4: Hsf B1: Digestive System

Front 1

What happens in the alimentary canal?

Back 1

Tubular portion of the digestive cavity where food is churned, liquefied, digested - nutritional elements/water absorbed, indigestible components eliminated.

Front 2

1. How long is the alimentary canal?

2. It is subdivided into what 4 morphologically recognized regions?

3. What are the 4 parts of the stomach? How do they look histologically?

4. What are the three parts of the small intestine? Histologically, which ones look the same and which ones look different?

Back 2

1) 9 meters long
2) Esophagus, stomach, small intestine, large intestine
3) Cardiac, fundus, body, pylorus. Histologically separate.
4) Duodenum, jejunum, ileum. Jejunum and ileum look the same, duodenum is different.

Front 3

5. What are the five parts of the large intestine? How do all the parts compare histologically?

6. What is the appendix, what kind of tissue can be found in it and why, and how can you identify it histologically?

Back 3

5) Cecum, colon, anal canal, rectum, appendix. All look alike except termination of anal canal region because the pelvic diaphragm inserts into it and disrupts it.

6) Blind ended tube off large intestine, lots of LYMPHOID TISSUE and lumen is usually filled with debris

Front 4

1. What are the four tunics/layers of the alimentary canal?

2. What is the difference between adventitia and serosa?

3. How much of the digestive tube is covered by serosa? What parts are not?

4. When does the esophagus pick up mesentery? When is it only adventitia?

Back 4

1) (Inside out) Mucosa, submucosa, muscularis externa, adventitia

2) Serosa is adventitia covered by mesentery/mesothelium.

3) Most of digestive tube covered by serosa except ESOPHAGUS, portion of DUODENUM

4) Adventitia/diaphragm/mesentery

Front 5

1. What are the three layers of the mucosa and what is found in each layer?

2. What is the epithelium like?

3. How does the esophagus' muscularis mucosa differ?

Back 5

1) Mucosa: 1) epithelium 2) lamina propria - loose connective tissue w/ vasculature, glands, lymph nodules 3) muscularis mucosa - inner circular, outer longitudinal

2) Upper portions (ie esophagus) = PARAKERATINIZATION. Rest = simple columnar.

3) Only has outer longitudinal layer

Front 6

1. What four things are found in the submucosa?

2. How is the submucosa's connective tissue different from the mucosa's?

3. How can you tell the esophagus from the duodenum based off of epithelial types?

4. What does meissner's submucosal plexus contain? What nervous systems is it a part of? What will the nerves and neurons inside primarily control?

Back 6

1) Irregular fibroelastic CT, glands in esophagus/duodenum, vasculature, Meissner's submucosal plexus

2) Submucosa has denser CT with more collagen and elastic fibers

3) Esophagus = stratified squamous, duodenum = simple columnar

4) Postganglionic parasympathetics, enteric nervous system/autonomic. Controls muscularis mucosa, glands in lamina propria/submucosa

Front 7

1. What three things are found in the muscularis externa?

2. What is auerbach's plexus also known as? What does it contain? What does it control?

3. What additional layer does the stomach have?

Back 7

1) Inner circular, outer longitudinal, Auerbach's plexus

2) Myenteric plexus - parasympathetic + sympathetic, controls muscularis externa muscles

3) Oblique layer to really mix the food

Front 8

1. What kind of tissue is the serosa/adventitia?
2. When do you refer to it as "serosa"?
3. When do you refer to it as "adventitia"?

Back 8

1) Thin connective tissue
2) When it's intraperitoneal
3) When it's retroperitoneal

Front 9

1. What are the two sources of stomach innervation and what are their components? What stimulates these systems?

2. Which system will control peristalsis more?

Back 9

1) Autonomic ns (sympathetic and parasympathetic), enteric (Meissner's and Auerbach's)

2) Enteric

Front 10

1. Where is meissner's found and what function does it perform? What kind of conditions does it respond to?
2. Where is auerbach's found and what is its function? What kind of conditions does it respond to?

Back 10

1) Meissner's - submucosa. Secretion/mucosal function of glands in LP, submucosa. Regulation of blood flow. Responsive to focal local conditions.

2) Muscularis externa. Peristalsis. Responds to local conditions along length of whole digestive tract.

Front 11

1) What do parasympathetics control?
2) What do sympathetics control?

Back 11

1) Stimulates peristalsis, inhibits sphincter muscles, triggers secretion
2) Inhibit peristalsis, activate sphincter muscles

Front 12

1. Why is the esophagus folded?
2. What kind of muscle is found in the muscularis externa of the esophagus?
3) How do you identify regions of the esophagus?

Back 12

1) To give flexibility so you don't choke
2) Skeletal muscle!
3) Upper 1/3 of esophagus = skeletal muscle, middle 1/3 = skeletal + smooth, lower 1/3 = smooth only

Front 13

Esophageal mucosa:

1. What kind of cells are in the esophageal mucosa's epithelium
2. What is the lamina propria like?
3. What is the muscularis mucosa like?

Back 13

1) Stratified squamous, Langerhans
2) Fibroelastic
3) Longitudinal smooth muscle layer

Front 14

1. What does the esophagus' lamina propria look like? What does it house and where are they located?

2. Why is the muscularis mucosa unique?

Back 14

1) Nothing much, lamina propria - esophageal cardiac glands. M

2) Only has longitudial muscle

Front 15

1. What does the submucosa of the esophagus look like and what kind of glands does it house? What are the two cell types in these glands?


2. What do mucous cells in the submucosa look like? What is the mucous used for?

3. What do serous cells look like? What do the secretory granules of these cells contain?

4. Besides glands, mucous cells/serous cells, what else is contained in the submucosa?

Back 15

1) Dense, fibroelastic CT, esophageal glands proper

2) Mucous cells (basally located, flattened nuclei and apical accumulations of mucus filled secretory granules)

3) Serous cells with round, centrally placed nuclei with secretory granules of pepsinogen and lysozyme.

4) Submucosal nerve plexus (Meissner's)

Front 16

1. What are the layers of the muscularis externa of the esophagus?

2. What kind of muscle fibers are located in the muscularis externa and adventitia of the esophagus?

3. What kind of nervous system is found in the muscularis externa?

4. When is the esophagus covered by adventitia and when is it covered by serosa?

Back 16

1) 2 layers - inner circular, outer longitudinal

2) Skeletal and smooth muscle

3) Auerbach's

4) Adventitia until below diaphragm, then serosa

3)

Front 17

1. What are the two physiological sphincters in the esophagus?

2) How quickly do they propel the food bolus?

Back 17

1) Pharyngoesophageal (lets food down and prevents it from going into the lungs) and gastroesphageal

2) 50 mm/sec

Front 18

1. What is the most dilated part of the digestive tract?

2. How much food can it hold?

3. What does the stomach empty into, and via what valve?

4. How does the stomach liquify food, and what does it use to do so?

Back 18

1) Stomach
2) 1500 mL
3) Duodenum via pyloric valve
4) Enzymatic digestion - pepsin, renin, gastric lipase, paracrine hormones

Front 19

5. What are the 4 regions of the stomach? Histologically, what two parts look alike?

6. What is an internal characteristic of the stomach?

7. What does the epithelium invaginate to form?

Back 19

5) (From esophagus) Cardiac, fundus, body, pylorus (to small intestine)

6) Folds/rugae

7) Gastric pits that 5-7 gastric glands empty into

8) Cardiac region

Front 20

9. What kind of cells form the epithelium?

10. How can you tell the stomach apart from the rest of the digestive tract histologically?

Back 20

9) Simple columnar

10) NO GOBLET CELLS!!! (All the rest of the cells that have simple columnar have goblet)

Front 21

Stomach mucosa:

1. What shape are the epithelial cells? What two kinds of cells are found in the epithelium?

2. What is found in the lamina propria?

3. What happens at the base of the rugae?

4. What happens with the epithelium of the lining and the epithelium of the gastric glands?

Back 21

1) Simple columnar - surface lining cells and regenerative cells

2) Glands

3) There are openings of gastric glands

4) Transition from simple columnar epithelium of lining and gastric pit that transitions into glandular epithelium of gastric glands

Front 22

What is the deficient enzyme in McArdle's Dz?

Back 22

skeletal muscle glycogen phosphorylase

Front 23

1. What glands are the most highly organized and well developed glands of the stomach?

2. What kind of glands are found in the fundus?

3. Where does the secretory gland of the fundus empty?

4. What shape are the fundus gland's cells?

Back 23

1) Fundic glands
2) Simple branched tubular
3) Straight in - no duct
4) Simple cuboidal

Front 24

5. What are the 6 cells in the fundus? How do they stain and what do they secrete?

6. What are the only cells in the human body that secrete acid?

7. What is the key identifying cell of the stomach? How do they stain?

Back 24

5. SMOREZ - surface lining, mucous neck, parietal, regenerative, enteroendocrine, chief cell (zymogenic)

6. Parietal

7. ***Parietal cells are like big fried eggs*

Front 25

1. What are the three regions of the fundic glands?

2. What are the six types of cells found in the fundus?

3. What does the surface lining of the fundus look like?

Back 25

1. Isthmus, neck, base.

2) SMOREZ - surface lining, mucous, parietal, regenerative, enteroendocrine, zymogenic (chief)

Front 26

1. What kind of organelle is seen frequently in the parietal cell?

2. Describe the layout of the parietal cell.

Back 26

1) RER
2) Canaliculi arrangement. When it's active, not many tubulovesicles present!

Front 27

1. What does the chief cell produce?
2. What organelle is predominant in the chief cell?

Back 27

1) Zymogens
2) RER - also look for "ZG" - zymogen granules

Front 28

What do DNES need to be stained with? What does DNES control?

Back 28

Silver salt - it appears black. Controls what happens in the enteric nervous system, in a more focal local manner.

Front 29

1. What layers are in the muscularis mucosa of the stomach?

2. What is found in the submucosa of the stomach?

3. What are the layers of the muscularis externa?

Back 29

1) Inner circular, outer longitudinal, outermost circular

2) Vasculature, lymph, C.T., Meissner's

3) Inner oblique (to mix up food), middle circular, outer longitudinal

Front 30

1. Histologically, how is the pyloric part of the stomach different from the fundus??

2. How can you identify the fundus part of the stomach histologically?

Back 30

1) LOTS of mucus cells, no parietal cells.

2) Parietal cells - fried eggs

Front 31

1. What two important things do parietal cells secrete?

Back 31

1. HCl and intrinsic factor

Front 32

1. What are the 3 regions of the small intestine? When do they become distinguishable?
2. What are peyer's patches?
3. How do you distinguish between the duodenum and the jejunum in the submucosa?
4. How can you tell that you're in the small intestine and not the stomach?
5. What type of secretion is exhibited by goblet cells in the small intestine?
6. What does the lining of the small intestine look like?
7. Where do paneth cells reside? What shape are they? What does it look like? What kind of substances do they produce?

Back 32

1. Duodenum, jejunum, ileum. Duodenum has glands in the submucosa.
2) Lymphatic tissue we see along the intestine
3) Duodenum has glands in the submucosa
4) Look for villi, and then look for glands in the submucosa to see if you're in the duodenum
5) Apocrine - top of cell opens up and mucous goes out
6) Lining of basophilic cells interspersed with goblet
7) Base of intestinal gland, apical cytoplasm is full of acidophilic staining granules. Produce bacteriocidal substances that regulate type of flora in intestine.

Front 33

1. How long is the small intestine? Why is this length unique?
2. What kind of structures does it have to enhance absorption?
3. What are the three regions of the small intestine?
4. What are some circular muscles around it called?

Back 33

1) 7M - longest region of digestive tube
2) Villi, microvilli
3) Duodenum, jejnum, ileum
4) Plicae circularis (valves of Kerckring)

Front 34

1. Small intestine epithelium - what shape are the cells? What are the 6 types of cells found in it?
2. What is found in the lamina propria of the small intestine?
3. Where are brunner's glands found?

Back 34

1) Simple columnar - DRAG on till the PM. DNES, Regenerative, Absorptive, Goblet, Paneth, M cells
2) Crypts of Lieberkuhn
3) **Duodenum submucosa**
4)

Front 35

1. How can you tell the large intestine from the small intestine?
2. How can you tell the difference between the large intestine and the stomach?
3. Why does the amount of goblet cells increase as you go deeper into the intestine?

Back 35

1) DOES NOT HAVE VILLI
2) HAS GOBLET CELLS - stomach does not have goblet cells
3) More water is absorbed from the food the deeper you get, so it gets more abrasive. Need more protection in the lining!

Front 36

1. What are the regions of the large intestine? (4)

Back 36

1) Cecum (appendix), colon (ascending, transverse descending, sigmoid), rectum, anus

Front 37

1. What two major things do the large intestines lack?
2. How often is there epithelial turnover?
3. What's going on in the large intestine's muscularis externa? What is the function of this?
4) What are the most numerous cells? What cells do you see an increase in?
5) Do you have Crypts?

Back 37

1) Villi, paneth cells
2) 6-7 days
3) Outer longitudinal layer gathered into 3 ribbons (taenia coli), continuous tone that causes large intestine to pucker and form
sacculations called haustra coli
4) Surface absorptive cells, but you see an increase in goblet
5) Yes, large intestine has Crypts of Lieberkuhn

Front 38

1. What does the rectum resemble?
2. What is NOT found in the distal portion of the anal canal?
3. What do the anal columns of morgagni form?
4. At the anal valves (pectinate line), what shape does the epithelium take on?
5. What does the lamina propria of the anal canal contain?
6. What layer of the mucosa is not found below the pectinate line?
7. What does the muscularis externa become at the pectinate line?
8. What forms the external sphincter?

Back 38

1) Colon
2) Crypts of Lieberkuhn
3) Longitudinal folds that form anal valves (w/ intervening sinuses) that support column of feces
4) Stratified squamous, keratinized at the anus
5) Anal glands, circumanal glands
6) Muscularis mucosa
7) Internal anal sphincter
8) Skeletal muscle on the floor of the pelvis that inserts into the wall of the anal canal