Grand tour of the alimentary canal

Question 1

what are the functions of the alimentary canal?

Answer 1

• Digestion
• absorption
• Motility
• Secretion

Question 2

Where does digestion take place

Answer 2

Stomach to SI

Question 3

Where does motility take place

Answer 3

Throughout the gut tube

Question 4

where do secretion and absorption take place?

Answer 4

In the SI and LI

Question 5

Brief description of what occurs in different parts of the GI

Answer 5

-Mouth:
mechanical digestion
release of saliva- adds moisture 
-Oesophagus
Connector 
-Stomach
chemical digestion begins
protein breakdown 
temporary storage 
Food into liquid form 
-Pancreas
enzymatic breakdown of carbs, fat and protein 
-Liver  
releases bile for the breakdown of fats 
-Gallbladder
stores and concentrates bile 
-SI
chemical digestion- mainly in first 2/3rds
-LI
water absorption and formation of faeces

Question 6

Structure Layers

Answer 6

Mucosa: 
-epithelium 
-lamina propria
-muscularis mucosae
Submucosa 
Muscular externa:
-concentric 
-longitudinal 
Serosa/adventia

Question 7

Stratified squamous in mucosa:

where is it found

Answer 7

Mouth
Oesophagus
Anal canal

Question 8

Simple columnar in mucosa:

where is it found

Answer 8

Stomach
SI
LI

Question 9

What are the main functions of the mucosa

Answer 9

• separates the lumen of the digestive system
• Secretes digestive enzymes
• absorbs products of digestion

Question 10

what is the lamina propria made of?

Answer 10

Lose connective tissue containing glands, blood and lymph

Question 11

what is the muscularis mucosae made of?

Answer 11

smooth muscle

Question 12

what is submucosa made of

Answer 12

irregular/dense connective tissue containing neurones, blood vessels and lymph

Question 13

function of inner circular muscularis external

Answer 13

constricts the lumen - peristalsis

Question 14

function of outer longitudinal muscularis externa

Answer 14

shortens tube- segmentation

Question 15

what type of muscle is the muscularis externa

Answer 15

concentric and smooth

Question 16

Function of the serosa/adventia

Answer 16

Outside of peritoneal cavity: the adventia attaches oesophagus and rectum to surrounding organs

Inside the peritoneal cavity: the serosa surrounds the stomach, the SI and the LI

Question 17

What is found between the submucosa and the muscularis externa

Answer 17

the submucosal plexus

Question 18

what is found between the two layers of concentric muscle?

Answer 18

the myenteric plexus

Question 19

different nervous systems?

Answer 19

autonomic- control gut motility 
-Long reflexes- gut to CNS
-short reflexes- within the gut 
parasympathetic
-vagus nerve- enhancesl secretion and motility- NOT SALIVATION
sympathetic 
-inhibits secretion and motility

Question 20

what controls salivation?

Answer 20

the glassopharangeal and facial nerves

Question 21

Arterial supply

Answer 21

abdominal aorta :
celiac trunk
superior mesenteric artery
inferior mesenteric artery

Question 22

venous drainage of stomach

Answer 22

gastric veins

Question 23

venous drainage of the pancreas

Answer 23

splenic veins

Question 24

venous drainage of SI to transverse colon

Answer 24

superior mesenteric vein

Question 25

venous drainage from descending colon to rectum

Answer 25

inferior mesenteric vein

Question 26

where to the gastric, splenic, SMV and IMV drain?

Answer 26

the hepatic portal vein- into the hepatic vein-into the IVC

Question 27

why are the liver and gut in series?

Answer 27

so gut blood can be filtered before entering systemic circulation

Question 28

What makes up the autonomic enteric nervous system

Answer 28

• Meissners plexus

- Myenteric plexus