IB Biology Topic C3.1.16 Control of Peristalsis in the Digestive System Revision Notes (SL/HL)

IB Biology Topic C3.1.16 Control of Peristalsis in the Digestive System Revision Notes (SL/HL) | RevisionDojo

Written by official IB examiners

The CNS and Enteric Nervous System Together Move Food Through the Gut

Food is moved through the digestive system by both voluntary and involuntary control.
When you swallow, food travels down the oesophagus, through the stomach, and into the intestines.
This journey is powered by peristalsis, waves of muscle contraction that push food along the tract.

Definition

Peristalsis

Peristalsis is a wave-like contraction of smooth muscles that pushes food through the digestive tract.

The CNS Controls the Voluntary Steps: Swallowing and Egestion

The CNS, made up of the brain and spinal cord, initiates and controls the voluntary parts of digestion, such as swallowing and egestion.

Swallowing: A Two-Phase Process

Voluntary phase: you consciously push food to the back of your mouth with your tongue.
Involuntary phase: once food reaches the pharynx, sensory receptors trigger a brainstem reflex that moves it into the oesophagus.

Tip

Swallowing is a rare action that starts voluntarily but quickly becomes involuntary.

Egestion: Voluntary Control of Defecation

Rectal filling: as the rectum fills, stretch receptors send signals to the CNS.
Voluntary decision: the brain decides whether to relax the external anal sphincter, allowing defecation.

Nice try, unfortunately this paywall isn't as easy to bypass as you think. Want to help devleop the site? Join the team at https://revisiondojo.com/join-us. exercitation voluptate cillum ullamco excepteur sint officia do tempor Lorem irure minim Lorem elit id voluptate reprehenderit voluptate laboris in nostrud qui non Lorem nostrud laborum culpa sit occaecat reprehenderit

Definition

Paywall

(on a website) an arrangement whereby access is restricted to users who have paid to subscribe to the site.

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.

Duis aute irure dolor in reprehenderit

Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.

Note

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam quis nostrud exercitation.

Excepteur sint occaecat cupidatat non proident

Nemo enim ipsam voluptatem quia voluptas sit aspernatur aut odit aut fugit, sed quia consequuntur magni dolores eos qui ratione voluptatem sequi nesciunt. Neque porro quisquam est, qui dolorem ipsum quia dolor sit amet, consectetur, adipisci velit.

Tip

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.

Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

Unlock the rest of this chapter with a free account

The CNS and Enteric Nervous System Together Move Food Through the Gut

Food is moved through the digestive system by both voluntary and involuntary control.
When you swallow, food travels down the oesophagus, through the stomach, and into the intestines.
This journey is powered by peristalsis, waves of muscle contraction that push food along the tract.

Definition

Peristalsis

Peristalsis is a wave-like contraction of smooth muscles that pushes food through the digestive tract.

The CNS Controls the Voluntary Steps: Swallowing and Egestion

The CNS, made up of the brain and spinal cord, initiates and controls the voluntary parts of digestion, such as swallowing and egestion.

Swallowing: A Two-Phase Process

Voluntary phase: you consciously push food to the back of your mouth with your tongue.
Involuntary phase: once food reaches the pharynx, sensory receptors trigger a brainstem reflex that moves it into the oesophagus.

Tip

Swallowing is a rare action that starts voluntarily but quickly becomes involuntary.

Egestion: Voluntary Control of Defecation

Rectal filling: as the rectum fills, stretch receptors send signals to the CNS.
Voluntary decision: the brain decides whether to relax the external anal sphincter, allowing defecation.

Definition

Paywall

(on a website) an arrangement whereby access is restricted to users who have paid to subscribe to the site.

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Note

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam quis nostrud exercitation.

Excepteur sint occaecat cupidatat non proident

Tip

Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

A - Unity and Diversity9 subtopics

B - Form and Function10 subtopics

C - Interaction and Interdependence9 subtopics

D - Continuity and Change12 subtopics

IB Biology Topic C3.1.16: Control of Peristalsis in the Digestive System Notes

A - Unity and Diversity9 subtopics

B - Form and Function10 subtopics

C - Interaction and Interdependence9 subtopics

D - Continuity and Change12 subtopics

The CNS and Enteric Nervous System Together Move Food Through the Gut

The CNS Controls the Voluntary Steps: Swallowing and Egestion

Swallowing: A Two-Phase Process

Egestion: Voluntary Control of Defecation

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account

The CNS and Enteric Nervous System Together Move Food Through the Gut

The CNS Controls the Voluntary Steps: Swallowing and Egestion

Swallowing: A Two-Phase Process

Egestion: Voluntary Control of Defecation

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account