Gizzard - Anatomy & Physiology
Revision as of 16:39, 7 September 2010 by Bara (talk | contribs) (moved The Gizzard - Anamtomy & Physiology to Gizzard - Anatomy & Physiology)
Introduction
The gizzard is also referred to as the muscular stomach or ventriculus. It is connected by the isthmus to the proventriculus and to the duodenum.
Structure and Function
- Mechanical reduction of tougher material through powerful muscular development
- Contacts the sternum and lower left abdominal wall
- Dorsally the abdominal air sacs separate it from the intestines and gonads
- More caudal than the proventriculus
- Roughly on the midline of the bird
- Lens shaped
- Interior elongated by cranial and caudal blind sacs
- Cranial blind sac contacts proventriculus
- Pylorus on right surface next to cranial blind sac
- Two thick masses of muscle that insert on tendonous surfaces
- In seed eating birds grit is digested to increase grinding down of food particles
- Surface covered by glistening tendonous layer
- The cranial and caudal extremities are formed by powerful red muscular tissue
- A circular aponeurosis is present connecting the cranial end of the gizzard to the isthmus and the caudal end to the duodenum
- Appears yellow due to bile reflux from the duodenum
- When the thin muscles of the gizzard contract, food passes from the gizzard into the duodenum
- When the thick muscles of the gizzard contract, food moves back into the proventriculus
Histology
Species Differences
- No gizzard in falconiformes (raptors etc.)
- No gizzard in stringiformes (owls etc.)
- No gizzard in gulls
Other Information
- Grit should be provided in seed eating birds diet. It is radiodense and marks out where the gizzard is located on radiographs.