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Gastrointestinal System > Rectum and Anal Cavity > Flashcards

Rectum and Anal Cavity Flashcards

1
Q

Describe the rectum

A

Rectum passes through pelvic floor and has continuous band of outer longitudinal muscle

Has curved shaped and lies anterior to the sacrum

Parts are covered in peritoneum while others are extra-peritoneal

Stretching of the rectum stimulates urge to defaecate

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2
Q

What arteries supply the rectum and anal canal

A

Superior rectal

Middle rectal - from internal iliac

Inferior rectal - pudendal

Form a plexus around the rectum and anal canal

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3
Q

Which veins drain the rectum and anal canal

A

Portal drainage via superior rectal vein

Systemic drainage through internal iliac vein - from middle and inferior rectal veins

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4
Q

What is the anal canal and describe its structure

A

Anal canal is narrowest portion of the GI tract and continues on from the rectum

Starts proximal to border of anal sphincter complex

Rectum points anteriorly but puborectal sling changes direction of the anatomy so anal canal points posteriorly

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5
Q

What factors are involved in maintaining continence

A

Distensible rectum

Firm bulky faeces

Normal anorectal angle

Anal cushions

Normal anal sphinters

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6
Q

What is the dentate line and what are the differences between the two sides

A

Dentate line is the junction of the hindgut and ectoderm

Above line - visceral receptors and columnar epithelium

Below line - somatic receptors and stratified squamous epithelium

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7
Q

What are the two parts of the anal sphincter complex and what are the differences between the two

A

Internal involuntary sphincter - autonomic control. Maintains 80% of resting anal pressure

External anal sphincter - voluntary control. Maintains 20% of resting anal pressure

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8
Q

Describe the process of defaecation

A

Mass movement

Defaecation reflex - distension in rectum causes contraction of rectum, sigmoid colon and external anal sphincter while relaxation of internal sphincter

Increases pressure in rectum

Defaecation - relaxation of external sphincter, relaxation of puborectalis muscle, forward peristalsis in rectum and sigmoids colon, increased abdominal pressure

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9
Q

Describe the two types of diarrhoea

A

Secretory - electrolyte transport is affected. Either too much secretion of ions (Cl) or too little absorption

Osmotic - gut lumen contains too much osmotic material whihc draws water into lumen. Settles if patient stops consuming offending substance

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10
Q

What is diarrhoea

A

Loose of watery stools

Occurs >3 times a day

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11
Q

What is constipation

A

Hard or lumpy stools

Difficulty or inability to pass stools

Feeling of incomplete evacuation, obstruction or blockage of defaecation

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12
Q

What are risk factors of constipation

A

Female have higher risk

Certain medications

Low levels of activity - immobility

Increasing age

Children under 4

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13
Q

What is the pathophysiology behind constipation

A

Normal transit constipation

Slow colonic constipation - more chance to absorb water:

  • Large colon
  • Fewer peristaltic movements and shorter movements
  • Fever intestinal pacemaker cells present
  • Systemic disorders
  • Nervous system disease

Defaecation problems - cannot coordinate muscle of defaecation or disorders of the pelvic floor or anorectum

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14
Q

What is the treatment for constipation

A

Physiological support

Increase fluid intake

Increase activity

Increase dietary fibre

Fibre medication

Laxatives

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15
Q

What is the appendix, where is it normally found and what type of pain does appendicitis commonly present with

A

Appendix is a diverticulum of the caecum. Has complete longitudinal layer of muscle

Found at McBurney’s point - 2/3 the way from umbilicus to ASIS

Causes peri-umbilical pain, radiating to the right iliac fossa

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16
Q

Describe how appendicitis develops

A

Blockage of the appedix lumen creates high pressure in the appendix

This results in increased venous pressure which makes it harder for arterial blood to supply the appendix

Then have ischaemia of the appendix walls -> perforation and bacterial invasion

17
Q

What are the signs and symptoms of appendicitis

A

Poorly localised peri-umbilical pain

Anorexia

Nausea/vomiting

Low grade fever/appears slightly ill

Pain more intense in right iliac fossa after 12-24hrs

Slight tachycardia

Lie still as peritoneum is inflamed

Rebound tenderness in right iliac fossa

May have supra-pubic, right sided rectal or vaginal pain instead of right iliac fossa pain depending on position of the appendix

18
Q

What tests are performed to diagnose appendicitis and what is the treatment

A

Blood tests - raised WBC

History/physical examination

Pregnancy test/urine dip

CT scan for non-classical presentation

Treatment - open or laproscopic appendicetomy

19
Q

What is diverticulosis

A

Outpouchings of the mucosa and submucosa that herinate through the muscularis layers

Occurs where nutrient vessels penetrate the bowel wall

Is asymptomatic

20
Q

What is acute diverticulosis and how does it develop

A

When diverticula become inflamed or perforate, +/- bleeding and abscess formation

Caused by blockage of the entrance to the diverticulum resulting in inflammation

Inflammation allows bacterial invasion of the wall of the diverticulum -> abscess can form

Can lead to perforation

21
Q

What are the signs and symptoms of acute diverticulosis

A

Abdominal pain at site of inflammation - commonly left lower quadrant

Fever

Bloating

Constipation

Haematochezia

Localised abdominal tenderness

Distension

Reduced bowel sounds

Signs of peritonitis

22
Q

What tests are used to diagnose acute diverticulosis and what is the treatment for it

A

Blood tests

USS

CT scan

Colonoscopy

Treatment: antibiotics, fluid restriction, analgesia, surgery if perforated or large abscess needs drainage

23
Q

What are anal cushions

A

Anus contains complex venous plexus divided into 3+ areas of tissues

These play a role in anal continence and help determine if air, fluid or solid is in the rectum

24
Q

What are the types of haemorrhoids

A

Internal - cause by loss of CT support. Occur above dentate line and are relatively painless but can irritate and cause discomfort

External - below dentate line. Are painful

25
Q

What is the treatment for haemorrhoids

A

Increase hydration and fibre in diet

Avoid straining

Rubber band ligation

Surgery

26
Q

What is an anal fissure and how is it treated

A

Linear tear in anoderm and can be caused by passing of hard stool

Have pain on defaecation and haematochezia

Treatment - hydration, dietary fibre, analgesia, warm baths, medication to relax internal anal sphincter

Gastrointestinal System (15 decks)

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