The Alimentary Canal

The four basic layers of the gut: 1. [blank_start]Mucosa[blank_end] 2. [blank_start]Submucosa[blank_end] 3. [blank_start]Musculosa[blank_end] 4. [blank_start]Adventitia[blank_end] / [blank_start]Serosa[blank_end]

[blank_start]Mucosa[blank_end] is the innermost layer lining the lumen. It consists of: 1. [blank_start]Epithelium[blank_end] 2. [blank_start]Lamina propria[blank_end] 3. [blank_start]Muscularis mucosae[blank_end]

Muscularis mucosae is a [blank_start]thin[blank_end] layer of [blank_start]smooth muscle fibers[blank_end]. Inner - [blank_start]circular[blank_end] Outer - [blank_start]longitudinal[blank_end]

Movement of muscularis mucosae is dependent from movements of wall of digestive tract.

Function of muscularis mucosae: 1. [blank_start]Separate mucosa from submucosa[blank_end] 2. [blank_start]Promote movement of mucosa[blank_end] to [blank_start]increase contact with food[blank_end]

Submucosa is a layer of [blank_start]dense fibroelastic CT[blank_end] rich in [blank_start]blood[blank_end] and [blank_start]lymph vessel[blank_end].

Submucosa may contain: 1. [blank_start]Glands[blank_end] 2. [blank_start]Lymphoid tissue[blank_end]

Musculosa consists of [blank_start]spirally arranged[blank_end] [blank_start]smooth muscle fibers[blank_end].

Musculosa is divided into: Inner - [blank_start]circular[blank_end] Outer - [blank_start]longitudinal[blank_end]

Musculosa contraction produces a series of [blank_start]peristaltic waves[blank_end].

Serosa is composed of: 1. [blank_start]Loose connective tissue[blank_end] (traversed by large [blank_start]blood[blank_end] and [blank_start]lymph vessel[blank_end] and [blank_start]nerve trunks[blank_end]) 2. A [blank_start]mesothelial[blank_end] covering of [blank_start]simple squamous epithelium[blank_end].

In places not covered by [blank_start]peritoneum[blank_end], serosa is replaced with [blank_start]adventitia[blank_end] ([blank_start]fibrosa[blank_end]).