Digestive System Flashcards

1
Q

Components of the tubular part of the alimentary tract?

A

esophagus, stomach, small intestines, large intestines

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2
Q

4 concentric layers of alimentary canal?

A

mucosa, submucosa, muscularis externa, serosa/adventitia

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3
Q

Components of mucosa?

A

epithelium, lamina propria (w lymphatic tissue), muscularis mucosae

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4
Q

Components of submucosa?

A

dense irregular connective tissue

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5
Q

Components of muscularis externa?

A

2-3 layers of smooth muscle, often longitudinal and circular muscle. Also has an Auerbach nerve plexus between muscle layers

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6
Q

Components of serosa?

A

squamous epithelium and connective tissue

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7
Q

Components of adventitia?

A

connective tissue

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8
Q

Serosa vs Adventitia?

A

Serosa is present in peritoneal cavity while adventitia is found on retroperitoneal organs that are joined to other tissue/organ

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9
Q

Function of mucosal layers?

A

secretion, absorption, and protection

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10
Q

Function of muscularis externa?

A

rhythmic contraction that produces peristalsis

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11
Q

Function of esophagus?

A

transport food and liquid from pharynx to stomach

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12
Q

Describe muscosa of esophagus.

A

nonkeratinized stratified squamous epithelium with thin lamina propria with cardiac glands

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13
Q

Describe muscular transition of esophagus.

A

upper third is all skeletal muscle (voluntary control), middle third is mixed, lower third is all smooth muscle (involuntary control)

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14
Q

What can an incompetent inferior esophageal sphincter cause?

A

chronic heartburn and erosion of the mucosa (GERD)

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15
Q

4 regions of the stomach?

A

cardia, fundus, body, pylorus

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16
Q

What is rugae?

A

the large longitudinal mucosal folds of the stomach; they disappear when the stomach is distended

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17
Q

Function of stomach?

A

digestion; adds acidic fluid to content and mixes into chyme

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18
Q

Describe mucosa of stomach.

A

simple columnar epithelium, lamina propria with glands & CT w lymphatic cells, typical muscularis mucosa

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19
Q

Describe the submucosa of the stomach.

A

thick and not easily divisible into layers, forms the core of rugae

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20
Q

Describe the muscularis externa of the stomach.

A

inner oblique layer, middle circular layer, outer longitudinal layer (these 3 layers are important to churn food)

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21
Q

What type of cells is the surface epithelium of the stomach composed of?

A

surface mucous cells

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22
Q

Function of mucous cells?

A

produce alkaline mucous to protect the stomach

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23
Q

Describe the epithelium of the GI tract.

A

the esophagus has stratified squamous epithelium but the remainder has simple columnar

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24
Q

What are the 5 types of cells in gastric glands?

A

mucous neck cells, chief cells, parietal cells, enteroendocrine cells, stem cells

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25
Q

Role of chief cells?

A

secret pepsinogen

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26
Q

Role of parietal cells?

A

secrete HCL and intrinsic factor which facilitates the absorption of vitamin B12 in the ileum

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27
Q

Role of enteroendocrine cells?

A

secrete a variety of gastric hormones into the lamina propria

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28
Q

Location of chief cells and parietal cells?

A

Chief cells are found in the deeper part of the gastric glands and parietal cells are more numerous in the upper part of the glands

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29
Q

Describe the appearance of parietal cells?

A

large and pyramidal in shape

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30
Q

Where does cell division in the stomach occur?

A

at the isthmus where the stem cells are located

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31
Q

Describe cell movement and duration of cell life in the stomach?

A

Most new cells move up to become surface mucous cells which live 3-5 days which other cells move down to become gland cells. Parietal cells live about 6 months while chief and enteroendocrine cells live about 3 months

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32
Q

Difference in rugae and mammillated folds?

A

Rugae elevations contain mucosa and submucosa while mammilated folds ar small elevations of mucosa only

33
Q

Major function of small intestine?

A

absorption of nutrients

34
Q

What are the 3 modifications of the intestinal wall to increase surface area for absorption?

A

plicae circulares, villi, microvilli

35
Q

Where are plicae circulares most common?

A

jejunum

36
Q

Describe plicae circulares

A

permanent transverse folds of the mucosa that contain a core of submucosa and extend about half way around the wall of the intestine

37
Q

What are villi?

A

finger-like projections of the mucosa that increase surface area 10 fold

38
Q

Where are crypts of Lieberkuhn most common?

A

duodenum

39
Q

Describe the role celiac disease has on the structure of the small intestine

A

Celiac disease damages or destroys villi in the small intestine. Gluten triggers the immune system to destroy the villi

40
Q

Role of actin in microvilli?

A

leads to contraction of terminal web and spreads the microvilli so material can get between them

41
Q

6 cell types of small intestine?

A

enterocytes, goblet cells, paneth cells, M cells, enteroendocrine cells, stem cells

42
Q

primary absorptive cell found on the villi?

A

enterocytes

43
Q

Function of enterocytes?

A

secrete water and electolytes; attached to neighboring cells by tight junctions to keep material out of the lamina propria

44
Q

Function of paneth cells?

A

secretes lysozyme and other antibacterial substances which can digest bacterial cell walls, also regulates gut bacteria by phagocytosing certain bacteria and protozoa

45
Q

Function of M cells?

A

endocytose microorganisms and macromolecules from intestinal lumen and discharge them into underlying lymphatic tissue

46
Q

Where are peyer’s patches located?

A

ileum

47
Q

How often are absorptive cells, goblet cells, and paneth cells renewed?

A

absorptive and goblet=every 5-6 days and paneth cells=every 4 weeks

48
Q

What is a lacteal?

A

a lymphatic capillary in each villus of the small intestine that absorbs fat

49
Q

Location and function of Brunner’s glands?

A

Located in the duodenum and they buffer acid from the stomach by making the pH more alkaline

50
Q

Function of large intestine?

A

absorption of water and electrolytes and elimination of solid wastes and undigested foods

51
Q

What separates the small and large intestines?

A

ileocecal valve

52
Q

Cell types in large intestines?

A

Large intestines has the same 6 cell types as small intestines: enterocytes, goblet cells, paneth cells, M cells, enteroendocrine cells, and stem cells. However, there are very few paneth cells and more goblet cells

53
Q

Describe the structure of the appendix.

A

No teniae coli; distinguished from other parts of the large intestine by the many lymph nodules in the propria and usually much debris is seen in the lumen

54
Q

Functions of the liver?

A

production and distribution of many circulating plasma proteins, vitamin storage/regulation/distribution, degradation of drugs and toxic substances, secretion of bile, modification & release of hormones into the blood

55
Q

What is a portal vein?

A

a vessel that carries blood between 2 capillary beds

56
Q

Path of bile output?

A

Hepatic bile duct takes bile away from the liver to the gallbladder and then to the duodenum

57
Q

Components of the portal triad?

A

portal vein, hepatic artery, bile duct

58
Q

Components of portal canal?

A

portal triad, lymphatic vessels, nerves, CT

59
Q

Blood flow through liver?

A

blood from the portal vein and hepatic artery mix in the sinusoids, go to the central vein, to the sublobular vein, to the hepatic vein, & to the IVC

60
Q

Structure of classic lobule?

A

6 sided prism with a portal canal at each corner

61
Q

What cells make up approximately 80% of the cells in the liver?

A

hepatocytes

62
Q

Describe hepatocytes structure and function.

A

large polyhedral binucleated cells w large amounts of heterochromatin, rER, sER, and golgi units that make proteins and are involved in storage, metabolism and waste removal. these cells are capable of regeneration

63
Q

Function of Ito (stellate) cells?

A

store vitamin A

64
Q

What/where are Kupffer cells?

A

macrophages responsible for removing bacteria and damaged RBCs from the blood; located in the sinusoids

65
Q

What is the space of Disse?

A

perisinusoidal space between the fenestrated endothelium of sinusoids and hepatocytes

66
Q

Where is bile produced?

A

hepatocytes

67
Q

biliary pathway?

A

canaliculi to canal of Hering to interlobular bile ducts to right/left hepatic duct

68
Q

what type of vessel is the central vein?

A

venule

69
Q

What good components of bile are taken to the intestines for reabsorption?

A

phospholipids, cholesterol, bile salts, electrolytes

70
Q

What bad components of bile are taken to the gut for disposal?

A

bile pigments (end product of hemoglobin degradation from bilirubin)

71
Q

Describe acini model of liver.

A

3 zones: Zone 1 is where the hepatic artery starts and receives the best oxygenated blood while zone 3 receives the least oxygenated blood thus making it more susceptible to necrosis

72
Q

Structure of the gallbladder?

A

simple columnar epithelium with irregular muscularis externa and adventitia/serosa. NO MUSCULARIS MUCOSAE OR SUBMUCOSA

73
Q

Functions of gallbladder?

A

concentrates and stores bile

74
Q

2 types of gallstones?

A

cholesterol and pigment stones

75
Q

Function of exocrine pancreas?

A

synthesizes and secretes enzymes and bicarbonate into ducts

76
Q

Function of endocrine pancreas?

A

synthesizes and secretes insulin, glucagon, and somatostain into the blood

77
Q

Location of exocrine and endocrine compartments of the pancreas?

A

exocrine is located in the acinar pancreas and endocrine in the islets of Langerhans

78
Q

Duct system of pancreas?

A

Intercalated Ducts to Intralobular Ducts to Interlobular Ducts to Main Pancreatic Duct

79
Q

structure of pancreas duct system?

A

Intercalated duct has squamous cells; intralobular ducts have low columnar cells; interlobular ducts have low columnar cells with lots of CT