Module 7.2 Regulation of Digestive Functions

Question 1

Within the digestive system, motility and secretion are regulated to maximize digestion and absorption.

This regulation occurs by what four mechanisms?

Answer 1

1. autonomous smooth muscle function,
2. enteric nervous system (ENS) activity,
3. extrinsic innervation, and
4. digestive hormones

Question 2

Autonomous smooth muscle contains ____\_(also called ____\_ of_______)

Answer 2

Autonomous smooth muscle contains pacemaker cells (also called interstitial cells of Cajal)

Question 3

What is the function of pacemaker cells in the Autonomous smooth muscle?

Answer 3

to generate slow-wave potentials

Question 4

What is the purpose of the slow-wave potentials generated by autonomous smooth muscle?

Answer 4

Slow-wave potentials generate action potentials that cause smooth muscle to contract

Question 5

Digestive system pacemaker cell activity:

(Top) Autonomous smooth muscle pacemaker cells generate ______\_that, upon reaching threshold, produce ______\_.

(Bottom) The strength of the corresponding smooth muscle contraction varies with the _____\_ of the action potentials.

Answer 5

Digestive system pacemaker cell activity:

(Top) Autonomous smooth muscle pacemaker cells generate slow-wave potentials that, upon reaching threshold, produce action potentials.

(Bottom) The strength of the corresponding smooth muscle contraction varies with the frequency of the action potentials.

Question 6

The degree of depolarization of the slow-wave potentials is dependent on ___\_, ___\_, and ___\_ factors

Answer 6

The degree of depolarization of the slow-wave potentials is dependent on mechanical, neural, and hormonal factors

Question 7

The frequency of the slow-wave potentials is called the _________\_, which varies in different regions of the digestive tract

Answer 7

The frequency of the slow-wave potentials is called the basic electric rhythm (BER), which varies in different regions of the digestive tract

Question 8

The ENS is composed of the ____\_and ____\_ and the associated neurons

Answer 8

The ENS is composed of the submucosal plexus and myenteric plexus and the associated neurons

Question 9

The neurons of the submucosal plexus and myenteric plexus of the Enteric Nervous System (ENS) include

1. __________ neurons,
2. _______, and
3. _______ neurons

Answer 9

The neurons of the submucosal plexus and myenteric plexus of the Enteric Nervous System (ENS) include

1. afferent sensory neurons,
2. interneurons, and
3. efferent neurons

Question 10

In the Enteric Nervous System (ENS), the efferent neurons __________ cells, __________ cells, and __________ cells.

Answer 10

In the Enteric Nervous System (ENS), the efferent neurons innervate smooth muscle cells, endocrine cells, and exocrine cells.

Question 11

What is the function of the Enteric Nervous System (ENS)?

Answer 11

To coordinate digestive system activity independent of the central nervous system (CNS)

Question 12

Extrinsic innervation to the digestive system is mediated through the __________\_

Answer 12

Extrinsic innervation to the digestive system is mediated through the autonomic nervous system (ANS)

Question 13

Overall, an increase in sympathetic nervous system activity decreases digestive system activity,

whereas an increase in parasympathetic nervous system activity increases digestive system activity

Answer 13

Overall, an increase in sympathetic nervous system activity decreases digestive system activity, (fight or flight)

whereas an increase in parasympathetic nervous system activity increases digestive system activity (rest and digest)

Question 14

Parasympathetic nervous system activity is primarily mediated by the ____\_ nerve, which is cranial nerve ten (CN X)

Answer 14

Parasympathetic nervous system activity is primarily mediated by the vagus nerve, which is cranial nerve ten (CN X)

Question 15

_______ ______\_ nerve fibres also form part of the ENS

Answer 15

Postganglionic parasympathetic nerve fibres also form part of the ENS

Question 16

The digestive hormones are secreted from the _____\_ cells of the digestive tract

Answer 16

The digestive hormones are secreted from the endocrine cells of the digestive tract

Question 17

What are four digestive hormones?

Answer 17

1. gastrin,
2. cholecystokinin (CCK),
3. secretin, and
4. glucose-dependent peptide (GIP)

Question 18

Regulation of digestive function is coordinated through _______\_

Answer 18

Regulation of digestive function is coordinated through reflex pathways

Question 19

What are the three types of receptors contained in the walls of the digestive tract?

Answer 19

The walls of the digestive tract contain three types of receptors:

1. chemoreceptors
2. mechanoreceptors
3. osmoreceptors

Question 20

The afferent information received by the three types of receptors in the digestive tract wall is relayed through long reflex pathways to the ___\_or is relayed through short reflex pathways to the _____\_.

Efferent information is then sent out to _____\_cells, _____\_ cells, or _____\_ cells.

Answer 20

The afferent information received by the three types of receptors in the digestive tract wall is relayed through long reflex pathways to the CNS or is relayed through short reflex pathways to the ENS.

Efferent information is then sent out to smooth muscle cells, endocrine cells, or exocrine cells.

Question 21

Regulation of digestive system function by reflex pathways.

Answer 21