Enteric nervous system Flashcards Preview

Foundations of Neuroscience > Enteric nervous system > Flashcards

Flashcards in Enteric nervous system Deck (48):
1

What nervous system is the enteric a part of?

The 3rd division autonomic nervous system

2

What does intramural plexus mean?

It means the same as enteric nervous system

3

What is the enteric nervous system?

Intrinsic innervation of the GI tract

4

What area does the enteric nervous system cover?

Oesophagus to rectum

5

What size is the network of neurones?

80-100 million

6

Where is the enteric nervous system?

In two plexuses
Submucosal
Myenteric

7

Describe the submucosal plexus

Also known as Meissner's plexus
Stomach and intestine only

8

Describe the myenteric plexus

Also know as Auerbach's plexus
Full length of the GIT

9

Do the submucosal and myenteric plexuses interact?

Yes
Extensively interconnected

10

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

Lumen
Mucosa
Submucosa
Circular muscle
Longitudinal muscle

11

Where do you find the myenteric plexus?

Between the circular muscle and longitudinal muscle

12

Where will you find the submucosal plexus?

Between the submucosa and circular muscle

13

What types of neurones are present?

Afferent sensory neurones
Interneurones
Efferent secretomotor neurones

14

What kind of reflex is this?

A short reflex

15

What type of sensory neurones are present?

Mechanoreceptors
Chemoreceptors

16

What do interneurones do?

Coordinate input and output

17

What types of interneurones are present?

Excitatory and inhibatory

18

What neurotransmitter do excitatory interneurones use?

Acetylcholine

19

What neurotransmitter do inhibitory interneurones use?

Many various neurotransmitters

20

What do efferent neurones do?

Excitatory or inhibitory
They innervate motor and sensory effectors

21

What are the motor effectors?

Smooth muscle

22

What neurotransmitter do excitatory efferent neurones use?

Acetylcholine
Substance P
5-HT (seratonin)

23

What neurotransmitter do inhibitory efferent neurones use?

Nitric oxide
Vasoactive intestinal peptide
Adenosine triphosphate
(more)

24

What are secretory effectors?

Cells that secrete enzymes

25

What neurotransmitter do efferent neurones from secretory effectors use?

Excitatory
Acetylcholine
VIP

26

What three things does the enteric nervous system control?

Motility
Secretion
Blood flow to the gut

27

What is the motor reflex in the enteric nervous system?

Peristalsis

28

Which plexus is involved in peristalsis

Myenteric plexus

29

How does information reach the myenteric plexus?

Afferent sensory neurones run from the lumen to the myenteric plexus

30

How does the myenteric plexus have an effect?

Efferent neurones innervate the muscle layers

31

What effect on the GI tract will a bolus have?

Mucosal stimulation (chemoreceptor)
Distension (mechanoreceptor)

32

What happens before and after the bolus?

Contraction behind
Relaxation in front

33

How does the muscle contract?

Via excitatory interneurones

34

How does the muscle relax?

Via inhibitory interneurones

35

Which plexus is responsible for the secretory reflex?

The submucosal plexus

36

How does sensory information reach the submucosal plexus?

Sensory afferent neurone from the lumen

37

Where do efferents of the secretory reflex go?

From the submucosal plexus to the lumen

38

List the chain of events of the secretory reflex

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

39

How does the enteric nervous system affect blood flow?

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

40

Which plexus is involved in controlling blood flow?

Myenteric plexus

41

How does the myenteric plexus affect blood flow?

By release of vasoactive neurotransmitters

42

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

Via the sympathetic and parasympathetic pathways to the brain

43

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

Long reflex

44

CNS influence _____ along the GIT. Give an example

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

45

Describe Hirschprung's disease (megacolon)

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

46

How do you treat Hirschprung's disease

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

47

What is Chaga's disease?

Trypanosome parasite
Releases toxin that causes neurone death

48

What is IBS?

Dysfunctional interaction between the central nervous system and enteric nervous system