Digestive system Flashcards
(114 cards)
1
Q
What are the 6 functions of the digestive system
A
Ingestion, motility, secretion, digestion, absorption of nutrients, formation of feces
2
Q
What is ingestion and why do we need it
A
food intake
we need it for energy, source of building blocks and essential nutrients
3
Q
what is motility
A
movement of food through the GI tract
4
Q
what is deglotition
A
swallowing
5
Q
what is peristaisis
A
rhythmic contractions that pushes material through a tube
6
Q
what are the 2 types of secretion
A
exocrine and endocrine
7
Q
what are exocrine secritions
A
water, mucus, enzymes, HCl, bicarbonate solution
8
Q
what are endocrine secretions
A
hormones for hunger, thrist, and motility
9
Q
what is digestion and what are the 2 types
A
breakdown of food into substances that can be used by the body
physical vs chemical
10
Q
physical digestion
A
big chunks to smaller chunks
11
Q
what is chemical digestion
A
large marcromolecules use enzymes to breakdown into smaller subunits
12
Q
what are the steps of absorption of nutrients
A
small subunits get absorbed (moslty at the small intestine) then goes into the blood and then the liver. sometimes to lymphatic
13
Q
where does most absoprion of nutruients take place
A
small intestine, duodenum
14
Q
where does the formation of feces occur
A
the large intestine. it needs to absorb lots of water
15
Q
How long is the digestive tract system
A
35 feet long tube. its open at both ends
16
Q
structures of digestive tract… 8
A
oral cavity, pharynx, esophagus, stomach, small intestine, large intestine, rectum, anus
17
Q
structures in mouth
A
teeth, tongue, salivary glands
18
Q
accessory structures of small intestine
A
liver, gall bladder, and pancreas
19
Q
What does the liver do
A
makes bile withich then emulsifies fat
20
Q
what does the gall bladder do
A
store/concentrate bile
21
Q
what the pancreas do
A
make bicarbonate solution and digestive enzymes
22
Q
what are the 4 layers of the digestive tract
A
mucosa, submucosa, muscularis externa, and adventitia/serosa
23
Q
what are the parts of the mucosa
A
the epithelial layer
the lamina propria
the muscularis mucosa
24
Q
what is the epithelial layer of the mucosa made of
A
stratified squamous epithelium at the mouth and anus but
simple columnar epithelium everywhere else
25
mucus functions from golbel cells in the epithelial layer of the mucosa
lubricate
cause food to bolus to stick together
in stomach it can protect lining from digestive juice
26
what is the lamina propria of the mucosa layer have
losse ct tissue, blood capillaries and lymphatic capillaries, nerves, and lymphoid nodules
27
what is the muscularis mucosa
a thin layer of smooth muscle
28
what is the submucosa layer
loose ct
bigger blood vessels and lymphatics
29
where and what is the meissners plexus
in the submucosa layer
it is a network of nerves that controls secretions, and is a part of the enteric nervous system
30
what does the muscularis externa layer have and do
an inner and outer layer
they allow for peristaliss and mixing of contents
31
inner vs outer layer of muscularis externa
inner is a circular layer of smooth m.
outer is a longitudinal layer of smooth m.
and the stomach has a 3rd layer that is oblique
32
what and where is the myenteric plexus
between the 2 layers of muscularis external
a network of nerves associated with motility between the 2 layers
33
diff between adventitia and serosa layers
adventitia is above diaphragm, dennse irregular CT, and anchors tube to nearby structes
serosa is below diaphragm.
visceral peritoneum
serous membrane is loose Ct, simple squamous epithelium
34
what are messentaries
areas for b.v. and nerves
anchors GI tract to back wall
35
What controls the GI tract
nervous system and the endocrine system
36
how does the enteric NS control GI tract
meissners plexus controls secretion
myetteric plexus controls motility
37
what is the GI tract modulated by, and how
the autonomic NS.
the SNS inhibits digestion
the PSNS stimulates digestion
(both communicate with the plexi )
38
what are the 3 endocrines produced by the endocrine system
gastrin
secretin
cholecytokinin (CCK)
39
what does gastrin do
increase gastric juic production
increase gastirc motility
stimulate proliferation of gastric lining
40
what does secretin do
increase release of bicarbonate solution form pancrease
decrease gastric motility and secretion
41
what does CCK do
decrease gastric motility and secretion
increase release of digestive enzymes from pancreas
increase release of bile from gall bladder
signal end of meal
42
portions of oral cavity
tongue and teeth
43
what is the tongue and what does it do
skeletal muscle that positions food under teeth
moves food toward back of mouth swallowing. has papillae ,,, tastebuds
44
what is the frenulum
a CT strand. connects tongue to bottom of oral cavity . it prevents tongue from blocking oral cavity
45
teeth do what
aid in mastication (chewing ) which is physical digestion
46
how many deciduous teeth vs permant teeth
20 deciduous and 32 permanent
47
what are the 4 types of teeth
incisor
canine
premolar
molar
48
what do incisor, canine, premolar, and molar do
incisor (2) for biting
canine (1) for tearing meat
premolar (2 in adults ) for grinding plants
molar (2 or 3) csups for grinding plants
49
parts of a tooth 8
crown
gingiva
root
enamel
dentin
pulp
cementum
periodontal ligament
50
crown portion
exposed
51
gingiva portion
gums
52
root portion
below gum line
53
enamel info
covers crown, hardset substnace in body
54
dentin portion
middle layer
55
pulp portion
innermost part, has bood vessel and nerves
56
cementum info
thin layers of CT along root. "glue"
57
periodontal ligament info
CT strands that insert into cementum and alveolar processes of bone
58
what do salivary glands secrete
saliva and mucus
59
what is saliva and fxn
99 % water, it disovles chemicals in food
60
Salivary amylase does what
starts chemical digestion of CHO
61
pH of saliva
6.0 to 6.9
62
what does the mucus in saliva do
causes food to stick together in to food bolus
63
parts of pharynx
nasopharynx
oropharynx
laryngopharynx
64
lining of esophagus
stratified squamous epithelium
65
what is the esophagus
tube thtat connects pharynx and stomach behind trachea
66
muscular portions of esophagus
upper is skeletal
lower is smooth muscle
67
what does the upper and lower esophageal sphincter do
upper prevents air entry
lower prevents gastric reflux
68
what happens prior to swallowing
solf palate down, epiglottis up and it doesn't block larynx, upper esophagus sphinter is contracted
69
what happens during deglution
food bolus shifted to back of mouth
tongue presses against roof of mouth
initates swallowing where upper eso sphincter relaxes, soft palate shifts up to block off nasal cavity
larynx shifts up and epiglottis folds down over glottis of larynx
70
what pushes blous to stomach
waves of peristalis
71
when is upper esophagus sphinter contracted vs relaxed
contracted prior to deglutiton but relaxed during swallowing
72
2 muslces of peristalsis
circular and longitudinal
73
what do circular muscles do. when do they contract vs relax
contract behind food bolus
relax in front of food bolus
74
what do longitudinal muslces do. when do they contract vs relax
contract in front of food bolus
relax behind the food bolus
75
what are the functions of the stomach . 5
storage of food
physical digestion
chemical digestion
secretion of intrinsic factor
absorption
76
physical digestion in stomacch info
churning b cuz of 3 layers of smooth muslce
77
77
chemical digestion in stomach
usually protein /pepsin
78
secretion of intrinsic factor in stomach info
absoption of vitamin B12 which leads to RBC production
79
what does the stomach absorb
water, OH-, druges
80
what are the portions of the stomach
cardiac sphincter, cardiac region, fundus, body, pylorus, pyloric sphincter, lesser curvature, greater curvature
81
what is the cardiac sphinter
ring of smooth m. also called the lower esophageal sphincter, it relaxes as food arives
82
what is the pylorus
funnel shaped rerinal portion
83
what is the pyloric sphinter
a 2nd ring of smooth m. that regulates entry of chyme into small intestine
84
what is in gastric pits of the stomach
mucus neck cells
parietal cells
chief cells
85
what do mucus neck cells do
produce muus and form a protextive mucus layer
86
80 % of ulcers are due to what
H. pylori
87
what do parietal cells secrete
HCl and intrinsic factor
88
what does Hcl do in gastirc pits
inhibits digestion of CHO whcih starts in the mouth (chemical digestion), also it denatures proteins, and does autolysis of pepsinogen (cuts it)
89
what do chief cells secrete
pepsinogen (inactive form )
90
what does HCL cut pepinogen to make
pepsin, which allows for chemical digestion of proteins
91
what are rugae . what do they allow for
large folds of mucosa
they allow for distention of stomach as it fills
92
what does the inner oblique layer do
allow for churning. aids in physical digestion of food. makes chyme to enter small intestine .
93
what are the 3 phases of controling castric juice secretion
cephalic phase
gastric phase
intestinal phase
94
what makes up gastiv juice
pepsinogen and HCl
95
what activity does the cephalic and gastric phase increase
stomach
96
what activity does the intestinal phase increase
intestine
97
97
what occus in the cephalic phase
what is it mediated by.
what does it increase
sight, small, tast, thought of food
mediated via vagus nerve
increases in gastic juice production
increase in gastrin
98
what does gastrin do
increases gastirc juic production and increases gastric motility
stimulates proliferation of gastric mucosa
99
what occurs during the gastric phase
food enters stomach
NS local reflex
stretch receptors and chemoreceptors increase pH
100
what are secretagues
chemicals that stimulate gastric juice secretion to a greater extent
101
what occus in the intestinal phase
begins as chyme enters the duodenum
decrease in stomach emptying
decrease ig gastirc secretions (enterogastric relex)
102
Why is CCK released and when . (what phases)
CCK released due to acids and peptides. releases bile, enzymes released
103
what does secretin acid lead to
bicarbonate solution gets released
104
parts of the small intestine
duodenum (1 foot)
jejunum (8 foot)
ileum (12 foot)
105
what happens during final digestion
segmental contrations to mixing
chemical digestion of intestinal enterokinase
and absorption of nutrients
106
what does trypsinogen turn to
trypisin
107
how is absoption maximized in small intestion
increased surface area
increased blood flow following meal
108
what are the 3 modifications to the small intestine to increase surface area
plicae circuaris
villi
microvilli
109
plicae circularis def
circular folds with core of submucosa
increases SA by 3x
110
villi def
finger like projections of mucosa with core of lamina propria
increases SA by 10x
111
microvilli def
tiny finger like projections of cell membrane of epithelial cells
brush border increase SA by 10x
112
