1. The Breakdown and General Structure Flashcards
What are the main Organs of the Alimentary Tract?
- The Mouth
- The Oesophagus
- The Stomach
- The Small Intestines
- The Large Intestines
- The Anal Canal / Rectum
What are the parts of the Small Intestines?
- The Duodenum
- The Jejunum
- The Ileum
What are the parts of the Large Intestines?
- The Caecum
- The Ascending Colon
- The Transverse Colon
- The Descending Colon
- The Sigmoid Colon
What are the Accessory Organs of the Alimentary Tract?
- The Liver
- The Gallbladder
- The Pancreas
- The Spleen
What are the functions of the Mouth?
- Foodstuff is broken down by mastication to make a bolus
2. Saliva is added as a lubricant
What is the function of the Oesophagus?
It is a conduit between the Mouth and the Stomach
What are the functions of the Stomach?
Ingested Material
- The Sterilization of Ingested Material
- To Dissolve the Bolus and Initiate the Digestive Process
- Control the Release of Chyme into the Duodenum
- To Produce Intrinsic Factor in the Parietal Cells
What is the function of the Liver?
The Production of Bile Salts for Digestion / Absorption of Fats in the Small Intestine
What is the function of the Gallbladder?
Stores and Concentrates Bile
What is the function of the Pancreas?
The site of Production of the Digestive Enzymes, needed for the Digestion of Fats, Carbohydrates, and Proteins
What are the functions of the Small Intestines?
- The Final Stages of Chemical Digestion
2. Nutrient Absorption
What are the functions of the Large Intestines?
- Water absorption
- Bacterial Fermentation
- Faeces formation
What is the general structure of the Alimentary Tract?
A continuous tube of various diameter
How many layers does the Alimentary Canal have?
4
What are the 4 Layers of the Alimentary Canal?
- The Mucosa
- The Sub-Mucosa
- The Muscularis Externa
- The Serosa / Adventitia
What is the Mucosa Sub-Divided into?
- The Epithelium
- The Lamina Propria
- The Muscularis Mucosae (Interna)
What is the function of the Epithelium?
- It acts as a Barrier, separating the Lumen from the Rest of the Body
- It absorbs the Products of Digestion
Is there only one type of Epithelium?
No, the Epithelium has different composition of Types depending on the Environment
Where in the Alimentary Tract would there be Stratified Squamous Epithelium?
- The Mouth
- The Oesophagus
- The Anus
Where in the Alimentary Tract would there be Simple Columnar Epithelium?
- The Stomach
- The Small Intestines
- The Colon
What is the Lamina Propria?
A Layer of Loose Connective Tissue supporting the Epithelium
What is contained in the Lamina Propria?
- Glands
- Blood Vessels
- Lymphatics
What is the Muscularis Mucosae (Interna)?
A Thin layer of Smooth Muscle
What is the Sub-Mucosa?
A thick layer of Irregular Connective Tissue which supports the Mucosa
What is contained within the Sub-Mucosa?
- The Mucosa
- Blood Vessels
- Lymphatics
- Neurons
- Glands
What do the Neurons contained within the Sub-Mucosa form?
An extensive network from the Sub-Mucosal (Meissner’s) Plexus
Where does the Sub-Mucosal (Meissner’s) Plexus lie?
Superficial to the Sub-Mucosa
Which Autonomic Nervous System has the greatest Neural Influence on the Sub-Mucosal (Meissner’s) Plexus?
The Parasympathetic System
Where can Glands be found in the Sub-Mucosa?
- The Oesophagus
2. The Duodenum
What do the Sub-Mucosal Glands in the Oesophagus secrete?
Mucinous Lubrication, for the Bolus
What do the Sub-Mucosal Glands in the Duodenum secrete?
Bicarbonate, to neutralize the Gastric Acid
What are the 2 Layers of the Muscularis Externa?
- The Inner Circular Muscle
2. The Outer Longitudinal Muscle
What lies between the 2 Layers of the Muscularis Externa?
The Mesenteric (Auerbach’s) Nerve Plexus
What is the function of the Circular Muscle of the Muscularis Externa?
This Constricts the Alimentary Canal
What is the function of the Longitudinal Muscle of the Muscularis Externa?
This Shortens the Alimentary Canal
What is the function of the Mesenteric (Auerbach’s) Plexus?
This controls the actions of the Muscularis Externa
What is the Serosa?
The Superficial-most layer of the Alimentary Tract, within the Peritoneal Cavity
What is the Adventitia?
The Superficial-most layer of the Alimentary Tract, outiwith the Peritoneal Cavity
Is the Serosa present in the Mesentery?
No
What is the Function of the Adventitia?
To attach the Oesophagus / Rectum to the Surrounding Structures