Have you ever wondered how marvellous the human body is? All of the organs and systems that work in the body enable us to survive and live in this world. It is amazing to know that these organs that made up the body system, were once a very small cell that is not seen with the naked eyes. Many diseases can occur due to the changes in the cell itself. In this DoctorOnCall’s article, we will learn the differences between hypoplasia and aplasia. Hypoplasia and aplasia are terms commonly used to describe changes in cells.
To understand these conditions, it is best to know a bit more about cells in general. The human body is made up of a vast amount of cells that is trillion of cells. Study shows that the average adult male human has around 36 trillion cells, females 28 trillion and children around 17 trillion. However, there is no one clear cut answer on how many cells in the human body as cells in the bodies are not packed in an uniform way. Think of a jar full of jelly beans, it is difficult to count merely by looking and even counting 10 cells each second, it would take thousands of years before counting can be finished. This is because cells come in different sizes and they grow with different densities.
There’s over 200 different cell types. Cells in the body divide and grow to become tissue. These tissues will then make up the organs. A number of organs will then make a system. It means that cells are the basic building of the human body. In normal cells, there are hundreds of genes controlling the cell division. Cell division allows cells to multiply and increase tissue sizes. Cell size is determined by the cell growth and cell division. Thus, when there is something wrong with the cell growth or cell division, the cell size is not regulated or becomes uniform as it should in normal people.
Hypoplasia is described as the incomplete or underdevelopment of an organ or tissue. This means that an organ or tissue with hypoplasia is below the average number of cells. Hypoplasia may occur in many parts of the body. There have been an array of conditions identified with hypoplasia being the main feature. Among the common ones are cerebellar hypoplasia, optic nerve hypoplasia, enamel hypoplasia, pulmonary hypoplasia and cardiac hypoplasia. Symptoms of hypoplasia depend on the organ affected. For example, in optic nerve hypoplasia, known as congenital anomaly that is presented at birth, it can cause abnormal eye movement and severe vision impairment.
The term hypoplasia may often be confused with aplasia. However, aplasia describes the absence of organ or tissue as it is not developed at the earliest stage. This is contrast with hypoplasia as in hypoplasia it is more of a reduced or abnormal shape of the organ or tissue. In most cases of aplasia, there are no precursor cells. Precursor cells are found in hypoplasia but are usually not enough. Precursor cells are stem cells that have the capacity to form new cells. Thus, aplasia can be said to be a condition where there is no precursor cell to even develop organs or tissues, making the organ or tissue absent.
Aplasia, similar to hypoplasia, can occur at any organ or tissue. Common ones include acquired pure red cell aplasia (PRCA), aplasia cutis congenita, germ cell aplasia, thymic aplasia, radial aplasia and aplasia of the lung. In some cases, conditions associated with aplasia may be associated with hypoplasia. For example, a person with radial aplasia may not be missing the whole radius bone but have a radius bone that is shorter than usual.
Both hypoplasia and aplasia are the result of growth failures during embryogenesis. This means that both conditions already occur at birth but in some condition, may only be diagnosed or identified as children or adults. Both hypoplasia and aplasia can cause life long conditions which require long-life care or support.
Speaking of abnormal cells, hypoplasia and aplasia should not be confused with dysplasia. Dysplasia is a term used to describe the abnormal cells found within tissue. Dysplasia is usually a response toward chronic irritation such as inflammation or smoke. Dysplasia may occur in babies such as developmental dysplasia of the hip. Dysplasia causes changes in the normal shape, size or organisation of the cells. Dysplasia is often associated with pre-cancer lesions.
In essence, cells are the brick of the many tissues and organs in the human body. Abnormal changes in cells can cause symptoms or diseases. Among the common changes in cells are hypoplasia and aplasia. Hypoplasia and aplasia are not the same condition. Both hypoplasia and aplasia can affect any part of the human body. Most cases of hypoplasia and aplasia occur at birth but some are only seen by doctors in later life. It is important for those with diseases mediated by hypoplasia or aplasia to get proper treatment and support.