Term
| What are 4 physiological functions of Ca2+? |
|
Definition
1. Neural transmission
2. Muscle contraction
3. Blood clotting
4. Bone and teeth formation |
|
|
Term
| If you have a __________ in Ca2+ then you get a _____________ in neuronal firing thus _____________ membrane permeability. |
|
Definition
Increase
Decrease
Decrease
(get lethargy) |
|
|
Term
| If you have __________ Ca2+ then you _______________ firing rates and increase ______________ and ___________. |
|
Definition
decreased
increase
excitability and tetany |
|
|
Term
| How does Ca2+ contribute to muscle contractions? |
|
Definition
| It inactivates troponin/tropomyosin complexes to allow expression of active sites on actin filaments. |
|
|
Term
| How does Ca2+ aid in blood clotting? |
|
Definition
| It helps to convert prothrombin to thrombin |
|
|
Term
| T/F: Ca2+ is needed to make bone salts and is in our dentine and enamel. |
|
Definition
|
|
Term
| What are 4 physiological functions of PO4? |
|
Definition
1. Major cytoplasmic buffer- stabilizes pH
2. Major component in bone salts
3. Basis for energy
4. Essential for members and nucleic acids |
|
|
Term
| Around what levels do we want to maintain for both Ca2+ and PO4 in the blood? |
|
Definition
Ca2+ = 9-10 mg/100 mL
PO4 = 3.5-4 mg/100 mL |
|
|
Term
| What 3 principal calcitropic hormones are needed for Ca2+ and PO4 regulation? |
|
Definition
1. Parathyroid hormone (PTH)
2. Calciferols (Vit D. metabolites)
3. Calcitonin (CT) |
|
|
Term
| PTH acts by ____________ blood Ca2+ and _____________ blood PO4. |
|
Definition
|
|
Term
| Calciferols ______________ blood Ca2+. |
|
Definition
|
|
Term
| CT ___________ blood Ca2+ and ________ blood PO4. |
|
Definition
|
|
Term
| What is the principal function of Vit. D and its metabolites? |
|
Definition
| To promote Ca2+ absorption from the intestine |
|
|
Term
| T/F: Ca2+ is readily absorbed fromt he intestine while PO4 is not. |
|
Definition
| False; PO4 is can readily cross the intestinal lumen whereas the Ca2+ forms poorly soluble salts and does not get much absorbed. |
|
|
Term
| What is the precursor for 7 - dehydrocholesterol? |
|
Definition
|
|
Term
|
Definition
| 7- dehydrocholesterol in the skin + UV light & heat |
|
|
Term
|
Definition
|
|
Term
| In the liver, Vit. D3 is converted to _______________. |
|
Definition
25-hydroxycholecalciferol
aka
25(OH)D3 |
|
|
Term
| In which organ does the 25(OH)D3 get hydroxylated to become the active metabolite for Ca2+? |
|
Definition
|
|
Term
| What is the name of the active metabolite for Ca2+? |
|
Definition
Calcitriol
or
1, 25 dihydroxycholecalciferol |
|
|
Term
| What hormone regulates the hydroxylation reaction that occurs in the kidney to make Calcitriol? |
|
Definition
|
|
Term
| What is Calcitriol effect in the intestines? |
|
Definition
| It increases Ca2+ absorption by inducing Ca-binding proteins. |
|
|
Term
| What is an Calcitriol effect in bone? |
|
Definition
It increases Ca2+ absorption from bone.
It does this by increasing osteoclast activity and decreasing collagen synthesis by the osteoblasts. |
|
|
Term
| In the kidneys, Calcitriol _____________ Ca2+ reabsorption at the distal tubule. |
|
Definition
|
|
Term
| How does Calcitriol affect PTH levels? |
|
Definition
| It works via negative feedback within the parathyroid gland to inhibit the synthesis of PTH |
|
|
Term
| What is the net effect of Vit.D metabolites? |
|
Definition
| To increase plasma Ca2+ levels with little or no direct effect on PO4 levels. |
|
|
Term
| PTH is synthetized and secreted from ______________ located in the parathyroid glands. |
|
Definition
|
|
Term
| Which hormone was the first to be shown to undergo post-translational processing? |
|
Definition
|
|
Term
| What are the 3 effects PTH has in the kidneys? |
|
Definition
1. Increases Ca2+ reabsorption = Increase in plasma Ca2+
2. Decreases PO4 reabsorption = decrease in plasma PO4
3. Converts to active Calcitriol via 1-a-hydorxylase |
|
|
Term
| PTH works on osteoblasts in bone to release this substance? |
|
Definition
| Osteoclast differentiating factor (ODF) and IL-6 |
|
|
Term
| ODF and IL-6 increase the number and activity of ___________ which increases __________ thereby ___________ Ca2+ in the blood. |
|
Definition
Osteoclasts
bone reabsorption (breakdown)
Increasing |
|
|
Term
| The net effect of PTH is to ___________ plasma Ca2+ levels and ________ PO4 levels. |
|
Definition
|
|
Term
| Calcitonin is synthesized from ____________ which are aka C-cells located in they ___________ gland. |
|
Definition
Parafollicular cells
thyroid |
|
|
Term
| What is the physiological function of Calcitonin? |
|
Definition
| To decrease Ca2+ blood levels via cAMP. |
|
|
Term
| Calcitonin promotes new bone formation by |
|
Definition
| Blocking the formation of osteoclasts from reticulo-endothelial cells which thus decreases osteoclasts activity. |
|
|
Term
| What effect does Calcitonin have on PO4 levels in the kidneys? |
|
Definition
| It decreases there reabsorption thus decreasing their plasma PO4. |
|
|
Term
| What is the net effect of Calcitonin? |
|
Definition
| To decrease plasma Ca2+ and to a lesser extent decrease PO4 levels. |
|
|
Term
| An increase of Ca2+ in plasma above the normal of 10 mg/100 mL is to be |
|
Definition
|
|
Term
| A decrease in Ca2+ below the normal of 9 mg/100 mL is said to be |
|
Definition
|
|
Term
| What are 3 causes for Hypercalciemia? |
|
Definition
1. Primary Hyperparathyroidism (major)
2. secondary Hyperparathyroidism
3. Malignancy assocaited |
|
|
Term
| What are some clinical manifestations of Hypercalciemia? |
|
Definition
1. Increase calcium stones
2. Osteitis fibrosa cystica
3. Hypertension/ bradycardia
4. Constipation, nausea, vomiting, anoxeria
5. Weakness, hypertonia
6. Depression, lethargy, psychosis, slow witted |
|
|
Term
| What pnuemonic did he mention to remember Hypercalciemia? |
|
Definition
| Stones, bones, abdominal groans, and psychic moans. |
|
|
Term
| What is osteitis fibrosa cystic? |
|
Definition
Weakening and demineralization of the bone
Get bone pain
Tumors and cysts
Leads to increase incidence of fractures |
|
|
Term
| What are the 2 known causes for Hypercalciemia associated with Primary Hyperparathyroidism. |
|
Definition
1. Adenoma of 1 or + of the parathyroid glands
2. Hyperplasia of all 4 glands |
|
|
Term
| With Primary Hyperparathyroidism you can expect to find ________ levels of PTH and a _____________ in both PO4 and Cl. |
|
Definition
|
|
Term
| T/F: Primary Hyperparathyroidism is more prevalent in males and is age associated. |
|
Definition
| False; although it is age associated it is not more common in males but more in females. |
|
|
Term
| What is secondary hyperparathyroidism? |
|
Definition
| Is associated with chornic renal disease/failure where there is reduced or damaged Ca2+ receptors in the kidney. |
|
|
Term
| Hypercalciemia due to metastatic diseases are associated with |
|
Definition
| Carcinomas of lung, kidneys and breast |
|
|
Term
| Why do metastatic diseases show similar clinical presentations as does hyperparathyroidism? |
|
Definition
| Because there is this PTH related protein (looks like PTH) that binds to the PTH receptors and mimics there bioactivity. |
|
|
Term
| What are 3 causes for Hypocalciemia? |
|
Definition
1. Hypoparathyroidism
2. Pseudohypoparathyroidism
3. Vit. d. associated disorders |
|
|
Term
| In Hypoparathyroidism there is decrease in parathyroid activity due to |
|
Definition
| thyroid surgery or destruction of parathyroid glands |
|
|
Term
| In Hypoparathyroidism there is a decrease in __________. |
|
Definition
|
|
Term
| T/F: In pseudohypoparathyroidism there is PTH resistance that thus increases the PTH in plasma. |
|
Definition
|
|
Term
| What are some clinical manifestations of Hypocalciemia? |
|
Definition
1. Tetany
2. Heart Failure
3. Dry skin and brittle nails
4. Hypoplasia of enamel
5. Cataract
6. Osteomalacia and rickets
7. Seizures, confusion
8. Movement disorders due to calcification of basal ganglia |
|
|
Term
|
Definition
|
|
Term
|
Definition
It is epiphyseal dysplasia and longitunidal growth delay in childer
or aka bone dimineralization |
|
|
Term
| Hypocalciemia due to Vit D. deficiency can be caused by |
|
Definition
1. diet
2. Lack of sunlight
3. Defect in 1-a-hydroxylase activity at the kidney
|
|
|
Term
| A Vit. D deficiency can produce Vit. D. dependent rickets ________. |
|
Definition
|
|
Term
| A defective Vit. D receptor can lead to Vitamin D-dependent Rickets ____________ |
|
Definition
Type II
(Childhood Rickets) |
|
|
Term
| With Type II rickets there is a ____________ in both Vit. D and PTH |
|
Definition
|
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