What is the Difference Between Undifferentiated Sperm Cells and Sperm

The main difference between undifferentiated sperm cells and sperm is that the undifferentiated sperm cells are the spermatogonia in the seminiferous tubules of the testis that differentiate and undergo meiosis to form spermatids, which differentiate into sperms whereas the sperm is the functionally-specialized, male gamete. Furthermore, undifferentiated sperm cells are diploid while the sperm is haploid. 

Undifferentiated stem cells and sperm are two types of cells that occur at the beginning and the end of the sperm formation process respectively. Moreover, this process of sperm formation is known as spermatogenesis. 

Key Areas Covered 

1. What are Undifferentiated Sperm Cells
     – Definition, Differentiation, Meiosis
2. What is the Sperm
     – Definition, Maturation, Features
3. What are the Similarities Between Undifferentiated Sperm Cells and Sperm
     – Outline of Common Features
4. What is the Difference Between Undifferentiated Sperm Cells and Sperm
     – Comparison of Key Differences

Key Terms 

Differentiation, Meiosis, Sperm, Spermatogenesis, Spermiogenesis, Undifferentiated Sperm Cells 

What are Undifferentiated Sperm Cells 

Undifferentiated sperm cells are the spermatogonia inside the seminiferous tubules of the testis. In general, these cells undergo mitosis to produce new cells. The dividing cells have two functions. A part of the dividing cells (Type A cells) replenishes the cell population of the spermatogonia. Meanwhile, the second part of the dividing cells (Type B cells) undergoes spermatogenesis which produces haploid sperms.

Figure 1: Spermatogenesis

Generally, Type B spermatogonia are diploid. They differentiate into the primary spermatocytes, which undergo meiosis I to form secondary spermatocytes. In addition, each secondary spermatocyte undergoes meiosis II to form two, haploid spermatids. These spermatids are small, circular cells, which undergo differentiation and maturation to form the sperms.  

What is the Sperm 

The sperm is the mature and motile male gamete specialized from the spermatids. Spermiogenesis is the name for this maturation process; this is also the final part of spermatogenesis. There are four phases of spermiogenesis as well. They are: 

1. Golgi phase – The polarity of the circular spermatids increases to form a head region. Also, the enzymes of the Golgi apparatus are responsible for the formation of acrosome in the head region. Mitochondria of the cell gather to form an axoneme in the distal region of the head. For instance, the chromatin condenses to inactivate transcription. 
2. Cap phase – Golgi apparatus covers the nucleus to form the acrosomal cap. 
3. Tail formation – One of the centrioles of the cell elongates to form the tail. 
4. Maturation – Sertoli’s cells phagocytose the excess cytoplasm of the spermatids.  

Figure 2: A Mature Human Sperm

Furthermore, spermiogenesis ends with the production of a mature sperm, which is a small, compact and elongated cell. Its tail is made up of a flagellum. Moreover, the sperm contains a very small amount of the cytoplasm. It also has the ability to fertilize the ovum by travelling towards it.  

Similarities Between Undifferentiated Sperm Cells and Sperm 

• Undifferentiated sperm cells and sperm are two types of cells in the seminiferous tubules of the testis. 
• Moreover, they are responsible for forming male gametes. 

Difference Between Undifferentiated Sperm Cells and Sperm 

Definition 

Undifferentiated sperm cells are the cells produced at an early stage in the formation of spermatozoa, formed in the wall of a seminiferous tubule and giving rise to spermatocytes by mitosis. In contrast, sperm refers to a cell which is produced in the sex organs of a male animal and can enter a female animal’s egg and fertilize it. Hence, this is the main difference between undifferentiated sperm cells and sperm.

Significance 

Also, undifferentiated sperm cells are spermatogonia while sperm is the functionally-specialized male gamete. 

Ploidy 

Ploidy is also a major difference between undifferentiated sperm cells and sperm. Undifferentiated sperm cells are diploid while the sperm is haploid. 

Process 

Besides, undifferentiated sperm cells differentiate into primary spermatocytes, which undergo meiosis to form spermatids while spermatids differentiate into sperms. 

Structure 

Another difference between undifferentiated sperm cells and sperm is their structure. Undifferentiated sperm cells are rounded cells while the sperm is an elongated cell. 

Mobility 

Moreover, undifferentiated sperm cells are non-motile while the sperm is motile. 

Conclusion 

In brief, undifferentiated sperm cells are the spermatogonia inside the seminiferous tubules of the testis. They undergo spermatogenesis, producing a mature sperm that has the ability to serve as the male gamete. In contrast, sperm is a specialized cell for its function. Though undifferentiated sperm cells are round in shape, sperms are elongated cells with a tail and a very small amount of the cytoplasm. Therefore, the main difference between undifferentiated sperm cells and sperm is their structure and the function.

Reference:

1. Gilbert SF. Developmental Biology. 6th edition. Sunderland (MA): Sinauer Associates; 2000. Spermatogenesis. Available Here

Image Courtesy:

1. “Figure 28 01 04” By OpenStax College – Anatomy & Physiology, Connexions Web site, Jun 19, 2013. (CC BY 3.0) via Commons Wikimedia  
2. “Simplified spermatozoon diagram” By Mariana Ruiz – I made the diagram myself in Adobe Illustrator using the diagram found in the book “Gray’s Anatomy” 36th edition from williams and warwick, 1980. I also used this websites: [1], [2], and [3]. (Public Domain) via Commons Wikimedia