Upper GI Tract Flashcards
What is the hard palate?
Palatine bone and maxilla
What is the soft palate?
Muscles covered in mucous membrane - prevent things from going up into nasal cavity
Salivary glands produce _______ that help with several process related to digestion.
saliva
saliva is made of what?
water, mucus and enzymes
how does saliva help with chemical digestion?
Salivary amylase starts with carbohydrate digestion
What type of epithelial cells line the pharynx & esophagus? Why?
stratified squamous- prevent scraping
What type of muscle is found in the muscular layer of the esophagus?
mix of skeletal in upper part to smooth in lower part
What are three roles of the stomach
1- store food
2- mechanical digestion
3- initial chemical digestion (proteins)
What are sphincters?
rings of muscle at top and bottom of stomach controlling movement of food in and out
what is chyme?
mix of food traveling through digestive tract
what are the two sphincters called?
Lower esophageal sphincter
Pyloric sphincter
What type of muscle tissue makes up the lower esophageal and pyloric sphincters?
smooth
Which type of motor neuron would you expect to trigger relaxation of the pyloric sphincter (causing it to open)?
Parasympathetic
what is Rugae?
allow the stomach to expand
Why would you want more muscle layers in the stomach?
improve mechanical digestion
mucosa layer is covered in small depressions called ______ ____. What do these do?
gastric pits- have gastric glands
Compared to most tissues, the pH of the stomach is __________.
low
Chief cells secrete what?
pepsinogen
what is pepsinogen converted to?
pepsin by HCL (active form for protein digestion)
What do parietal cells secrete?
HCL- helps denature (unfold) proteins
Enteroendocrone (EE) cells secrete which two hormones?
Gastrin- stimulates parietal cells to release HCL and chief cells to release pepsinogen
Histamine- stimulates release of acid
why does chyme enter the small intestine in a slow, controlled manner?
to maximize absorption
What are the parts of the intestine in order?
Duodenum- digestion (pancreatic juices/bile enter here)
Jejunum
Ileum
what is the purpose of villi and microvilli?
helps improve the surface area for absorption of nutrients
The mucosa layer of the intestine has ______ similar to gastric pits.
crypts
what do crypt contain?
absorptive cells, mucus producing cells, intestinal enteroendocrine cells
What do enteroendocrine cells secrete?
Secretin- stimulates pancreas and liver, promote insulin release
Cholecystokinin- stimulate pancreas, liver, gallbladder, inhibits stomach function
Where is the Pancreas located?
by the duodenum
what two organs share a common entry point into the duodenum?
Pancreas and Gallbladder
What are the two main functions of the Pancreas?
produce digestive enzymes and secrete insulin/glucagon
difference between endocrine and exocrine glands
Exocrine glands: secrete into ducts (acing cells)
Endocrine glands: secrete directly into blood stream (Langerhans)
what neutralizes acid in the small intestine?
sodium bicarbonate
CCK and secretin produced in the small intestine trigger release of what to break down chyme?
pancreatic juices
What are the functions of the liver and gallbladder?
bile is secreted by liver cells and stored in the gallbladder. The gallbladder will release bile into the duodenum via vild duct.
Neurons and hormones will stimulate the _______ layer in the gallbladder to contract and release bile into the duodenum?
muscularis
Which of the following macromolecules would be difficult to digest if a gallstone blocked the gallbladder?
Lipids
What are the roles of…
bile salts
cholesterol
bile pigments
bile salts: digestion of fat
cholesterol: produced in and removed by liver as waste
bile pigments: Bilirubin is breakdown of hemoglobin- is toxic and must be removed
