3-muscularis-contains 1/3 skeletal muscle, 1/3 mix of skeletal and smooth muscle and 1/3 of smooth muscle
4-adventitia-attached esophagus to surrounding structures
name the two sphincters associated to the esophagus
1-upper esophageal sphincter-related when larynx is elevated
2-lower esophageal sphincter-connected at the stomach
what type of cells can you find in the mucosa layer of the stomach?
1-surface mucus cells
2-mucus neck cells
what does surface mucus cells produce?
secretes mucus at surface of mucosa
what does the mucous neck cell produce?
secretes mucous in the gastric pit
what is the function of parietal cells?
secretes hydrochloric acid and intrinsic factors.
what is the function of chief cells?
secrete pepsinogen and gastric lipase
what is the function of G cells?
secrete the hormone gastrin
what is the function intrinsic factor in the parietal cell?
needed for absorption of vitamin B12 for rbc formation
what is the function of HCL in the parietal cell?
1-kill microbes in food
3-convert pepsinogen into pepsin
what is the difference between pepsinogen and pepsin?
pepsinogen is not activated while pepsin is the activated form
what is the function of pepsin?
break down proteins into peptides
what are peptides?
two or more amino acids linked together
what is the function of gastric lipase?
splits triglycerides into fatty acids and monoglycerides
what is the function of gastrin?
1-stimulate parietal cells to secrete HCL and chief cells to secrete pepsinogen.
2-contracts lower esophageal sphincter
3-relaxes pyloric sphincter
4-increase stomach motility
what is the pancreas composed of?
small clusters of glandular epithelium cells
what are the cluster of the pancreas composed of?
1-99% of cluster is composed of Acini
2-1% of cluster is composed of pancreatic islets
What is pancreatic Acini?
the exocrine portion of the pancreas that creates pancreatic juice.
what does exocrine mean?
what is the function of pancreatic juice?
1-buffer acidic gastric juice in chyme
2-stops the action of pepsin in the stomach
3-creates proper pH for the action of digestive enzymes in the small intestine
what are pancreatic islets?
the endocrine portion of the pancreas that secrete glucagon, insulin, somatostatin and pancreatic polypeptide.
what is the function of the exocrine portion of the pancreas?
to create digestive enzymes
what is the function of the pancreatic islets?
what type of hormones does the pancreas produce?
what is the function of insulin?
control blood sugar levels
what is the function of glucagon?
deals with low levels of glucose
what is the function of pancreatic polypeptide
stimulates secretion of ions and water by the intestines and inhibits gastric acid secretion
what is the function of somatostatin?
inhibits gastrin release
what are the 11 functions of the liver?
1-metabolises carbs, lipids and proteins
3-removes drugs and hormones
4-synthesis, store and break down glycogen
5-manufactures plasma membrane
8-storage of copper, iron and some vits
9-activates vitamin D
10-synthesises bile salt
11-secretion of bile
name the three parts the small intestine is divided into
what type of cells can one expect to find in the mucosa layer of small intestine?
1-absorptive cells with microvilli
what is the function of absorptive cells?
digestion and absorption
what is the function of goblet cells?
what is the function of the paneth cell?
what are the e hormones enteroendocrine cells produce?
produce 3 hormones,
3-Glucose-dependent insulinotropic peptide (GIP)
what are the four processes needed to digest food?
what is the daily ingested or secreted fluid by the body?
1.0 liter of secreted saliva
2.3 liters of ingested fluid
2.0 liters of gastric juice
1.0 liter of secreted bile
2.0 liters of secreted pancreatic juice
1.0 liter of intestinal juice
total of 9.3 liters
what is the daily amount of fluid absorbed by the body?
8.3 liters absorbed by the small intestine
0.9 liter absorbed by the large intestine
total of 9.2 liters
how is the regulation of gastric secretion and motility controlled?
the nervous system or endocrine system
what are the e phases of digestion?
describe the physiology of the cephalic phase of digestion
sensory inputs sends signals to cerebral cortex and feeding center in the hypothalamus which in response sends signals to medulla oblongata to parasympathetic preganglionic fibers of the vagus nerve to postganglionic fibers that go the the myenteric and submucosal plexus.
what does the myenteric plexus stimulate?
what does the submucosal plexus stimulate?
secretion into the stomach
describe the physiology of the gastric phase
food reaches stomach, receptors in the stomach will stimulate
what does neural reflex do?
1-motility and secretion
2-increase gastric juices
3-increase contraction of stomach which will force 10-15 ml of food into intestine
what does hormonal reflex do?
what is the function of gastrin?
3-tighten lower esophageal sphinceter
4-relax the pyloric sphincter
what releases gastrin?
1-distention of stomach
2-partially digested proteins
3-high pH of chyme
what is the function of secretin?
stimulates the flow of pancreatic juice that is rich in bicarbonate ions to buffer the acidic chyme that enters the duodenum
what is the function of Cholecystokinin (CCK)?
stimulates secretion of pancreatic
juice that is rich in digestive enzymes. It also causes contraction of gallbladder, which squeezes out stored bile
what digestive enzyme substrates (acts on) carbs?
lingual lipase and pancreatic amylase
what digestive enzyme substrates on protein?
what digestive enzyme substrates on triglycerides?
what digestive enzyme substrates on nucleic acid?
how is pancreatic secretion regulated?
pancreatic secretion is regulated by sphincter or oddi
true or false?
digestive enzymes in the pancreas are released in an active form?
pancreatic enzymes are released in an inactive form so they don't digest the pancreas
what are brush border enzymes?
brush border enzymes are digestive enzymes located at the surface of microvilli
what macromolecules do brush border border enzymes break down?
what are the 2 mixing and mechanical digestion that occurs in the small intestine?
2-migrating motility complexes
what is the stage of each of the 4 macromolecules when they are absorbed into the cells?
1-monosaccharides are simple sugars
2-amino acids stay amino acids
3-triglycerides are small/large chains of fatty acids
4-nucleotides are nucleic acids
what happens to lipids in the small intestine?
they are broken down to monoglycerides
what does your body in terms of carbs, proteins, triglycerides and nucleic acid absorpb?
which molecules are actively absorbed?
glucose, galactose, amino acids, di and tripeptides
which molecules are absorbed by diffusion?
fructose, short and long chain fatty acids
how is water absorbed?
what components of diet helps your body absorb water?
electrolytes, monosaccharides and amino acids
how are electrolytes and amino acids absorbed?
via active transport mechanisms?
what are the two types of movement in the large intestine?
does the large intestine secrete any enzymes?
what type of chemical digestion takes place in the large intestine?
what important component of your diet is absorbed in the large intestine?
vitamin B and K
when does chyme become feces?
3-10 hours when chyme has become solid or semisolid