesophageal reflux disease
49
Hydrochloric acid (HCl) from the stomach contents can irritate the esophageal wall, resulting in a burning sensation that is called
heartburn
50
Storage of large quantities of food until the food can be processed in the stomach, duodenum, and lower intestinal tract
STOMACH
51
Mixing of this food with gastric secretions until it forms a semifluid mixture called
chyme
52
adult stomach can typically hold
1 - 1.5 liters
53
four regions of stomach
1. Cardia
2. Fundus
3. Body
4. Pyloric part
54
When the stomach is empty, the mucosa lies in large folds called
rugae (wrinkles)
55
the muscle sphincter connecting the stomach to the duodenum
Pyloric sphincter
56
Forward and backward movement of
gastric contents, mixing food with gastric juices to form chyme.
CHURNING
57
Peristaltic waves move gastric contents from the body of the stomach down into the antrum
propulsion
58
food particles are forced back
into the body of the stomach
retropulsion
59
Secreted by parietal cells
Needed for absorption of vitamin B12
Intrinsic factor
60
Secreted by parietal cells
H+ and Cl- are secreted separately
Kills microbes in food
Denatures proteins
Creates an acidic environment that converts
pepsinogen into pepsin
Hydrochloric acid
61
Secreted by chief cells
Converted into pepsin, the most important enzyme in gastric juice
Pepsin converts proteins into smaller peptides
Pepsinogen
62
Secreted by chief cells
Splits triglycerides into fatty acids and monoglycerides
Gastric lipase
63
-Hormone secreted by G cells
-Stimulates parietal cells to secrete HCl and chief cells to secrete pepsinogen
-Contracts lower esophageal sphincter, increases motility of stomach, and relaxes pyloric sphincter
Gastrin
64
occur when the stomach
has been empty for several hours or more.
Hunger contractions
65
person sometimes experiences mild pain in the pit of the stomach during hunger contractions
hunger pangs.
66
forcible expulsion of the contents of the upper GI tract (stomach and sometimes
duodenum) through the mouth.
VOMITING
67
characterized by overeating at
least twice a week followed by purging by
self-induced vomiting, strict dieting or fasting,
vigorous exercise, or use of laxatives or
diuretics
Bulimia nervosa
68
involved in both digestion and absorption.
SMALL INTESTINE
69
-shortest, C-shaped tube arising from the pyloric sphincter to the jejunum
- Where the pancreas, liver, and
gallbladder release their secretions
Duodenum
70
longest region that ends at the
ileocecal sphincter
Ileum
71
___contractions “chop” the chyme two to three times per minute, in this way promoting progressive mixing of the food with secretions of the small intestine.
segmentation
71
___contractions “chop” the chyme two to three times per minute, in this way promoting progressive mixing of the food with secretions of the small intestine.
segmentation
72
Secreted by the acinar cells of the pancreas
Contains various enzymes
PANCREATIC JUICE
73
- secreted as trypsinogen (inactive form)
- Converted by enterokinase in the intestinal tract.
- activates chymotrypsin, pancreatic lipase, nucleases, and amylase
Trypsin
74
starch-digesting enzyme
Pancreatic amylase
75
Triglyceride-digesting enzyme
Pancreatic lipase
76
Digest RNA and DNA into nucleotides
Ribonuclease and deoxyribonuclease
77
Secreted by the liver and stored and
concentrated by the gallbladder
BILE
78
Contains lecithin and bile salts that help break
down large drops of fat into smaller droplets,
making fat more digestible
BILE
79
- contain sodium bicarbonate which helps
neutralize chyme
- contain waste products for excretion
BILE
80
-Produced by goblet cells in the intestinal
mucosa
-Buffers and lubricates material in the intestinal
lumen
-Increased pH of chyme also allows optimum
enzyme function
INTESTINAL JUICE
81
If bile contains either insufficient bile salts or
lecithin or excessive cholesterol, the cholesterol
may crystallize to form
gallstones
82
DIGESTION OF CARBOHYDRATES
Salivary amylase and pancreatic amylase
83
DIGESTION OF PROTEINS
Pepsin (stomach) and Trypsin (pancreatic juice)
84
DIGESTION OF LIPIDS
Lingual lipase, gastric lipase, and pancreatic lipase
85
DIGESTION OF NUCLEIC ACIDS
- Ribonuclease and deoxyribonuclease
86
Absorption of materials occurs via
diffusion
facilitated diffusion
osmosis
active transport
87
Any undigested or unabsorbed material
left in the small intestine passes on to
the
large intestine
88
enhance absorption by increasing surface area
and causing the chyme to spiral
The circular folds of the small intestine (plica)
89
vastly increases the surface area of the epithelium available for
absorption and digestion.
large number of villi
90
terminal portion of the GI tract.
large intestine
91
overall functions of the large intestine
completion of absorption
-production of certain vitamins
-formation of feces
-expulsion of feces from the body
92
intensifies peristalsis in the ileum
and forces any chyme into the cecum
gastroileal reflex
93
remain relaxed and become distended while they fill up.
When the distension reaches a certain
point, the walls contract and squeeze the
contents
Haustral churning
94
strong peristaltic wave that begins at about
the middle of the transverse colon and quickly
drives the contents of the colon into the
rectum.
Mass peristalsis
95
final stage of digestion occurs in the
colon
96
which gives feces their brown color
stercobilin (simpler pigment of bilirubin)
97
By the time chyme has remained in the large
intestine 3–10 hours, it has become solid or
semisolid because of water absorption and
is now called
feces
98
act of expelling feces is called
defecation
99
increase in the frequency, volume,
and fluid content of the feces caused by
increased motility of and decreased
absorption by the intestines.
Diarrhea
100
Frequent diarrhea can result in
dehydration and electrolyte imbalances
101
refers to infrequent or difficult defecation
caused by decreased motility of the
intestines
Constipation
102
Excessive motility may be caused by
-lactose intolerance
-stress
-microbes that irritate the gastrointestinal mucosa
