Digestive System

Question 1

Explain the functions of the digestive system

Answer 1

The digestive system is a specialized tube with the following functions:

1) Intake of food
2) Digestion (break down of food)
3) Absorption of products of digestion
4) Elimination of wastes

Question 2

Peristaltic Contractions

Answer 2

Traveling waves of contractions in circular smooth muscle.

Question 3

What kind of muscle makes up the digestive system?

Answer 3

Smooth muscle

Question 4

Why is the digestive system made up of smooth muscle?

Answer 4

Smooth muscle is slower than cardiac and striated muscle. It doesn’t produce the same strength as striated muscle, and it doesn’t contract as quickly as striated muscle. Striated muscle would cause fast, twitch-like contractions, which we don’t want! Smooth muscle makes long and slow contractions.

Question 5

Purpose of stomach contractions

Answer 5

Mechanical digestion - mix and mash. This goes along with chemical digestion.

Question 6

What is the main function of the large intestine?

Answer 6

To extract water from feces.

Question 7

Mastication

Answer 7

chewing - mechanical breakdown

Question 8

As a part of the digestive system, what happens in the mouth?

Answer 8

Breakdown and lubrication. Secretion of digestive enzymes from salivary glands.

Question 9

What role does the tongue play in digestion?

Answer 9

The tongue manipulates food to form a ball in the back of the “tongue-part” of the throat.

Question 10

Explain how swallowing is initiated.

Answer 10

• –Swallowing is initiated voluntarily but completed via reflexes.
• –Once the tongue forms the ball of food at the back of the throat, the swallowing center in the medulla is activated.
• –The respiratory center of the medulla is directly inhibited by the swallowing center for the very brief time that it takes to swallow. This means that it is briefly impossible to breathe during this phase of swallowing and the moment where breathing is prevented is known as deglutition apnea.

Question 11

Explain the steps of swallowing after food is balled up at the back of the throat by the tongue.

Answer 11

1) Food is pushed into the pharynx. This activates stretch receptors and triggers activity in the swallowing center of the medulla. This triggers the following reflexes:
a)