1.1 introduction to GIT

Question 1

function of the GIT

Answer 1

• prehension of food
• mastication
• digestion
• absorption
• expulsion unabsorbed portions of food

Question 2

what does headgut consists of

Answer 2

oral cavity:

lips, tongue, teeth, salivary glands

pharynx:

epiglottis

Question 3

what does foregut consists of

Answer 3

oesophagus

stomach

Question 4

what does midgut consists of

Answer 4

small intestines
- duodenum
- jejunum
- ileum

liver
pancreas
gall bladder

Question 5

what does the hindgut consists of

Answer 5

large intestines
- caecum
colon
rectum

anal canal and anus

Question 6

function of salivary glands and saliva

Answer 6

• moisturize food and lubricate it
• amylase - breakdown of starch
• aids with mastication, bolus formation, digestion, and swallowing

Question 7

what is the basic secretory unit of salivary glands

Answer 7

acini

Question 8

3 major pair of salivary glands

Answer 8

• parotid glands
• submaxillary glands (aka mandibular glands)
• sublingual glands

Question 9

where are the locations of the 3 major salivary glands

Answer 9

look at the graph

Question 10

what do each pair of the 3 major salivary glands produce

Answer 10

parotid glands:

• produce a serous secretion

mandibular glands:

• produce a mixed serous and mucous secretion

sublingual glands:

• produces a mucous secretion

Question 11

which 3 parts is the oesophagus divided into

Answer 11

cervical
thoracic
abdominal

Question 12

give the 4 layers of the oesophagus

Answer 12

mucosa
submucosa
tunica muscularis
serosa/ adventitia

Question 13

what are the characteristics of the 4 layers of oesophagus

Answer 13

• Mucosa

○ Nonkeratinized stratified squamous epithelium that covers the lumen

• Submucosa

○ Consists of elastic and collagen fibres that forms a dense, irregular connective tissue

○ This layer consists of blood and lymphatic vessels

• Tunica muscularis

○ Longitudinal and circular muscles forms a tube

 § Longitudinal muscle fibres are located superficially
		
 § Circular muscle fibres are located deeply

• Serosa/adventitia

○ This layer surrounds most of the oesophagus
It consists of loose connective tissues

Question 14

what type of epithelium is the mucosa

Answer 14

non-keratinized stratified squamous epithelium

Question 15

function of the stomach

Answer 15

• Temporary food container before it is passed into the intestines
• Enzymatic breakdown of food

Question 16

adaptation of the stomach of the muscular wall

Answer 16

• Muscular wall with rugae (folds)
• Enable increase area, hence churning (mixing of food) is optimized

Question 17

what are the two sphincters of the stomach

Answer 17

lower oesophageal sphincter (LSE)

pyloric sphincter

Question 18

what are the 3 layers of the stomach

Answer 18

• mucosa
• submucosa
• muscularis externa

Question 19

what is special about the mucosa in the stomach

Answer 19

it has a layer of smooth muscle called muscularis mucosa

Question 20

what are the 3 layers of muscle in muscularis externa

Answer 20

inner oblique
middle circular
external longitudinal

Question 21

what is the use of the muscles in the mucosa

Answer 21

helps with excretion of the glands

Question 22

what is the use of the muscularis externa

Answer 22

contraction to help with breaking down food (churning)

Question 23

differences between monogastric and ruminants and pseudoruminants

Answer 23

ruminants: 4 stomach chambers

pseudoruminants: 3 stomach chambers

monogastric: 1 stomach chamber

Question 24

what are the four chambers of stomach in a ruminant

Answer 24

rumen, reticulum, omasum, abomasum

Question 25

what are the 3 parts of the small intestines

Answer 25

duodenum, jejunum, ileum

Question 26

what is the functional unit of the liver

Answer 26

hepatocytes

Question 27

histology of the liver

Answer 27

• Sheets of connective tissues divide liver into many lobules
• A lobule is roughly hexagonal in shape
• Each lobule has portal triads at the vertices and a central vein in the middle
• Portal triads
  ○ Bile duct
  ○ Hepatic arteriole
  ○ Portal venule

Question 28

what is the artery that supply blood to the pancreas

Answer 28

splenic artery
celiac artery

Question 29

the 2 compound glands in the pancreas

Answer 29

pancreatic acini
islets of langerhans