GI Tract and Motility

Question 1

Accessory structures of the GI tract?

Answer 1

Pancreas
Salivary Gland
Liver and Gall Bladder

Question 2

What muscle is mainly involved in the GI tract?

Answer 2

Smooth Muscle

Question 3

Describe digestion of Carbohydrates?

Answer 3

Polysaccharides (Eg: Starch and Glycogen) go to Monosaccharides (Glucose, Galactose, Fructose)
Mediated by Amylases

Question 4

Describe protein digestion?

Answer 4

Protein goes to amino acids, dipeptides and tripeptides

Mediated by proteases

Question 5

Describe fat digestion?

Answer 5

Fat goes to Monoglyceride and Free Fatty Acids

Mediated by Lipase

Question 6

What two liquids are the products of digestion transferred to?

Answer 6

Blood and Lymph
Protein and Carbohydrates go to blood
Fats go to lymph

Question 7

What are the four basic processes of digestion?

Answer 7

Motility
Secretion
Digestion
Absorption

Question 8

Describe the digestive tract wall?

How to remember this?

Answer 8

Mucosa:
Epithelial
Lamina Propria
Muscularis Mucosae
Submucosa
Muscularis Externa
Serosa

Mate: Every little person might make some meaty eaty sausages

Question 9

Mum, every little person might make some meaty eaty sasuage

Answer 9

Mucosa - Epithelium, lamina propria, musclaris mucosa
Submucosa
Muscularis Externia
Serosa

Question 10

What happens if circle muscle contracts?

Answer 10

Lumen becomes narrower and longer

Question 11

What happens in longitudinal muscle contracts?

Answer 11

Intestine becomes shorter and fatter

Question 12

What happens when the Muscularis Mucosa contacts?

Answer 12

Changes the absorptive and secretory area of the mucosa

Question 13

How does electrical signals pass through smooth muscle?

Answer 13

Through gap junctions. There is a functional synctium which allows hundreds of cells to depolarise and contract at the same time

Question 14

What drives slow wave activity?

Answer 14

Interstitial Cells of Cajal

Question 15

In smooth muscle slow wave, what mediates upstroke? What mediates downstroke?

Answer 15

Voltage activated Ca2+ channels

Voltage activated K+ channels

Question 16

What parts of the GI tract are skeletal muscle?

Answer 16

Mouth
Pharynx
Upper Oesophagus
External Anal Sphincter

Question 17

Name all the sphincters?

Answer 17

Upper Oesophageal Sphincter
Lower Oesophageal Sphincter
Pyloric Sphincter
Ileocaecal Sphincter
Internal Anal Sphincter
External Anal Sphincter

Sphincter of Oddi

Question 18

Where is the swallowing centre?

Answer 18

medulla

Question 19

What are the three pairs of salivary glands?

Answer 19

Parotids
Submandibular
Sublingular

Question 20

Where is salivary primarily secreted from?

Answer 20

The Acinus

Question 21

What is in the primary secretion?

Answer 21

Na+
K+
Cl-
HCO3-

Question 22

Describe the modification of the primary secretion?

Answer 22

The Duct Cells
Na+ Removed
Cl- removed
HCO3- added
K+ added

Question 23

What kind of nerves are sent when food is detected?

Answer 23

Afferent

Question 24

What receptors are involved in parasympathetic stimulation of saliva?

Answer 24

Muscarinic Acetylcholine (M3)

Question 25

What receptors are involved in sympathetic stimulation of saliva?

Answer 25

B2 adrenoreceptors

Question 26

What two factors affect gastric emptying?

Answer 26

``` Gastric Factors (Lots of thin chyme) Duodenal Factors (If it's not ready) ```

Question 27

What are the two glands of the stomach?

Answer 27

Antrum and OM

Question 28

What is the Cephalic phase of the stomach?

Answer 28

Before food reaching stomach | - Increased secretion

Question 29

What is the gastric phase of the stomach?

Answer 29

When the food is in the stomach - distension of the stomach and products of digestion stimulate gastrin and ACh

Question 30

What is the intestinal phase of the stomach?

Answer 30

A while after eating | Stimuli for secretion decrease and somatostatin secretion increases

Question 31

Name a muscarinic receptor antagonist?

Answer 31

Pirenzipine

Question 32

Name a H2 receptor antagonist?

Answer 32

Ranitidine

Question 33

Name a PPI?

Answer 33

Omeprazole

Question 34

What is zollinger-Ellison syndrome?

Answer 34

Acid hypersecretion

Question 35

Describe amylose branches?

Answer 35

Alpha 1-4

Question 36

Describe amylopectin branches?

Answer 36

Alpha 1-4, alpha 1-6

Question 37

Describe glycogen branches?

Answer 37

Alpha 1-4, Alpha 1-6

Question 38

Describe Sucrose branches? What is sucrose made of?

Answer 38

Alpha 1-2 (Glucose + Fructose)

Question 39

Describe lactose branches? What is lactose made of?

Answer 39

Beta 1-4 (Glucose + Galactose)

Question 40

Is cellulose digestible or not?

Answer 40

NO

Question 41

Where does most digestion occur?

Answer 41

Enterocytes of the small intestine

Question 42

What are the two types of digestion?

Answer 42

Luminal (Pancreatic enzmes) | Membrane (Brush border enzymes)

Question 43

What does Alpha Amylase break down?

Answer 43

Internal alpha 1-4 but not terminal so can't make glucose | Makes maltose instead

Question 44

What does Lactase break down?

Answer 44

Lactose to glucose and galactose

Question 45

What does Sucrase break down?

Answer 45

Sucrose to glucose and fructose