Overview of the Human Digestive System Structure

What is the primary cavity that the digestive system occupies?

The abdomen.

How many total organs are contained in the abdomen related to the digestive system?

Five: the spleen, two kidneys, and two adrenal glands.

What are the two main parts of the digestive system?

1. Large muscular tube (Gastrointestinal tract: Mouth to Anus). 2. Accessory organs (Tongue, teeth, salivary glands, liver, gall bladder, pancreas).

What is the lumen in the context of the digestive system?

The cavity within the long cylindrical structure of the gut.

What are the four consecutive layers of the gut wall?

1. Mucosa, 2. Submucosa, 3. Muscularis externa, 4. Serosa.

What is the function of the mucosa layer in the gut?

It lines the body cavity open to the exterior and is composed of epithelial tissue, mucus, and connective tissue.

What is the lamina propria and its significance in the mucosa?

It is loose connective tissue beneath the epithelium containing small vessels and lymphatic tissue, associated with immune response.

What is the role of the muscularis mucosae?

It consists of smooth muscle cells that influence the surface topography of the gut and affect absorption and secretion.

What is the primary composition of the submucosa?

Dense connective tissue that serves as a distribution center for vessels and nerves.

What is the function of the submucosal plexus (Meissner's plexus)?

It controls the activity of the muscularis mucosae.

What are Brunner's glands and where are they found?

Glands located in the submucosa of the duodenum of the small intestine.

What is the muscularis externa composed of?

Two layers of smooth muscle: an inner circular layer and an outer longitudinal layer.

What is the myenteric plexus and its function?

A collection of nerve fibers between the inner and outer smooth muscle that controls peristalsis.

What is the composition of the serosa?

A simple squamous epithelium (mesothelium) and a thin layer of connective tissue.

What is the function of the serous membrane?

It lubricates the surfaces of closed ventral body cavities and the organs suspended within them.

What are the three patterns of masticatory mucosa?

1. Gums & raphe (incomplete mucosa)

2. Fatty zone (incomplete mucosa with submucosa)

3. Glandular zone (incomplete mucosa with mucous glands).

What are the three forms of stratified squamous epithelium?

1. Keratinized, 2. Non-keratinized, 3. Para-keratinized.

Where is non-masticatory mucosa found?

In the cheeks, ventral surface of the tongue, floor of the mouth, and soft palate.

What is the composition of non-masticatory mucosa?

Non-keratinized stratified squamous epithelium, lamina propria, and submucosa.

What is specialized mucosa and where is it located?

It is found on the dorsal surface of the tongue and contains taste buds.

What separates the root and specialized mucosa of the tongue?

The sulcus terminalis and foramen cecum.