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Please note, that most of the literature about the anatomy of cats is in English.

Important note:
Some articles are based on experiments done with cats: We are strictly against all animal experiments, which harm the animal. But, even it is very tough to read such articles about animal experiments, they provide necessary information to understand the cat's anatomy better.



Skeleton of cats

The heart of the cat


the heart Click on the term to get a short description.

What is Diastole and Systole?

The heart is a muscular hollow organ, whose masculature (myocard) is covered by an outer skin (Epicard, Pericard) and outlaid with a multi-level inner skin (Endocard). The heart is separated into two halves by the cardiac septum, the two halves work like pumps. These pumps provide the blood circulation in its circulation system by the automatic change between the contraction of the muscle (systole) and dilatation of the muscle (diastole).

Contraction of atria Contraction of chambers
1. Contraction of atria 2. Contraction of chambers

The black arrows show the electrical pathway.
The red, thick arrows show the blood flow.

Sequence of heartbeats

  • The sinoatrial node (SA-node) in the right atrium works like a small built-in timer. It fires off an electrical impulse in regular intervals (About 110-130 per minute when the cat rests and faster when the cat runs fast. This controls the heart rate.) Each impulse spreads across both atria which causes them to contract. This pumps blood through the one-way valves into the ventricles.
  • The electrical impulse gets to the atrioventricular node (AV-node) located at the lower right atrium. The AV-node acts like a junction box and the impulse is delayed slightly. Most of the tissue between the atria and ventricles does not conduct the impulse. But a thin band of conducting fibers, called the atrioventricular bundle (AV-bundle), acts like thin wires and carries the impulse from the AV-node to the ventricles.
  • The AV-bundle is split into two branches - a right and a left branch. These branches then split into many tiny fibers (the Purkinje system) which carry the electrical impulse throughout the ventricles. Thus the ventricles contract and pump blood through the one-way valves into large arteries.
    • The arteries coming from the right ventricle take the blood to the lungs.  
    • The arteries coming from the left ventricle take the blood to the rest of the body.
  • After the contraction the heart rests for a short time (diastole). The blood coming back to the heart from the large veins fills the atria during the diastole.
    • The veins coming into the left atrium come from the lungs and their blood is full of oxygen.
    • The veins coming into the right atrium come from the rest of the body and carry blood depleted of oxygen.

This sequence is repeated during each heartbeat. Closing of the valves causes a tone which can be heard by the veterinary with the stethoscope.

Heart rate

The heartbeats normally match the pulse.

Heart rate (beats = heart cycles / minute)
Organism average rate normal range
Horse 44 23 - 70
Cow 65 60 - 70
Human 70 58 - 104
Dog 115 100 - 130
Cat 120 110 - 140
Rabbit 205 123 - 304
Rat 328 261 - 600
Guinea pig 280 260 - 400
Hamster 450 300 - 600




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