Lecture 1 : The digestive system

Question 1

Alimentary canal def

Answer 1

The long, muscular tube that begins at the mouth and ends at the anus

Question 2

Oral Cavity

Answer 2

• Starts process of digestion

3 Cavities
- Orifice (anterior opening)
- Vestibule (space between teeth and lips)
- Cavity proper (area of tongue and teeth)

Roof has hard palate and soft palate at posterior.

Question 3

Tongue

Answer 3

Innervated by hypoglossal nerve

Functions :
- Articulation
- Directs food into oropharynx during deglutition
- Taste (covered in papillae)

Question 4

Salivary Glands

Answer 4

3 subdivisions of glands

Parotid gland
- Largest, main one
- Near ears
- Innervated by glossopharyngeal nerve

Submandibular Gland
- Near lower mandible

Sublingual Gland
- Smallest, deepest
- Floor of mouth
- Inntervated by facial nerve

Question 5

Pharynx

Answer 5

The pharynx is a muscular tube that connects the nasal and oral cavities to the larynx and esophagus

3 parts :
- Nasopharynx
- Oropharynx
- Laryngopharynx

Question 6

Foregut, Midgut and Hindgut

Answer 6

Question 7

The 4 main tissue layers in GI Tract

Answer 7

Mucosa
- Epithelium

Sub Mucosa
- Connective tissues, blood vessels, nerves

Muscularis Externa
- Smooth muscles

Serosa
- Connective tissue

Question 8

2 Nerve Plexuses

Answer 8

Myenteric Nerve Plexus
- In Muscularis Externa layer
- Controls peristalsis and segmentation

Submucosal Nerve Plexus
- Located within submucosa layer
- Stimulates glands in mucosal layer to secrete mucous

Question 9

What is the peritoneum?

Answer 9

Question 10

What is the mesentery?

Answer 10

Question 11

Esophagus

Answer 11

Muscular tube connecting pharynx and stomach

Uses peristalsus to push food down to stomach.

Has a sphincter at the bottom to preventacid reflux.

Question 12

Stomach

Answer 12

4 main parts :
- Cardia (surrounds opening of esophagus into stomach)
- Fundus (area above cardial area)
- Body (largest region of stomach)
- Plyoric part (divided into plyoric antrum and plyoric canal)

Stores food temporarily, churning it and mixing it with gastric juices, breaking down food with enzymes and acid, turning food to chyme which is released into small intestine.

Question 13

3 Main Parts of the Small Intestine

Answer 13

Duodenum, Jejunum, Ileum

Question 14

Duodenum

Answer 14

Question 15

Jejunum

Answer 15

Question 16

Ileum

Answer 16

Question 17

Large Intestine

Answer 17

Caecum is first part, appendix connected to it

Question 18

Colon

Answer 18

Question 19

Rectum / Anal Canal

Answer 19

Question 20

Liver

Answer 20

Question 21

Biliary Tree

Answer 21

Question 22

Pancreas

Answer 22