Anal canal Flashcards Preview

GI > Anal canal > Flashcards

Flashcards in Anal canal Deck (33):
1

Where does the anal canal run from and to

From the rectal ampulla to the anus

2

What does the anal canal run between (Anteroposteriorly)

Anococcygeal ligament (posterior) and the perineal body (anterior)

3

What is the anal canal located within

The anal triangle of the perineum

4

Length of the anal canal

4cm

5

What direction does the anal canal follow

Posteroinferior

6

What surrounds the anal canal and what is there function

Internal and external anal sphincters
They maintain faecal continence

7

Which anal sphincters are voluntary and involuntary muscle

External is voluntary
Internal is involuntary

8

Where is the internal anal sphincter

Surrounds the upper 2/3 of the anal canal

9

Where is the external anal sphincter

Surrounds the lower 2/3 of the anal canal

10

What does the external anal sphincter blend with

Puborectalis muscle

11

What must occur to allow defecation

Relaxation of both anal sphincters

12

What is at the anorectal junction

Anorectal ring (muscular ring formed by fusion of the internal anal sphincter, external anal sphincter and puborectalis muscle)

13

What are anal canals

Series of longitudinal ridges in the superior aspect of the mucous membrane

14

What do anal columns contain

Terminal branches of the superior rectal vessels

15

What joins the anal columns inferiorly

Anal valves

16

What's superior to the anal valves and what do they contain

Anal sinuses which contain glands that secrete mucus

17

When do anal sinuses secrete mucus

When compressed by faeces to aid defecation

18

What do the anal valves form

The pectinate line

19

Embryological origin above and below the pectinate line

Above - hindgut
Below - ectoderm of the proctodeum

20

Epithelial lining above and below the pectinate line

Above - columnar
Below - non keratinised stratified squamous which transitions to keratinised (I.e skin) at the inter-sphincteric groove

21

How does the anal canal superior to the pectinate line differ from the anal canal inferior to the pectinate line

Blood supply
Innervation
Lymphatic drainage
Embryological origin

22

Arterial supply above the pectinate line

Aorta -> IMA -> Superior rectal artery

23

Arterial supply below the pectinate line

Aorta -> common iliac -> internal iliac -> internal pudendal -> inferior rectal artery

24

What other artery contributes to supply of the anal canal

Middle rectal arteries anastomose with the superior and inferior rectal arteries

25

Venous drainage above and below the pectinate line

Above - superior rectal vein which drains into the IMV
Below - inferior rectal vein which drains into the internal pudendal vein

26

Innervation above and below the pectinate line

Above (visceral) - inferior hypogastric plexus
Below (somatic) - inferior anal nerves which are branches of the pudendal nerve

27

Where is pain above the pectinate line referred to

S2-4 dermatomes

28

What is the anal canal sensitive to above and below the pectinate line

Above - stretch
Below - pain, touch, temperature and pressure

29

What does lymph drain into from above and below the pectinate line

Above - internal iliac lymph nodes
Below - superficial inguinal lymph nodes

30

What are haemorrhoids

Vascular cushions found within the anal canal which help with the maintenance of faecal continence

31

What are pathological haemorrhoids

Swollen or distended haemorrhoids

32

Who are pathological haemorrhoids seen in

People who suffer from:
Constipation
Prolonged straining when defecating
Raised intra-abdominal pressure (pregnancy, ascites)

33

Consequences of pathological haemorrhoids

Bleeding and pain on defecation