Lecture 15: Digestive system one Flashcards Preview

1st Year: Physiology and Anatomy > Lecture 15: Digestive system one > Flashcards

Flashcards in Lecture 15: Digestive system one Deck (74)
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1
Q

what does GI stand for?

A

Gastrointestinal tract

2
Q

How long is the GI tract?

A

Hollow tube that is 30 feet long

3
Q

what is the Gi tract composed of?

A
mouth
pharynx
oesophagus
stomach
small intestines 
large intestines(colon)
anus
4
Q

what are the accessory organs to the GI tract?

A

teeth, tongue, salivary glands, liver, gallbladder, pancreas

5
Q

what are the 3 main functions of the GI tract?

A

transportation, digestion, and absorption of food

6
Q

what are the 6 main processes of the digestive system?

A
ingestion 
propulsion (motility)
mechanical digestion 
chemical digestion 
absorption 
defecation
7
Q

what is ingestion and where does it happen?

A

intake of food done by the mouth

8
Q

what is population where does it take place?

A

moving food along the digestion tract, involves the entire tract

9
Q

what plays a role in swallowing?

A

oropharynx

10
Q

what is mechanical digestion and which parts of the GI tract are involved?

A

breaking food down to its simplest form, chewing from teeth in the mouth, churning of the stomach, segmentation in the small intestine

11
Q

what is chemical digestion and which parts of the GI tract are involved?

A

when enzymes break down food, in the mouth there’s salivary amylase, the liver has bile, also happens in the pancreas and stomach

12
Q

what happens during absorption?

A

nutrients absorbed via lymph vessels and blood vessels.

13
Q

what is Peristalsis?

A

movement of food going forwards due to the GI tract wall containing muscles which contract.

14
Q

what is segmentation and where does it usually take place?

A

The mixing of food via the muscles in the wall of the GI tract alternating contractions between intestinal segments. This takes place in the small intestines.

15
Q

how many layers does the wall of the GI tract have?

A

4

16
Q

what are the layers of the wall of the GI tract called?

A

mucosa
submucosa
musculares externa
serosa

17
Q

whats the functions of the mucosa?

A

secretes muscus, digestive enzymes
immune response
creates folds

18
Q

what is the mucosa made of?

A

surface epithelium
lamina propria
Muscularis mucosae

19
Q

what does the mucosa line?

A

Lines the lumen, separates GI lumen from internal environment

20
Q

what does the surface epithelium of the mucosa contain?

A

Simple columnar epithelium and mucus-secreting goblet cells. Enzyme -secreting cells and Hormone-secreting cells

21
Q

what does the lamina propria of the mucosa contain?

A

connective tissue: Small blood vessels and lymphatic vessels; Nerves; Lymphoid tissues: Lymph nodules and Peyer’s patches

22
Q

what is the Muscularis mucosae?

A

thin smooth muscle

23
Q

what is the submucosa?

A

Thick layer of connective tissue that is dense and has

elasticity

24
Q

what does the submucosa contain?

A

large blood vessels
Lymphatic vessels
nerves branching into the mucosa and muscularis mucosae
Submucosal plexus -part of enteric nervous system

25
Q

what is the Muscularis externa responsible for?

A

for the motility of GI tract

26
Q

what are the Two separate layers of smooth muscle that form the Muscularis externa?

A

Inner layer of circular muscle

Outer layer of longitudinal muscle

27
Q

what NS is myenteric plexus apart of?

A

enteric nervous system

28
Q

what does the myenteric plexus control?

A

GI tract motility

29
Q

what is the Outermost Layer of GI wall?

A

serosa

30
Q

How many layers does the serosa have?

A

2

31
Q

what are the layers of the serosa ?

A

Inner layer of connective tissue

Outer layer is mesothelium

32
Q

what is the serosa attached too?

A

the mesentery

33
Q

what does the mesentery do?

A

maintains position of organs in the GI tract but also allows the to move

34
Q

what’s the function of the serosa?

A

protective layer

35
Q

what part of food is chemically broken down so it can be digested?

A

carbohydrates, lipids and poteins

36
Q

what are carbohydrates?

A

polysaccharides

37
Q

what enzyme breaks down polysaccharides?

A

amylase

38
Q

what breaks down disacharides?

A

maltase

39
Q

what happens to monosaccharides ?

A

absorbed by specialised cells in the SI

40
Q

what are the two types of amylase?

A

salivary amylase and pancreatic amylase

41
Q

where is pancreatic amylase used?

A

small intentine

42
Q

name 3 types of disaccharides?

A

lactose, maltose, sucrose

43
Q

name three monosaccharides?

A

galactose, glucose and fructose

44
Q

what breaks down triglycerides?

A

lipase

45
Q

what does triglyceride break down into ?

A

monosaccharides and fatty acids

46
Q

what produces lipase?

A

pancreases produces pancreatic lipase

47
Q

what has to happen before pancreatic lipase can break down the fats?

A

the fats need to be emulsified by the bile salts from the liver

48
Q

what enzymes can break down protein into peptides?

A

pepsin
trypsin
chymotrypsin

49
Q

what enzymes break peptides down into amino acids?

A

aminopeptidase and carboxypeptidase

50
Q

where is pepsin produced and whats its site of action ?

A

produced and used in the stomach

51
Q

what are the pancreatic enzymes?

A

trypsin, chymotrypsin,

carboxypeptidase

52
Q

what do accessory glands do?

A

secrete products into the lumen of the GI tract

53
Q

what do salivary glands, liver and the pancreas secrete?

A

saliva
bile
pancreatic juice

54
Q

what are the three salivary glands?

A

parotid gland
sublingual gland
submandibular gland

55
Q

what is saliva comprised of?

A

99.5% water and 0.5% solutes

56
Q

what enzymes are in saliva?

A

salivary a amylase
salivary lipase
lysozyme

57
Q

what components are in saliva?

A

sodium, potassium chloride phosphate bicarbonate and mucus

58
Q

whats it called when you have low production of saliva?

A

Xerostomia

59
Q

what are the key components of bile?

A

bile salts, bile pigments, cholesterol

60
Q

what is bile secreted from?

A

hepatocytes

61
Q

what synthesize bile?

A

liver

62
Q

where is bile stored?

A

gallbladder

63
Q

what does the common bile duct do?

A

transports bile from liver/gallbladder to the duodenum

64
Q

what is the ampulla of vatar?

A

when the common bile duct joins the pancreatic duct

65
Q

what does the sphincter of oddi do?

A

regulates flow from the pancreas and gallbladder to the duodenum

66
Q

what do exocrine glands of the pancreas produce?

A

pancreatic juice

67
Q

what is the endocrine portion of the pancreas known as and what des it do?

A

Islets of Langerhans

secretes hormones

68
Q

what does pancreatic juice neutralise?

A

neutralisesacidic chyme as it enters the duodenum

69
Q

what enzymes does pancreatic juice contain ?

A

pancreatic amylase
pancreatic lipase
proteases:trypsin chymotrypsin, carboxypeptidase
nucleases

70
Q

what does the pancreatic acinar cell do?

A

synthesizes, stores, and secretes digestive enzymes.

71
Q

what are zymogens?

A

Inactive forms of digestive enzymes

72
Q

when and how do zymogen become active?

A

in the lumen of the intestinal tract by proteolytic enzymes

73
Q

what are two types of zymogens?

A

trypsinogen and chymotrypsinogen

74
Q

what’s the structure of the liver composed of?

A

hepatic duct and cystic duct