Gastro Intestinal System

Front 1

4 layers in alimentary system

Back 1

Mucosa (made up of epithelial, lamina propria and muscularis mucosae), submucosa, muscularis external, serosa/adventitia

Front 2

What structures does squamous stratified epithelium line?

Back 2

Mouth, oesophagus, anal canal

Front 3

What structures does simple columnar epithelium line?

Back 3

Stomach, small and large intestines

Front 4

Inner circular layer of muscularis external does what?

Back 4

Constricts lumen

Front 5

Outer longitudinal layer of muscularis externa does what?

Back 5

Shortens tube

Front 6

What does the vagus nerve do for the alimentary canal?

Back 6

Parasympathetic stimulation increasing secretion and motility

Front 7

What does the splanchnic nerve do for the alimentary system?

Back 7

Sympathetic stimulation inhibiting secretion and motility.

Front 8

Peristaltic waves in the stomach direct food from which parts of the stomach?

Back 8

Body to the antrum. Body has thin muscle which means there is a weak contraction so doesn't mix food. ANtrum has thick muscle leading to a more powerful contraction which is able to mix food

Front 9

What produces gastric peristalsis?

Back 9

Rhythm produced by pacemaker cells in the longitudinal muscle layer.

Slow waves are a product of spontaneous depolarisation. It is the basic electrical rhythm conducted which is coducted through gap junctions.

Front 10

What neutralises acid in duodenum?

Back 10

HCO3 from Brunner's cells.

Controlled by vagal ad ENS reflexes.

Secretin also increases HCO3 secretion from pancreas and liver.

Neutralisation of acid inhibits secretin release which is a negative feedback mechanism

Front 11

Describe exocrine part of pancreas

Back 11

Acini go to ducts go to pancreatic ducts.

Secrete bicarbonate in duct cells and digestive enzymes in acinar cells

Front 12

What is a zymogen?

Back 12

Digestive enzymes which are stored in an inactive form. Prevents auto digestion of pancreas.

Usually require an enzyme to convert zymogen to respective enzyme

Front 13

What is bicarbonate secretion stimulated by?

Back 13

Secretin

Front 14

What is secretin release stimulated by?

Back 14

Acid in duodenum

Front 15

Zymogen release is stimulated by?

Back 15

Cholecystokinin

Front 16

CCK is release in response to what?

Back 16

Fat/ amino acids in duodenum.

Front 17

Name the 2 major lobes of the liver.

Back 17

Right and left

Front 18

Name the 2 minor lobes of the liver

Back 18

Caudate and quadrate

Front 19

Where do vessels, lymphatic vessel and nerves enter or exit the liver?

Back 19

The porta which is located on the inferior surface.

Front 20

What covers the liver?

Back 20

Connective tissue and visceral peritoneum (except from bare area which is surrounded by coronary ligament)

Front 21

What are hepatic cords?

Back 21

Radiate out from central veins like spokes on a wheel. They are made up of hepatocytes which are the functional cells of the liver

Front 22

What are bile canaliculus?

Back 22

Lie between cells within each cord

Front 23

What is the space between cords called?

Back 23

hepatic sinusoids (blood channels)

Front 24

Describe the function of the liver.

Back 24

Produces and secretes bile

Front 25

What is bile made up of?

Back 25

Bile acids, lecithin, cholesterol (all synthesised in liver) bile pigments (taken from bilirubin from haemoglobin), toxic metals and bicarbonate. All of them except from bicarbonate are secreted by hepatocytes which is secreted by duct cells

Front 26

What are bile pigments?

Back 26

Breakdown products of haemoglobin from dead eryhtrocytes

Bilirubin is extracted from th eblood stream by hepatocytes and secreted into bile (giving it a yellow colour)

Bilirubin modified by bacterial enzymes goes brown

reabsorbed bilirubin excreted in urine is yellow

Front 27

What are bile acids?

Back 27

They are synthesised in liver from cholesterol.

Before they are secreted they conjugate with glycine to increase solubility

Front 28

What is the structure of the gallbladder?

Back 28

Has 3 layers, mucosa (folded into rugae), muscularis (smooth) and serosa (connective tissue)

Front 29

How is the secretion of bile controlled?

Back 29

Sphincter of Oddi controls release of bile and pancreatic juice into duodenum.

Front 30

How does stuff enter the large intestine from the small intestine?

Back 30

Through the ileum and through the ileocaecal valve and into the caecum.

Front 31

How many parts are there in the large intestine?

Back 31

Ascending transvers descending and sigmoid.

Front 32

Describe the muscularis externis in the Large intestine.

Back 32

Circular muscle layer is complete but the longitudinal muscle is incomplete

Front 33

What is the name of the 3 bands that span the entire length of the colon?

Back 33

Teniae coli. Contractions of which give puckered appearance.

Front 34

What is the mucosa of the large intestine made up of?

Back 34

Simple columnar epithelium which is flat.

Front 35

What is the purpose of goblet cells in the large intestine?

Back 35

Lubrication for the movement of faeces.

Front 36

What is the mucosa of the rectum made up of?

Back 36

Simple columnar epithelium.

Front 37

Muscularis externa is thick or thinner compared to other regions of the alimentary canal?

Back 37

THick

Front 38

What is the epithelium of the anal canal?

Back 38

Starts off simple columnar before turning into stratified squamous.