She used glass to make a slightly larger than life size interpretation of a resin cast on display at Guy's Hospital, London. She has titled it "Access", because it presents to us anatomical organs that we never see, although they are part of us.
Glass exposes that illusive intimacy perfectly. Like our innards, it is solid. But, unlike our innards, you can see right through it.
Cattrell, 35, an RCA graduate, consulted George Bridgeman, senior chief technician at Guy's Hospital, London. He sees cadavers every day. She never saw one, but she studied the detailed casts he makes by pouring resin into the tree-like formations of blood or air vessels before removing the flesh itself with a corrosive solution. His colourfully painted casts are used to teach students anatomy.
It is impossible to work so closely with nature - even expired nature - without developing an aesthetic appreciation of it. Mr Bridgeman's aesthetic is somewhat different from Cattrell's concept of paradox. For him, the wonder lies in the way veins and alveolae not only transport blood and air, but also form the substance of heart and lungs.
He says: "If you pour resin into the aorta then dissolve the tissue away, you end up with something that looks exactly like a heart because there is not a single square centimetre of tissue that does not have a blood supply. If it had none, it would die.
"It is the same with the bronchial tree. The branches go to every part. I sit back and think how beautiful it is".
The minds of the medic and the artist came together when Mr Bridgeman started to show Cattrell the anatomy of the nervous system (which has to be copied in wire, instead of cast, because its channels are tiny and tubeless). He showed her one of those cartoon-like diagrams showing how different areas of the body's surface vary in sensitivity according to how many nerve-endings they have - the head, hands and feet are shown big, the lips and tongue grotesquely so, the torso tiny. There are far fewer nerve endings in the internal organs, he told her, than in the surface of the skin. That confirmed her vision of an interior world of which we are scarcely aware. "As a child", she says, "I had seen a diagram like that, but I didn't understand it. In fact, I found it rather frightening.
She adds: "We know we have an outside and an inside, but there are also these channels that are unconsciously taking outside things - air, food, even dust - straight into the centre of our bodies. When things are running well, we take for granted all the automatic processes that are going on - the rhythms of breathing, the pulse. I'm not a religious person, but this is the closest I have come to a belief system.
"I'm also fascinated by the way cells divide to create a person. You wonder how it happens - and this is one of the advantages of using glass. You can look closely at a glass sculpture but it's still difficult to work out how it has been made".
She commissioned a professional glass-blower to make the trachea and the twin chambers of the heart - alternate heating and blowing produced the appropriate bulges. The delicate filigree of the bronchial tree she made herself, heating, sticking on and teasing out thin rods of glass under a turret flame lamp of the kind used by glass sculptors on seaside piers. She chose strong Pyrex silicate glass, used by makers of laboratory apparatus, rather than the soda glass of pier sculptors.
She intended the result to look like a cross between a diagram and reality. "It's so fragile, so fine, that it looks like something that's not really there. But if you brushed past it, it would break".
Cattrell has exhibited widely and is currently a senior lecturer in fine art at the Cheltenham and Gloucester College of Higher Education. Her next challenge will be the nervous system.
Prices: from pounds 1,500. Annie Cattrell: 0181-964 5153. `Access' is in the group show `Small Miracles' organised by Rose Frain at Miracles, 5 St Stephen Street, Edinburgh EH3 5AN (0131-225 2294)