Esophagus To Stomach Flashcards
4 layers of the GIT histology (innermost facing lumen to outermost)
(1) mucosa
(2) submucosa
(3) tunica muscularis/ muscularis externa
(4) serosa/ adventitia
Submucosa tissue type
Dense irregular connective tissue
What layer can blood vessels be found?
Submucosa - connective tissue layer
2 layers of the tunica muscularis or muscularis externa (inner to outer)
(1) circular layer
(2) longitudinal layer
Serosa tissue composition
- serous membrane - simple squamous epithelium
- mesothelium
- small amount of underlying CT
3 layers of the mucosa
(1) lining epithelium
(2) lamina propria
(3) muscularis mucosa
Lamina propria tissue type
Loose areolar connective tissue
Muscularis mucosa composition
Smooth muscle
3 Functions of the Epithelial lining
- Protection
- Absorption
- Secretion
Esophagus epithelium
Stratified squamous non-keratinized epithelium
What structure is found in the submucosa that is not found in the lamina propria
Submucosal plexus or Meissner’s plexus
Group of Nerves contained at the muscularis externa - between its 2 layers
Myenteric plexus or Auerbach’s plexus
Disease described as the absence of the Myenteric plexus in segments of the alimentary tract
Hirschsprung’s disease
Sphincters in the GIT
- Pharyngoesophageal
- Inferior esophageal sphincter - gastro
esophageal sphincter - Pyloric sphincter
- Ileocecal valve
- Internal anal sphincter
Serosa vs. Adventitia
Organ outside the peritoneal cavity or attached to the abdominal cavity wall it is Adventitia
Length of the esophagus
25 cm
Muscularis externa of the esophagus
Proximal 3rd: skeletal muscle
Middle 3rd: both
Distal 3rd: smooth
Which part of the esophagus is covered by serosa
Distal 1-2cm
Most dilated portion in the GIT where food would stay the longest
Stomach
Muscularis externa layers of the stomach
Inner oblique, middle circular, outer longitudinal
Maximal sites of acid production in the stomach; max mucous production sites
Acid - fundus & body
Mucous - cardia & pylorus
Stomach Epithelial lining
Simple columnar
Gastric gland morphology
Simple branched tubular glands
Function:
(1) Inner circular layer
(2) Outer longitudinal layer
(3) Muscularis mucosa
(1) churning and food mixing - digestion
(2) peristalsis
(3) increase absorption
True/False
Esophagus is exposed to friction, and functions for absorption and secretions.
False
Esophagus is exposed to friction; NO absorption and excretions - except for mucous secretions to aid in lubrication when swallowing
Tissue layer that surrounds organs and functions to protect internal structures
ex. pleura, pericardium, peritoneum, mesentery, etc.
mesothelium - simple squamous
GIT structures covered with adventitia
- proximal part of the esophagus
- 2nd - 4th part of the duodenum
- ascending colon
- descending colon
GIT structures covered with serosa
- distal 1-2 cm of the esophagus
- stomach
- 1st part of the duodenum, jejunum, & ileum
- transverse colon
Cells found in the fundus and body of the stomach
*parietal cells
*chief cells
Invagination of the lining epithelium towards the submucosa in the stomach
Gastric pits/ Foveolae
Surface mucous cells contain (1) and secrete (2)
(1) mucinogen granules
(2) mucous
Area in between the gastric pit and the gastric gland
Isthmus
Submucosal glands in the stomach
Gastric glands
Parietal cell location and characteristics
- at neck and base of gastric glands; between mucous neck cells
- Triangular
- red color
- contains cannaliculi (small canals), abundant mitochondria
Parietal cell secretion
*Hydrochloric acid (HCl) via hydrogen potassium ATPase Pump
*Intrinsic factor
Serve as reservoir of plasma membrane with proton pumps (H-K ATPase pump) in parietal cells
Tubulovesicular membrane system
T/F
Parietal cells have microvilli
True
Cells present at the base of the gastric glands
- parietal cells
- enterochromaffin like cells
- chief cells
- D cells
- G cells
Chief cells (basophilic or acidophilic)
Basophilic
Present in the submucosa of the esophagus
(1) esophageal glands
(2) Meissner’s plexus
Gastric pits to Gastric glands parts
(1) surface
(2) isthmus
(3) neck
(4) base
Cells at the gastric pits
Surface mucous cells
Simple columnar cells secrete
(1) bicarbonate
(2) prostaglandin E2 - enhances bicarbonate
Misoprostol drug
Prostaglandin drug - enhance bicarbs to treat ulcer and high acidity
Also has receptor for uterine muscle - misused for abortion
Cells abundant in the isthmus
Stem cells
Longitudinal folds of the stomach composed of mucosa and submucosa
Rugae
Deep pits that open to relatively straight glands - mostly mucous cells
pyloric glands
Microscopy: what part of the stomach?
Shallow gastric pits, long gastric glands w/ mucous cells - lightly staining
Cardia
Microscopy: what part of the stomach?
Deep gastric pits, short gastric glands w/ mucous cells - lightly staining
Pylorus
Microscopy: what part of the stomach?
w/ numerous acidophilic parietal cells
Fundus or Body
Cells of the Gastric pit - gland and their secretions
GASTRIC PIT
(1) surface mucous cells: mucous, bicarbonate, prostaglandin E2
ISTHMUS
(1) stem cells
NECK
(1) parietal cells: HCl and intrinsic factor
(2) mucous neck cells: mucous
BASE
(1) Enterochromaffin-like cells: histamine
(2) chief cells: pepsinogen
(3) G cells: Gastrin
(4) D cells: somatostatin
Esophagus Histology Summary
