Difference between revisions of "Egg Incubation Physiology - Anatomy & Physiology"
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== Changes in Composition of the Egg during Incubation == | == Changes in Composition of the Egg during Incubation == | ||
*As the embryo grows within the egg, the composition of the egg changes. | *As the embryo grows within the egg, the composition of the egg changes. | ||
| − | * Both yolk and albumin diminish. | + | * Both [[Egg Composition and Formation - Anatomy & Physiology#Yolk|yolk]] and albumin diminish. |
** Yolk providing energy for growth and maintenance of the embryo. | ** Yolk providing energy for growth and maintenance of the embryo. | ||
| − | ** Albumin providing protein for the embryo and giving up water, which is lost through pores in the shell. | + | ** Albumin providing protein for the embryo and giving up water, which is lost through pores in the [[Egg Composition and Formation - Anatomy & Physiology#Shell|shell]]. |
* Water is produced when yolk fat is oxidised. | * Water is produced when yolk fat is oxidised. | ||
* Water lost from the egg is replaced by air, creating the 'air cell' at the blunt end of the egg. | * Water lost from the egg is replaced by air, creating the 'air cell' at the blunt end of the egg. | ||
| − | * Embryo punctures the | + | * Embryo punctures the [[Egg Composition and Formation - Anatomy & Physiology#Embryonic_Membranes|chorioallantoic]] and [[Egg Composition and Formation - Anatomy & Physiology#Shell_membranes|internal shell membrane]]. |
** Able to begin pulmonary ventilation, rebreathing the 'air cell' gas. | ** Able to begin pulmonary ventilation, rebreathing the 'air cell' gas. | ||
| − | ** Transition from diffusive respiration through the chorioallantois to breathing through the lungs. | + | ** Transition from diffusive respiration through the [[Egg Composition and Formation - Anatomy & Physiology#Embryonic_Membranes|chorioallantois]] to breathing through the [[Lungs_- Anatomy & Physiology|lungs]]. |
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== Heat Transfer to the Egg == | == Heat Transfer to the Egg == | ||
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| + | === Heat Transfer to the Egg === | ||
* Transfer of heat from the body to the egg is the most important contribution of the incubating adult to incubation. | * Transfer of heat from the body to the egg is the most important contribution of the incubating adult to incubation. | ||
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** This is 1.1-5.5ºC higher than the egg temperature. | ** This is 1.1-5.5ºC higher than the egg temperature. | ||
| + | === Heat Loss from the Egg === | ||
| − | * Heat loss from the egg is prevented by a thin boundary layer of air adjacent to the shell. | + | * Heat loss from the egg is prevented by a thin boundary layer of air adjacent to the [[Egg Composition and Formation - Anatomy & Physiology#Shell|shell]]. |
* If the egg is in a nest, the nest will also provide resistance to heat loss. | * If the egg is in a nest, the nest will also provide resistance to heat loss. | ||
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| + | [[Category:Avian Reproduction]] | ||
| + | [[Category:Bullet Points]] | ||
Latest revision as of 14:05, 5 July 2012
Changes in Composition of the Egg during Incubation
- As the embryo grows within the egg, the composition of the egg changes.
- Both yolk and albumin diminish.
- Yolk providing energy for growth and maintenance of the embryo.
- Albumin providing protein for the embryo and giving up water, which is lost through pores in the shell.
- Water is produced when yolk fat is oxidised.
- Water lost from the egg is replaced by air, creating the 'air cell' at the blunt end of the egg.
- Embryo punctures the chorioallantoic and internal shell membrane.
- Able to begin pulmonary ventilation, rebreathing the 'air cell' gas.
- Transition from diffusive respiration through the chorioallantois to breathing through the lungs.
Heat Transfer to the Egg
Heat Transfer to the Egg
- Transfer of heat from the body to the egg is the most important contribution of the incubating adult to incubation.
- Most birds develop a seasonal bare patch of skin known as the 'brood patch' on part of the thorax and abdomen.
- 'Brood patch' is in direct contact with the egg to permit a greater heat transfer than if there were feathers between them.
- At the same time, there is an increase in the size and number of blood vessels in the bare skin.
- Serves to increase heat transfer, as hot blood runs closer to the surface.
- Adult can adjust the rate of heat transfer by:
- Standing or leaving the egg.
- The closeness with which the 'brood patch' is applied to the egg.
- Responding physiologically to the temperature of the egg, thus increasing or decreasing metabolic heat production.
- 'Brood patch' temperature is 34.9-42.4ºC.
- This is 1.1-5.5ºC higher than the egg temperature.
Heat Loss from the Egg
- Heat loss from the egg is prevented by a thin boundary layer of air adjacent to the shell.
- If the egg is in a nest, the nest will also provide resistance to heat loss.