Brainscape's Knowledge GenomeTM

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


See full index

GI > Control of GI > Flashcards

Control of GI Flashcards

1
Q

Describe sympathetic control of the GI tract

A

T5-L3
Short preganglionic fibres, post ganglionic fibres long
Form presynaptic sphlanchnic nerves, synapse with prevertebral ganglia - Coeliac, renal, superior and inferior mesenteric.
Release NA
Innervate blood vessels
Inhibits GI function

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

Describe parasympathetic control of the GI tract

A

Vagus - oesophagus to transverse colon
Pelvic splanchnic (s2-s4)
Release Ach, gastrin releasing peptide, vaso inhibitory peptide (cholinergic and peptidergic)

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

Describe enteric control of the GI tract

A

Innervates oesophagus to anus
Submucosal division - controls secretions and blood flow
Myenteric division - Between circular and longitudinal muscle, controls motility

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

Describe paracrine control of the GI tract

A

D cells in antrum of stomach and pancreas
Secrete somatostatin when stimulated by H+ in stomach lumen
Inhibits G cells and histamine release

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

What cells secrete histamine in the GI tract?

A

Enterochromafin

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

Describe neurocrine control of the GI tract

A

Gastrin releasing peptide, increases release of gastrin from g cells

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

Describe the gastrin family of hormones

A

Gastrin: G cells in antrum, increases gastric acid secretion
Cholecystokinin: I cells in duodenum and jejunum, stimulates pancreatic and contracts gallbladder to increase secretions, stimulated by fat and protein,

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

Describe the secretin family of hormones

A

Secretin: S cells in duodenum, increases HCO3 from pancreas and gallbladder, decreases gastric acid secretion. Stimulate by H+ and fatty acids
Gastric inhibitory peptide: release from duodenum and jejunum, increases insulin and decreases gastric acid secretion. Stimulated by sugar, protien and fatty acids

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

Where in the GI tract does not have smooth muscle?

A

Pharynx
Upper 1/3 oesophagus
External anal sphincter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is tonic contraction and where does it occur?

A

Constant level of contraction
Upper stomach
Ileocaecal valve
Internal anal sphincter

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

What is peristalsis?

A

Adjacent segments of the canal contract proximal to contents, relax distally to propel contents distally

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

What is segmentation?

A

Non-adjacent segments of canal relax and contract, moving food backwards and forwards, mixing it and mechanically breaking down.

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

What is mass movement?

A

A gastrocolic reflex that moves contents from distal colon into rectum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Describe the autonomic control of GI motility

A

Sympathetic- releases NA to reduce motility

Parasympathetic - releases Ach to increase motility

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

What is Hirschprung’s disease?

A

Lack of myenteric and submucosal plexuses, results in functional obstruction - newborns wont have 1st poo

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

What is achalasia?

A

Failure of lower oesophageal sphincter to relax, causing dysphagia

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

What is paralytic ileus?

A

Often following GI surgery, obstruction of intestine causing failure of forward movement of bowel contents

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

What are the cites of GI secretion?

A

Acini of salivary glands
Gastric glands in the stomach
Brunner’s glands in duodenum
Crypts of lieberkuln in the intestines
Acini of exocrine pancreas
Hepatocytes, secretions stored in gallbladder
Goblet cells (increasing numbers from duodenum to colon)

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

What is the function of stomach acid?

A

Innate barrier to infection
Prepares proteins for digestion
Activates enzymes

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

What is the function of HCO3 and where is it secreted?

A 
Neutralises acid
Saliva
Stomach 
Duodenum 
Pancreas
Liver (as bile)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the function of liver waste products?

A

Bile contains waste products
Cholesterol - used in cell membranes
Bilirubin - breakdown of RBCs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the function of emulsifiers?

A

Bile salts that increase the surface area of lipids, aiding digestion by lipases and allowing it to be transported as micelles in gut

23
Q

What is the function of mucus?

A

Protects against acid in stomach
Protects against bacteria in small intestine (antibacterial)
Provides food source for bacteria in large intestine while seperating them from epithelium
Lubricates

24
Q

How is a large surface area created in the gut?

A

Permanent folds - plica circulares
Villi
Microvilli

25
Q

How is water absorbed in the GI tract?

A

Passively - after a meal, water uptake driven by sodium co-transporters
In between meals, Na and Cl are absorbed, water follows
In colon - ENaC channels so water can be reabsorbed before excreted in stool

26
Q

Where does the gatrocolic ligament connect?

A

Stomach to transverse colon

27
Q

Where does the gastrosplenic ligament connect?

A

Stomach to spleen

28
Q

Where does the falciform ligament connect?

A

Liver to anterior abdominal wall

29
Q

Where does the triangular ligament connect?

A

Liver to diaphragm

30
Q

Define a portal system

A

Where blood from capillaries of one organ is transported to capillaries of another organ by a connecting vein

31
Q

What are the sphincters of the GI tract?

A 
Upper oesophageal 
Lower oesophageal 
Pyloric sphincter 
Sphincter of Oddi 
Ileo-caecal valve
Internal anal 
External anal - voluntary
32
Q

Describe the venous drainage of the GI tract

A

Foregut - portal vein
Midgut - Superior mesenteric vein
Hindgut - Inferior mesenteric vein
All eventually drain into portal vein

33
Q

Describe the development of the pancreas

A

Develops from the foregut
Dorsal portion forms the gland
Ventral portion forms the duct system

34
Q

What happens when the liver grows into the ventral mesentery?

A

Divides it into 2 parts:
Faliciform ligaments
Lesser omentum

35
Q

Describe the development of the midgut

A

Grows faster than the abdominal cavity so by week 6, with liver also growing rapidly there isn’t enough space in abdominal cavity so protrudes through abdominal wall into umbilical cord - physiological herniation
Herniated midgut forms a loop with superior mesenteric artery within umbilical cord, distal loop develops caecal bulge, proximal part becomes twisted
Midgut rotates while in the umbilical cord, undergoes 3X90 degree rotations then returns to the abdomen in week 10

36
Q

What causes umbilical hernias?

A

Abnormally large opening between abdominal cavity and umbilical cord that persists

37
Q

What is Meckel’s diverticulum?

A

Persistent yolk sac remaining in midgut, can contain ectopic gastric or pancreatic tissue

38
Q

Describe the dual origin of the anal canal

A

Hindgut forms superior portion of anal canal
Hindgut ends blindly at cloacal membrane, which separates it from the proctodaeum. When membrane ruptures, hindgut is connected to exterior

39
Q

What effect does the dual origin of the anal canal have?

A

Above the pectinate line only stretch detected

Below the pectinate line detects pain and temperature

40
Q

When does the development of the lumen occur and where does it occur?

A

Recanalisation occurs weeks 6-8
Oesophagus
Bile duct
Small intestine

41
Q

What are the consequences of failed recanalisation?

A

Most often in duodenum
Atresia (obliteration of lumen)
Stenosis (narrowing of lumen)

42
Q

What is pyloric stenosis and what are the consequences?

A

Not a recanalisation failure, hypertrophy of the circular muscle in the pyloric sphincter
Narrows the exit from stomach, causing projectile vomiting

43
Q

What is gastroschisis?

A

A failure of the abdominal wall to close following the folding of the embryo, causes gut tube and its derivatives to be outside the body

44
Q

What is an omphalocoele and how is it different to an umbilical hernia?

A

Persistence of a pathological herniation of midgut
Different to hernia as hernia has a covering of skin and sub cutaneous tissue, omphalocoele is an incomplete physiological herniation

45
Q

Describe the anal canal above the pectinate line

A

Supplied by the inferior mesenteric artery
S2-S4 pelvic parasympathetics
Columnar epithelium
Lymph drainage by internal iliac nodes

46
Q

Describe the anal canal below the pectinate line

A

Supplied by the pudendal artery
S2-S4 pudendal nerve
Stratified epithelium
Lymph drainage by superficial inguinal nodes

47
Q

Describe hindgut abnormalities

A

Imperforate anus, failure of anal membrane to rupture
Anal agenesis
Hindgut fistulae

48
Q

Which structures in midgut and hindgut retain mesenteries?

A 
Jejunum 
Ileum 
Appendix
Transverse colon
Sigmoid colon
49
Q

Which structures in the midgut and hindgut have fused mesenteries?

A

Duodenum
Ascending colon
Descending colon
Rectum

50
Q

What are the derivitives of the midgut?

A 
Small intestine, most of duodenum
Caecum 
Appendix 
Ascending colon 
Proximal 2/3 transverse  colon
51
Q

What types of malrotation can occur?

A

Incomplete rotation - midgut loop makes only 1X90 degree rotation, results in left sided colon
Reversed rotation - midgut loop makes a 90 degree rotation clockwise, transverse colon passes posterior to duodenum

52
Q

What are the risks of midgut defects?

A

Volvulus - loop of intestine twists around itself and its mesentery, creating a bowel obstruction that results in strangulation and ischaemia

53
Q

What can a persistent vitelline duct cause?

A 
Vitelline cyst (forms fibrous strands)
Vitelline fistula (direct link between umbilicus and intestinal tract) 
Meckel's diverticulum (persistent yolk sac remains in midgut)

GI (12 decks)

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