Key Phrases:

1. Transplant operations [are carried out at specialist transplant units. They] are never split across more than one unit.
An operation takes place at 1 Unit.

2. Each unit is based at one hospital only
A unit can only be in 1 hospital

3. Specialises in one type of transplantation
A unit has 1 specialisation

4. A unit can transplant the other types of organ which lie outside of its area of expertise.
A unit does not specifically have to transplant it's specialisation

5. Some hospitals host more than one transplant unit.
However some do not have a transplant unit.
A hospital can have 0, 1 or many transplant units.

- **Transplant Operation**:
    - Involves a **Donor** [1:1] and a **Patient** [1:1].
        - Encompasses one or more **Organs** [1:M].
- **Donor**:
    - May be associated with one or more **Transplant Operations** [1:M].
- **Patient**:
    - May be associated with one or more **Transplant Operations** [1:M].
- **Organ**:
    - Is involved in one or more **Transplant Operations** [M:1].
- **Specialist Transplant Unit**:
    - Is tied to one **Hospital** [1:1].
    - Specialises in one type of **Organ** transplantation [o:1].
    - Can handle other types of **Organ** transplants outside its specialization [o:M].
- **Hospital**:
    - Can host one or more **Specialist Transplant Units** [1:M].
    - Not all hospitals have a **Transplant Unit** [o:1].

`Hospital` -|---o-< `TransplantUnit`

- One hospital can have 0, 1 or many Units.
- A unit must have a hospital, and only 1.