GI Flashcards

1
Q

Whats the functions of the digestive system?

A

Digestion
Secretion
Absorption
Motility

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

What comprises the Alimentary system?

A
  1. Mouth
  2. Sublingual salivary gland
  3. Submandibular salivary gland
  4. Parotid salivary gland
  5. Pharynx
  6. Trachea
  7. Oesophagus
  8. Stomach
  9. Liver
  10. Pancreas
  11. Gallbladder
  12. Small intestine
  13. Colon
  14. Large intestine (Colon, Cecum, Rectum )
  15. Anus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Whats the function of

the mouth, oesophagus, stomach, pancreas, liver, gallbladder, small intestine, large intestine?

A

Mouth: Breaks down and lubricates food with teeth and saliva

Oesophagus: Conduit between mouth and stomach

Stomach: Digestion of proteins: foodstuffs reduced to liquid form; storage; sterilization

Pancreas: Digestive enzymes for digestion of fats, carbohydrates and proteins.

Liver: Bile salts for digestion/absorption of fats in small intestine

Gallbladder: Stores and concentrates bile

Small intestine: Final stages of chemical digestion and nutrient absorption

Large intestine: Water absorption, bacterial fermentation and formation of faeces

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

Describe the general structure of the alimentary canal?

A

Continious hollow tube with varying diameter

Oesophagues to rectum is around 8 meteres long#

Tube wall has same structural organisation throughout length

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

Whats the four distinctive layers (tunics)?

A

Mucosa: epithelium , lamina propria, muscularis mucosae

  • Submucosa
  • Muscularis externa
  • Serosa/adventitia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

List the 4 tunics in order deep to superficial.

A

Mucosa;

  • Mucosa epithelium
  • Lamina propria
  • Muscularis mucosae

Submucosa

Muscularis;

  • Circular muscle layer
  • Longitudinal muscle layer

Serosa;

  • Connective tissue layer
  • Peritoneum
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Explain the Mucosas function and role?

A

Epithelium

  • Mouth, oesophagus, anal canal = stratified squamous
  • Barrier separating lumen of alimentary canal from body
  • Synthesis and secretion of digestive enzymes, hormones, mucus
  • Absorbs products of digestion
  • Epithelium differs along length of gut tube to adaptation for function.

Lamina propria
- Loose connective tissue ( glands, blood/lymph vessels)

Muscularis mucosae
- Thin smooth muscle layer

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

Describe Submucosa?

A
  • Thick, irregular connective tissue -> Supports mucosa
  • Contains neurones, blood vessels (-> mucosa, muscularis externa, serosa), lymphatic vessels
  • Neurones form extensive network -> submucosal ( Meissner’s) plexus ( parasympathetic)
  • Submucosal glands in oesophagus and duodenum
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe Serosa/Adventitia?

A
  • Connective tissue outer layer of alimentary canal

Outside peritoneal cavity:
- Adventitia attaches oesophagus and rectum to surrounding structures

Inside peritoneal cavity:
- Serosa surrounds stomach, small intestine and large intestine

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

Describe Muscularis Externa?

A
  • Two concentric thick layers of smooth muscle
    Inner layer= circular muscle (constricts lumen)
    Outer layer= longitudinal muscle (shortens tube)
  • Produce motility -> peristalsis, segmentation
  • Myenteric ( Auerbach’s) plexus between circular and longitudinal muscle
  • Subcostal + myenteric plexuses = enteric nervous system (ENS) => Independent control of gut function
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Nervous control of alimentary function

A

Autonomic control:
Long (parasympathettic) and short (ENS) reflexes

Parasympathetic => vagus nerve (X)
(except salivation => facial (VII) and glossopharyngeal (IX))

Stimulatory
Increases secretion
Increases motility

Sympathetic => Splanchnic nerve
Inhibitory (except salivation)
Decreases secretion
Decreases motility

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

Arterial supply to GI tract

A

Descending (abdominal) aorta ;

  • Celiac trunk: Stomach, Small intestine, Pancreas, Liver.
  • Superior mesenteric artery: Small intestine, Caecum, Ascending colon, Transverse colon.
  • Inferior mesenteric artery: Decending colon, Sigmoid colon, Rectum.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Arterial supply to GI tract;

Name the arteries

A

Splenic- spleen
Celiac trunk- Foregut
Superior mesenteric- midgut
Inferior mesenteric- hindgut

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

Venous drainage from GI tract

A

4 stages

Stomach drains to Gastric veins

Pancreas drains to splenic vein

Small intestine, Caecum, Ascending colon and Transverse colon all drains to superior mesenteric vein.

Decending colon, sigmoid and Rectum all drains to Inferior mesenteric vein.

The Gastric vein, Splenic vein, Superior mesenteric vein and Inferior mesenteric vein all drains to Hepatic portal vein.

The hepatic portal vein drains to the Hepatic vein.

The Hepatic vein drains to the Inferior vena cava.

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

Describe the Hepatic Portal Circulation

A

Aorta travels to Digestive tract arteries and Hepatic artery. Which then goes to the Liver capillaries.

Digestive tract arteries travel through the capillaries of digestive tract: stomach, intestines, pancreas and spleen. Which goes to Hepatic portal vein then the Liver capillaries.

The Liver blood supply then goes from the capillaries of liver then to Hepatic vein which drains to Inferior vena cava.

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