Lecture 11 - Alimentary 3 Flashcards Preview

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Flashcards in Lecture 11 - Alimentary 3 Deck (71):
1

Where does the rectum extend between?

S3 to pelvic diaphragm

2

The ampulla is the superior more narrow section, true or false?

False

3

How do you distinguish the rectum from the sigmoid colon? (5)

1. No mesentery
2. Retroperitoneal
3. No sacculations
4. No epiploic appendices
5. No taenia

4

What is the special feature of the mucous in the wall of the rectum?

The submucosa contains a venous plexus linking superior and inferior rectal veins

5

What are the 2 planes of curvatures in the rectum?

1. Anterior to posterior - follows the curve of the sacrum (sacral flexure)
2. Laterall - Right to Left (largest) then Right

6

Where and what kind of folds are temporary in the rectum?

Longitudinal and in the ampulla

7

What are the features of the permanent folds in the rectum? (4)

1. Variable in number
2. Size and shape but commonly three
3. Include mucosa, submucosa and a variable amount of external muscle
4. The folds produce lateral folds?

8

Which permanent fold of the rectum is the largest and most constant

The middle fold

9

Where is the middle fold located? Where are the other folds located in relation to this?

Immediately above ampulla and roughly at the level of the rectovesicular/uterine pouch. The others are 4cm above or below

10

The peritoneum is loosely attached to the rectum true or false?

True

11

Where is the peritoneum attached on the rectum (3 points)?

Upper 1/3 - anterior and sides
Middle 1/3 - anterior only
Lower 1/3 - no periteoneum

12

What does the reflection of the middle 1/3 attachment of the peritoneum form?

The rectovesicular pouch

13

What are the posterior relations of the rectum (3)?

Sacrum, coccyx and pelvic diaphragm

14

What are the lateral relations of the rectum (3)?

Sigmoid colon, ileum, pelvic diaphragm

15

What are the anterior relations of the rectum in the male? (5)

Rectovesicular pouch, base of bladder, ductus deferens, prostate, seminal vesicle

16

What are the anterior relations of the rectum in females? (3)

Rectovesicular pouch (Pouch of Douglas), uterus and vagina

17

How does the anal canal sit/run

Using it's legs hah
Postero-inferiorly through the pelvic diaphragm (coccygeus) to anus

18

What is the sling of skeletal muscle at the rectoanal junction called?

Puborectalis

19

How many columns are in the upper part of the rectum

6-10

20

How are the lower ends of the columns joined?

Transverse folds or valves

21

What is the space between columns called?

Sinuses

22

What is the line of valves in the rectum called?

Pectinate or dentate or mucocutaneous line

23

Where is the cloacal membrane?

At the pectinate/dentate/mucocutaneous line

24

What is the cloacal membrane? (2)

Junction of mucosa with skin with its own blood supply

25

How do the different layers of mucosa change in the rectum?

From epithelium to simple columnar than a transitional zone or non keratinised stratified squamous epithelium

26

There are sphincters over the entire length of the anal canal true or false?

True

27

Where are the internal and external sphincters?

Upper 2/3 and lower 2/3 of the anal canal

28

What do the internal sphincters consist of?

Thickened circular layer of external smooth muscle which stop at the junction of skin

29

What do the external sphincters consist of?

A tube of skeletal muscle outside external muscle (3 parts)

30

The movement of the external sphincters is voluntary, true or false?

False, it is only partly voluntary

31

Where is the rectoanal junction?

At the level of the tops of the columns

32

The rectoanal junction is narrower than the ampulla, true or false?

True

33

What if a posterior relation to the anal canal?

Anococcygeal ligament (dense connective tissue which extends from coccyx to anal margin)

34

What are the anterior relationships to the anal canal?

Perineal body and membranous urethra/bulb of penis OR vagina

35

What is the lateral relation to the anal canal?

Ischiorectal fossa

36

How long does the bolus spend in the stomach and small intestine?

1-3 hours and 1-6 hours

37

How does the bolus move from the stomach to the small intestine

Segmenting contractions and peristalsis from one end to the other (motilin)

38

How does the bolus move from the ileum to the large intestine?

Gastrocolic reflex

39

What keeps the anus closed?

Muscle tone stimulated by sympathetic nerves

40

When does the muscle tone normally increase

When intraabdominal pressure rises e.g. coughing

41

What are 4 things that keep the anus closed?

muscle tone, puborectalis, reverse peristalsis and relaxation of muscle wall of rectum and sigmoid

42

Where is the faeces held prior to defecation?

In the ampulla

43

What sends the defecation reflex?

Medulla oblongata

44

Where is faeces voided from?

The splenic flexure down

45

What is defecation?

Rectal stretching

46

What are three things that occur during defecation?

Relaxation of sphincters and puborectalis
Peristalsis in descending and sigmoid colon increases
Contraction of abdominal muscles and diaphragm which raise abdominal pressure

47

What are the functions of the two pancreas?

Exocrine - digestive enzymes
Endocrine - Islets of Langerhans

48

What does the pancreas develop from?

Two outgrowths from the foregut (dorsal and ventral pancreatic bud)

49

How do the buds turn into the pancreas? (3)

1) Buds form a series of branching epithelial lined tubules arising from distal/caudal foregut
2) Form pancreatic ducts which then develop into acini
3) Islets also arise from tubule cells which then separate and come to lie in connective tissue between the tubules.
4) The ventral pancreas rotates posteriorly so that i ultimately lies behind the dorsal pancreas
5) The two primordia then fuse.

50

When does insulin secretion first begin?

10 weeks into gestation

51

What causes the ventral pancreas to rotate posteriorly so that it lies behind the dorsal pancreas?

Rotation of the stomach and differential growth

52

Which duct remains as the main pancreatic duct?

The ventral duct

53

What happens to the dorsal pancreatic duct during development (2)

The dorsal duct also rearranges to drain into the ventral duct the part most proximal the duodenum may persist as a minor pancreatic duct

54

What causes the pancreas to become retroperitoneal?

Pressure from adjacent organs pushes the pancreas against the abdominal wall and layers of peritoneum fuse

55

What does the ventral pancreatic bud form? (2)

The uncinate process and inferior head

56

What does the dorsal pancreatic bud form?

The rest of the pancreas

57

How long is the mature pancreas?

12-15 cm long

58

The entire mature pancreas is retroperitoneal true or false?

False, everything is retroperitoneal apart from the tail

59

Where does the mature pancreas extend from?

Duodenum to spleen behind the stomach

60

What are the four regions of the pancreas?

Head, uncinate process, body, tail

61

Where does the head and uncinate process lie?

Within the curve of the duodenum

62

What is posterior to the head and uncinate process (2)?

IVC and aorta

63

What is the uncinate process?

Lower extension of head behind superior mesenteric vessels

64

What do the anterosuperior faces of the body of the pancreas face?

Lesser and greater sac

65

Where does the transverse mesocolon attach to the pancreas?

Anterior angle of the body

66

Where does the tail travel?

It accompanies the splenic vessels into splenorenal ligament

67

Where does the main duct drain into?

The greater duodenal papilla in the posteromedial wall of descending duodenum.

68

What may the bile and main pancreatic duct unite to form?

The hepatopancreatic ampulla

69

Where would the accessory duct open if it exists?

2cm superior to the main duct

70

What is a defining feature of the main pancreatic duct?

A herringbone pattern of lobar ducts drain into the main duct

71

Where does the main pancreatic duct sit?

Within the pancreas towards posterior surface