GI Physiology/Pharmacology

Question 1

What are the accessory organs of the GI tract?

Answer 1

Salivary glands
Pancreas
Liver and gall bladder

Question 2

What are the functions of the GI tract?

Answer 2

Motility
Scretion
Digestion
Absorption

Question 3

What are the components of the general digestive wall?

Answer 3

Mucosa
Submucosa
Muscularis externa

Question 4

The mucosa consists of?

Answer 4

Epithelial cells
exocrine/endocrine cells
Lamina propria
Muscularis mucosae

Question 5

Where are the enteric neurones located?

Answer 5

Lamina propria

Question 6

Where is the sub mucous plexus?

Answer 6

Submucosa

Question 7

The serosa is part of the _____ and helps to suspend the organs in the abdominal cavity

Answer 7

mesentery

Question 8

Circular muscle contraction makes the lumen?

Answer 8

Narrower and longer

Question 9

Longitudinal contraction makes the lumen?

Answer 9

Shorter and fatter

Question 10

What allows the spread of electrical current through smooth muscle cells in the GI tract?

Answer 10

Gap junctions

Question 11

What is the term given to describe how the cells in the GI tract all depolarise at the same tome to form a synchronous wave?

Answer 11

Functional syncytium

Question 12

What drives spontaneous activity across the syncytium?

Answer 12

Pacemaker cells

Question 13

What modulates pacemaker cells in the GI tract?

Answer 13

Intrinsic (enteric) and extrinsic (autonomic) nerves and hormones

Question 14

What drives electrical activity in the GI tract?

Answer 14

Interstitial Cells of Cajal

Question 15

Together, the sub mucous plexus and myenteric plexus make up the?

Answer 15

Enteric Nervous System

Question 16

Upstroke in the interstitial cells of Cajal is mediated by?

Downstroke?

Answer 16

Ca channels 
K channels 
(both voltage-activated)

Question 17

The GI tract has a BER. What does this stand for?

Answer 17

Basal electrical rhythm

Question 18

The basal electric rhythm is fastest in the?

Answer 18

Small intestine

Question 19

What is the effect of parasympathetic stimulation on the GI tract?

Answer 19

Increase gastric, pancreatic and SI secretion
increase blood flow
Increase smooth muscle contraction
Inhibit some sphincters and receptive relaxation of stomach

Question 20

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

Answer 20

Increase sphincter tone

Decrease motility, secretion and blood flow

Question 21

What is the short (intestine-intestinal) reflex?

Answer 21

Local distension activates sensory neutrons exciting sympathetic pre-ganglionic fibres that cause inhibition of muscle activity in adjacent areas

Question 22

Wha tis the long (gastro-ileac) reflex?

Answer 22

Increase in gastric activity causes increased propulsive activity in the terminal ileum

Question 23

What is peristalsis?

Answer 23

Wave of relaxation followed by relaxation, normally in an aboral direction triggered by distension in the wall of the gut

Question 24

What causes circular muscle and longitudinal muscle to contract?

Answer 24

Release of ACh and substance P from excitatory motor neurone

Question 25

What causes circular / longitudinal muscle to relax?

Answer 25

Release of VIP and NO from inhibitory motor neurone

Question 26

What is segmentation? (occurs in fed state)

Answer 26

Rhythmic contraction of circular muscle to mix and divide luminal contents

Question 27

What is meant by "colonic mass movement"?

Answer 27

powerful sweeping contraction that forces faeces into the rectum

Question 28

What is meant my "migrating motor complex"?

Answer 28

powerful sweeping contraction from stomach to terminal ileum

Question 29

Which sphincters are made of skeletal muscle?

Answer 29

Upper oesophageal sphincter | External anal sphincter

Question 30

What are the 6 sphincters?

Answer 30

``` UOS LOS Pyloric IC valve Internal and external anal ```

Question 31

Which anatomical structure allows simultaneous breathing and chewing?

Answer 31

Palate - by separating the mouth and nasal passages

Question 32

The tongue pushes bolus of food to the?

Answer 32

Oropharynx

Question 33

When food reaches the oropharynx it stimulates?

Answer 33

Mechanoreceptors

Question 34

Stimulation of mechanoreceptors in the oropharynx during swallowing marks?

Answer 34

End of voluntary phase

Question 35

Mechanoreceptors in the oropharynx send signals to the pons and medulla via?

Answer 35

CN IX and X

Question 36

Which cranial nerves send efferent impulses to skeletal muscle of pharynx during swallowing? What's the effect?

Answer 36

CN VII, X, and XI Soft palate moves up Pharnygeal wall contracts posteriorly, separating oro and nasopharynx

Question 37

How is entry of the bolus into the airway prevented?

Answer 37

inhibition of ventilation, laryngeal muscles close glottis and raise larynx bolus forces epiglottis over larynx

Question 38

The bolus enters the oesophagus through the open _______, the glottis reopens and _____ recommences

Answer 38

oesophageal sphincter | ventilation

Question 39

How long is the pharyngeal phase? (swallowing)

Answer 39

1 second

Question 40

What happens during the oesophageal phase of swallowing? (4-10 seconds)

Answer 40

Swallowing centre (pons/medulla) triggers closing of UOS and primary peristaltic wave via vagus nerve

Question 41

The LOS opens within ___ seconds of swallowing initiation and closes after bolus passes to prevent?

Answer 41

2-3 seconds | reflux

Question 42

Sticky food that becomes lodged stimulates local pressure receptors that cause a _______

Answer 42

secondary peristaltic wave