3. Anatomy of the Abdomen 2 (HARC) GI Tract, peritoneum, embryology, anal canal Flashcards

1
Q

the GI TRACT is a HOLLOW TUBE with different regions specialised to facilitate which actions:

A
  • MECHANICAL DIGESTION
  • CHEMICAL DIGESTION
  • WATER REABSORPTION
  • Formation, Storage, Expulsion of FAECES
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2
Q

BELOW the DIAPHRAGM what are the MUSCULAR TUBE elements of GI Tract

A
  • OESOPHAGUS
  • STOMACH
  • SMALL INTESTINE
  • LARGE INTESTINE
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3
Q

BELOW DIAPHRAGM, ACCESSORY ORGANS of GI Tract

A
  • LIVER
  • GALLBLADDER
  • PANCREAS
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4
Q

the STOMACH (J-shaped) is HIGHLY..

A

DISTENSIBLE (can EXPAND)

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5
Q

what are the 4 REGIONS of the STOMACH

A
  • CARDIA (surrounds opening of oesophagus)
  • FUNDUS (superior)
  • BODY
  • PYLORUS (last)
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6
Q

name the 2 SPHINCTERS of the STOMACH

A
  1. LOWER OESOPHAGEAL SPHINCTER
    (physiological - prevents backflow)
  2. PYLORIC SPHINCTER
    (Anatomical - muscle contracted to keep closed)
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7
Q

what are the 3 LAYERS of SMOOTH MUSCLE in the STOMACH

A

LONGITUDINAL
CIRCULAR
OBLIQUE

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8
Q

what do the SMOOTH MUSCLE of the STOMACH allow for

A

powerful CHURNING
- MECHANICAL DIGESTION

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9
Q

what are the names of the FOLDS in the MUCOSA of the stomach that LINE in

A

RUGAE

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10
Q

what do the RUGAE of the STOMACH allow for

A

INCREASE SURFACE
& allow for STOMACH EXPANSION

(flatten when stomach fills)

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11
Q

STOMACH releases CHYME (semi-fluid of partially digested food) into the..

A

DUODENUM (1st part small intestine)

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12
Q

STOMACH RELEASE of CHYME INTO DUODEUM is controlled / occurs via the..

A

PYLORIC SPHINCTER

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13
Q

1ST PART of DUODEUM is at which level

A

L1

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14
Q

SMALL INTESTINE is a MUSCULAR TUBE which 3 PARTS:

A
  1. DUODENUM
  2. JEJUNUM
  3. ILEUM
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15
Q

what is in the WALL of the SMALL INTESTINE and what is this for

A

MUSCLE LAYERS

  • MIX and MOVE FOOD
    (mechanical digestion)
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16
Q

what is in the MUCOSA of the SMALL INTESTINE and what is this for

A

CIRCULAR FOLDS
- INCREASE SURFACE AREA (have VILLI and MICROVILLI on surface)

& slow chyme down

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17
Q

purpose of CONCENTRIC/CIRCULAR FOLDS in the MUCOSA of the SMALL INTESTINE

A

INCREASE SURFACE AREA

(VILLI & MICROVILLI)

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18
Q

UNIQUE Feature about the DUODENUM and why is this

A

IMMOBILE
- as it RECEIVES INPUT from the ACCESSORY ORGANS

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19
Q

in which QUADRANT is JEJUNUM

A

LEFT UPPER

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20
Q

in which QUADRANT is ILEUM

A

RIGHT LOWER

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21
Q

subtle vascular and internal DIFFERENCES between JEJUNUM and ILEUM

A

Jejunum : MORE VASCULAR (‘church wall’ shapes)
LARGER,
WIDER Lumen diameter
THICKER MUSCULAR WALL

MORE CIRCULAR FOLDS

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22
Q

how do the CIRCULAR FOLDS change from JEJUNUM to ILEUM

A

become gradually LESS PROMINENT

  • MORE in JEJUNUM (therefore MORE ABSORPTION)
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23
Q

LARGE INTESTINE / COLON is from the … to the …

A

from ILIOCAECAL JUNCTION
to
RECTUM

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24
Q

parts of LARGE INTESTINE

A
  1. CAECUM & APPENDIX
  2. ASCENDING COLON

~ HEPATIC FLEXURE

  1. TRANSVERSE COLON

~ SPLENIC FLEXURE

  1. DESCENDING COLON
  2. SIGMOID COLON (S shape)
  3. RECTUM
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25
Q

name of the LARGE POUCHES on LARGE INTESTINE

A

HAUSTRA

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26
Q

name of the THIN BAND of MUSCLE found on LARGE INTESTINE

A

TAENIA COLI

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27
Q

what other UNIQUE FEATURE can be found on LARGE INTESTINES

A

FATTY TAGS

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28
Q

PRIMARY FUNCTION of the LARGE INTESTINES

A

WATER REABSORPTION

-> to Create and Excrete FAECES

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29
Q

what is the PERITONEUM

A

THIN, SEROUS MEMBRANE that lines the ABDOMINOPELVIC CAVITY and COVERS its VISCERA

(like pleura / pericardium)

30
Q

2 things PERITONEUM does

A
  • produces SEROUS FLUID to LUBRICATE MOBILE ORGANS
  • offers a SAFE PASSAGEWAY for NERVES / BLOOD / LYMPH (run in small gaps between the peritoneum, prevent twisting etc)
31
Q

2 LAYERS of PERITONEUM

A
  • PARIETAL : on WALLS
  • VISCERAL: on ORGANS

both are 1 CONTINUOUS STRUCTURE
(single layers)

32
Q

where are RETROPERITONEAL Organs

A

BEHIND (POSTERIOR) PERITONEUM

  • only their ANTERIOR SURFACE is COVERED by
    peritoneum

FIXED to POSTERIOR ABDOMINAL WALL (IMMOBILE)

(in retroperitoneal space)

33
Q

why are VISCERA in RETROPERITONEAL SPACE IMMOBILE

A

they are FIXED to POSTERIOR ABDOMINAL WALL

(and anteriorly held in place by peritoneum)

34
Q

examples of RETROPERITONEAL Structures

A

GI Tract:
OESOPHAGUS, DUODENUM, PANCREAS, ASCENDING COLON, DESCENDING COLON, RECTUM

other:
AORTA, IVC, KIDNEYS & SUPRARENAL GLANDS, URETERS

35
Q

how are INTRAPERITONEAL structures

A

SURROUNDED BY PERITONEUM (covering all sides)

  • MOBILE, FREE-FLOWING structures

SUSPENDED by a MESENTERY
eg Stomach, Jejunum, Ileum

36
Q

INTRAPERITONEAL Structures are SUSPENDED BY a..

A

MESENTERY - DOUBLE LAYER OF PERITONEUM, 2 PARALLEL LAYERS

Between Organ and Wall

where single visceral and parietal peritoneum come together

37
Q

MESENTERY is … LAYERED

A

DOUBLE

2 PARALLEL layers of PERITONEUM

Visceral (single)
Parietal (single)

38
Q

where is ‘THE MESENTERY’

A

in the SMALL INTESTINE (JEJUNUM, ILEUM)

  • Biggest, most extensive mesentery
39
Q

Name of the MESENTERY of the TRANSVERSE COLON

A

TRANSVERSE MESOCOLON

40
Q

Name of the MESENTERY of the SIGMOIDAL COLON

A

SIGMOID MESOCOLON

41
Q

Each MESENTERY has an ATTACHMENT to the ABDOMINAL WALL
CALLED A..

A

ROOT

eg. ROOT of THE MESENTERY,
ROOT OF THE TRANSVERSE MESOCOLON

42
Q

what is a ROOT of a MESENTERY

A

where it ATTACHES to the ABDOMINAL WALL

43
Q

EMBRYOLOGICALLY, what is the GI TRACT / whole GI System DERIVED FROM

A

single GUT TUBE
(primitive structure only in embryo)

  • becomes Hollow GI Tract
  • ACCESSORY ORGANS develop as BUDS (DIVERTICULAE) which STEM FROM THE TUBE
44
Q

EMBRYOLOGICALLY, how do the ACCESSORY ORGANS form

A

as DIVERTICULAE / BUDS from the MAIN GUT TUBE

Pancreas from 2 diverticulae which later fuse,
liver and gallbladder from single diverticulae

45
Q

GUT TUBE has 3 PARTS:

A

FOREGUT,
MIDGUT,
HINDGUT

46
Q

what is DERIVED from the FOREGUT (GUT TUBE)

A
  • LOWER OESOPHAGUS
  • STOMACH
  • 1st and 2nd parts DUODENUM
  • LIVER
  • GALLBLADDER
  • PANCREAS
47
Q

what is DERIVED from the MIDGUT (GUT TUBE)

A
  • rest of SMALL INTESTINE:
    3rd and 4th parts DUODENUM, JUJENUM, ILEUM
  • CAECUM (& APPENDIX)
  • ASCENDING COLON
  • 3/4 TRANSVERSE COLON
48
Q

what is DERIVED from the HINDGUT (GUT TUBE)

A
  • last 1/4 TRANSVERSE COLON
  • DESCENDING COLON
  • SIGMOIDAL COLON
  • RECTUM
49
Q

At WEEK 5, what form from the DUODENUM

A

DIVERTICULA BUD

  • develop into ACCESSORY ORGANS and their DUCTS:
    hence LIVER, GALLBLADDER, PANCREAS empty INTO DUODENUM (papilla)
50
Q

why do LIVER, GALLBLADDER and PANCREAS drain into the DUODENUM

A

they FORM FROM THE DUODENUM - DIVERTICULA BUD

at week 5

51
Q

how do the LIVER and STOMACH MOVE after FORMATION (embryology)

A

LIVER moves LEFT

STOMACH ROTATES towards liver and moves RIGHT

52
Q

describe DEVELOPMENT of MIDGUT in EMBRYO

A
  • Massive INCREASE in LENGTH
  • begins to FOLD
  • HERNIATES OUT OF BODY THROUGH UMBILICUS
  • 270 DEGREE ANTI-CLOCKWISE ROTATION around SMA axis
  • HERNIATED BOWEL RETURNS to abdomen, more GROWTH and REPOSITIONED into adult position
53
Q

Embryology: what DEVELOPS SIMULTANEOUSLY to the MIDGUT

A

HINDGUT

54
Q

Embryology: MIDGUT HERNIATES out of the body via the..

A

UMBILICUS

55
Q

Embryology: MIDGUT undergoes a series of ROTATIONS.
what is the TOTAL ROTATION degree and direction?

A

270 DEGREES ANTI-CLOCKWISE

56
Q

Embryology: MIDGUT ROTATES 270 DEGREES ANTI-CLOCKWISE around the AXIS of the..

A

SMA (SUPERIOR MESENTERIC ARTERY)

(therefore blood supply)

57
Q

Embryology: the 3RD and 4TH parts of the DUODENUM are DERIVED from which part of the EMBRYONIC GUT TUBE?

A

MIDGUT

58
Q

Embryology: how much of the TRANSVERSE COLON is DERIVED from the HINDGUT

A

last 1/4TH

(first 3/4 Midgut)

59
Q

Embryology: LIVER, GALLBLADDER, PANCREAS are DERIVED from which part of embryonic GUT TUBE

A

FOREGUT

60
Q

the ANAL CANAL is BETWEEN the.. and ..

A

PELVIC FLOOR and ANUS (opening)

(in anal triangle)

61
Q

ANORECTAL JUNCTION is at the..

A

PELVIC FLOOR

(Anal canal is NARROWER than Rectum)

62
Q

how is CONTROL of the INTERNAL ANAL SPHINCTER

A

AUTONOMIC - INVOLUNTARY/unconscious
(SMOOTH MUSCLE)

S2,S3,S4

63
Q

which SPINAL NERVES CONTROL INTERNAL ANAL SPHINCTER

A

S2,S3,S4

  • Autonomic
64
Q

How is CONTROL of the EXTERNAL ANAL SPHINCTER

A

SOMATIC - VOLUNTARY/conscious
(Skeletal muscle)

S2,S3,S4 - PUDENDAL NERVE

65
Q

INNVERVATION to EXTERNAL ANAL SPHINCTER (skeletal muscles) by..

A

S2,S3,S4
- PUDENDAL NERVE

66
Q

PECTINATE LINE on the ANAL CANAL does what

A

DIVIDES the UPPER and LOWER portions

67
Q

what are the ANAL COLUMNS in ANAL CANAL

A

VERTICAL FOLDS in the Mucosa

ANAL SINUSES between (gaps between folds)

68
Q

what are BETWEEN the ANAL COLUMNS (Vertical Folds) in the ANAL CANAL

A

ANAL SINUSES

69
Q

what are the ANAL VALVES in the ANAL CANCAL

A

HORIZONTAL FOLDS in the Mucosa

  • HOLD FLUID in the GI Tract and prevent it seeping out of the body
70
Q

what does the WHITE LINE mark in the ANAL CANAL

A

the TRANSITION from KERATINIZED TO NON-KERATINIZED EPITHELIA

71
Q

what feature DIVIDES the ANAL CANAL into UPPER and LOWER portions

A

PECTINATE LINE

72
Q

WHITE LINE in ANAL CANAL marks the TRANSITION between what type of EPITHELIUM

A

KERATINIZED –> NON-KERATINIZED