Gastrointestinal Tract- structure and function Flashcards Preview

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Flashcards in Gastrointestinal Tract- structure and function Deck (58):
1

What are related organs in the GI tract

Salivary glands, liver, gall bladder and pancreas

2

What are the main components of the upper GI tract

1. Epiglottis protects the respiratory system 2. Pharynx 3. Larnyx 4. Oral cavity- surprisingly small hole 5. Tongue 6. Oral cavity

3

What are the 3 main functions of the GI tract

1. Mixing food with saliva 2. Mastication 3. Gustation

4

How much saliva is produced per day

500-900 mls

5

Why is there so much saliva produced daily

To keep the oral cavity lubricated

6

What is saliva

A mixture of water and mucous

7

What does saliva contain

Electrolytes and amylase

8

Why is amylase contained in saliva

For starting the process of dissolving food so it can react with taste buds

9

What is saliva produced by

Salivary glands

10

What is mastication

Chewing

11

The coordination of which 6 components is required during mastication

Teeth, jaw, tongue, cheeks, palate, lips

12

What does mastication produce

A bolus of food to be passed into the oesophagus

13

What is gustation

The sense of taste

14

Which nerves innervate the taste receptor organs

Cranial nerves 7 and 9

15

Where are taste receptor organs located

On the top of the tongue

16

What are the 5 types of taste receptors

Salt, sweet, sour, bitter, umami

17

What does the sense of taste inform you of

Whether a foodstuff will benefit you or not

18

What can the taste and smell of food combine to stimulate

Secretion of saliva and gastric acid or vomiting

19

Which nerves control all GI functions that take place in the mouth

The cranial nerves

20

What are the layers of the GI tract (Send Mr Larry Coulsen Some Magnificant Loving Electric Vinyls)

Serosa Muscularis externa Longitudinal muscle Circular muscle Submucosa Muscularis mucosae Lamina propria Epithelium Villus

21

Which nerves control the gut wall

Myenteric plexus and submucosal plexus

22

What does the myenteric plexus control

Muscle contraction

23

What does the submucosal plexus control

The muscularis mucosae

24

What makes up the gut lining

Villus and epithelium

25

What combines to move food from the oral cavity to the anus

Myenteric plexus, longitudinal muscle and circular muscle

26

How are arteries, veins and nerves transmitted into the intestine

Via teh mesentry

27

What is the first phase of swallowing

Formation of the bolus

28

What is the second phase of swallowing

Ensuring the bolus enters the GI tract not the respiratory tract

29

What is the role of the epiglottis

Guiding the bolus into the oesophagus

30

What does the oesophagus do

Receives bolus of food and pushes it down to the stomach

31

What does the stomach do

Stores food, digests it with acid, churns it up (to break it down). Passes it to the duodenum of the small intestine

32

What does the SI consist of

Duodenum, ileum and jejunum

33

Where does the SI receive ducts from

Pancreas, liver and gall bladder

34

What is the role of the Si

To complete digestion and absorb nutrients

35

What does the large intestine consist of

Colon and rectum

36

What is the role of the LI

To absorb water and electrolytes and create faeces

37

How is faeces expelled

By the rectum through the anal canal

38

What is a sphincter

A thickening of the circular layer of the muscularis externa

39

What are 3 different sphincters in the GI tract

Oesophageal sphincter. Pyloric sphincter. Sphincter of Oddi

40

What is the role of the pyloric sphincter

Preventing HCl from entering the duodenum

41

What is the role of the oesophageal sphincter

Prevents HCl from entering the oesophagus

42

When does the sphincter of Oddi open

When food is present in the duodenum

43

What is peristalsis

The moving of the GI contents from oral -> anal by contractions of the muscularis externa

44

What 2 things must the musculature stomach be able to do

1. Expand greatly. 2. Help break up the food by churning the contents of the stomach.

45

How is the stomach able to carry out its muscular functions

1. The relaxation of the smooth muscle in the muscular externa 2. The presence of an extra oblique smooth muscle layer

46

Why are there villus on the small intestine mucosa

To increase the surface area for absorption of nutrients

47

Describe the anatomy of the small intestine

Villus, lacteal, blood capillaries, goblet cell, intestinal gland

48

What is the functional relationship of the pancreas to the GI tract

Secretion of pancreatic juice from the exocrine system into the pancreatic duct then into the duodenum

49

How does pancreatic juice enter the duodenum

Via the sphincter of Oddi

50

What is the functional relationship of the liver to the GI tract

1. Receiving substances absorbed from the small intetsine via the hepatic portal vein. These substances are metabolised. 2. Produces bile 3. Transfers waste products of metabolism to the gall bladder

51

Describe the hepatic portal system

Splenic vein and superior mesenteric vein -> hepatic portal vein -> liver. Liver -> hepatic portal veins -> inferior vena cava -> heart -> abdominal aorta -> proper hepatic aorta

52

What is the functional relationship of the gall bladder to the GI tract

Secretion of bile into the duodenum. The bile duct joins the pancreatic duct.

53

What is the secretion of bile regulated by

The sphincter of Oddi

54

Outline the immune system of the GI tract in terms of where lymphoid tissue is found

1. In the tonsils and adenoids of the oropharynx 2. In Peyer's patches in the SI 3. In lymphoid tissue in LI

55

Why is lymphoid tissue in some of the mucosa of the GI tract

To detect antigenic material in the GI tract and to initiate antibody-mediated and cytotoxic immune responses. They all produce classes of antibodies

56

What does the submucosa plexus do

Innervated secretory cells in the mucosa and contains sensory neurones that monitor the pH and chemical composition of the GI tract contents

57

How do both plexuses act

Auntomonously

58

What regulates both plexuses

They sympathetic and parasympathetic divisions of the ANS