The Large Intestine

Question 1

2. Describe the features of segmentation of the large intestine

Answer 1

1 contraction/ 30 mins
Haustral churning

Question 2

3. Describe the features of mass movement of materials in the large intestine

Answer 2

3-4 times/ day (usually following a meal)
Wave of intense contraction moves material from transverse colon

Question 3

4. Describe what secretion occurs in the large intestine

Answer 3

Mucus from goblet cells

Question 4

5. Describe what digestion occurs in the large intestine

Answer 4

Gut microbiota metabolise foodstuffs

Question 5

6. What 3 things are absorbed in the large intestine

Answer 5

Water
Vitamins (K, B5, Biotin)
Electrolytes

Question 6

7. What is the main function of the large intestine?

Answer 6

to absorb water and salt and produce a more solid waste product

Question 7

8. What does the rectum act as

Answer 7

temporary storage for faeces

Question 8

9. What does the movement of material into the rectum trigger

Answer 8

the urge to defecate

Question 9

10. What 6 sections is the large intestine made up of

Answer 9

• caecum
• ascending colon
• transverse colon
• descending colon
• sigmoid colon
• rectum

Question 10

12. What are enterocytes responsible for in the large intestine

Answer 10

they are responsible for absorption through active membrane transport

Question 11

14. What does the appendix contain

Answer 11

contains prominent lymphoid material

Question 12

18. what is the large intestine specialised for

Answer 12

Specialised for water & salt absorption

Question 13

19. how is large intestine arranged

Answer 13

tubular glands

Question 14

20. what type of absorptive cells does the large intestine have

Answer 14

has tall columnar absorptive cells

Question 15

21. what does the large number of mucous cells mean for the large intestine

Answer 15

there is more friction so therefore mucous cells provide more mucus for lubrication

Question 16

22. describe the 7 overall differences between the small and large intestine

Answer 16

Colon diameter is approx x3 small intestine
Colon has a thinner wall
No villi in colon
large intestine has Abundant mucus cells
Distinctive glands that are mainly mucus producing
No enzyme production in large intestine
In large intestine, Longitudinal layer of muscularis externa becomes teniae coli

Question 17

25. what can change or defects in microbiota cause

Answer 17

causes diseases and problems with immune function

Question 18

27. what is vitamin K required for

Answer 18

required for synthesising clotting factors

Question 19

29. what is biotin required for

Answer 19

required for various reactions including glucose metabolism

Question 20

1. what is vitamin B5 required for

Answer 20

required for making steroid hormones and some neurotransmitters

Question 21

41. what do anal glands do for the passage of faeces

Answer 21

lubricates the anal canal for the passage of faeces

Question 22

46. what are 2 features of the internal anal sphincter

Answer 22

• smooth muscle
• involuntary

Question 23

47. what are 2 features of the external anal sphincter

Answer 23

• skeletal muscle
• voluntary control

Question 24

48. what initiates and causes the defecation reflex

Answer 24

Initiated by sudden distension of walls of rectum due to movement of faecal material into it, stimulating stretch receptors