Lecture 14: GI Tract Flashcards
Where is gastrin synthesized and what is its action?
Stomach- Gastric acid secretion
Where is ghrelin synthesized and what is its action?
Stomach- stimulates appeptites and inhibits lipid metabolism
Where is Gastric inhibitory polypeptide synthesized and action?
small intestine- inhibits gastric acid secretion, stimulates insulin release
Cholecystokinin (CCK) is synthesized where and what is its action?
small intestine- secretion of pancreatic enzymes, bicarbonate release, contraction of gall bladder (release of bile –> duodenum)
where is secretin synthesized and what is its action?
duodenum- increases bicarbonate and water secretion from the pancreas and inhibits gastric acid secretion
Where is motilin synthesized and what is its action?
small intestine- increases gastric intestinal motility
Where is pancreatic polypeptide synthesized and what is its action?
Pancreas- opposes CCK, relaxes gallbladder, inhibits pancreatic secretions
Where is somatostatin synthesized, what is its action?
GI tract- inhibits the release of GI hormones
What is the characteristic features of the duodenum?
Brunner’s Glands
What is the characteristic feature of the jejunum
Large plicae circulares (transverse folds of the submucosa)
What is the characteristic feature of the ileum
Peyer’s patches
What are the cells of the small intestine? (5)
enterocytes- secretion/ absorption goblet cells- antimicrobial (lysozymes) M-cells- antigen presenting stem cell- found in intestinal crypts APUD
What APUDs are secreted by the pancreas (3)
secretin, CCK, PP
What are glycocalyx and where are they found?
collectively known as the brush border - in the pancreas
Where are enterocytes and what do they do?
secrete enterokinase (trypsinogen –> trypsin) they are found in the glycocalyx of the pancreas
What are the two functions of bile?
- to emulsify fat
2. excretion of cholesterol and bilirubin in feces
what are lacteals?
lymph capillaries
what kind of lipids get absorbed in the lymph?
long-chain lipids (chylomicron)
What is a chylomicron?
lipid protein particles which make protein coat of long-chain lipids made of triglyceride and lipoprotein
What is the function of the colon/rectum?
Absorption of water, production of feces
Describe ulcerative colitis
Path: primarily in colon/rectum, it only effects mucosa.
Symptoms: Ab. pain, bloody stool, anemia, fatigue
Rx: corticosteroid (preduison), 5-aminosalicylates
Describe Crohn’s Disaese
IBD, can effect any part of the GI tract and it effects the entire wall.
Diagnostic: String Sign (thickening of wall), pain in lower right quad
Rx: nutrition, cortico steroids, surgery
What muscle is used in involuntary control of defecation? Describe the sequence
Internal anal sphincter
enternic and autonomic neurons sense that poop has filled colon –> reflexes internal anal sphincter –> feces in rectum = urge to poo
What muscle is used in voluntary control of defecation?
external anal sphincter
also diaphram and ab. muscles
What is the difference in venous drainage above and below the pectinate line?
above- superior rectal v. –> inferior mesenteric –> hepatic portal
below- inferior vena cava (caval system)
The molecules that form HCl in the stomach begin where and ultimately form the HCl where?
H+ and Cl- are first in the cytoplasm of the parietal cell, they then form HCl in the canaliculi
What are the four layers of the wall of the trachea?
Mucousa, submucousa, Carilagenous layer, adventitia
What are the five layers of bronchi
mucosa, muscularis, submucosa, cartilage layer, adventitia
Describe what a pink puffer is
emphysema - less surface area for gas exchange, and less vascular bed for gas exchange. Body compensates by hyperventilation
Describe what a blue bloater is
chronic bronchitis - body response to obstruction by decreasing ventilation and increasing cardiac output, residual lung space gradually increases
describe pneumonia
Inflammatory condition of the lung especially affecting the alveoli, also disrupts gas exchange and capillary beds
VIRAL- lymphocytes
BACTERIAL - neutrophils
Describe cystic fibrosis
CFTR Cl- transporter works differently in different tissue.
the muco- cillary elevator is dehydrated and malfunctions
