Beginning of the Digestive System

ingest nutrients, digest/break them down, absorb nutrients, and eliminate unusable remains (defecation)

What are the 4 main functions of the digestive system?

mechanical (physical) digestion

breaking down into smaller units w/o change of chemical composition

chemical digestion

breaking down molecules by breaking covalent bonds

increase surface area

mechanical digestion helps to…

alimentary canal (digestive tract)

What is the primary part of the digestive system?

accessory organs

teeth, tongue, salivary glands, liver, gallbladder, and pancreas are all…

aid processes within the digestive tract

What do accessory organs do?

they longitudinally contract

What do the intestines do to help digest food quicker?

duodenum, jejunum, and ileum

What are the 3 regions of the small intestines in order?

jejunum

What is the most active part of the small intestines?

ileum

What is the longest part of the small intestines?

6-7 m (dead); 3 m (alive)

length of small intestines

1\.5 m (dead); 1 m (alive)

length of large intestines

mucosa

layer of the alimentary canal just above the lumen that has circular folds, villi, and microvilli present in absorptive areas

submucosa

layer of the alimentary canal right above the mucosa

muscularis externa

layer of the alimentary canal that contains both a circular and longitudinal layer of muscle

peristalsis

2 layers of muscle alternating contracting is called…

serosa

adeventia of the oral cavity, pharynx, esophagus, and rectum

mesentery

holds abdominal viscera in place

to allow time for the food to be broken down

Why does the smooth muscle of the digestive tract have to be slow moving?

mixing

movement that ensures gastric juices are being churned with the food

segmentation

movement that occurs in the duodenum and is similar to mixing

peristalsis

movement that has a wave-like effect that moves contents

the mouth

What is the only place where ingestion occurs?

papillae

texture on the tongue that is important to breaking down food

stratified squamous epithelium

The mucosa is made of what type of tissue?

bicarbonate, amylase, serous fluid, and mucus

What 4 things do salivary glands secrete?

maltose

amylase breaks down starch into…

neutral oral pH

salivary glands help to maintain…