Digestion & Metabolism Flashcards
 Where does most absorption occur in the G.I. tract?
Small intestine (specifically jejunum)
What epithelium likes the peritoneum?
Serous membrane
Explain lesser omentum
Between the stomach and the liver
Explain the falciform ligament
Connects the liver to the diaphragm
Explain the mesocolon
Connects the transverse colon to the back wall
Explain mesentery proper
Connects the parietal peritoneal and the small intestines
What are the 4layers of the GI tract histology
Mucosa, submucosa, muscularis externa, serosa or adventitia
Mucosa: name the 3 layers and the tissues
Epithelium: simple squamous
Laminate propria: areolar connective tissue
Muscularis mucosa: smooth muscle and elastic fibers
Submucosa: what epithelium
Dense irregular tissue
Muscularis externa: what are the basic layers, and what falls in between them?
Inner circular layer of muscle and outer longitudinal layer of muscle.
The myenteric plexus
Serosa: what tissue?
Areolar connective tissue (serous membrane= visceral peritoneum; adventitia= partial peritoneum)
What two body systems control digestion in the GI tract?
Endocrine & nervous system
The parasympathetic NS ______ motility, innervated by the ____ nerve.
Increases, vagus nerve.
The sympathetic NS _____ motility I’m the GI tract
Decreases
What tissues are found in the gingiva?
Keritinized stratified squamous
What’s the purpose of the soft palate?
Helps chew, swallow, covers nasopharynx when swallowing
What’s the purpose of the uvula?
Prevents food down the wrong pipe or up the nose
Function of your tonsils?
Immune function,prevents germs from entering body
Name the 3 salivary glands in the oral cavity
Parotid
Submandibular
Sublingual
Parotid gland: name location, cells in the gland, produces anything?
Deep in skin by the zygomatic arch, made of serous cells, and produces the enzyme salivary amylase
Submandibular: name location, cells in gland, produces anything?
Inner surface of mandible, contains both serous and mucus cells
Sublingual: name location, cells in gland, produces anything?
On the floor of the mouth, contains mucus cells
Name the 2 acini in the salivary glands:
Serous and mucus
Some functions of saliva?
Flushes surface, lubricators
Name 4 key components of saliva:
(Water: 99.4%) lysozyme, electrolytes, amylase, and buffers
What is the function of amylase? Where is it made? What’s it pH
Amylase breaks down molecules(complex starches -> simple sugars), it’s made in the oral cavity and the pancreas (salivary and pancreatic), optimal pH is near 7.0.
How is salvation controlled?
The autonomic NS (parasympathetic)
What 2 bones have alveolar sockets for teeth?
Maxilla and mandible
Name the parts of the pharynx:
Nasopharynx, oropharynx, laryngopharynx
Nasopharynx- epithelium? Smooth or skeletal?
Psuedostratified ciliated columnar, skeletal
Oropharynx- epithelium? Skeletal?
Stratified squamous, underlying skeletal
Latyngopharynx- epithelium?
Stratified squamous
Where does the esophagus penetrate the diaphragm?
Lower Esophageal sphincter
How does food go to the esophagus and not the larynx?
The uvula blocks it
4 histologies layers of the esophagus:
Mucosa
Submucosa
Muscularis externa
Adventitia
Esophagus mucosa- epithelium?
Nonkeratinized stratified squamous
Esophagus submucosa- epithelium?
Glands including longitudinal folds
Esophagus muscularis layer-epithelium?
Inner circ, outer long
Why does the esophagus have adventitia?
Because it is Retroperitoneal
Name the phases of deglutition & what happens
Buccal- bolus goes to oropharynx
Pharyngeal- soft palate blocks nasopharynx so no food gets in, bolus passes the glottis
Esophageal- the bolus is passed down esophagus through peristalsis to the stomach.
Define GERD
Stomach acid fellows back into the esophagus (acid reflux)
Define hiatal hernia
Part of the stomach protrudes into chest through the diaphragm
Stomach mucosa- epithelium?
Simple columnar epithelium
Stomach mucosa- includes several different types of cells….?
Mucus cells
Partial cell
chief cells
Goblet crlls
G-cells
What’s the purpose of mucus cells?
Replaces superficial cells that go into the chyme
What are the products of parietAl cells
Intrinsic factor & HCL
HCL function
Helps create good condition of H & Cl, keeps pH in stomach, activates pepsinogen
Intrinsic factor function
A glycoprotein that’s held absorb B12
What proenzyme is made by chief cells?
Pepsinogen
What activates pepsinogen? and what does it activate to ?
HCL or stomach acid, Pepsin
Product of G cells
Gastrin
Name tissue of the stomachs submucosa
Areolar and dense connective tissue
Why does the stomach have and extra layer of muscularis externa?
For extra churning and break down
What reaction does pepsin catalyze?
Hydrolysis of peptide bonds
What are the 3 stages of digestion?
Cephalic phase
Gastric phase
Intestinal phase
Is the cephalic phase under endocrine or nervous control?
Nervous control
What’s the primary hormone during the gastric phase?
Gastrin
The intestinal phase is under endocrine control, what 2 hormones are primarily here?
CCK & secretin
Function of CCK, & where’s it made?
Decreases stomach secretion into the small intestine, and made in the duodenum
Function of secretin, & where’s it made?
Decreases stomach secretion and increase bicarbonate secretion, and made in the duodenum
What kind of epithelium is found in the small intestine?
Simple columnar
What is found in the small intestines laminate propria?
Capillaries and vessels such as LACTEAL
LACTEAL purpose?
Transports materials that cannot be absorbed though capillaries, such as fats
What is a brush border?
What enzymes are in the brush border, if any?
Border increases surface area & holds enzymes such as enteropeptidase, dipeptidase, disaccharides
Where are intestinal glands(crypts of Lieberkühn) located?
Deep within the small intestines villi
What cells are located in the crypts of lieberkühn?
Enteroendocrine cells
Paneth cells
What hormones are made by enteroendocrine cells?
Gastrin
Secretin
Cholecystokinin
Where are burners glands located?
What do they make?
They are located in the submucosa of the duodenum & the make mucus to protect the epithelium form acidity
Peyers patches are located where?
In the ileum of the small intestine, primarily (peyers patches have a lymphatic function including T & B cells, and macrophages)
What part of the small intestine would have an adventitia?
The duodenum, bc it’s retroperitoneal
What is the general digestive function of the liver?
Make and secrete bile
What is the general digestive function for the gall bladder?
Stores bile
What is the general digestive function of the pancreas?
Makes pancreatic juice that exits with bile
The triad region of the liver includes what?
The hepatic portal vein
Hepatic artery
Bile duct
What are the layers of the gall bladder?
Mucosa
Muscularis externa
Serosa
What causes bile to be released from the gall bladder?
The release of CCK
What makes the duodenum releases CCK?
The introduction of amino acids of fatty acids
What does the Isley of langerhan in the pancreas create
Insulin
Glucagon
Does the pancreas have more serious acini or islets of langerhan?
Does this mean the pancreas is more exocrine or endocrine?
There’s more serious acini, exocrine
What enzymes are created by the pancreas?
Amylase
Trypsinogen, chymotrypsinogen, procarboxypeptidase
Lipase
Ribonuclease, deoxyribonuclease
Pancreatic amylase digests ______
Starches
Pancreatic lipase digests_____
Triglycerides -> fatty acids
Ribo/deoxyribonuclesse digests___.
Nucleic acids
What activates trypsinogen?
Enteropeptidase
What activates chymotypsinogen and procarboxypeptidase?
Trypsin
What does typsinogen, chymotrypsinogen, & procarboxypeptidase activated to?
Trypsin
Chymotrypsin
Carboxypeptidsase
Is enteropeptidase in the mix of pancreatic juice?
YES
What’s the purpose of bicarbonate in pancreatic juice?
Raises pH of chyme
What hormone causes the increase of bicarbonate in the pancreas?
Secretin
CCK made by _____ cells in the ____. CCK stimulates acini in the pancreatic juice to be rich in ____
Enteroendocrine cells,
duodenum,
digestive enzymes
Secretin made by ___ of the ___. Secretin stimulates acini of the pancreatic juice to be rich in____
S-cells
Duodenum
Bicarbonate
Carbohydrates, proteins and fats have to be broken down to what to be digested?
Carbs-»» monosaccharides
Proteins-»»amino acids
Fats-»» fatty acids and monoglycerides
3 enzymes in duodenum
Sucrose
Lactase
Maltase
3 enzymes in pancreas
Trypsin
Amylase
Lipase
4 functions of HCL
Kills microorganisms with food
Denatures proteins
Breaks down plant cells
Activates pepsinogen
3 chemicals that increase the HCL production
Acetylcholine
Histamine
Gastrin
Is chyme acid or basic
Acidic
What do goblet cells produce?
A protective mucus layer
