Digestive System

What is the Function of the digestive system?

Converts the food we eat into energy and raw materials that build and fuel our bodies.

What happens to the Macromolecules in our food AFTER we eat them?

Macromolecules in our food gets broken down mechanically and chemically into their simplest forms. Then gets absorbed into our blood and transported by the capillaries (and the rest of our blood vessels) to wherever the nutrients are needed in the body.

What is the Alimentary Canal (also know as the Gastrointestinal Tract)?

The hollow muscular tube from the mouth to the anus that digests and absorbs our foods.

What does the Alimentary Canal (Gl Tract) include?

Mouth, pharynx, esophagus, stomach, small intestine, and large intestine.

What are the Accessory (support) Structures of the Alimentary Canal (Gl Tract)?

Teeth, tongue, salivary glands, gallbladder, liver, and pancreas.

What happens in Ingestion (eating)?

Teeth begin mechanical breakdown with chewing. Salivary glands begin chemical digestion by releasing enzymes that start digesting starches.

What happens in Propulsion?

It’s the movement of food through the Gl tract. Starts with consciously swallowing the bolus and continues with automatic peristalsis.

Define Peristalsis and Bolus.

Peristalsis is the contraction and relaxation of smooth muscles in the esophagus, stomach, and intestines to move food through the canal. Bolus is a ball of chewed up food we swallow.

What happens in Mechanical Breakdown?

Physically breaking down food to increase surface area (helps with absorption) and mix it with enzymes (helps with chemical digestion).

What happens in Chemical Digestion?

Secreted enzymes that chemically break down food molecules into their simplest forms (monomers) in order to get absorbed into the blood, transported, and used by our cells.

What happens in Absorption?

When our digested food (monomers, vitamins, and minerals) moves from the Gl tract and into the blood or lymph. These nutrients are then used by cells for energy or other processes.

What happens in Defecation?

The elimination of indigestible substances through the anus as feces.

What are the 4 main layers of the Gl tract?

Mucosa, submucosa , muscularis external, and serosa.

What happens in the Mucosa layer?

It’s the inner most layer, secretes mucus, enzymes and hormones. Absorbs nutrients into the blood and protects against infectious diseases.

What happens in the Submucosa layer?

It’s the middle layer of loose areolar connective tissue and provides the tube with elasticity.

What happens in the Muscularis Externa layer?

It’s the middle layer of smooth muscle and it’s critical for peristalsis.

What happens in the Serosa layer?

It’s the outermost layer of loose connective tissue and houses the nerves, blood vessels and lymphatic vessels for each structure.

What does the Stratified Squamous Epithelial Cells do?

It protects the mouth, esophagus and anus against damage from rough foods.

What does the Simple Columnar Epithelial Cells do?

Loves our stomach and intestines for absorption and secretion.

Explain the Enteric Nervous system

It’s the nerve supply just for the Gl tract for regulating activities of the D.S. It’s part of the autonomic nerves system and responds to external and internal stimuli.