Digestive system Flashcards by Andrew White

What are the 3 functions of the digestive system

Nutrient break down
Absorption
Elimination of waste

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What is the largest salivary gland and produces ~30% of total saliva output

parotid gland

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Is the parotid gland affected by mumps?

yes; very much so

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What CN passes through the parotid gland

VII

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As we age what typically infiltrates our parotid glands

adipose

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What 3 things does our parotid gland produce?

Salivary amylase (carb break down) & Salivary lipase (fat breakdown)
Lysozyme (antibacterial)
Secretory IgA

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What smaller salivary gland produces 60% of total salivary output

submandibular gland

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True or false; the parotid gland produces mucus and serous products

false; it only produces serous

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True or false; the submandibular gland only produces mucus

false; it produces both mucus and serous products (~80-90% serous)

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What is the smallest salivary gland that only produces 5% of salivary output

sublingual gland

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True or false; the sublingual gland is a mixed gland producing both mucus and serous products

true

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What does the sublingual gland produce more of, serous or mucus products

mucus (80%)

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What is the function of the esophagus

transfer bolus to stomach from oropharynx

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What are the 4 luminal wall structures that make up the esophagus

Mucosa
Submucosa
Muscularis externa
Andevtitia/Serosa

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True or false; the mucosa of the esophagus contains Langerhan cells which are antigen presenting cells with some phagocytosis

true (part of problem with food allergies)

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What part of the mucosa of the esophagus produces mucus to help movement of food

lamina propria

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True or false; the muscularis mucosa within the mucosa of the esophagus is a discontinuous layer of longitudinal muscle which is thinner by the pharynx and thicker by stomach

true

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What is the submucosa of the esophagus made of? What is its primary function

dense fibroelastic ct.

Primary to produce mucus and some serous products (lysozyme and pepsinogen)

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True or false; the normal pattern of the muscularis externa of the esophagus is a inner circular and outer longitudinal

true

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Is there a difference between the amount of smooth vs. skeletal muscle in the muscularis externa of the esophagus as you travel to the stomach?

yes; Upper 1/3 all skeletal - Middle 1/3 mixed - Lower 1/3 all smooth

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True or false; once you pass through the diaphragm the adventitia becomes the serosa

true

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What are the 2 physiological sphincters associated with the esophagus

Pharyngoesophageal sphincter (between oropharynx and esophagus) 
Gastroesophageal sphincter (lower esophageal sphincter)

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True or false; 2 characteristics of the physiological sphincters of the esophagus are:
No thickening of circular muscle
And pressure gradient aids movement of bolus

true

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What are the 2 functions of the stomach

breakdown of food

storage

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What are the 4 luminal wall structures of the stomach

Mucosa Submucosa Muscularis Externa Serosa

The surface epithelium in the mucosa of the stomach is made up of simple columnar cells. What function do these cells have

produce thick mucus and release bicarbonate

True or false; the mucosa of the stomach is made up of surface epithelium, lamina propria, and muscularis mucosa just like the esophagus

true; though the muscularis mucosa of the stomach has muscle fibers arranged in 3 layers instead of just one discontinuous longitudinal layer like the esophagus

How is the smooth muscle of the muscularis mucosa in the mucosa of the stomach arranged

Inner circular outer longitudinal outermost circular

The submucosa of the stomach is highly vascular and has what function

shut down stomach activity fast

True or false; the submucosal (Meissner's) plexus lies next to inner circular layer of muscle

true; this plexus influences the mucosa (secretion, blood flow, movements)

What are the 3 possible layers of muscle in the muscularis externa of the stomach

``` innermost oblique (sometimes absent) Middle circular (well developed) Outer longitudinal ```

Where does the myenteric (Auerbach's) plexus lie? What does it do?

between circular and longitudinal layers of muscle control muscularis externa

True or false; the stomach is all serosa

true

True or false; there are no chief cells in the cardiac region of the stomach

true; primarily surface mucus, a few DNES cells and parietal cells (a lot of mucus is made here)

What does DNES cells stand for?

Diffuse neuroendocrine system cells

What are the 3 regions in the gastric gland of the stomach

Isthmus Neck Base

The isthmus of the gastric gland of the stomach has surface mucus cells that produce what?

thick mucus and bicarbonate

What are the 3 kinds of DNES cells in the stomach? What do each produce?

Type D: Produce somatostatin (inhibits release of hormones by nearby DNES) Type EC: Produce serotonin and substance P (increase peristalsis) Type G: Produce gastrin (stimulates HCL and Pepsinogen secretion, gastric motility, and regenerative cells)

True or false; gastrin secretion by Type G DNES cells in the stomach can be induced in response to food entering (i.e. stretching) and certain foods (caffeine, alcohol)

true

The Neck of the gastric gland has neck mucus cells that have what function?

produce soluble mucus which will mix with chyme to lubricate gastric contents

True or false; while most cells of the stomach have a short turn over rate (matter of days) Parietal (oxyntic) cells in the neck of the gastric gland can live between 150-200 days

true

What is the function of parietal (oxyntic) cells in the neck of the gastric gland

Produce HCl and gastric intrinsic factors (necessary for absorption of vit. B12 - which is necessary for RBC maturation)

True or false; chronic gastritis can lead to pernicious anemia due to a decrease in parietal cells -> leading to decrease in gastric intrinsic factors -> decrease in vitamin B12 absorption

true

The base of the gastric gland of the stomach contains many chief cells. What do chief cells produce?

Pepsinogen - to break down proteins | And some gastric lipases (fat breakdown)

How long do chief cells and DNES cells live?

around 60-90 days

Which kind of DNES cell produces somatostatin

Type D

Which kind of DNES cell produces serotonin and substance P

Type EC

Which kind of DNES cell produces gastrin

Type G

True or false; Well developed inner circular layer of muscle and inner circular layer can be independently controlled are two characteristics of the pyloric sphincter

true

True or false; the pyloric region of the stomach contains DNES cells, parietal cells, and chief cells

false; it does not contain chief, but does contain the other 2

True or false; the pyloric region of the stomach has some neck mucus cells that produce mucus and some lysozyme

true

What are the 3 general functions of the small intestine

digestion absorb nutrients produce intestinal hormones

What are the 3 surface adaptations in the small intestine that increase the surface area by 400 fold

Plicae circulares Villi Microvilli

What is the main function in the mucosa of the small intestine

absorb water and nutrients

Where are goblet cells fewest and most numerous in the small intestine

fewest in duodenum | most in ileum

How many types of DNES cells are there in the small intestine

What do type 1 DNES cells do?

produce cholecystokinin (CCK) which stimulates gallbladder contraction and pancreas secretion

What do type K DNES cells do?

produce GIP (gastric inhibitory peptide) inhibits HCl

What do type S DNES cells do?

produce secretin (stimulates pancreas secretion of bicarbonate from duct cells)

What do type VIP DNES cells do/

produce vasoactive intestinal peptide

What is the function of paneth cells in the mucosa of the small intestine

produce lysozyme

Is there a muscularis mucosa in the small intestine

yes; but it is thin - connects smooth muscle in villi

What are lacteals? What are they found in?

lymphatic capillaries - fxn. lipid absorption found in lamina propria of mucosa

True or false; the submucosa of the duodenum produces an alkaline mucus which is the 2nd way our body neutralizes chyme

true; mucus from Brunner's glands (seromucus glands)

Where would you find Peyer's patches? What are they/

In Ileum Groups of regularly occurring large lymph nodules

True or false; the submucosal (Meissner's) plexus can be found in the submucosa of the small intestine and supplies Parasympathetic information that influences the mucosa

true

True or false; the muscularis externa of the small intestine has a normal fiber arrangement (i.e. inner circular and outer longitudinal)

true

What plexus would you expect to find in the muscularis externa of the small intestine? What function would it have?

Myenteric (Auerbach's) plexus (found between circular and longitudinal layers) stimulates peristalsis

What parts of the small intestine are considered serosa? What about adventitia?

Serosa: All of jejunum and ileum; first and last cm of duodenum Adventitia: vertical portion of duodenum

Where would you find the Ileocecal valve? Is it a physiological or anatomical sphincter?

Between ileum and caecum of colon It is both a physiological and anatomical sphincter

What is the blind pouch on extending on the right side of the cecum?

appendix

True or false; the appendix has the 4 normal features of digestive organs (i.e. Mucosa, submucosa, muscularis externa, and serosa)

true

Does the appendix have goblet, regenerative, and DNES cells in its surface epithelium

yes

Does the appendix have a lamina propria? What about a muscularis mucosa

yes | yes; but poorly developed

Would you expect to see villi or paneth cells in the appendix

What is located in the submucosa of the appendix?

thick layer of large blood vessels and numerous lymph vessels

What is the function of the appendix?

provide humoral immunity and a reservoir for good bacteria

What are the 3 functions of the colon?

Absorption of water Compaction, lubrication and elimination of feces Some bacteria are producing some vitamins (K and B12)

True or false; there are many DNES cells in the colon

false; there are only a few (many goblet though)

True or false; the mucosa of the colon lacks villi and paneth cells

true

True or false; the colon has a typical muscularis externa fiber arrangement (inner circular and outer longitudinal)

false; Outer longitudinal muscle gathered into bands called "Teniae Coli" and is discontinuous

Constant tonus of teniae coli (the abnormal bundling of muscle fibers) results in what?

Sacculations called "Haustra coli"

What parts of the colon are Adventitia? What about Serosa?

Ascending and descending: Adventitia Transverse and sigmoid: Serosa

What are the fat filled pouches made by the serosa of the colon called?

Appendices epiploicae

What are the 2 general causes of peptic ulcers?

Insufficient protection from HCl and Pepsin (Damaged mucus coat-Too much HCl and Pepsin) Helicobacter pylori

True or false; cigarette smoking, alcohol, and coffee drinking are a few examples of what can delay healing of a peptic ulcer

true

What is the cause of gastroesophageal reflux

stomach chyme backing up into lower esophagus

Barrett's Esophagus (a problem with bulimia) occurs when what happens?

Stratified squamous epithelium is replaced by Mucus-secreting simple columnar epithelium in lower esophagus This is metaplasia - sign of chronic problem (precursor to cancer)