Gastrointestinal system

Question 1

What are the main cells of the Large intestine

Answer 1

Absorptive cells - help with water absorption

Goblet cells - Secrete mucous that lubricates passage

Question 2

What are the four major regions of the large intestine

Answer 2

Caecum, Colon, Rectum and Anal canal

Question 3

Describe the cells of the small intestine

Answer 3

Goblet cells - secrete mucous
Enteroendocrine cell - secrete hormones like secretin or GIP
Paneth cells - secrete lysozyme and is capable of phagocytosis

Question 4

Describe the structural features the facilitate absorption and digestion

Answer 4

Circular folds - enhance absorption by increasing surface area
Villi - finger like mucosa, increases surface area
Microvilli - Increase surface area

Question 5

Describe the structure of the small intestine

Answer 5

Duodenum - shortest region
Jejunum - Found empty at death
Ileum - Longest (end)

Question 6

Where does most digestion and absorption of nutrients occur

Answer 6

Small intestine

Question 7

What is the main movement that occurs in the small intestine and then oesophagus

Answer 7

small intestine - segmentation

oesophagus - peristalsis

Question 8

Define G cells

Answer 8

Stimulates parietal cells to secrete HCL
Chief cells to secrete pepsinogen
Controls sphincters
Increases motility of stomach

Question 9

What is the function of a Chief cell

Answer 9

Breaks down proteins into peptides

Splits triglycerides into fatty acids and monoglycerides

Question 10

What is the function of a parietal cell

Answer 10

Absorbs vitamin B12 (red blood cells formation

Kills microbes in food

Question 11

What are the three cells contained by gastric glands

Answer 11

Parietal cells, chief cells and G cells

Question 12

Describe the muscularis externa of the GI tract

Answer 12

Oesophagus - proximal 1/3 - skeletal muscle
mid 1/3 - skeletal muscle and smooth muscle
distal 1/3 - smooth muscle (inner circular and outer longitudinal fibres)

Rectum/Anus - Skeletal muscle

Stomach - 3 layers of smooth muscle (mixing waves)

Question 13

Describe the submucosa of the GI tract

Answer 13

In the oesophagus and duodenum - submucosal glands (secrete alkaline mucous and neutralizes acidic content

Question 14

Describe the mucosa in the GI tract

Answer 14

Oesophagus, oral cavity and anus - non-Keratinised stratified squamous (protection

Stomach, Small and Large intestine - Simple columnar
Function (in order of organ) Secretion, Microvilli (absorption) and Colonic Crypts

Question 15

Define the serosa

Answer 15

Areolar connective tissue and simple squamous - lubricates the internal structures of the body
Oesophagus lacks - single layer of areolar connective tissue (adventitia) - holds structure together

Question 16

Define the submucosa

Answer 16

Areolar connective tissue (binds mucosa and muscularis)
Contains blood and lymphatic vessels
Extensive network of neurons

Question 17

Define the muscularis

Answer 17

In certain areas produces voluntary swallowing
Also forms the external sphincter (voluntary defecation

Most the time its smooth muscle (inner circular and outer longitudinal fibres)

Question 18

Define the Mucosa

Answer 18

Inner lining of 3 layers
Epithelium - Every 5 to 7 days is replaced by new cells
Exocrine cells are located in epithelial cells and they secrete mucous and fluid into the lumen

Lamina propria - areolar connective tissue (contains blood and lymphatic vessels)
Binds epithelium to next layer

Muscularis mucosae - thin layer of smooth muscle fibres (gives stomach and small intestine the fold shape)
Increases surface area for digestion and absorption

Question 19

Define the same basic four-layered arrangement of tissues in the GI tract

Answer 19

Mucosa
Submucosa
Muscularis
Serosa/Adventitia

Question 20

What are the 6 basic procedures of the GI tract

Answer 20

Ingestion 
Secretion 
Mixing and propulsion 
Digestion (Mechanical and Chemical) 
Absorption 
Defecation