Esophagus, Stomach, & Intestines (Exam 2) Flashcards
What are the digestive tract organs?
-esophagus (lower, or abdominal)
-stomach
-SI (duodenum, jejunum, ilieum)
-LI (including sigmoid colon)
What are the accessory organs of the duodenum?
Liver, gallbladder, and pancreas
What are the urinary tract organs?
-kidneys (renal) glands
-ureters (upper, or abdominal)
What are the 4 layers of the digestive tract?
1) serosa or adventitia
2) muscularis externa (muscularis propria)
3) submucosal
4) mucosa
How many layers are in the muscularis externa in most of the digestive tract?
2 layers of smooth muscle
-outer layer is longitudinal
-inner layer is circular
What does the submucosa of the digestive tract contain?
CT containing blood, lymph, and nerve fibers
What is the innermost epithelial lining of the digestive tract?
Mucosal layer
What is the function of the mucosal layer of the digestive tract?
-secrete mucous
-absorb nutrients
The stomach is the only part of the digestive tract that has 3 layers for the muscularis externa. What are the 3 layers?
-outer = longitudinal layer
-middle= circular layer
-inner= oblique layer
What are the 4 features of the lower esophagus?
-diaphragmatic constrictions
-cardiac (also known as lower esophageal, gastroesophageal, or cardio-esophageal) sphincter
-cardiac notch
-cardiac orifice
What are the 3 esophageal constrictors?
1) cervical constriction (upper esophageal sphincter)
2) thoracic (broncho-aortic) constriction
3) diaphragmatic constriction
The cardiac sphincter (also known as gastroesophageal or cardio-esophageal sphincter) is a ____________ muscle ring. Is it voluntary or involuntary?
Test q
Smooth, involuntary
Where is the cardiac sphincter (also known as gastroesophageal or cardio-esophageal sphincter) located and what does it prevent?
Test q
-located between the diaphragmatic constriction where the esophagus meets the stomach
-prevents reflux of stomach contents
What are the muscles of the esophagus?
Muscularis mucosae and muscularis propria/externa
What are the sympathetic nerves of the esophagus?
T1-T10
What are the parasympathetic nerves of the esophagus?
CN X (vagus n.) from the esophageal plexus
What artery innervates the esophagus?
Esophageal branches of the L gastric a. (bottom 1/3 of esophagus)
The esophageal v. drains into the…..
L gastric v. (bottom 1/3 of esophagus)
What are the 4 parts of the stomach?
1) cardia
2) fundus
3) body
4) pylorus
What does the pyloric sphincter regulate?
Test q
Passage of chyme from stomach into SI
What are the characteristics of the mucosal layer of the stomach?
-has mucus membrane
-has folds and rugae
-contains gastric pits and glands
Note: gastric glands are cells that are located in the pits (lamina propria) and open into bases of the gastric pits
What epithelium makes up the mucosal layer of the stomach?
Simple columnar epithelium
What are rugae?
-also known as gastric folds
-it’s longitudinal wrinkles in the gastric mucosa
-allows for expansion of the stomach
What are gastric pits and what are they lined with?
-indentations of gastric mucosa
-contain entrances to gastric glands
-lined with surface mucus cells
What do the foveolar cells secrete?
Test q
Mucus
What do the parietal (oxyntic) cells secrete?
Test q
HCI and intrinsic factor (aids in absorption of vitamin B12 in the terminal ileum)
What do the chief (zymogenic) cells secrete?
Test q
Pepsinogen and gastric lipase
What do the enteroendocrine cells secrete?
Test q
Hormones
-gastrin
-ghrelin
-serotonin
-somatostatin
Where is gastrin secreted from and what does it stimulate?
Test q
-secreted by G cells
-stimulates parietal cells to produce HCI (gastric acid)
What is ghrelin and what does it stimulate?
Test q
-“hunger hormone”
-stimulates appetite
-increases food intake and fat storage
What is the function of serotonin?
Test q
Arousal, mood, and emotions
What does somatostatin inhibit?
Test q
Gastric secretions
What are the sympathetic innervations to the stomach, liver, gallbladder, pancreas, and adrenal medulla?
Test q
T5-T9 -> greater splanchnic n. -> celiac prevertebral ganglia -> stomach
What is the parasympathetic innervation of the stomach, liver, gallbladder, pancreas, and adrenal medulla?
Test q
CN X
What are the 3 parts of the SI?
Duodenum, jejunum, and ileum
Which section of the SI surrounds the head of the pancreas?
Test q
Duodenum
Which section of the SI has the most chemical digestion?
Test q
Duodenum
Which section of the SI starts intraperitoneal but ends retroperitoneal?
Duodenum
Which section of the SI is the shortest?
Jejunum