Lecture 15: Digestive system one

Question 1

what does GI stand for?

Answer 1

Gastrointestinal tract

Question 2

How long is the GI tract?

Answer 2

Hollow tube that is 30 feet long

Question 3

what is the Gi tract composed of?

Answer 3

mouth
pharynx
oesophagus
stomach
small intestines 
large intestines(colon)
anus

Question 4

what are the accessory organs to the GI tract?

Answer 4

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

Question 5

what are the 3 main functions of the GI tract?

Answer 5

transportation, digestion, and absorption of food

Question 6

what are the 6 main processes of the digestive system?

Answer 6

ingestion 
propulsion (motility)
mechanical digestion 
chemical digestion 
absorption 
defecation

Question 7

what is ingestion and where does it happen?

Answer 7

intake of food done by the mouth

Question 8

what is population where does it take place?

Answer 8

moving food along the digestion tract, involves the entire tract

Question 9

what plays a role in swallowing?

Answer 9

oropharynx

Question 10

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

Answer 10

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

Question 11

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

Answer 11

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

Question 12

what happens during absorption?

Answer 12

nutrients absorbed via lymph vessels and blood vessels.

Question 13

what is Peristalsis?

Answer 13

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

Question 14

what is segmentation and where does it usually take place?

Answer 14

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.

Question 15

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

Answer 15

4

Question 16

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

Answer 16

mucosa
submucosa
musculares externa
serosa

Question 17

whats the functions of the mucosa?

Answer 17

secretes muscus, digestive enzymes
immune response
creates folds

Question 18

what is the mucosa made of?

Answer 18

surface epithelium
lamina propria
Muscularis mucosae

Question 19

what does the mucosa line?

Answer 19

Lines the lumen, separates GI lumen from internal environment

Question 20

what does the surface epithelium of the mucosa contain?

Answer 20

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

Question 21

what does the lamina propria of the mucosa contain?

Answer 21

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

Question 22

what is the Muscularis mucosae?

Answer 22

thin smooth muscle

Question 23

what is the submucosa?

Answer 23

Thick layer of connective tissue that is dense and has

elasticity

Question 24

what does the submucosa contain?

Answer 24

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

Question 25

what is the Muscularis externa responsible for?

Answer 25

for the motility of GI tract

Question 26

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

Answer 26

Inner layer of circular muscle | Outer layer of longitudinal muscle

Question 27

what NS is myenteric plexus apart of?

Answer 27

enteric nervous system

Question 28

what does the myenteric plexus control?

Answer 28

GI tract motility

Question 29

what is the Outermost Layer of GI wall?

Answer 29

serosa

Question 30

How many layers does the serosa have?

Answer 30

2

Question 31

what are the layers of the serosa ?

Answer 31

Inner layer of connective tissue | Outer layer is mesothelium

Question 32

what is the serosa attached too?

Answer 32

the mesentery

Question 33

what does the mesentery do?

Answer 33

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

Question 34

what's the function of the serosa?

Answer 34

protective layer

Question 35

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

Answer 35

carbohydrates, lipids and poteins

Question 36

what are carbohydrates?

Answer 36

polysaccharides

Question 37

what enzyme breaks down polysaccharides?

Answer 37

amylase

Question 38

what breaks down disacharides?

Answer 38

maltase

Question 39

what happens to monosaccharides ?

Answer 39

absorbed by specialised cells in the SI

Question 40

what are the two types of amylase?

Answer 40

salivary amylase and pancreatic amylase

Question 41

where is pancreatic amylase used?

Answer 41

small intentine

Question 42

name 3 types of disaccharides?

Answer 42

lactose, maltose, sucrose

Question 43

name three monosaccharides?

Answer 43

galactose, glucose and fructose

Question 44

what breaks down triglycerides?

Answer 44

lipase

Question 45

what does triglyceride break down into ?

Answer 45

monosaccharides and fatty acids

Question 46

what produces lipase?

Answer 46

pancreases produces pancreatic lipase

Question 47

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

Answer 47

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

Question 48

what enzymes can break down protein into peptides?

Answer 48

pepsin trypsin chymotrypsin

Question 49

what enzymes break peptides down into amino acids?

Answer 49

aminopeptidase and carboxypeptidase

Question 50

where is pepsin produced and whats its site of action ?

Answer 50

produced and used in the stomach

Question 51

what are the pancreatic enzymes?

Answer 51

trypsin, chymotrypsin, | carboxypeptidase

Question 52

what do accessory glands do?

Answer 52

secrete products into the lumen of the GI tract

Question 53

what do salivary glands, liver and the pancreas secrete?

Answer 53

saliva bile pancreatic juice

Question 54

what are the three salivary glands?

Answer 54

parotid gland sublingual gland submandibular gland

Question 55

what is saliva comprised of?

Answer 55

99.5% water and 0.5% solutes

Question 56

what enzymes are in saliva?

Answer 56

salivary a amylase salivary lipase lysozyme

Question 57

what components are in saliva?

Answer 57

sodium, potassium chloride phosphate bicarbonate and mucus

Question 58

whats it called when you have low production of saliva?

Answer 58

Xerostomia

Question 59

what are the key components of bile?

Answer 59

bile salts, bile pigments, cholesterol

Question 60

what is bile secreted from?

Answer 60

hepatocytes

Question 61

what synthesize bile?

Answer 61

liver

Question 62

where is bile stored?

Answer 62

gallbladder

Question 63

what does the common bile duct do?

Answer 63

transports bile from liver/gallbladder to the duodenum

Question 64

what is the ampulla of vatar?

Answer 64

when the common bile duct joins the pancreatic duct

Question 65

what does the sphincter of oddi do?

Answer 65

regulates flow from the pancreas and gallbladder to the duodenum

Question 66

what do exocrine glands of the pancreas produce?

Answer 66

pancreatic juice

Question 67

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

Answer 67

Islets of Langerhans | secretes hormones

Question 68

what does pancreatic juice neutralise?

Answer 68

neutralisesacidic chyme as it enters the duodenum

Question 69

what enzymes does pancreatic juice contain ?

Answer 69

pancreatic amylase pancreatic lipase proteases:trypsin chymotrypsin, carboxypeptidase nucleases

Question 70

what does the pancreatic acinar cell do?

Answer 70

synthesizes, stores, and secretes digestive enzymes.

Question 71

what are zymogens?

Answer 71

Inactive forms of digestive enzymes

Question 72

when and how do zymogen become active?

Answer 72

in the lumen of the intestinal tract by proteolytic enzymes

Question 73

what are two types of zymogens?

Answer 73

trypsinogen and chymotrypsinogen

Question 74

what's the structure of the liver composed of?

Answer 74

hepatic duct and cystic duct