Stomach Flashcards
What are the regions of the stomach?
- cardia
- fundus
- body
- pylorus
Carida of the Stomach
- smooth muscle
- contains predominantly
mucus-secreting glands
Fundus of the stomach
glandular portion of stomach
the fundus of the stomach secretes
- acid
- pepsin
- some mucus
body of the stomach
- where food is mixed and starts to break
down - contains acid- & enyzme-secreting glands.
what is the largest portion of the stomach
the body
pylorus of stomach
contains 1’
mucus & gastrin
secreting glands
Pyloric sphincter
controls
outflow from stomach
into duodenum
The stomach is a _______ organ
deistensible
Chyme
broken down food mixed with gastirc secretions
What are the layers of the stomach?
- inner circular
- outer longitundinal
* inner oblique*
3 layers
inner oblique layer
- in the musclaris externa
Does a lot of absorption occur in the stomach??
NO, only a little does
What are things that get abosrbed in the stomach?
- water
- alcohol
- some drugs (aspirin)
Rugae
prominent
longitudinal fold of the stomach
What is prominant in the glandular body of the stomach mucosa?
gastric pits = foveolae
Gastric glands secrete _____ litters of water gastric juice per day
2
What is contained in the gastric juice?
secreted by the gastric gland
- HCl
- Pepsinogen
- Gatrin
- Lipase
Pepsinogen
- inactive percursor of pepsin
What converts pepsinogen to pepsin?
HCl (gastric acid)
What are the 5 cell types of the gastric epithelium?
- parietal cell
- cheif cells
- mucus secreting
- stem cell
- enteroendocrine cells
What are the 3 secretions of the gastric epithelium?
- hydrochloric acid
- proteolytic enzyme (mainly pepsin)
- Mucus (mainly neutral)
What are parietal cell also refered to as
- acid-producing
- oxyntic
How often do mucus secreting cell of the stomach renew themselves?
every 3- 7 days
Where are mucus secreting cells of the stomach found
located on surface
Surface mucus cells secrete
thick, insoluble mucus &
bicarbonate ions
Surface cells are
- tall columnar with basal nuclei
- clear cytoplasm
- Many mucin vacuoles
Mucus neck cells
- smaller & less regular in shape
- more compressed & distorted by adjacent cells
- basal nucleus
- small mucin vacuole
Mucus Neck Cells secrete
soluble mucus
Where are mucus neck cells of the stomach located?
in the upper third of the pit
What are the two types of mucus-secreting cells
- Surface
- neck
Paretial cells secrete
HCl
and produce intrinsic factor
What cells produce intrinsic factor?
parietal cells
What is intrisic factor necessary for?
absorption of Vitamun B12
Parietal cells are
- Pyramidal in shape
- Narrow luminal aspect
- Central nucleus
- Pale, eosinophilic cytoplasm
- Luminal surface area increased by deep microvilli
What is the life span of a parietal cell?
1 year
Chief cells are
- Large, basophilic nuclei
- Eosinophilic cytoplasm (look like exocrine pancreas cells)
chief cell granules contain
pepsinogen
Pepsin
breaks down large protein molecules into small peptides
Where are parietal cell most numerous?
inthe middle third of the gland
Where are chief cells located?
Located at base of gland (bottom third)
Why do chief cells stain purple?
due to the large # of ribosomes
What color do parietal cells stain?
pink to purple
What is the life span of chief cells
about a year
What controls parietal and chief cells?
autonomic nervous system & hormones from endocrine cells in region of pylorus
enteroendocrine cells =
APUD cells (amine precursor uptake & decarboxylation)
enteroendocrine cells are ______ cells
paracrine (target within local vicinity)
enteroendocrine cells secrete
variety of peptide hormones
enteroendocrine cells secrete peptide hormones in response to
local factors
the peptide hormones that enteroendocrine cells secrete control
- GI motility
- gastric secretion
What secrete gastrin?
G cells
What are examples of enteroendocrine cells
- G cell
- D cell
- S cell
Gastrin
stimulates secretion of HCl & pepsin
What secretes somatostatin
D cells
somatostatin
inhibits secretion of gastrin
What secretes secretin?
S cells
Secretin inhibits
gastric secretion
secretin stimulates
smooth muscle contraction
Gastric Endocrine Cells
- Small & round
- Found in base of glands
Gastric Endocrine Cells Secrete
gastrin and serotonin
Where do you mainly find stem cell in the gastric gland
in the neck of gland
Undifferentiated stem cells of the gastric gland
- Continuously divide to replace lost or damaged epithelial cells (can replace all cells)
- mature, migrate up or down gland
Gastritis
inflamtion to the stomach
What can cause gastritis?
- excessive alcohol use
- chronic vomiting
- stress
- certain medications (aspirin)
- bile reflux
- helicbacter pylori
- infections (virus or bacteria)
helicobacter pylori produce
urease
Urease
- increases gastric pH
*this causes 2’ acid production
Helicobacter pylori
bacteria that lives in the mucous lining
of the stomach
Bile Reflux
A backflow of bile into the stomach from the bile tract (that connects to the liver and gallbladder)
Ulcers frequently associated
with chronic infection with
helicobacter pylori
What is used to treat helicobacter pylori?
triple therapy
triple therapy
2 long-term abx & proton
pump inhibitor (prevents H+
secretion)
used to treat helicbacter pylori
Stomach ulcer
gastric ulcer
painful sores in
the stomach lining
Stomach ulcers are a type of
peptic ulcer disease
peptic ulcers are
any ulcers
that affect both the
stomach and small
intestines
What causes stomach peptic?
- H. pylori
- mental stress
- smoking
- alcohol
- genetics
- non-steriodal anti-inflamtory drugs
