Lecture 20

Question 1

What is the role of the GI system? (4)

Answer 1

motility, secretion, digestion and absorption

Question 2

what are the key structures of the GI system? (6)

Answer 2

mouth (oral cavity), pharynx, oesophagus, stomach, small intestines, large intestine

Question 3

What are the accessory structures of the GiI system? (6)

Answer 3

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

Question 4

What muscle closes off ends to seperate different tube of the GI system?

Answer 4

sphincters (smooth muscle)

Question 5

What epithelium lines the oral cavity/oesophagus + purpose?

Answer 5

stratified squamous (protection from abrasion)

Question 6

What epithelium lines the intestines (small/large) + purpose?

Answer 6

simple columnar (secretion and absorption)

Question 7

What epithelium lines the anus + purpose?

Answer 7

Stratified squamous (protection for abrasion)

Question 8

What type/structure of glands are goblet cells? (5)

Answer 8

unicellular, columnar, apical mucus granules, basal nucleus, mucus secreting

Question 9

what are the two types of multicellular glands?

Answer 9

simple and compound

Question 10

simple gland?

Answer 10

gland with single duct (stomach/small intestine)

Question 11

compound gland?

Answer 11

gland with 2 or more ducts (salivary glands)

Question 12

What are the four layers of the gut tube?

Answer 12

mucosa, submucosa, muscularis (externa/proper) and adventitia

Question 13

What does the mucosa layer consist of? (5)

Answer 13

epithelium, basement membrane, laminate propia (FCT) and mucularis mucosae, sometimes glands

Question 14

What does the submucosa consist of? (3)

Answer 14

FCT, glands and blood vessels

Question 15

what regulates secretion of the submucosa?

Answer 15

submucosal nerve plexus (part of the enteric nervous system)

Question 16

What muscle does the muscularis (external/proper) consist of?

Answer 16

smooth muscle

Question 17

what are the two main layers of the muscularis (external/proper)

Answer 17

inner circular and outer longitudinal

Question 18

What is the myenteric plexus?

Answer 18

part of the ENS, located between muscles layers, regulates motility

Question 19

What is the function of having two layers of smooth muscles with different orientation?

Answer 19

different motility patterns from different orientations causes different gut tube movemnts

Question 20

why are there glands in both mucosa and submucosa in some regions?

Answer 20

increases SA if more secretions are required (e.g for extra protection)

Question 21

What is the function of the mouth/oral cavity?

Answer 21

beginning of digestion, mechanical and chemical (chewing/amylase in salvia), lubrication of food

Question 22

What is the pathway of food from mouth to oesophagus?

Answer 22

Mouth - fauces - oropharynx - laryngopharynx - oesophagus

Question 23

What are the three pairs of salivary glands?

Answer 23

paraotid, sublingual and submandibular

Question 24

What type of saliva does the paraotid glands secrete?

Answer 24

serous (watery) fluid with amylase (enzyme)

Question 25

What does the sublingual glands secrete?

Answer 25

mucus only

Question 26

what does the submandibular glands secrete?

Answer 26

mixture of serous fluid with amylase and mucus

Question 27

where are the paraotid glands located?

Answer 27

para - alongside Otid - ear

Question 28

where are the sublingual glands lacoated

Answer 28

sub - under Lingual - tongue

Question 29

where are the submandibular glands located?

Answer 29

sub - under Mandibular - mandible

Question 30

what type of multicellular glands are saliva glands?

Answer 30

compound

Question 31

What is a cluster of salivary cells called

Answer 31

acinus made up of acinar cells

Question 32

what do acinar cells secrete?

Answer 32

Serous fluid, amylase and mucus

Question 33

what do duct cells secrete?

Answer 33

bicarbonate for PH buffering in the mouth

Question 34

Length and location of the oesophagus?

Answer 34

~ 25 cm long, posterior to to the trachea, extending from the pharynx to the stomach

Question 35

What muscle is the oesophagus composed of?

Answer 35

muscularis externa: - 1/3 skeletal (voluntary) - 1/3 mix of smooth/skeletal - 1/3 smooth

Question 36

why is the mucosa and submucosa of the oesophagus highly folded?

Answer 36

has the capacity to expand for passage of bolus

Question 37

why does the oesophagus need mucus and what secretes it?

Answer 37

lubrication and protection (allows passage of bolus), glands and ducts in sub mucosa and muscular near stomach secrete to the surface (no goblet cells)