Archive for December, 2012

Chemotaxis for Phagocyte!

Chemotaxis

When the body is invaded by infectious organisms such as bacteria, viruses or parasites, it is vital that the body’s immune cells get to the sourse of infection as quickly as possible.

Infectious organisms (known as ‘pathogens‘) as well as damaged cells all release chemicals into the tissues around the infection or area of cell damage.  The immune system recognises the presence of these chemicals and sends its immune cells in the direction of the chemicals in order to fight the pathogens or remove the damaged cells.  This process is known as ‘Chemotaxis‘ and the first immune cells to arrive at the problem are the ‘Phagocytes‘.

Neutrophil engulfing anthrax bacteria, taken w...

Neutrophil (a type of phagocyte) engulfing anthrax bacteria. (Photo credit: Wikipedia)

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There are six basic nutrient groups.  Three of them provide energy and three are non-energy nutrients.

Energy Nutrients

  • Carbohydrates (provide energy and fibre)
  • Fats (provide slow release energy, improves taste, stores vitamins A, D, E & K)
  • Proteins (provides energy and used for growth and healing)

Non-Energy Nutrients

  • Vitamins (required for the body’s chemical reactions for metabolism)
  • Minerals (required for the body’s functions)
  • Water (essential for all the body’s cells, makes up 60-70% of the body’s weight)


There are three forms of carbohydrates:

Sugars – Provide energy quickly, they are relatively simple molecules and are absorbed and used efficiently by the body – glucose is the most important simple sugar.

Starches – Provide energy more slowly as they are longer chains which must first be broken down into simple sugars before they can be used.

Domestic Rabbit

Fibre – Fibre is an indigestible form of carbohydrate in cats and dogs.  Rabbits, Horses and Ruminants (like cattle and sheep) can break down fibre to use as energy.  Cats and dogs cannot break down fibre and so it can be used to bulk out the diet and control an animal’s weight by  making the animal feel full without providing lots of energy.