Bone 1000 g Ca++ stored in bone Calcium homeostasis Blood Ca++ small intestine kidney Ca++ lost in...
-
Upload
raquel-jenkin -
Category
Documents
-
view
216 -
download
1
Transcript of Bone 1000 g Ca++ stored in bone Calcium homeostasis Blood Ca++ small intestine kidney Ca++ lost in...
![Page 1: Bone 1000 g Ca++ stored in bone Calcium homeostasis Blood Ca++ small intestine kidney Ca++ lost in urine Calcium in the diet calcium lost in feces Ca++](https://reader035.fdocuments.us/reader035/viewer/2022062421/56649c775503460f9492c0f5/html5/thumbnails/1.jpg)
bone
1000 g Ca++ stored in bone
Calcium homeostasis
BloodCa++
small intestine
kidney
Ca++lost in urine
Calcium in the diet
calcium lost in feces
Ca++ absorbed into blood
calcium resorption
calcium deposition
![Page 2: Bone 1000 g Ca++ stored in bone Calcium homeostasis Blood Ca++ small intestine kidney Ca++ lost in urine Calcium in the diet calcium lost in feces Ca++](https://reader035.fdocuments.us/reader035/viewer/2022062421/56649c775503460f9492c0f5/html5/thumbnails/2.jpg)
intakeexcretion
1000 g Ca++ stored in bone
Calcium homeostasis
BloodCa++
small intestine
kidney
Ca++lost in urine
Calcium in the diet
calcium lost in feces
Ca++ absorbed into blood
calcium resorption
calcium deposition
storage
bone
![Page 3: Bone 1000 g Ca++ stored in bone Calcium homeostasis Blood Ca++ small intestine kidney Ca++ lost in urine Calcium in the diet calcium lost in feces Ca++](https://reader035.fdocuments.us/reader035/viewer/2022062421/56649c775503460f9492c0f5/html5/thumbnails/3.jpg)
Calcium cycling in bone tissue• Bone formation
– Osteoblasts• Synthesize a collagen matrix that holds Calcium
Phospate in crystallized form
• Once surrounded by bone, become osteocyte
• Bone resorption– Osteoclasts
• Change local pH, causing Ca++ and phosphate to dissolve from crystals into extracellular fluids
![Page 4: Bone 1000 g Ca++ stored in bone Calcium homeostasis Blood Ca++ small intestine kidney Ca++ lost in urine Calcium in the diet calcium lost in feces Ca++](https://reader035.fdocuments.us/reader035/viewer/2022062421/56649c775503460f9492c0f5/html5/thumbnails/4.jpg)
Calcium homeostasis
BloodCa++
small intestine
kidney
Ca++lost in urine
Calcium in the diet
calcium lost in feces
bone
Ca++ absorbed into blood
calcium resorption
calcium deposition
![Page 5: Bone 1000 g Ca++ stored in bone Calcium homeostasis Blood Ca++ small intestine kidney Ca++ lost in urine Calcium in the diet calcium lost in feces Ca++](https://reader035.fdocuments.us/reader035/viewer/2022062421/56649c775503460f9492c0f5/html5/thumbnails/5.jpg)
Hormonal Regulators
• Calcitonin (CT)
• Parathormone (PTH)
• 1,25 Vitamin D3
![Page 6: Bone 1000 g Ca++ stored in bone Calcium homeostasis Blood Ca++ small intestine kidney Ca++ lost in urine Calcium in the diet calcium lost in feces Ca++](https://reader035.fdocuments.us/reader035/viewer/2022062421/56649c775503460f9492c0f5/html5/thumbnails/6.jpg)
Calcitonin (CT)
• Secreted from the C cells in the thyroid
• Lowers Ca++ in blood
• Promotes deposition of Ca++ into bone (inhibits osteoclasts)
• Control of secretion from c-cells:
CT
![Page 7: Bone 1000 g Ca++ stored in bone Calcium homeostasis Blood Ca++ small intestine kidney Ca++ lost in urine Calcium in the diet calcium lost in feces Ca++](https://reader035.fdocuments.us/reader035/viewer/2022062421/56649c775503460f9492c0f5/html5/thumbnails/7.jpg)
Hormonal Regulators
• Calcitonin (CT)– Lowers Ca++ in the blood
– Inhibits osteoclasts
• Parathormone (PTH)
• 1,25 Vitamin D3
![Page 8: Bone 1000 g Ca++ stored in bone Calcium homeostasis Blood Ca++ small intestine kidney Ca++ lost in urine Calcium in the diet calcium lost in feces Ca++](https://reader035.fdocuments.us/reader035/viewer/2022062421/56649c775503460f9492c0f5/html5/thumbnails/8.jpg)
Parathormone (PTH)• Increases Ca++ in blood• Increases Ca++ resorption from the bone
– Stimulates osteoclasts– Increases number of osteoclasts
• Increases Ca++ resorption from nephron• Control of secretion:
• Necessary for fine control of Ca++ plasma levels
![Page 9: Bone 1000 g Ca++ stored in bone Calcium homeostasis Blood Ca++ small intestine kidney Ca++ lost in urine Calcium in the diet calcium lost in feces Ca++](https://reader035.fdocuments.us/reader035/viewer/2022062421/56649c775503460f9492c0f5/html5/thumbnails/9.jpg)
Hormonal Regulators• Calcitonin (CT)
– Lowers Ca++ in the blood
– Inhibits osteoclasts
• Parathormone (PTH)– Increases Ca++ in the blood
– Stimulates osteoclasts
• 1,25 Vitamin D3
![Page 10: Bone 1000 g Ca++ stored in bone Calcium homeostasis Blood Ca++ small intestine kidney Ca++ lost in urine Calcium in the diet calcium lost in feces Ca++](https://reader035.fdocuments.us/reader035/viewer/2022062421/56649c775503460f9492c0f5/html5/thumbnails/10.jpg)
1,25 Vitamin D3• Increases Ca++ uptake from the gut
– Increase transcription and translation of Ca++ transport proteins in gut epithelium
• Minor roll: also stimulates osteoclasts– Increase Ca++ resorption from the bone
Cholesterol precursor 7-dehydrocholesterol
UV
Vitamin D3
25 Vitamin D3
1,25 Vitamin D3
Low plasma Ca++ increase kidney enzymes
![Page 11: Bone 1000 g Ca++ stored in bone Calcium homeostasis Blood Ca++ small intestine kidney Ca++ lost in urine Calcium in the diet calcium lost in feces Ca++](https://reader035.fdocuments.us/reader035/viewer/2022062421/56649c775503460f9492c0f5/html5/thumbnails/11.jpg)
Hormonal Regulators• Calcitonin (CT)
– Lowers Ca++ in the blood– Inhibits osteoclasts
• Parathormone (PTH)– Increases Ca++ in the blood– Stimulates osteoclasts
• 1,25 Vitamin D3– Increases Ca++ in the blood– Increase Ca++ uptake from the gut– Stimulates osteoclasts
![Page 12: Bone 1000 g Ca++ stored in bone Calcium homeostasis Blood Ca++ small intestine kidney Ca++ lost in urine Calcium in the diet calcium lost in feces Ca++](https://reader035.fdocuments.us/reader035/viewer/2022062421/56649c775503460f9492c0f5/html5/thumbnails/12.jpg)
Calcium homeostasis
BloodCa++
small intestine
kidney
Ca++
Ca++
Ca++
bone 1,25 Vit. D3 (+)
1,25 Vit D3
deposition
Calcitonin (-)
Ca++PTH
Parathormone (+)
resorption