Regulation Of GI function

Question 1

When sensory cells are stimulated, what do they send out a signal to do?

Answer 1

Stimulate smooth muscles

Stimulate release of hormones

Question 2

What do sensory cells detect?

Answer 2

Osmolarity 
PH
Stretch
Nutrient/metabolite conc
Irritation of mucous membranes
NOT PAIN

Question 3

What type of feedback is digestion (mainly) and what coordinates it?

Answer 3

Negative feedback

Neural and hormonal regulation

Question 4

In short reflex arcs of the GI tract, which nervous system is stimulated? Where are these nerve cells?

Answer 4

Enteric nervous system

In the wall of the GI tract

Question 5

In long reflex arcs of the GI system,what nervous system is stimulated?

Answer 5

Autonomic
Parasympathetic speeds up digestion
Sympathetic slows down digestion

Question 6

Most reflex arcs are stimulatory. What is the neurotransmitter for this?

Answer 6

Acetylcholine

Question 7

What are complex reflex arcs?

Answer 7

Simple reflex arcs connected by interneurons

Question 8

In the parasympathetic ANS, where do pre ganglionic fibres run?

Answer 8

Vagus nerve

Question 9

In the parasympathetic ANS, where do post ganglionic fibres run? What do they connect to?

Answer 9

Wall of the GI tract

Connect to the enteric nervous system

Question 10

In the sympathetic nervous system, where do the pre ganglionic fibres run, and what is the neurotransmitter?

Answer 10

Splanchnic nerves

Acetylcholine

Question 11

In the sympathetic nervous system, where do the post ganglionic fibres run and what is their neurotransmitter?

Answer 11

Run through organ of innervation or hypogastric nerves

Noradrenaline

Question 12

What do entero-enteric reflexes do?

Answer 12

Coordinate activity between different parts of the GI tract

Question 13

What are the three phases of regulation?

Answer 13

Cephalic (head)
Gastric (stomach)
Intestinal

Question 14

What stimulates the cephalic phase to cause a release of more gastric juices and which NS controls this?

Answer 14

Emotion

ANS

Question 15

The gastric phase is coordinated by which nervous system and which main hormone?

Answer 15

ANS
ENS
Gastrin

Question 16

Which nervous systems and hormones coordinate the intestinal phase?

Answer 16

ANS
ENS
Secretin, CCK, GIP

Question 17

Where is the site of appetite regulation?

Answer 17

Hypothalamus

Question 18

What does the ventro lateral hypothalamus cause?

Answer 18

Food searching

Question 19

What does the ventro medial hypothalamus cause?

Answer 19

Refusal of food (inhibit appetite)

Question 20

The hypothalamus regulates appetite. What are the 3 theories as to how it does this?

Answer 20

Measures levels of fat, glucose or CCK

Question 21

What is motility?

Answer 21

Coordinated contraction of smooth muscle in the GI tract

Question 22

What are the 4 types of motility?

Answer 22

Segmental
Peristalsis
Anti peristalsis
Mass movement

Question 23

What is segmental motility?

Answer 23

The mixing of contents and mechanical breakdown

Question 24

What is peristalsis?

Answer 24

The movement of intestinal contents in aboral direction

Question 25

What is anti peristalsis?

Answer 25

The movement of intestinal contents in an oral direction

Question 26

What is mass movement?

Answer 26

The emptying of entire sections of the GI tract

Eg. Evacuation of colon contents to rectum

Question 27

In the membrane potential of groups of pacemaker cells, there are approx. 5 per minute of…

Answer 27

Repetitive and spontaneous oscillations

Question 28

If a stimulus is present in pacemaker cells, an action potential causes smooth muscle contraction. The strength of contraction is dependent on what?

Answer 28

The frequency of action potentials