digestive tract 1 Flashcards
(26 cards)
What are the tissue layers of the digestive tract?
starting from the lumen, there is the mucosa, submucosa, muscularis externa, and serosa or adventitia
Which plexues are found in the digestive tract wall?
submucosal pplexus and mysentric plexus
What are peyers patches?
Lymphatic nodules in small intestine that trigger a immune response
What are the specialized structures of the small intestine?
plicae circulares, which are circular folds, vili, and microvilli
What is the role of the submucosal plexus?
It determiens how much mucus is secreted from the mucosa and the muscularis mucosae
What is the role of the myenteric plexus?
It controls contractions like peristalsis of the muscularis externa
peristalsis
involunatary contraction of muscles
What is the role of the autonomic system in the digestive tract?
It is in charge of reflexes via vagus nerve (vagovagal reflexes), hormones and paracrines
Which part of the esophagus has peristaltic contractions?
the muscualris externa
What is the difference between long and short reflexes?
Both come from internal stimuli (GI tract) and are noticed by receptors in the epithelium like chemo, osmor, or mechano, but long reflexes input informtion to the CNS before the action is received by a local (intrinistic) nerve plexus (gut brain). SHort reflexes send info from receptors straight to plexus
WHich parts of the digestive tract have skeletal muscle?
esophagus and external anal sphinctor
What does the submuscosal esophegael gland secrete?
mucus
What structure regulates passage of food into the stomach?
The lower esophageal sphinctor or cardiac spinctor
Which structure of the digestive system produces intrinisic factor?
the stomach
What type of epithelium is found onthe stomacH?
simple columnar epitheliam
What are some of the protective structures of the stomach?
To save its self from very low ph, stomach has a thick mucous coat produced by surface mucus, rapid epithelial cell replacement, and tight junctions between cells
What are mucous neck cells?
secrete thin mucus through gastric pits
what are regenerative cells?
repleace lost cells of stomach
What are parietal cells?
secrete HCl (gastric acid) and intrinsitic factor
What are chief cells?
secrete pepsinogen and gastric lipase
What are enteroendocrine cells?
serete hormones and paracrines
what is pepsinogen?
a precursor to pepsin (enzyme that breaks down proteins) that is activated by HCl or gastric acid
What inhibits and stimulates gastric acid secretion?
D cell secretion of somatostatin: inhibit
G cells:gastrin
What buffers gastric acid?
bicarbonate, secreted by muscus neck cells
