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more than 4 weeks ago
The corpuscles of Stannius are specialized structures found in the kidneys of fishes. They are small, round bodies composed of secretory cells that produce a hormone called stanniocalcin. This hormone plays a role in regulating calcium and phosphate levels in the blood by inhibiting the action of parathyroid hormone.
The corpuscles of Stannius are unique to fishes and are not found in other vertebrates. They are located near the junction of the afferent and efferent arterioles in the kidney, where they release stanniocalcin directly into the bloodstream. This hormone helps to maintain the proper balance of calcium and phosphate in the fish's body, which is essential for normal physiological functions such as bone formation and muscle contraction.
Overall, the corpuscles of Stannius play a crucial role in the homeostasis of calcium and phosphate levels in fishes, helping to ensure their overall health and well-being.
The corpuscles of Stannius are unique to fishes and are not found in other vertebrates. They are located near the junction of the afferent and efferent arterioles in the kidney, where they release stanniocalcin directly into the bloodstream. This hormone helps to maintain the proper balance of calcium and phosphate in the fish's body, which is essential for normal physiological functions such as bone formation and muscle contraction.
Overall, the corpuscles of Stannius play a crucial role in the homeostasis of calcium and phosphate levels in fishes, helping to ensure their overall health and well-being.
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Google Gemini AI
more than 4 weeks ago
Corpuscles of Stannius (Corpora Stannii)
The corpuscles of Stannius are small, ovoid or spherical endocrine glands located in the connective tissue between the kidneys and swim bladder of teleost fishes.
Structure:
- Composed of polygonal cells arranged in cords or follicles
- Cells contain large, centrally located nuclei
- Cytoplasm contains secretory granules
Location:
- Typically found in pairs, one on either side of the dorsal aorta
- Positioned ventral to the kidneys and lateral to the swim bladder
Physiology:
- Primary function is to regulate calcium homeostasis
- Secrete a hormone called stanniocalcin that:
- Inhibits calcium uptake by the gills
- Promotes calcium excretion by the kidneys
- May also play a role in:
- Osmotic regulation
- Ion transport
- Growth and development
Regulation:
- Activity of the corpuscles of Stannius is regulated by:
- Calcium levels in the blood
- Hormones such as prolactin and growth hormone
Experimental Evidence:
- Removal of the corpuscles of Stannius leads to:
- Increased calcium uptake by the gills
- Decreased calcium excretion by the kidneys
- Elevated blood calcium levels
- Injection of stanniocalcin has the opposite effects:
- Inhibits calcium uptake
- Promotes calcium excretion
- Decreases blood calcium levels
Evolution:
- The corpuscles of Stannius are homologous to the ultimobranchial bodies in mammals, which also play a role in calcium regulation. This suggests that the corpuscles of Stannius evolved from a common ancestral structure.
The corpuscles of Stannius are small, ovoid or spherical endocrine glands located in the connective tissue between the kidneys and swim bladder of teleost fishes.
Structure:
- Composed of polygonal cells arranged in cords or follicles
- Cells contain large, centrally located nuclei
- Cytoplasm contains secretory granules
Location:
- Typically found in pairs, one on either side of the dorsal aorta
- Positioned ventral to the kidneys and lateral to the swim bladder
Physiology:
- Primary function is to regulate calcium homeostasis
- Secrete a hormone called stanniocalcin that:
- Inhibits calcium uptake by the gills
- Promotes calcium excretion by the kidneys
- May also play a role in:
- Osmotic regulation
- Ion transport
- Growth and development
Regulation:
- Activity of the corpuscles of Stannius is regulated by:
- Calcium levels in the blood
- Hormones such as prolactin and growth hormone
Experimental Evidence:
- Removal of the corpuscles of Stannius leads to:
- Increased calcium uptake by the gills
- Decreased calcium excretion by the kidneys
- Elevated blood calcium levels
- Injection of stanniocalcin has the opposite effects:
- Inhibits calcium uptake
- Promotes calcium excretion
- Decreases blood calcium levels
Evolution:
- The corpuscles of Stannius are homologous to the ultimobranchial bodies in mammals, which also play a role in calcium regulation. This suggests that the corpuscles of Stannius evolved from a common ancestral structure.
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