Enteric nervous system

Question 1

What nervous system is the enteric a part of?

Answer 1

The 3rd division autonomic nervous system

Question 2

What does intramural plexus mean?

Answer 2

It means the same as enteric nervous system

Question 3

What is the enteric nervous system?

Answer 3

Intrinsic innervation of the GI tract

Question 4

What area does the enteric nervous system cover?

Answer 4

Oesophagus to rectum

Question 5

What size is the network of neurones?

Answer 5

80-100 million

Question 6

Where is the enteric nervous system?

Answer 6

In two plexuses
Submucosal
Myenteric

Question 7

Describe the submucosal plexus

Answer 7

Also known as Meissner’s plexus

Stomach and intestine only

Question 8

Describe the myenteric plexus

Answer 8

Also know as Auerbach’s plexus

Full length of the GIT

Question 9

Do the submucosal and myenteric plexuses interact?

Answer 9

Yes

Extensively interconnected

Question 10

List the layers of the small intestine from the lumen moving out

Answer 10

Lumen
Mucosa
Submucosa
Circular muscle
Longitudinal muscle

Question 11

Where do you find the myenteric plexus?

Answer 11

Between the circular muscle and longitudinal muscle

Question 12

Where will you find the submucosal plexus?

Answer 12

Between the submucosa and circular muscle

Question 13

What types of neurones are present?

Answer 13

Afferent sensory neurones
Interneurones
Efferent secretomotor neurones

Question 14

What kind of reflex is this?

Answer 14

A short reflex

Question 15

What type of sensory neurones are present?

Answer 15

Mechanoreceptors

Chemoreceptors

Question 16

What do interneurones do?

Answer 16

Coordinate input and output

Question 17

What types of interneurones are present?

Answer 17

Excitatory and inhibatory

Question 18

What neurotransmitter do excitatory interneurones use?

Answer 18

Acetylcholine

Question 19

What neurotransmitter do inhibitory interneurones use?

Answer 19

Many various neurotransmitters

Question 20

What do efferent neurones do?

Answer 20

Excitatory or inhibitory

They innervate motor and sensory effectors

Question 21

What are the motor effectors?

Answer 21

Smooth muscle

Question 22

What neurotransmitter do excitatory efferent neurones use?

Answer 22

Acetylcholine
Substance P
5-HT (seratonin)

Question 23

What neurotransmitter do inhibitory efferent neurones use?

Answer 23

Nitric oxide
Vasoactive intestinal peptide
Adenosine triphosphate
(more)

Question 24

What are secretory effectors?

Answer 24

Cells that secrete enzymes

Question 25

What neurotransmitter do efferent neurones from secretory effectors use?

Answer 25

Excitatory Acetylcholine VIP

Question 26

What three things does the enteric nervous system control?

Answer 26

Motility Secretion Blood flow to the gut

Question 27

What is the motor reflex in the enteric nervous system?

Answer 27

Peristalsis

Question 28

Which plexus is involved in peristalsis

Answer 28

Myenteric plexus

Question 29

How does information reach the myenteric plexus?

Answer 29

Afferent sensory neurones run from the lumen to the myenteric plexus

Question 30

How does the myenteric plexus have an effect?

Answer 30

Efferent neurones innervate the muscle layers

Question 31

What effect on the GI tract will a bolus have?

Answer 31

``` Mucosal stimulation (chemoreceptor) Distension (mechanoreceptor) ```

Question 32

What happens before and after the bolus?

Answer 32

Contraction behind | Relaxation in front

Question 33

How does the muscle contract?

Answer 33

Via excitatory interneurones

Question 34

How does the muscle relax?

Answer 34

Via inhibitory interneurones

Question 35

Which plexus is responsible for the secretory reflex?

Answer 35

The submucosal plexus

Question 36

How does sensory information reach the submucosal plexus?

Answer 36

Sensory afferent neurone from the lumen

Question 37

Where do efferents of the secretory reflex go?

Answer 37

From the submucosal plexus to the lumen

Question 38

List the chain of events of the secretory reflex

Answer 38

Sensory receptors (mechano and chemo) ENS (submucosal plexus) Secretory neurones Secretion (mucus, enzymes or acid)

Question 39

How does the enteric nervous system affect blood flow?

Answer 39

Blood flow should increase when digesting food | Decrease when no food being digested

Question 40

Which plexus is involved in controlling blood flow?

Answer 40

Myenteric plexus

Question 41

How does the myenteric plexus affect blood flow?

Answer 41

By release of vasoactive neurotransmitters

Question 42

How does the enteric nervous system integrate with the central nervous system?

Answer 42

Via the sympathetic and parasympathetic pathways to the brain

Question 43

What kind of reflex is the involvement of the central nervous system?

Answer 43

Long reflex

Question 44

CNS influence _____ along the GIT. Give an example

Answer 44

varies We cannot control movement of food in the oesophagus We can control the anal sphincter

Question 45

Describe Hirschprung's disease (megacolon)

Answer 45

``` Absence of enteric nervous system neurones Distal colon Manifest soon after birth No ejection of faeces Leads to distension and colitis ```

Question 46

How do you treat Hirschprung's disease

Answer 46

Remove (via surgery) the a-ganglionic section of the colon

Question 47

What is Chaga's disease?

Answer 47

Trypanosome parasite | Releases toxin that causes neurone death

Question 48

What is IBS?

Answer 48

Dysfunctional interaction between the central nervous system and enteric nervous system