Physiology

Question 1

What is the function of the mouth and saliva?

Answer 1

Foodstuffs broken down by chewing (mastication) and saliva is added as lubricant

Question 2

What is the function of the oesophagus?

Answer 2

Conduit between the mouth and the stomach

Question 3

What is the function of the pancreas?

Answer 3

Digestion enzymes for digestion of lipids.

Helps with the absorption of fats, carbohydrates and proteins

Question 4

What is the function of the liver?

Answer 4

Secretes bile salts to aid the absorption of fats in the ileum

Question 5

What is the function of the gallbladder?

Answer 5

Stores and concentrates bile

Question 6

What is the function of the small intestine?

Answer 6

Final stage of chemical digestion and nutrient absorption

Question 7

What is the function of the stomach?

Answer 7

Digestion of proteins; foodstuffs reduced to liquid.

Also plays a role in storage and sterilisation

Question 8

What is the function of the large intestine?

Answer 8

Water absorption, bacterial fermentation and formation of faeces

Question 9

Describe the length, diameter and organisation of the GI tract

Answer 9

Approx. 8m long, varying diameter and organisation of cells vary depending on function

Question 10

Describe the difference in the microscopic composition of the GI tract

Answer 10

Mouth, anal canal and oesophagus - Stratified Squamous epithelium

Stomach and intestines - simple columnar epithelium

Question 11

What are the four layers common to the GI tract?

Answer 11

• Mucosa
• Submucosa
• Muscularis externa
• Serosa/Adventitia

Question 12

What structures comprise the mucosa?

Answer 12

Epithelium, lamina propria, muscularis mucosa

Question 13

What is the function of the mucosa?

Answer 13

• Synthesis and secretion of enzymes

- Absorbs products of digestion

Question 14

What is the lamina propria?

Answer 14

Loose connective tissue containing glands and blood/lymph vessels

Question 15

What is the muscularis externa?

Answer 15

A thin layer of muscle

Question 16

What is the structure of the submucosa?

Answer 16

Thick, irregular connective tissue

Question 17

What is the function of the submucosa?

Answer 17

Supports the mucosa

Question 18

What structures permeate the submucosa?

Answer 18

Neurones, blood vessels (to the mucosa, adventitia and muscularis externa)

Question 19

What is the network of neurones in the mucosa known as?

Answer 19

Meissner’s plexus (parasympathetic)

Question 20

Where are submucosal glands located?

Answer 20

Oesophagus and duodenum

Question 21

What is the structure of the muscularis externa?

Answer 21

Two layered ring of muscle

Question 22

What are the function s of the two layers of muscle in the muscularis externa?

Answer 22

Inner - circular - contraction of lumen

Outer - longitudinal - constriction of tube length

Allows peristalsis and segmentation

Question 23

What is peristalsis?

Answer 23

Rhythmic longitudinal contractions of the lumen of the GI tract to promote transit of bolus

Question 24

What is segmentation?

Answer 24

Contraction of the circular (inner) muscles of the gut tube - slowing down the transit of chyme through the system.

Question 25

What neural system lies between the layers of the muscularis externa?

Answer 25

Auerbach's Myenteric Plexus

Question 26

What is the enteric nervous system comprised of?

Answer 26

Submucosal (Meissner's) and Myenteric (Auerbach's) plexi

Question 27

What is the function of the enteric nervous system?

Answer 27

Independent control of the GI tract

Question 28

What is the difference between the adventitia and the serosa?

Answer 28

Both are outer layers of connective tissue for the alimentary canal Location is the difference: Serosa = inside the peritoneal cavity Adventitia = outside the peritoneal cavity

Question 29

What division of the autonomic nervous system governs long reflexes in the alimentary canal?

Answer 29

Parasympathetic

Question 30

What division of the autonomic nervous system governs short reflexes in the alimentary canal?

Answer 30

Sympathetic

Question 31

What nerve delivers parasympathetic innervation?

Answer 31

Vagus nerve (CN X) except for salivation (Facial CN VII and glossopharyngeal IX)

Question 32

What is the effect of the parasympathetic system in the GI tract?

Answer 32

Increases gut motility and secretion

Question 33

What is the effect of the sympathetic system on the GI tract?

Answer 33

Decreases gut motility and secretion

Question 34

What nerve delivers sympathetic innervation to the GI tract?

Answer 34

Splanchnic

Question 35

What three branches of the descending aorta supply the GI tract?

Answer 35

Celiac trunk, superior and inferior mesenteric arteries

Question 36

What organs does the coeliac trunk supply?

Answer 36

Stomach, small intestine, pancreas and liver

Question 37

What organs does the superior mesenteric artery supply?

Answer 37

Small intestine, caecum, ascending colon and transverse colon

Question 38

What organs do the inferior mesenteric artery supply?

Answer 38

Descending colon, sigmoid colon and rectum

Question 39

What vein(s) drain from the stomach?

Answer 39

Gastric

Question 40

What vein(s) drain from the pancreas?

Answer 40

Splenic vein

Question 41

What organs rain into the superior mesenteric vein?

Answer 41

Small intestine, caecum, ascending and transverse colon

Question 42

What organs drain into the inferior mesenteric vein?

Answer 42

Descending colon, sigmoid colon and rectum

Question 43

Where do the gastric, splenic and mesenteric veins drain into?

Answer 43

Hepatic portal vein

Question 44

Outline the route to the inferior vena cava from the hepatic portal vein

Answer 44

Hepatic portal vein (through the liver) to the hepatic vein and into he inferior vena cava

Question 45

What is the purpose of the hepatic portal system?

Answer 45

To clean blood in the liver before deoxygenation in the CVS