Digestive System Flashcards
What is the digestive system of poultry referred to as?
Very simple but efficient.
Why is the avian digestive system simple?
To allow for flight, as a simpler digestive system is lighter.
What kind of diet do fowl need?
High quality and easily digestible.
What is the digestive system responsible for?
- Ingestion of food.
- Breakdown of food into its constituent nutrients.
- Absorption of nutrients into the bloodstream.
- Elimination of waste.
What is the alimentary canal?
A long, tube-like organ that starts at the beak and ends at the cloaca.
What are the orientations of the muscles surrounding the alimentary canal?
Longitudinal and perpendicular.
What is the inside of the alimentary canal lined with?
Mucous membranes.
What happens after food in the alimentary canal has been digested?
It is absorbed through the walls and into the circulatory system to be transported to the liver or other parts of the body.
What happens to the remaining waste after absorption?
It is eliminated via the cloaca.
What is the beak?
An area of horny and dense skin lying over the mandible and incisive bones.
What is the egg tooth?
A keratinous point that allows newly hatched chicks to escape
How long does the egg tooth last?
24-48 hours.
What is the hard palate?
A long, narrow median slit that forms the roof of the mouth and communicates with the nasal cavity.
What does the hard palate have 5 transverse rows of?
Backwards pointing, hard, conical papillae.
The ducts of what glands pierce the hard palate?
The salivary glands.
What kind of tissue covers the free surface of salivary glands?
Stratified squamous epithelium.
What do the salivary glands of the hard palate merge to form?
One mass of glandular tissue.
Where are the palatine salivary glands located?
One either side of the nasal opening in the roof of the mouth.
What are the 7 salivary glands?
- Maxillary.
- Palatine.
- Apheno-pteryoid.
- Posterior sub-mandibular.
- Lingual.
- Circo-arytenoid.
- Anterior sub-mandibular.
Where are the maxillary salivary glands located?
The roof of the mouth.
Where are the apheno-pteryoid salivary glands located?
In the roof of the pharynx on each side of the common opening for the eustachian tubes.
Where are the anterior sub-mandibular salivary glands located?
In the angle formed by the upper and lower beak.
Where are the posterior sub-mandibular salivary glands located?
In the angle formed by the upper and lower beak.
Where are the circo-arytenoid salivary glands located?
Around the glottis.
Where are the lingual salivary glands located?
In the tongue.
What structure is continuous with and follows the mouth?
The pharynx.
What is the oropharynx?
The mouth + the pharynx.
What is the tongue in poultry described as?
- Pointed.
- Long.
- Conformed to the shape of the beak.
What is the epithelium of the tongue described as?
- Horny.
- Thick.
*Especially towards the tip.
What is located on the posterior end of the tongue?
A transverse row of large, simple, rear-facing, horny papillae.
What bone provides the framework for the tongue?
The hyoid bone.
In what plane does the entoglossal bone extend?
Longitudinally in the median plane.
Which directions are the mucous glands of the tongue pointed?
Rearward.
How strong is a bird’s sense of taste?
Very weak if present at all.
What are the 2 major functions of the mouth?
- Pick up food.
- Direct food in to the esophagus.
What is the esophagus capable of?
Significant stretching.
*Is already wide.
What is the esophagus in close association with?
The trachea.
How many layers of tissue compose the wall of the esophagus?
4.
What is the innermost layer of the esophageal wall composed of?
Mucous membrane.
What is the mucous membrane a barrier against?
Microbes.
What does the mucus act as?
A lubricant that aids in the passage of food.
What does the esophagus connect the mouth to?
The crop.
What is the crop?
A large dilation of the esophagus.
Where is the crop located?
Just before the esophagus enters the thoracic cavity.
What is the function of the crop?
Hold food before further digestion, allowing for periodic feeding but continuous digestion.
Are there glands in the crop in chickens?
No.
*Ducks and geese do.
What is unique about pigeons?
Surface cells in the crop slough off during brooding, forming pigeon milk.
After the crop, what structure does the esophagus enter/become?
The proventriculus/glandular stomach.
How is the proventriculus described?
- Small.
- Tubular.
- Thick-walled.
How many layers compose the wall of the proventriculus?
5.
What are the 5 layers that compose the five layers?
- Outer serous membrane.
- Muscle layer composed of:
a. Areolar tissue containing blood and lymph vessels.
b. Thick layer composed mainly of glandular tissue.
c. Mucous membrane.
What forms the greater part of the thickness of the proventriculus?
Glands.
What do the proventriculus glands produce?
Enzymes for breaking down food into its constituent nutrients.
What does the mucous membrane in the proventriculus look-like?
Raised folds that contains glands that secrete HCL.
What is the function of HCL?
To neutralize the alkaline coating on the food from the saliva.