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Flashcards in Practical 4 Deck (53)
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1
Q

Describe the small intestines

A

Extends from pyloric orifice to the ileocaecal junction

Duodenum, jejunum and ileum

2
Q

How do you know when the duodenum becomes the jejunum?

A

When retroperitoneal duodenum gains a mesentery and becomes intraperitoneal (just below and L of attachment of transverse mesocolon to post ab. wall

3
Q

How does the jejunum differ from the ileum?

A

Wall of jejunum is thicker and more vascular with more plicae circulares and no Peyer’s patches.
Ileum is thinner, less vascular, no plicae circulares and large numbers of peyer’s patches

4
Q

Where does the mesentery attach?

A

Obliquely across post. ab. wall from L of L2 vetebra to R sacroiliac joint

5
Q

Describe the blood supply of the jejunum and ileum

A

Both by branches of superior mesenteric artery arranged in arcades
Jejunal, ileal (L side) and ileocolic (R side) branches

6
Q

Name the branches of the superior mesenteric artery

A

Inferior pancreaticoduodenal, jejunal, ileal, ileocolic and R and middle colic arteries

7
Q

What are the anastamoses of the ileal and jejunal blood supply called? Where are they most abundant?

A

Arcades

Many in ileum, fewer in jejunum

8
Q

Describe the ileocolic artery

A

From R sided branch of superior mesenteric artery, passes to R iliac fossa and supplies terminal ileum and ascending colon (+caecum and appendix)

9
Q

Describe the blood supply of the colon

A
Sup mes a.:
Ileocolic= caecum, appendix and ascending colon
R colic= ascending colon
Middle colic= transverse colon
Inf mes a.:
L colic ascending and descending= transverse and descending colon
2-3 sigmoid= sigmoid colon
Superior rectal= rectum
10
Q

Where are Peyer’s patches found?

A

In lamina propria and submuscosa of terminal ileum

11
Q

Describe the route of lymph from the small intestines

A

Peyer’s patches-> nodes in mesentery-> arterial arcades-> origin of sup. mes. a.-> cisterna chyli

12
Q

Describe the sympathetic and parasympathetic supply of the small intestines

A

Symp: T9-T10-> celiac or sup. mes. ganglia-> small intestine (+pain)
Para: Vagus (+reflex)

13
Q

What are the 3 bands of outer longitudinal muscle called in the large intestine?

A

Teniae coli

14
Q

What are teniae coli?

A

3 bands of outer longitudinal muscle in the large intestine

15
Q

What is the large intestine covered in?

A

Appendices epilocae (fatty tags)

16
Q

What are appendices epilocae?

A

Fatty tags between colonic wall and the visceral peritoneum

17
Q

What are the defining features of the large intestine?

A

Appendices epilocae (fatty tags), teniae coli (3 bands of outer longitudinal muscle) and haustra

18
Q

What are haustrations also called?

A

Sacculations

19
Q

Describe the caecum

A

Blind ended sac, continuous superiorly with ascending colon. Ileocaecal junction on medial wall. Vermiform appendix where teniae coli converge on posteriomedial wall

20
Q

Where is pain from an inflamed appendix felt?

A

Initially in umbilical region (visceral, referred to belly button)
Later localises to R iliac region (parietal, somatosensory innervation localised to anatomical location of appendix)

21
Q

Where does the ascending colon turn into the transverse colon?

A

At the visceral surface of the liver where is bends anteriorly and to the left (at the R colic flexure)

22
Q

What is different about the ascending colon?

A

No mesentery, direct contact with fascia over post.ab. wall muscles. Therefore fixed in position

23
Q

How does the L colic flexure maintain its position?

A

Via the phrenicocolic ligament where is attaches to the underside of the diaphragm

24
Q

Where is the paracolic gutter? Significance?

A

Between abdominal wall and colon. Allows distension of bowels when chyme is passing through

25
Q

Where is the infracolic space?

A

Between colon and mesentery of small intestine

26
Q

What is the significance of the R paracolic gutter?

A

Continuos superiorly with the hepatorenal pouch and the aditus to the lesser sac and inferiorly with the rectouterine/rectovesical pouch

27
Q

Describe the attachment of the sigmoid mesocolon

A

V shaped attachment to post. ab. wall with apex at bifurcation of L common iliac arteru and overlies L ureter

28
Q

What is the anastomosis between the superior and inferior mesenteric arteries called?

A

Marginal artery, found on L side of transverse colon

29
Q

Where does the inferior mesenteric vein drain?

A

To splenic vein behind body of pancreas

30
Q

Describe the sympathetic supply of the large intestine

A

T11-L2-> sup mes ganglion-> proximal 2/3 colon

T11-L2-> inf mes ganglion-> distal 1/3 colon

31
Q

Describe the parasympathetic supply of the large intestine

A

Prox 2/3= vagus

Distal 1/3= pelvis splanchnic nerves (S2-S4)

32
Q

What level is the recto-sigmoid junction?

A

S3

33
Q

Where is the anorectal junction? Also called what?

A

When rectum pierces pelvic floor muscles. Perineal flexure.

34
Q

What muscle of the pelvic floor is involved in defaecation?

A

Pubrectalis, relaxes and angle between rectum and anus increases

35
Q

What is the lower part of the rectum called?

A

Ampulla, dilated end

36
Q

Describe the peritoneal covering of the recum

A

Sup 1/3= covers ant and lateral surfaces
Middle 1/3= covers ant surface
Inf 1/3= no peritoneal covering: subperitoneal

37
Q

Why is there no peritoneal covering the posterior of the rectum?

A

Because it is contact with the sacrum

38
Q

What is found lateral to the rectum?

A

Coils of small intestine

39
Q

In males, what is the rectum related to anteriorly?

A

Base of urinary bladder, seminal vesicles, prostate and ductus deferens&ureters

40
Q

In females what is the rectum related to anteriorly?

A

Uterus and vagina

41
Q

Where does the anal canal begin?

A

At the level of the pelvic diaphragm

42
Q

Describe the internal anal canal

A

6-10 anal columns with anal valves and anal sinuses above

Anal valves are situated along the pectinate line (junction between endoderm and ectoderm)

43
Q

Describe the anal sphincters

A

Internal= involuntary circular fibres
External= voluntary skeletal muscle supplied by inf. rectal nerve (branch of pudendal nerve) and the perineal branch of S4
Subcutaneous, superficial and deep external parts (deep blends with pelvic floor)

44
Q

What is found on each side of the anal canal?

A

Ischioanal fossae, full of fibrous tissue, nerves and fat

Lateral wall of fossae= obturator internus

45
Q

What is found within obturator fascia?

A

Pudendal canal, hosuing the internal pudendal vessels and pudendal nerve
These give rise to the inferior rectal vessels and nerves

46
Q

Describe the blood supply of the anal canal

A

Superior part= inferior mesenteric artery-> superior rectal artery
Inf part= internal iliac artery-> middle rectal arteries->pelvic floor and lower rectum
Internal pudendal a.-> inferior rectal a.-> lower anal canal and sphincters

47
Q

Describe the drainage of the rectum and anal canal

A

Rectum& upper 1/2 anal canal-> internal rectal plexus-> superior rectal vain-> inferior mesenteric vein-> splenic vein-> hepatic portal vein
External plexus-> sup, middle, inf rectal veins-> some to inf mesenteric vein-> HPV and some to internal iliac and IVC

48
Q

What does the external plexus of veins around the rectum and anal canal also communicate with?

A

Pelvic viscera venous plexuses, internal vertebral venous plexus, IVC and HPV

49
Q

Describe the lymphatic drainage of the anal canal and rectum

A

Upper rectum= pararectal-> pre aortic
Anorectal region= internal iliac
Lower anal canal= superficial inguinal-> commmon iliac-> para aortic-> cisterna chyli

50
Q

Describe the parasympathetic and sympathetic supply for the rectum and anal canal

A
SNS= T11-L2-> inf mes ganglion-> sup & inf hypogastric plexus
PNS= S2-S4-> pelvic splanchnics-> inf hypogastric plexus
51
Q

How does pain from upper anal canal and rectum travel?

A

With both symp and parasympathetic afferents

52
Q

Describe the innervation of lower anal canal

A

Somatic nerves: inferior rectal branch of pudendal nerve (S2, 3, 4) and perineal branch of 4th sacral nerve

53
Q

Clinical difference between internal and external haemorrhoids?

A
Internal= painless rectal bleeding
External= pain and swelling