MSK 7 – Simplifying Calcium and Phosphate Regulation

Calcium and Phosphate regulation is complicated as it ties the GI, kidneys and bones together.
Join us as we go through how PTH, Calcitriol regulate calcium and phosphate.

Calcium and Phosphate regulation

Calcium and Phosphate regulation

In short:

PTH: increases [calcium], decreases [phosphate]
Calcitriol: increases [calcium], increases [phosphate]

FOUR actions of Parathyroid Hormone(PTH):

1. Increase bone resorption leading to rise in calcium and phosphate.
2. Phosphate is filtered in the kidney and it’s resorption is blocked by PTH. This leads to an overall drop in phosphate levels.
3. Calcium is filtered in the kidneys but the resorption is increased by PTH. This leads to an overall increase in calcium concentration.
4. PTH increases Calcitriol (activated Vit D) production in the kidneys. This indirectly increases calcium absorption from the intestines.

FOUR actions of Calcitriol (activated vitamin D)

1. Increases bone resorption causing a rise in calcium and phosphate levels.
2. Calcitriol INCREASES the reabsorption of phosphate in the kidneys.
3. Calcitriol increases the reabsorption of calcium in the kidneys.
4. Calcitriol acts DIRECTLY on the intestines to increase calcium absorption from diet.

MSK 1 – Overview of Muscles

Bicep muscles, heart muscle and stomach muscle. All very different.

Join us on the Common Rounds to find out how they are different at a fundamental level.

The FIVE white blood cells you must know.

White blood cells can be classified as either phagocytes or immunocytes. Of the phagocytes they can be further classified as granulocytes (Basophils, Eosinophils and Neutrophils) as well as monocytes. The immunocytes are the lymphocytes including B and T cells and Natural Killer Cells.

The following is a short blurb on what each does:

Basophils: Are the least common leucocyte, contributing to less than 1% of circulating leucocytes. They have a intensely basophilic (blue) granular appearance. Have IgE attachment sites that lead to histamine release for degranulation.  When migrated into the tissue, basophils mature into Mast Cells.

Eosinophils: Contribute towards 1% of circulating leucocytes. Stain red with eosin. Have a strong role in allergic responses and host defence against parasites. Their production is stimulated by IL-5. Release granules that contain basic proteins and also peroxides.

Neutrophils: Contribute 75% to the circulating leukocytes. Multi lobular nucleus with a granulated appearance. They usually maintain in the circulation. Only present in tissues in large numbers during acute inflammation, killing invading microorganisms via phagocytosis.

Monocytes: In the blood they are known as monocytes, once they migrate into the tissue they mature into macrophages (or histiocytes) . In different tissues they are known as different names.  You may know them by:

  • Kidney: Intraglomerular mesangial cells
  • Brain: Microglia
  • Serosa: Macrophages
  • Lung: Alveolar macrophages
  • Liver: Küpffer cells
  • Spleen: Sinus macrophages, Antigen Presenting Cells (APC)
  • Bone Marrow: macrophages, APC
  • Lymph nodes: macrophages, APC

Lymphocytes: Second most common circulating leukocytes making up nearly 25%. Appear round and have a densely stained nucleus. They include B cells, T cells and also NK cells.

Reference sources:

  1. Young B, Lowe J, Stevens A, Heath J. Blood. Wheater’s Functional Histology. 5th ed. Philadelphia: Elsevier limited; 2006. p. 46–56.
  2. Hoffbrand A, Moss P. White cells: Granulocytes and monocytes.Essential Haematology. 6th ed. Oxford: Wiley-Blackwell; 2011.

Episode 4: Control of body weight – How to survive in the obesogenic environment

Our world is an obesogenic environment. Join us as we explore the key hormones related to appetite regulation, neural pathways that control our appetite and also other hedonistic pathways that make us hungry.

Are you craving for maccas right now? Well put down that burger and listen to what we have to say before you take a bite. You’re craving may not be because you’re hungry and low on nutrition.

Listen to our show

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Episode 1: Upper GI physiology – What you need to know

Episode 1


What are the four layers of the GIT tract? What are the phases of swallowing? How does peristalsis occur? What nerves are involved up regulating and down regulating motility? What on earth are secretin, CCK, GIP?

Listen to Andy and Hamed attempt to describe these concepts in their very first show. They may be a bit shy, so be nice guys!

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