GI HARC 2

Question 1

Primitive gut tube has __ parts which develop into GI tract & organs

Answer 1

3

Question 2

What are the 3 parts of which delove into GI tract and organs

Answer 2

Foregut

Midgut

Hindgut

Question 3

• Foregut develops into:

Answer 3

• Oesophagus to 2nd part of duodenum
• Accessory organs – liver, gallbladder, pancreas

Question 4

• Midgut develops into:

Answer 4

• 2 nd part duodenum to ¾ transverse colo

Question 5

• Hindgut develops into:

Answer 5

• ¾ transverse colon to superior rectum

Question 6

Name the colours

Answer 6

Orange: Foregut

Purple: Midgut

Green: Hindgut

Question 7

What does the Lower GI tract consist of?

Answer 7

• Jejunum to anus

Question 8

Function of the small intestine

Answer 8

• Mechanical and chemical digestion
• Absorption of 90% of nutrients

Question 9

Function of large intestine

Answer 9

• Reabsorption of water & electrolytes
• Convert indigestible food into faeces – store & expel

Question 10

Histology of Small Intestine

What are the key microanatomical features of mucosa:

Answer 10

• Circular folds
• Villi & Microvilli
• Intestinal glands

Question 11

Properties of circular folds

Answer 11

• Increase surface area and slow chyme flow

Question 12

Properties of Villi and Microvilli

Answer 12

• Maximise surface area of intestinal wall
• Most abundant in proximal 2/3 of S.I. – most absorption

Question 13

Properties of Intestinal glands

Answer 13

• Enterocytes, Goblet cells, Paneth cells, etc. and multipotent stem cells to replace eroded epithelia
• Produce intestinal juices rich in digestive enzymes and hormones

Question 14

Small Intestine

Answer 14

Question 15

Small intestine

Answer 15

Question 16

Histology of Small Intestine

Answer 16

Micrograph of circular folds

Micrograph of villi

Electron micrograph of microvilli

Question 17

Histology of Large Intestine

What are the key microanatomical features:

Answer 17

• No circular folds or villi (except anal canal)
• Intestinal glands (many more, deeper crypts)
• Enterocytes – absorptive cells with a microvilli border
• Goblet cells – secrete mucous to facilitate faecal movement

Question 18

Large Intestine

Answer 18

Question 19

Histology of Large Intestine

What is this?

Answer 19

Section through wall of colon

Question 20

Name a congential anomalies

Answer 20

Hirschsprung’s Disease.

Meckel’s diverticulum

Omphalocele- Abdominal Wall Defects

Gastroschisis-Abdominal Wall Defects

Question 21

What is Hirschsprung’s Disease?

Answer 21

This disorder is characterized by the absence of particular nerve cells (ganglions) in a segment of the bowel in an infant. The absence of ganglion cells causes the muscles in the bowels to lose their ability to move stool through the intestine (peristalsis).

Question 22

• Enteric nervous system has ______ and ________ plexuses

Answer 22

myenteric

submucosal

Question 23

What does aganglionosis mean

Answer 23

The state of being without ganglia; for example, absence of ganglion cells from the myenteric plexus as a characteristic of congenital megacolon.

Question 24

What does Hirschsprung’s Disease involve?

Answer 24

• HD involves agangliosis of both plexuses in distal colon & rectum

SO the absent/damage to the ganglia here means that the nerves are not funcitonal = muscle atrophy/wastage

• Functional obstruction develops from spasms in denervated colon
• Becomes apparent as severe constipation within first 2 months

Question 25

How to identify Hirschsprung’s Disease?

Answer 25

• Biopsy to identify ‘transition zone’ between absent and present ganglionic cells. Surgery to remove affected segment

Question 26

What is Meckel’s diverticulum?

Answer 26

A Meckel's diverticulum, a true congenital diverticulum, is a slight bulge in the small intestine present at birth and a vestigial remnant of the omphalomesenteric duct (also called the vitelline duct or yolk stalk). the vitellointestinal duct should seperate over time during development but sometimes the connection does perisist =.

Question 27

What is vitellointestinal duct

Answer 27

(embryonic connection between yolk sac and midgut lumen)

Question 28

In Meckel’s diverticulum can cause gastric mucosa which may cause bleeding from ‘gastric’ ulceration in its mucous membrane What can this be mistaken for?

Answer 28

appendicitis

Question 29

Meckles's Diverticulum usually comes in Rule of 2s? What does this mean?

Answer 29

Rule of 2s: * 2% of population * Presents in first 2 years * 2 inches in length * Approx. 2ft from ileocaecal valve

Question 30

What is Omphalocele?

Answer 30

• Large herniation of intestines (and sometimes liver & other organs) out of umbilicus at birth (so more than usually comes out of umbilicus) This leads to: * Failure to return to abdomen after natural protrusion during development * May be related to embryonic folding defect IMPORTANT: herniation is covered by the peritoneal membrane and amnion

Question 31

What is Gastroshcisis?

Answer 31

* Herniation of bowel loops (sometimes also stomach & liver) through para-umbilical defect in abdominal wall * No surrounding membrane * Cause unknown but genetic & environmental factors linked * Possibly by compromise in vasculature to abdominal wall surgery to repair IMPORTANT: not covered by membrane

Question 32

Out of Gastroschisis and Omphalocele which one is covered by y peritoneal membrane and amnion

Answer 32

Omphalocele

Question 33

What does Antenatal US show on Gastroschisis and Omphalocele?

Answer 33

Omphalocele- Antenatal US shows herniated loops (but not free-flowing because contained within peritoneum) Gastroschisis- Antenatal US can show herniation to right of umbilicus, freefloating and small fetal abdominal circumference

Question 34

What imaging do we use to asses the GI tract?

Answer 34

X-ray Ultrasound Fluoroscopy Cross section imaging (computed tomography) CT MR- MAgnetic resonance imaging (MR)

Question 35

How do we use X ray in the GI tract?

Answer 35

Predominanty to look for perforation or bowel perfiration and to look at bowel patterns - abnormal/free gas - Bowel gas pattern (obstruction) - normal bowel gas,abnormal location - calcificaiton - tubes/lines/Fbs

Question 36

What do the two starts indicate?

Answer 36

Subdiaphragmatic free gas

Question 37

What are these X-rays showing?

Answer 37

Abdominal free gas

Question 38

What is this Xray showing?

Answer 38

Gas in the bowel wall- pneumotosis

Question 39

What is this Xray showing

Answer 39

Bowel gas pattern

Question 40

What does this Xray show?

Answer 40

Normal bowel gas, abnormal place so this is a diaphragmatic hernia

Question 41

What can you see in this X-Ray

Answer 41

Calcification

Question 42

Why would you do an ultrasound in the GI tract?

Answer 42

- Solid organs - Fluid filled structures - Free fluid/ collections - Masses Abnormal bowel

Question 43

What does this ultrasounds show

Answer 43

Question 44

What does this ultrasound show in children?

Answer 44

Question 45

What does this ultrasound show?

Answer 45

Crohn’s terminal ileitis

Question 46

What is a fluoroscopy?

Answer 46

Real time live xray where you use a dye that shows up on xray to fill a hallow structure.

Question 47

Why would you use a fluroscopy for GI

Answer 47

- Bowel lumen - Transit/peristalsis - Abnormal communications

Question 48

What does this fluroscopy show?

Answer 48

Malrotation

Question 49

What do these show

Answer 49

Hirschprung's disease

Question 50

Why do we do CT scans for GI

Answer 50

Free gas Free fluid/ collections Acute haemorrhage Soft tissues Vasculature Calcifications

Question 51

What is wrong is this CT?

Answer 51

Free gas

Question 52

Why would you do MR in GI

Answer 52

Soft tissues Free fluid/collections Vasculature

Question 53

Why do we need to know the circulation of peritoneal fluid, the spaces and how they communicate

Answer 53

Because it helps us understand the spread of tumour and infection also can localise pathology by identifying the space continuing abnormal fluid/gas/tissue also can predict disease behaviour

Question 54

How many sacs do the peritoneum have?

Answer 54

2 greater and lesser

Question 55

Falciform ligament attaches liver to \_\_\_\_\_\_\_\_\_

Answer 55

abdominal wall

Question 56

Answer 56

Question 57

Right Subhepatic space is bounded superiorly by the ____ \_\_\_\_\_ ___ of the l\_\_\_\_. Continues with right ______ space and right ___ space as well

Answer 57

bounded supreriorly by the **inferior right lobe** of the **liver**. Continues with right **subphrenic** space and right **colic** space as well

Question 58

Left Subhepatic space located between left lobe of _____ anteriorly and the ______ posteriorly.

Answer 58

located between left lobe of **liver** anteriorly and the **stomach** posteriorly.

Question 59

The top and bottom portion so the peritoneal cavity communicates through the ______ \_\_\_\_\_\_\_

Answer 59

The top and bottom portion so the peritoneal cavity communicates through the **paracolic spaces.**

Question 60

Between bladder and uterus we have\_\_\_\_\_\_

Answer 60

vesicouterine pouch

Question 61

Between Rectum and uterus-

Answer 61

rectouterine pouch

Question 62

Where is the lesser sac located?

Answer 62

lies anterior to pancreas and posterior to the stomach.