Digestive system

Question 1

Esophagus Location (4)

Answer 1

• deep midline structure
• neck to abdomen
• lies between vertebrae and trachea
• C6-T11

Question 2

Esophagus shape, size and appearance (4)

Answer 2

• collapsible muscular tube
• shape changes during deglutition (swallowing)
• around 25cm long
• has an upper and lower sphincter

Question 3

Esophagus Relations (5)

Answer 3

-superior = laryngopharynx
- inferior = diaphragm
- posterior = vertebrae
- lateral = lungs
- anterior = trachea

Question 4

Esophagus Blood supply and drainage (4)

Answer 4

• supply = branches of inferior thyroid and descending aorta
• drainage = azygous and hemi azygous veins

Question 5

Esophagus Lymphatic drainage (4)

Answer 5

• depends on level
• neck = level 4 nodes
• thorax = posterior mediastinal and paraoesophageal nodes
• abdomen = gastric nodes

Question 6

large intestine location (4)

Answer 6

• abdominopelvic organ
• 4 sections (caecum, colon, rectum, anal canal)
• colon has 4 sections (ascending, transverse, descending, sigmoid)
• 2 flextures

Question 7

Large intestine shape, size and appearance (6)

Answer 7

• 1.5m long
• 6-7cm diameter
• caecum is enlarged
• ileo-caecal sphincter
• teniae coli form haustra by tension from muscle shortening
• omental appendices = aggregations of fatty tissue

Question 8

Large intestine relations (7)

Answer 8

• not simple due to size/spread
• caecum = lateral = right ilium bone
• ascending = medial left = small intestine
• transverse = superior = liver
• descending = medial right = small intestine
• sigmoid = lateral = left ilium bone
• rectum = posterior = sacrum

Question 9

Large intestine blood supply and drainage (4)

Answer 9

• supply 1 = caecum, ascending +2/3 of transverse = superior mesenteric artery
• supply 2 = distal 1/3 of transverse, descending and sigmoid = inferior mesenteric artery
• supply 3 = rectum and anal canal = rectal arteries
• drainage = venous return from reciprocal veins to portal system

Question 10

Large intestine lymphatics (3)

Answer 10

• mirrors blood supply
• superior mesenteric nodes
• inferior mesenteric nodes

Question 11

GI tract organs

Answer 11

• esophagus
• stomach
• small intestine
• large intestine

Question 12

Layers of the GI tract (5)

Answer 12

• mucosa
• submucosa
• muscularis
• serosa
• 2 nerve plexi (submucosal and myetric)

Question 13

Mucosa construction and function (4)

Answer 13

• functions to line lumen and provide lymphatics/vascularization
• epithelium = lines lumen
• lamina proper = areolar connective tissue, contains vascularization and MALT
• muscularis mucosae = smooth muscle, produces fold for surface area to volume ratio

Question 14

Submucosa construction and function (2)

Answer 14

• functions to increase efficiency of absorption
• well vascularized areolar connective tissue

Question 15

Muscularis construction and function (3)

Answer 15

-function’s to contract/move food
deep layer of mostly smooth, some skeletal muscle arranged in a circular fashion
- outer same muscle layer arranged in a longitudal fashion

Question 16

Serosa construction and function (3)

Answer 16

• functions to create outer organ boundary
• sub layer of areolar connective tissue
• outer layer of simple squamous epithelium

Question 17

Submucosal nerve plexus location and function (2)

Answer 17

• sits between submucosa and muscularis
• functions to stimulate secretory cells of mucosa

Question 18

Myenteric nerve plexus location and function (2)

Answer 18

• sits between muscularis layers
• functions to generate motility of material in and along lumen via contractions

Question 19

Esophagus variations in microscopic anatomy (4)

Answer 19

• mucosa focused on lubrications - not secretion or absorption
• deepest layer is a non keratinized stratified squamous epithelium to withstand wear better
• muscularis varies in muscle type
• has an adventitia instead of serosa, only connective tissue to secure in place

Question 20

Esophagus muscularis muscle type variations (3)

Answer 20

• upper 1/3 = skeletal (under conscious control for swallowing)
• middle 1/3 = mix of skeletal and smooth (transition)
• lower 1/3 = smooth (fully autonomically controlled)

Question 21

Large intestine variations in microscopic anatomy (4)

Answer 21

• fewer structures to increase surface area (doesn’t need it)
• main focus in on absorption of water and secretion of mucous to solidify and lubricate waste
• longitudal muscle layer shortens to form haustra
• serosa has fat filled pouches (omental appendices)