Class notes
Calcium Disorders
- Course
- Institution
Lecture notes on Calcium Disorders
[Show more]
Seller
Follow
polinalobacheva
Reviews received
Content preview
Calcium functions:1. Structural: bone, teeth
2. Neuromuscular: release for neurotransmitters, initiation of muscle
contractions
3. Enzymic function: coenzyme for coagulation factors (transfusion
science)
4. Hormonal: intracellular second messenger
5. Cell adhesion
Plasma calcium exists in 3 forms:
1. Free ionised (Ca2+): 47% physiologically active
2. protein-bound : 46%
3. Complexed calcium (citrates, phosphates): 7%
Reference range:
- Total calcium 2.20-2.60 mmol/L
- Ionised calcium 1.20-1.37 mmol/L
- If the albumin concentration in the blood
changes, so will the total calcium concentration,
but not the free ionized Ca2+
Changes in [albumin] affect total calcium but not
[Ca2+]: correction factor is applied to get correct
[calcium]
1. If [albumin] < 40g/L:
a. Correct [calcium] = measured total
[calcium] + 0.02 (40 - [albumin])
2. If [albumin] > 45g/L:
a. Correct [calcium] = measured total
[calcium] - 0.02 ([albumin] - 45)
3. Alternative: measure ionised plasma [Ca2+]
directly
Factors affecting plasma [Ca2+] - pH
- Acid-base balance
- Binding of calcium to protein is pH dependent
Acidosis: high plasma [Ca2+]
Alkalosis: low plasma [Ca2+]
(Doesn’t change TOTAL calcium)
Regulation of plasma calcium
- Parathyroid hormone (PTH)
- Calcitriol or also called 1,25-dihydroxycholecalciferol or 1,25-DHCC
, Vitamin D derivative:
1. Diet: Cholecalciferol
2. Skin: Cholecalciferol
3. Liver: 25-dihydroxycholecalciferol
4. Kidneys: 1,25-dihydroxycholecalciferol; 24,25-dihydroxycholecalciferol (inactive)
1,25-DHCC synthesis activated by:
1. Increase in PTH
2. Decrease in Calcium
3. Decrease in Phosphate
Synthesis of calcitriol: Normal/high plasma calcium 24-hydroxylase converts 25-HCC to 24,25-DHCC (inactive)
Calcitriol function:
- Increase calcium absorption in gut
- Increase phosphate absorption in gut
- Increase bone resorption
Calcitonin - opposes PTH function:
1. Synthesised in C cells of thyroid
a. 32 amino acid peptide
b. Released in response to increase of Ca2+, inhibited by decrease of Ca2+
2. Inhibits Ca2+ release from bone
3. Inhibits renal calcium reabsorption
Regulation of calcium homeostasis
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller polinalobacheva. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $13.05. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
81989 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now