digestive tract 1 Flashcards
(41 cards)
1
Q
layers of the digestive system (interior to exterior)
A
- mucosa
- submucosa
- muscularis externa
- adventitia
- mesentary
2
Q
the mucosa of digestive system is
A
adjacent to the lumen
3
Q
the submucosa of the digestive tract is
A
- made highly of distensible connective tissue
- contain Meissner plexuses
4
Q
Meissner plexuses
A
- plexus of autonomic nerves innervating organs
- help with blood flow
5
Q
muscularis externa
A
- consists of smooth muscle oriented in different directions
- inner-circular and outer longitudinal layers facilitates the movement of food involuntarily
6
Q
adventitia (serosa) of digestive system
A
- secures organs to surrounding tissues
- fibrous connective tissue (serosa) in the peritoneal gap (gap between parietal and visceral layers) covers organs individually
- both covered by mesothelium for frictionless movement
7
Q
mesentery of digestive system
A
- not really a layer
- attaches stomach, small intestine, pancreas, spleen, and most other abdominal digestive organs to the posterior wall of abdomen
- organs with this layer are intraperitoneal and those without are retroperitoneal
8
Q
the digestive system includes the following structures/organs:
A
- oral cavity/teeth/tongue
- salivary glands
- pharynx
- esophagus
- stomach
- liver
- gall bladder
- pancreas
- large intestine
- small intestine
9
Q
the digestive system helps with:
A
- propulsion
- secretion
- absorption
- excretion
- immunologic protection
- hormone production
10
Q
the digestive system has 2 main parts:
A
- upper tract - initial phase (oral cavity, pharynx esophagus)
- lower tract (stomach, intestines, and anal canal)
11
Q
the structures of the digestive tract allow the following:
A
- ingestion
- mastication
- motility
- secretion
- hormone release
- chemical digestion
- absorption
- elimination
12
Q
the oral cavity
A
- has only mucosa and submucosa
- non-keratinized simple squamous epithelium on most of mucosa
- papillae on the tongue
- saliva enters invaginations of papilla and needs to be flushed
13
Q
type of papillae on the tongue
A
- filaform
- fungiform
- foliate
- circumvallate (vallate)
14
Q
filaform
A
- most abundant papillae
- no taste buds
- highly keratinized
15
Q
fungiform
A
- mushroom shaped
- some taste buds
16
Q
foliate
A
- rudimentary in humans
- on sides of tongue
17
Q
circumvallate (vallate)
A
- have most taste buds
- innervated by the most sensory nerves
18
Q
why is it important to have active salivary glands and brush your teeth?
A
- because saliva enters papillae and cleans out proliferation of bacteria in mouth
- if not cleaned it would carry lots of bacteria
19
Q
Ebner’s gland
A
- minor salivary glands
- only produce serous fluids
- help flush oral cavity
- all other glands are mixed or mucosal glands
20
Q
function of oral cavity
A
- food is chewed and broken down into bolus
- salivary amylase breaks down starch into glucose
21
Q
tongue
A
- non keratinized
- papillae
- skeletal muscle
22
Q
teeth
A
- enamel
- dentin
- pulp
- cementum
- gingiva
- periodontal ligament
23
Q
esophagus
A
- has 3 layers
- non-keratinized stratified squamous epithelium in upper and middle thirds and becomes columnar toward lower third
- submucosal glands are larger than mucosal glands
24
Q
layers of esophagus
A
- upper 1/3 = skeletal muscle
- middle 1/3 = skeletal and smooth muscle
- lower 1/3 = smooth muscle
25
innervation of the digestive tract
- enteric system
- has 2 subsections
- parasympathetic nerve fibers activate physiologic digestive process
- sympathetic nerve fibers are mainly inhibitory of digestive process
26
subsections of digestive tract
- myenteric plexus
- meissner plexus
27
myenteric plexus
- between inner and outer layers of smooth muscle
- regulates smooth muscle contraction
28
meissner plexus
- in submucosa
- regulates glandular secretion and blood flow
29
the stomach
- primary site of digestion of nutrients
- has 4 regions
- rugae
- glands secrete mucous, acid, digestive enzymes
30
4 regions of the stomach
- cardia
- fundus
- body
- pylorus
31
rugae
- the irregular folds of the inner lining of the stomach
- flatten out when stoamch expands
- simple columnar epithelium
32
glands of stomach
- pass through lamina propria
- cardiac glands are at esophageal orifice (mostly mucous secretion)
- gastric glands are in body and fundus (most developed and numerous, secrete mucous, acid and enzymes)
- pyloric glands (close to duodenum, mostly secrete mucous)
33
gastric pits
- shallow invaginations of the surface epithelium
- contain surface mucous cells
- highly alkaline (secrete carbonate)
- protect epithelial lining form low pH of stomach in lumen
34
gastric glands have 5 cell types:
- surface mucosa
- mucous neck cells
- parietal cells
- chief cells
- G cells
35
surface mucosa of gastric glands secrete
alkaline fluid (carbonate) to protect epithelium
36
mucous neck cells of gastric glands
- secretes acid (HCl) to reduce pH of stomach
- live and die quickly, replaced by stem cells that migrate to the neck of the gland from the base of the pit
37
parietal cells of gastric glands
- secretes intrinsic factor and HCl
- have receptors for gastrin
- controlled by ANS
- if damaged, no secretion of intrinsic factor = no vitamin B12 = subacute combined degeneration
38
chief cells of gastric glands
- secrete pepsinogen and gastric lipase
39
G cells of gastric glands
- secretes gastrin
- stimulates production of HCl by parietal cells
40
gastrin is secreted by
enteroendocrine cells
41
gastric glands are innervated by:
acetylcholine receptor (parasympathetic)
