L8 (T1): Calcium homeostasis, hyper and hypocalcaemia

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Questions and Answers

What percentage of normals have Chvostek’s Sign present?

20%

10% (correct)

15%

What percentage of calcium is protein-bound in the blood?

100%

60%

80%

40% (correct)

What percentage of calcium is ionized (free) in the blood?

20%

30%

50% (correct)

40%

What is the normal range for blood calcium level?

2.0 - 2.5 mmoles/l Signup and view all the answers

What determines the release of Parathyroid hormone (PTH)?

Serum Calcium concentration Signup and view all the answers

Where are the PTH1 receptors located?

Bone Signup and view all the answers

What is the biological effect of PTH on bone?

Stimulation of osteoblasts Signup and view all the answers

What is the primary action of PTH in the kidney?

Suppression of calcium excretion Signup and view all the answers

Which of the following is a complication of primary hyperparathyroidism?

Osteoporosis Signup and view all the answers

What is the common cause of secondary hyperparathyroidism?

Low serum 25 OH vitamin D Signup and view all the answers

What is a cause of hypoparathyroidism?

Autoimmune disorder Signup and view all the answers

What is the effect of vitamin D deficiency in the elderly?

Reduced bone mineral density Signup and view all the answers

What is the primary purpose of the presentation mentioned in the text?

To be used for private study only Signup and view all the answers

What may happen if the presenter disregards the instructions for the use of the presentation?

Breach of copyright Signup and view all the answers

Which medical condition can destabilize neurons due to low calcium levels?

Hypocalcaemia Signup and view all the answers

What is the physical sign of hypocalcaemia described as 'Trousseau’s sign'?

Carpopedal spasm Signup and view all the answers

What is the role of calcium in blood clotting as mentioned in the text?

It is involved in blood clotting Signup and view all the answers

Which medical professional is presenting in the mentioned presentation?

Dr. Trevor Wheatley Signup and view all the answers

Where is the Princess Royal Hospital located?

Sussex, UK Signup and view all the answers

What is the specialty of Dr. Trevor Wheatley as mentioned in the text?

Endocrinologist Signup and view all the answers

What is the effect of hypocalcaemia on neurons?

Destabilizes neurons Signup and view all the answers

What is the recommended action if someone has a first fit according to the text?

Check the serum calcium Signup and view all the answers

What is the significance of calcium in exocytosis as mentioned in the text?

It is involved in neurotransmitter secretion Signup and view all the answers

What is the primary biochemical process mentioned in relation to calcium in the text?

Many biochemical processes Signup and view all the answers

What is the primary focus of the presentation mentioned in the text?

Endocrinology and the regulation of hormones Signup and view all the answers

What is the suggested action if someone has a single nodule that autonomously produces excessive hormones?

Immediate removal of the affected gland Signup and view all the answers

What was the specialty of Dr. Trevor Wheatley mentioned in the text?

Endocrinology Signup and view all the answers

What is the effect of having an excess of hormones, as mentioned in the text?

Mechanisms for hormone removal are activated Signup and view all the answers

What was the humorous perspective shared by the infectious diseases doctor about endocrinology?

Endocrinology is essentially very simple and easy to comprehend Signup and view all the answers

What is the primary problem associated with having an excess of hormones?

Mechanisms for hormone removal are activated Signup and view all the answers

What may be a consequence of an enlarged thyroid gland?

Breathing difficulties due to pressure on the trachea Signup and view all the answers

What is the consequence of hypercalcemia on kidney function?

Increased urinary calcium excretion Signup and view all the answers

What are Chvostek's sign and Trousseau's sign indicators of?

Neuromuscular irritability due to calcium imbalance Signup and view all the answers

What is the effect of hypocalcemia on the body?

Seizures Signup and view all the answers

What is the primary cause of osteoporosis?

Calcium imbalance Signup and view all the answers

What can result from surgeons damaging the parathyroid glands during thyroid surgery?

Low calcium levels and neuromuscular symptoms Signup and view all the answers

What is the main consequence of hypercalcemia mentioned in the text?

Increased risk of kidney stones and worsened osteoporosis Signup and view all the answers

What is the role of parathyroid glands in response to low calcium levels?

Secrete parathyroid hormone Signup and view all the answers

What is the function of the calcium-sensing receptor in the chief cells of the parathyroid glands?

Detect low calcium levels and trigger parathyroid hormone secretion Signup and view all the answers

How does the body adjust total calcium levels for albumin levels?

To closely align with ionized calcium Signup and view all the answers

What is the primary response of the body to low calcium levels?

Increased parathyroid hormone secretion Signup and view all the answers

What is the significance of the parathyroid glands in calcium control?

They play a crucial role due to their production of parathyroid hormone Signup and view all the answers

What is the primary site of action for parathyroid hormone (PTH) in the body?

Bone and kidney Signup and view all the answers

How does parathyroid hormone (PTH) affect calcium levels in the bloodstream?

It increases calcium absorption in the kidneys Signup and view all the answers

What is the consequence of low magnesium levels in relation to parathyroid hormone (PTH)?

Hypercalcemia and related health issues Signup and view all the answers

How does parathyroid hormone (PTH) influence phosphate levels in the kidneys?

It decreases phosphate absorption in the kidneys Signup and view all the answers

What is the role of the kidney in response to parathyroid hormone (PTH) activity?

Activation of vitamin D to enhance calcium absorption Signup and view all the answers

What is the primary effect of parathyroid hormone (PTH) on bone cells?

It stimulates bone breakdown cells to increase serum calcium levels Signup and view all the answers

What triggers the production of vitamin D in the body?

Ultraviolet light hitting the skin Signup and view all the answers

What is the primary role of the kidney in vitamin D processing?

Stimulating the production of active vitamin D Signup and view all the answers

What can lead to extremely low phosphate levels and related health issues?

Excessive parathyroid hormone production Signup and view all the answers

What inhibits the production of active vitamin D in the body?

Fibroblast growth factor 23 Signup and view all the answers

What is a consequence of excessive parathyroid hormone production?

Increased serum calcium levels Signup and view all the answers

How does the body's endocrine system regulate vitamin D production?

Through a negative feedback loop Signup and view all the answers

Study Notes

Vitamin D and Calcium Regulation in the Body

Ultraviolet light hitting the skin triggers the production of vitamin D, which is effective in younger people but requires initial stores of the vitamin.
Vitamin D levels in the United Kingdom's population are generally low due to limited sun exposure and diet.
Vitamin D can also be obtained from the diet, but its sources may not be sufficient to meet the body's needs.
Elderly individuals with poor diets and limited sun exposure can have very low vitamin D levels, leading to health issues.
Vitamin D is hydroxylated in the liver and then undergoes further processing in the kidney under the influence of parathyroid hormone (PTH).
The kidney's role in vitamin D processing includes increasing calcium reabsorption and stimulating the production of active vitamin D, which enhances calcium absorption in the gut.
The body's endocrine system regulates vitamin D production through a negative feedback loop to maintain balance.
Fibroblast growth factor 23, produced by bone cells, can inhibit the production of active vitamin D, contributing to the regulation of calcium and phosphate levels.
Excessive production of fibroblast growth factor 23 can lead to extremely low phosphate levels and related health issues.
Excessive parathyroid hormone production, often due to a single nodule behaving autonomously, can lead to increased serum calcium levels and phosphate excretion.
The diagnosis of excessive parathyroid hormone production is relatively straightforward, as it is associated with increased serum calcium levels.
High levels of parathyroid hormone increase phosphate excretion by the kidneys.

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Description

Test your knowledge of endocrine control of calcium homeostasis with this quiz designed for medical students. Covering topics such as parathyroid hormone, calcitonin, and vitamin D, this quiz will help you understand the intricate regulation of calcium levels in the body.