Rectum/Anal Canal Flashcards

1
Q

The rectum is technically a part of what gastrointestinal structure?

A

Large intestine (between the sigmoid colon and the anal canal)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the rectosigmoid junction of the rectum and where is it located?

A

Upper limit of the rectum located at the middle of the sacrum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the anorectal junction and where is it located?

A

The lower limit of the rectum located at the upper border of the pelvic diaphragm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What muscles forms a sling around the rectum at the anorectal junction?

A

Puborectalis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the rectal ampulla and where is it located?

A

Dilated terminal portion of the rectum located immediately above the pelvic diaphragm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How many transverse rectal folds are there?

A

Three

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Does the rectum have mesentery, omental appendices, or haustra?

A

No.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Does the rectum have taeniae coli?

A

Yes, but it’s spread out as a complete layer unlike the intestines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Peritoneum covers what parts of the upper third of the rectum?

A

Front and sides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Peritoneum covers what parts of the middle third of the rectum?

A

Front

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Peritoneum covers what parts of the lower third of the rectum?

A

There is no peritoneal covering here

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

The anal canal is between what two structures?

A

Pelvic diaphragm and anus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

About how many anal columns lie in the anal canal?

A

5-10

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What vascular structures do each anal column contain?

A

Small branch of the superior rectal artery and a small tributary of the superior rectal vein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the longitudinal folds of mucosa which lie in the upper half of the anal canal?

A

Anal columns

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the crescent-shaped folds which connect the lower ends of the anal columns?

A

Anal valves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the recesses located between the anal valves and the wall of the anal canal?

A

Anal sinuses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What marks the lower limit of the anal valves around the circumference of the anal canal?

A

Pectinate line

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the bluish white zone located inferior to the pectinate line?

A

Anal pecten

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the distal termination of the anal canal where it meets the skin?

A

Anocutaneous line

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Which anal sphincter is under involuntary control?

A

Internal anal sphincter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Which anal sphincter is a continuation of the smooth muscle layer of the rectum below the pelvic diaphragm?

A

Internal anal sphincter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are the three parts of the external anal sphincter?

A

Subcutaneous, superficial, and deep parts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the nerve supply of the external anal sphincter?

A

Nerve to external anal sphincter (S4)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is the function of the external anal sphincter?

A

Closes anal orifice

26
Q

Which anal sphincter is under voluntary control?

A

External anal sphincter

27
Q

From where does the superior rectal artery arise?

A

Inferior mesenteric artery

28
Q

From where does the middle rectal artery arise?

A

Internal iliac artery

29
Q

From where does the inferior rectal artery arise?

A

Internal pudendal artery

30
Q

From where does the median sacral artery arise?

A

Abdominal aorta

31
Q

What arteries make up the blood supply of the rectum and anal canal?

A

Superior, middle, and inferior rectal arteries and the median sacral artery

32
Q

What are internal hemorrhoids?

A

Varicosities of the superior rectal vein

33
Q

Internal hemorrhoids cause bulging of what anal structures?

A

Anal columns

34
Q

Are internal hemorrhoids painful?

A

No, painless

35
Q

Where do internal hemorrhoids occur?

A

Above the pectinate line

36
Q

What are external hemorrhoids?

A

Varicosities of the inferior rectal vein

37
Q

Where do external hemorrhoids occur?

A

Below the pectinate line

38
Q

Are external hemorrhoids painful?

A

Can be very painful

39
Q

What are the causes of both types of hemorrhoids?

A

Pregnancy, heavy lifting, sitting, straining-chronic constipation, portal hypertension

40
Q

Why can heavy lifting cause hemorrhoids?

A

Due to the increased intra-abdominal presure

41
Q

What would be a possible morbid underlying cause of hemorrhoids?

A

Portal hypertension

42
Q

What group of people are at a high risk for developing hemorrhoids?

A

Long distance trunk drivers

43
Q

What is the epithelium like in the anal canal above the pectinate line?

A

Columnar or cuboidal

44
Q

What is the epithelium like in the anal canal below the pectinate line?

A

Stratified squamous

45
Q

What is the nerve supply of the anal canal above the pectinate line?

A

Autonomic fibers

46
Q

What is the nerve supply of the anal canal below the pectinate line?

A

Pudendal nerve

47
Q

What is the venous supply of the anal canal above the pectinate line?

A

Superior rectal

48
Q

What is the venous supply of the anal canal below the pectinate line?

A

Middle, inferior rectal

49
Q

Which lymph nodes are found in the anal canal above the pectinate line?

A

Internal iliac

50
Q

Which lymph nodes are found in the anal canal below the pectinate line?

A

Superficial inguinal

51
Q

The upper visceral 2/3 of the anal canal is from which embryologically derived structure?

A

Hindgut

52
Q

The lower somatic 1/3 of the anal canal is from which embryologically derived structure?

A

Proctodeum

53
Q

What part of the GI tract accumulates fecal matter?

A

Sigmoid colon

54
Q

What is usually contained in the rectum?

A

Nothing; it is usually empty

55
Q

How does the sigmoid colon empty its contents into the rectum?

A

Through mass peristaltic movement

56
Q

During defecation, what muscles contract to increase pressure within the rectum?

A

The longitudinal muscle layer of the rectum and the anterior abdominal wall muscles

57
Q

What muscle relaxes during defecation to decrease the angle of the perineal flexure?

A

Puborectalis

58
Q

What is opened due to the increase in pressure within the rectum during defecation?

A

Internal anal sphincter

59
Q

What is relaxed under voluntary control during defecation?

A

External anal sphincter

60
Q

What are the steps of defecation?

A
  1. Sigmoid colon empties contents into rectum by mass peristalsis
  2. Muscles contract to increase rectal pressure
  3. Puborectalis relaxes
  4. Internal anal sphincter opens
  5. External anal sphincter relaxes