Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Metabolism 2 > Defecation > Flashcards

Defecation Flashcards

1
Q

what are the three embryological layers that the gut tube is made out of

A
  • ectoderm
  • mesoderm
  • endoderm
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

describe what the three embryological layers of the gut tube are made out of

A
  • Ectoderm - skin of epidermis, nerves exoskeleton)
  • Mesoderm - muscle (cardiac, skeletal, smooth), tube cells of the kidney, red blood cells (organs)
  • Endoderm - lung cell, thyroid cells, digestive cells of the pancreas (inner lining of organs)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is the gut tube fromed from

A
  • Gut tube is formed from endoderm lining the yolk sac as the result of cranial and caudal folding.
  • The gut smooth muscle is formed from mesoderm around the primitive gut endoderm
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what 3 things is the primitive gut tube made out of

A

Foregut
Midgut
Hindgut

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

when does the primitive gut tube develop and how

A

weeks 3-4

- incorporates the yolk sac during the craniocaudal and lateral folding of the embryo

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

What does the foregut give rise to

A

esophagus, stomach, liver, gallbladder, bile ducts, pancreas and proximal duodenum.

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

what does the midgut give rise to

A

distal duodenum, jejunum, ileum, cecum, appendix, ascending colon, and proximal 2/3 of transverse colon

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

what does the hindgut develop into

A

The hindgut becomes distal 1/3 of the transverse colon, descending colon, sigmoid colon and the upper anal canal.

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

what is the supply of the

  • foregut
  • midgut
  • hindgut
A
  • foregut - celiac artery
  • midgut - superior mesenteric artery
  • hindgut - inferior mesenteric artery
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what dives the foregut into the oesophagus and trachea

A

The tracheoesophageal septum divides foregut into the oesophagus and trachea

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

if the tracheoesophageal septum does not develop what happens

A

Failure of the Tracheoesophageal septum to fully develop results in Tracheoesophageal fistula (TEF) and or esophageal atresia.

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

name some foregut clinical problems

A

Oesophageal atresia

Tracheo-oesophageal fistula (TEF)

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

name some midgut clinical problems

A
  • duodenal atresia
  • meckel’s diverticulum
  • malrotation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

describe some midgut clinical problems

A

Duodenal atresia is due to failed canalization.

Meckel’s diverticulum occurs when a remnant of the yolk sac (Vitelline duct) persists.

Malrotation occurs if the midgut does not complete the rotation prior to returning to the abdomen.

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

Where does the Distal 1/3 of the transverse colon, descending colon and sigmoid colon develop from

A

Distal 1/3 of the transverse colon, descending colon and sigmoid colon develop from the cranial end of the hindgut.

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

where does the upper anal canal in the hindgut develop from

A

Upper anal canal develops from the terminal end of the hindgut with the urorectal septum dividing the upper anal canal and the urogenital sinus during 6th week.

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

What is the pectinate line

A

The pectinate line is the junction of proctodeum ectoderm and hindgut endoderm.

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

what gives rise to the anal membrane and the urogential membrane

A

7th week, the urorectal septum fuses with the cloacal membrane, giving rise to the anal membrane and the urogenital membrane

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

describe how the anal canals develop

A

The anal membrane ruptures during the 8th week allowing communication between the anal canal and the amniotic fluid.

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

what are most anorectal malformations due to

A

Most anorectal malformations are linked to failure of the urorectal septum to close the cloaca.

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

what is an imperforate anus

A
  • this is caused by failure of rupture of the anal membrane
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is a rectoanal atresia

A

failure of recanalisation or defective blood supply of the developing part.

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

What is a persistent clacoa

A
  • complete failure of development of the urorectal septum.
  • F>M
  • where the urinary bladder, vagina and rectum open in one cavity.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what is the intrinsic nervous supply of the gut

A

ENS - dervied from the vagal and sacral neural crest cells

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

what is the extrinsic nervous supply of the gut

A

vagal and sacral NCC forming the parasympathetic innervation and truncal NCC forming the sympathetic innervation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

what are the two nervous supply of the gut

A

intrinsic

extrinsic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Extrinsic nerve…

A

modulates the ENS (intrsinic nervous system of the gut0

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is hirschsprungs disease

A
  • briht defect charactersied by the absence of the enteric nervous system in the terminal part of the intestine
  • this causes the colon smooth msucle to permanelty be contracted
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

what are the symptoms of Hirschsprungs disease

A
  • failing to pass
  • meconiumwithin 48 hours
    a swollen belly
  • vomiting green fluid (bile)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

How is Hirschprungs disease treated

A
  • surgical resection of the aganglionic part of the colon ( part of the colon with no ENS)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

what is continence usually maintained by

A

anal canal

pelvic floor musculature

rectum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

what is the role of the rectum

A
  • store or expel stool
  • these both require cortical sensory awareness acting in conjunction with intramural and spinal reflexes that ensure defection
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

what is the role of the anal canal

A

Anal canal helps to maintain faecal continence and control defecation

34
Q

what do the pelvic muscles do

A
  • divides abdominal cavity from perineum
35
Q

what are the three muscles that make up the levator ani

A
  • puborectalis
  • puboccocygenous
  • illiococygenous
36
Q

what are the muscles that make up the pelvic wall

A

Levator Ani

  • puborectalis
  • puboccocygenous
  • illiococygenous

Coccygeous

37
Q

where does puborectalis attach from

A

Passes directly backward from the back of the pubic symphysis to form a ‘U-shaped loop’ that slings the rectum to the pubis.

38
Q

what type of muscle is the puborectalis

A

striated muscle

39
Q

what does the puborectalis surround

A
  • rectum
  • vagina
  • urethra
40
Q

what sphincter does puborectailis support

A
  • it supports the EAS

- assists in creating the anorectal angle

41
Q

what is the role of puborectalis

A

maintains the angle between the anal canal and rectum

42
Q

what makes up most of the pelvic floor

A

levator ani muscle

43
Q

What does continence mean

A
  • this refers to self control it is the ability to hold it in
44
Q

What is faecal continence maintained by

A

Anal sphincters

  • Internal anal sphincter (IAS)
  • External anal sphincter (EAS)

Pelvic floor muscles
- Puborectalis muscle

45
Q

what is the difference between the external anal sphincter and internal anal sphincter

A

External anal sphincter
- voluntary muscle which encircles the internal anal sphincter

internal anal sphincter

  • involuntary
  • thickened muscle
  • downward continuation of the inner circular muscle coat of the rectum surrounding the entire anal canal
46
Q

why is voluntary control of the external anal sphincter important

A

Voluntary control of the EAS is key in the voluntary deferring of evacuation until a socially opportune moment

47
Q

what is the nerve supply of the rectum, anus, bladder and urethra

A

S2-S4 parasympathetic supply = pudendal nerve

48
Q

S2, S3, S4 keeps…

A

S2,3,4 keeps the 3 P‘s off the floor (Penis, Poo, and Pee)

49
Q

what are the nerves responsible for continence

A

S2-S4 parasympathetic supply = pudendal nerve

50
Q

describe the nerve supply of the External anal sphincter

A
  • supplied by the inferior rectal branch of the pudendal nerve
  • which gives of the inferior rectal nerves

inferior rectal nerves divided into

  • perineal nerve and the dorsal nerve of the penis in males
  • dorsal nerve of the clitoris in females
51
Q

describe the nerve supply of the internal anal sphincter

A
  • enteric nervous system (autonomic nervous system)
  • sympathetic - L1-L2 via hypogastric nerves which are excitatory
  • parasympathetic - S2-S4 pelvic nerves are inhibitory
52
Q

what are the three reflexes that make up defaecation

A
  • initiation reflex - urge to go
  • defecation reflex - voiding reflex - opening of the anus
  • closure reflex - closing of the anus
53
Q

what has to relax in defecation

A

Defecation involves the relaxation of the EAS and puborectalis muscle, to create a broader anorectal angle.

54
Q

describe how filling happens in the anus

A
  • internal anal sphincter is in a continuously tonic state and is essential for maintaining the closure of the resting pressure of the anal canal
  • it initiates the act of defecation by reflex dilation in response to rectal distension
  • when a bolus of stool is in the anal canal the EAS contributes to the anal pressure which is know as the squeeze pressure
  • without this resting pressure we would be unable to prevent leakage of mucus and gas
55
Q

what is the rectoanal inhibitory reflex

A

this is when the anal canal distends and results in internal anal sphincter relaxation allowing slight distension
- this allows for sampling of the rectal contents and helps distinguish flatus from faeces

56
Q

what is sphincter function

A

Resting pressure,
Squeeze pressure,
Endurance Squeeze,
Rectoanal inhibitory reflex (RAIR)

57
Q

what is rectal sensation

A

hypersensitivity (associated with faecal incontinence)

hyposensitivity (associated with constipation

58
Q

more than 80% of children with constipation are…

A

faecal incontinence

59
Q

What is constipation

A
  • purely symptomatic - not a diagnosis

- can mean different things so important to ask the patient what they think it is

60
Q

who does constipation effect

A

more females than males

elderly

61
Q

what is the difference between defecation and continence

A

DEFAECATION
- begins with the urge to defaecate

CONTINENCE

  • dependent on an awareness of rectal filling
  • the sensation of impending defaecation
62
Q

what happens if continence is impaired

A
  • rectal evacuatory dysfunction
  • faecal incontinence
  • both
63
Q

how is continence felt

A
  • extrinsic afferent neurones mediate conscious sesation of urgency which is activated by mechanoreceptors
64
Q

what is the ability of the rectum to adapt to the imposed stretch called

A

rectal compliance

65
Q

What is hypersenstivity

A
  • reduced sensory threshold to volumetric rectal distension
  • associated with urge FI
  • bowel disorder, IBS, intussusception
66
Q

What is hyposensitive

A
  • increased sensory threshold to volumetric rectal distension
  • associated with evacuation difficulites, functional disorders, constipation
67
Q

what is normal transit constipation

A
  • this is normal transit yet the patient feels constipated

- usually overlaps with OBS since pain are bloating are common

68
Q

what is slow transit constipation

A
  • more common in young women and children
  • infrequency and slow movement of stool
  • bloating, abdominal pain and infrequent urge to defecate
69
Q

what is rectal evacuatory disorder

A
  • constipation common in children
  • associated with hard/painful stools
  • bloating, abdominal pain and infrequent urge to defecate
70
Q

what is disordered defecation

A

usually due to dysfunction of pelvic floor and anal sphincters.

71
Q

What pelvic wall abnormalities can occur

A

renal prolapse - when the rectal walls slide through the anus - tissues holding the rectum have weakend so it is no longer supported and pressure in the abdomen increases

rectal intussusception - this is a telescoping of the rectum into itself during straining which causes an obstruction on defecation

72
Q

What is daefection dyssynergia

A

is common in women and children and affects up to one half of patients with chronic constipation.
- due to the inability to coordinate the abdominal and pelvic floor muscles to evacuate stools

73
Q

what are the secondary things that can cause constipation

A

Endocrine: Diabetes; Hypothyroidism; Hyperparathyroidism; glucagonoma

Neurological: spinal injury; Parkinson’s disease; MS, autonomic neuropathy;

Psychogenic: affective disorders; eating disorders; dementia or learning difficulty

Metabolic: Hypercalcaemia; uraemia; hypokalaemia; amyloidosis; lead poisoning.

Colonic: tumour; diverticular disease stricture; ischaemia

Anal: Fissure; polyp; tumour

Physiological: pregnancy; old age

74
Q

what is faecal incontinence

A

Involuntary passage of rectal content (gas or stool) and it is a source of major embarrassment to the sufferer.
- more common with increasing age

75
Q

what clinical things do you look for in faecal incontience

A

External: visible soiling; excoriation (scars/defects)

Internal: organic disease (piles, fissures, fistula, tumour); defects; tone; squeeze; pelvic floor dysnergia; rectocele/intussusception (internal prolapse)

76
Q

what are the two types of faecal incontinence

A

passive incontinence

urge incontinence

77
Q

what is the difference between passive and urge incontinence

A

Passive
- structural and function lesion on the intenral sphincter

urge
- structural and function lesion on the external sphincter

78
Q

what can go wrong with the anus

A

Structure problems

  • obstetric sphincter tear
  • iatrogenic sphincter tear
  • radiation damage
  • congenital malformations

Function problems
- pudendal neuropathy

79
Q

How do you manage constiption

A

Diet:
Normal transit – augment dietary fibre and liquid intake and fibre supplements to those who can’t manage this.

Slow transit – less fibre as they tend to exacerbate bloating and does not help accelerate transit.

Laxatives:
Stimulant (Senna, bisacodyl) - better as required than regular to avoid laxative dependence;

Stool softeners (docusate) used as adjuvant agents; osmotic agents (mg salts, Lactulose) effective in slow transit and allow dose adjustment according to response.

80
Q

what drugs are used to manage consitpation

A

laxatives

81
Q

what is non conservative management for constipation

A
  • behavioural therapy
  • transanal irrigation - water pump systme
  • surgery
  • psychological therapy
  • neuromodulation - posterior tibial nerve stimulation and sacral nerve stimulation

Metabolism 2 (40 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions