2. digestive system Flashcards
(95 cards)
1
Q
includes
A
Gastrointestinal tract (GI) accessory organs
2
Q
GI tract
A
tube from mouth to anus
3
Q
accessory organs
A
- teeth, tongue, salivary glands
- pancreas
- liver, gallbladder
4
Q
digestive system processes
A
ingestion
digestion
absorption
defecation
5
Q
ingestion
A
food into oral cavity
6
Q
digestion
A
- large molecules broken down into smaller molecules
* 2 types: mechanical and chemical
7
Q
mechanical digestion
A
motility
eg. chewing
8
Q
chemical
A
enzymes and acid secretions
9
Q
absoroption
A
end products of digestion enter blood or lymph
10
Q
defecation
A
elimination of waste and undigested material
11
Q
GI tract histology
A
4 basic layers : mucosa submucosa muscularis externa serosa (or adventitia) enteric nervous system
12
Q
mucosa
A
3 layers:
- epithelium with numerous goblet cells
- lamina propria=areolar CT
- muscularis mucosa
13
Q
epithelium with numerous goblet cells
A
-stratified squamous: mouth, pharynx, esophagus anal canal
14
Q
lamina propria
A
areolar CT
-contains blood, lymph vessels , lymph nodules/tissues (immune)
15
Q
muscularis mucosa
A
smooth muscle-allows movement of mucosa
16
Q
submucosa
A
areolar CT
contains : blood and lymphatic vessels, submucosal nerve plexus
17
Q
muscularis externa
A
- smooth muscle
- inner circular layer
- outer longitudinal layer
- myenteric nerve plexus b/w layers
- contractions cause motility (mixing and movement)
18
Q
serosa
A
or adventitia
-cavity=lumen
19
Q
enteric nervous system
A
- nervous system of GI tract
- myenteric plexus
- submucous plexus
20
Q
myenteric plexus
A
controls muscularis externa
21
Q
submucous plexus
A
controls activity of mucosal glands and muscle
22
Q
structures:
A
oral cavity salivary glands dentition (teeth) oropharynx and laryngopharynx esophagus stomach small intestine small intestinal accessory organs large intestine
23
Q
oral cavity includes
A
lips
cheeks
palate
tongue
24
Q
palate parts
A
hard palate
soft
25
hard palate
-2 maxillae and 2 palatine bones
26
soft palate
posterior to hard palate
skeletal muscle
posterior projection = uvula
rises to close the nasopharynx when swallowing
27
tongue
attached to hyoid bone
skeletal muscle
projections of mucosa=papillae (taste buds)
28
salivary glands 3 pairs:
parotid
submandibular
sublingual
also contains saliva
29
parotid
- inferior and anterior to ears
| - mumps=inflammations of 1 of both parotids
30
submandibular
floor of mouth
31
sublingual
below tongue on floor of mouth
32
saliva
99. 5% H2O
| 0. %% solutes (eg.enzymes)
33
dentition (teeth)
-in maxillae and mandible
| go to page 3
34
child dentition
primary dentition-deciduous ("baby") teeth
| has 20 teeth
35
adult dentition
secondary dentition-permanent teeth
| has 32 teeth
36
tooth struture
```
crown
root
neck
periodontal ligaments
root canal extend to pulp cavity
```
37
crown
above the gum
dentin=majority of tooth
enamel overlay=acellular, highly calcified-hard!
38
root
dentin with cementum overlay
39
dentin, enamel and cementum
similar to bone, but avascular
40
neck
enamel and cementum boundary (gums)
41
periodontal ligaments
attach root to bones
42
root canal extends to pulp cavity
contains CT, blood/lymph vessels, and nerves
43
oropharynx and laryngopharynx
only muscularis externa (skeletal muscle) and mucosa (stratified squamous epithelium)
44
esophagus
- posterior to trachea
- passes through diaphragm to the abdominal cavity
- all 4 histological layers in GI tract from this point on
45
exceptions in esophagus
- muscularis externa
| - has adventitia in mediastinum
46
muscularis externa
- upper 1/3-skeletal muscle
- middle 1/3-skeletal and smooth muscle (transition zone)
- lower 1/3-smooth muscle
47
has adventitia in mediastinum
-outermost layer
| =fibrous CT (no epithelium)
48
stomach has 4 regions
- cardiac region
- fundus
- body
- pyloric region
49
cardiac region
cardia
| attached to esophagus
50
fundus
above esophageal entrance
51
pyloric region
pylorus
| has pyloric sphincter
52
stomach
- greater and less curvatures
- converts food into chime (food and gastric juice)
- stomach mucosa
53
stomach mucosa
- invaginations of epithelium forms gastric glands (exocrine)
- secrete gastric juice to lumen
54
gastric glands contain:
chief cells
parietal cells
goblet cells
G cells
55
chief cells
secrete pepsinogen and gastric lipase (enzymes)
56
parietal cells
secrete HCl and intrinsic factor (for vit B12 abs in ileum)
57
goblet cells
mucus ( surface epithelium also contains many goblet cells)
58
G cells
enteroendocrine cells
| -secrete gastrin (hormone; to blood)
59
rugae
folds of the mucosa and submucosa due to contraction of muscularis mucosa
-allow expansion without tearing mucosa
60
muscularis externa
```
-function = churning
3 layers:
inner oblique
middle circular
outer longitudinal
```
61
small intestine
pyloric sphincter to ileocaecal valve
62
small intestine 3 segments
duodenum
jejunum
ileum
63
duodenum
```
first fold (short)- retroperitoneal
-extra glands here secrete alkaline mucus to protect against stomach acid
```
64
jejunum
middle section
65
ileium
has groups of lymph nodules=peyer's patches
| -prevent infection of small intestine and bacteria from entering blood
66
segments specialized to increase absorption surface area in the small intestine
plicae circulares
villi
microvilli
67
plicae circulares
submucosa thrown into folds
68
villi
projections of mucosa into lumen
contains:
blood capillaries
lacteals (lymph capillaries that absorb eg. fats )
69
microvilli
brush border on enterocytes (simple columnar)
-extend into lumen
-within epithelium, separate enteroendocrine cells secrete the hormones:
secretin
cholecystokinin
70
small intestinal accessory organs
pancreas
liver
gallbladder
71
pancreas
retroperitoneal
parts: head, body, tail
contains: exocrine portion and endocrine portion
72
exocrine portion
1. acinar cells/acini (most of pancreas)
| 2. duct cells
73
acinar cells/acini (most of pancreas)
secrete digestive enzymes ( into ducts )
74
duct cells
secrete alkaline fluid to neutralize stomach acid
| ->digestive enzymes and alkaline fluid =pancreatic juice
75
endocrine portion
=islets of langerhans (amid acini)
| -secrete hormones: insulin and glucagon to regulate blood sugar
76
liver
- 4 lobes (right, left, caudate, quadrate)
- cells=hepatocytes
- filters material from GI tract (nutrients, toxins etc) before going to rest of body produce bile
- produces bile-for fat digestion
77
gallbladder
```
muscular sac on surface of liver
rugae, no submucosa
stores, concentrates bile b/w meals
-> enzymes, alkaline fluid and bile enter duodenum by series of ducts
page 7
```
78
large intestine
- ileocaecal valve to anus
- appendix
- colon
- rectum
- anus
79
colon parts
- ascending (right side)
- hepatic flexure
- transverse
- splenic flexure
- descending (left side)
- sigmoid
80
colon
- muscularis externa longitudinal layer incomplete = taeniae coli
* contraction forms pouches = haustra
- epiploic appendages = fat- filled pouches
* function unknown
81
rectum
no taeniae coli
| -anal canal=last 3 cm
82
anus
-2 anal sphincters: internal (smooth muscle) and external (skeletal muscle-voluntary control)
83
lymphatic system of intestines contains
immune function
| digestive function
84
immune function
- lymph nodules in mucosa throughout small and large intestines
- peyer's patches in ileum
* prevents infection of small intestine and prevent bacteria from entering blood
85
digestive function
lymph vessels
-most absorbed fats from small intestine enter lacteals (some into blood)
lacteals ->lymph collecting vessels->cisterna chyli-> thoracic duct->left subclavian vein
86
lower GI tract blood circulation
page 9
| portal system
87
portal system
blood vessels b/w 2 capillary beds 9but blood doesn't pass through the heart b/w them)
88
peritoneum
```
serous membrane
serosa b/w organs
mesentery
retroperitoneal
peritonitis
(page 10 diagram)
```
89
serous membrane
- visceral peritoneum (against organ wall)
- parietal peritoneum (against abdominal cavity wall)
- peritoneal cavity = filled with serous fluid
90
serosa b/w organs
sheet of w fused visceral peritoneum layers
-contains blood/lymph vessels and nerves
-forms folds in some areas=omenta:
greater and lesser omentum
91
greater omentum
- fatty apron
- covers transverse colon and small intestine
- contains fat-protection, insulation, energy reserve
92
lesser omentum
suspends stomach from liver
93
mesentery
- suspends small intestine from cavity wall
| - double layer of parietal peritoneum
94
retroperitoneal
- an organ behind peritoneum
- peritoneum lines only one side
* anterior = parietal peritoneum
* posterior = CT (adventitia)
95
peritonitis
- inflammation of the peritoneum
| - due to:burst appendix, wounds etc.
