How much blood is in a cat's body?

I'm referring to the domestic cat. The domestic cat has about half a pint of blood inside the body that passes around their body once every 11 seconds. This is about 250+ milliliters (8.5 oz). The cat's heart beats at 110 bpm to 140 bpm. This is about twice the human heart rate. 

Photo: Pixabay

The cat's circulatory system comprises the heart, a network of arteries and veins, the spleen and a reservoir of blood. The blood goes from the heart to the lungs changing colour from blue to crimson. Iron atoms in the haemoglobin molecules of red blood cells discharge carbon dioxide and latch onto oxygen molecules which have been inhaled by the cat.

Red blood cells have a lifespan of about 2 to 6 weeks. They are produced in bone marrow on a hormonal signal. There are 270 million haemoglobin molecules in every red blood cell. Each molecule of haemoglobin contains four atoms of iron. Each molecule of haemoglobin can transport over 1 billion molecules of oxygen.

See a page on cat anatomy.