mouth to esophagus

unit 6 ppt 2

What is the starting point of the digestive system?

The mouth or oral cavity.

What structures form the mouth?

The mouth is formed by cheeks, hard palate, and soft palate.

What are the three pairs of salivary glands?

Parotid, submandibular, and sublingual.

What are the functions of saliva?

To begin chemical digestion and to lubricate food.

What enzyme in saliva starts starch breakdown?

Salivary amylase.

What is the role of lingual lipase in digestion?

It begins fat breakdown but is activated in the stomach.

What is the function of the tongue in the digestive system?

It forms the floor of the oral cavity and has receptors for taste; it is an accessory digestive organ.

What are the two types of muscles associated with the tongue?

Extrinsic muscles, which move the tongue, and intrinsic muscles, which alter its size and shape.

What are the four types of permanent teeth and their functions?

Incisors (cutting), canines (tearing), premolars (crushing), and molars (grinding).

What is the result of mechanical digestion in the mouth?

A soft, flexible mass called a bolus, which can be easily swallowed.

What are the three parts of the pharynx?

Nasopharynx, oropharynx, and laryngopharynx.

What are the two stages of swallowing?

Voluntary stage (tongue pushes food back) and involuntary stage (medulla oblongata is stimulated).

What prevents food from entering the nasopharynx during swallowing?

The soft palate and uvula move up.

What is the function of the epiglottis during swallowing?

It closes to prevent food from entering the trachea.

What is the esophagus and its function?

A muscular tube that transports food from the pharynx to the stomach.

What is peristalsis?

A wave-like motion of muscular contractions that forces food down the esophagus.

How long does it take for food to travel from the mouth to the stomach?

4 to 8 seconds.

What are the four main regions of the stomach?

Cardia, fundus, body, and pylorus.

What are rugae in the stomach?

Ridges or folds in the stomach lining.

What is gastric juice and its role?

A mixture of secretions that continues chemical breakdown in the stomach.

What does pepsin do in the stomach?

It breaks down proteins into amino acids.

What is chyme?

The mixture of food (from the bolus) and gastric juices.

How long does it take for the stomach to empty?

2 to 4 hours.

What substances are absorbed in the stomach?

Very little absorption occurs; only water, small ions, certain drugs, and alcohol.