What is the Difference Between Vascular and Avascular Tissue

The main difference between vascular and avascular tissue is that vascular tissue consists of vessels that conduct fluids like blood and lymph whereas avascular tissue does not contain such vessels. Therefore, vascular tissues have an active supply of oxygen and nutrients while the movement of nutrients and oxygen in avascular tissues occurs through diffusion.

Vascular and avascular tissue are two types of tissues occur in the body. They are classified based on the presence and absence of vessels.

Key Areas Covered

1. What is Vascular Tissue
     – Definition, Features, Examples
2. What is Avascular Tissue
     – Definition, Features, Examples
3. What are the Similarities Between Vascular and Avascular Tissue
     – Outline of Common Features
4. What is the Difference Between Vascular and Avascular Tissue
     – Comparison of Key Differences

Key Terms

Avascular Tissue, Diffusion, Blood Vessels, Lymphatic Vessels, Transport, Vascular Tissue

What is Vascular Tissue

Vascular tissue is a tissue with vessels. Here, two types of vessels occur in these tissues. They are blood vessels and lymphatic vessels. The three types of blood vessels found in a tissue are arteries, veins, and blood capillaries. Arteries are responsible for the transport of oxygen- and nutrient-rich blood to the tissue. These nutrients and oxygen move into the tissue at the capillary level. Also, metabolic wastes and carbon dioxide move into the blood at capillaries. This exchanging process is known as the capillary exchange. Therefore, the blood inside the veins contain both metabolic wastes as well as carbon dioxide and, veins are responsible for the removal of wastes from tissues.

Figure 1: Vessels in a Compact Bone

Moreover, some tissues like the lungs are highly-vascularized. This means that they contain a large number of blood vessels. In the lungs, the respiratory gases exchange between the atmosphere and blood. Liver tissue is another type of highly-vascularized tissue type. Furthermore, the lymphatic vessels of the tissue drain the excess extracellular fluid from the tissue. This system also contains immune cells that help to defend the tissue from pathogens.

What is Avascular Tissue

Avascular tissue is a tissue that does not contain vessels. Some examples of avascular tissues are the cornea of the eye, the epithelial layer of the skin, and cartilages. Moreover, some connective tissues that contain elastic fibers are also avascular. The main function of the epithelial tissue of the skin is to protect the underneath tissues from mechanical abrasion. Therefore, the absence of vessels in the epidermis becomes an advantage.

Figure 2: Avascularized Epidermis

In addition, the main disadvantage of an avascular tissue is the inefficient transport of nutrients and oxygen to the cells of the tissue. Both nutrients and oxygen transport occur through simple diffusion in these type of tissues.

Similarities Between Vascular and Avascular Tissue

• Vascular and avascular tissue are two types of tissues in the body.
• Both types of tissues require a supply of nutrients and oxygen.

Difference Between Vascular and Avascular Tissue

Definition

Vascular tissue refers to tissue that contains blood vessels while avascular tissue refers to the tissue that does not contain blood vessels. Hence, this is the main difference between vascular and avascular tissue.

Examples

Muscles, liver, lung, kidney, etc. contains vascularized tissue while epithelial layer of the skin, cornea of the eye, cartilage, etc. are avascular tissues.

Supply of Nutrients and Oxygen

Supply of nutrients and oxygen is also a major difference between vascular and avascular tissue. Blood vessels supply nutrients and oxygen to the vascular tissue while the supply of nutrients and oxygen occurs through diffusion in avascular tissues.

The Efficiency of Nutrient and Oxygen Supply

Vascular tissues have an efficient supply of nutrients and oxygen while avascular tissue has a poor supply of nutrients and oxygen. Thus, this is another difference between vascular and avascular tissue.

Conclusion

Vascular tissue is a tissue that contains both blood vessels and lymphatic vessels. Therefore, the supply of nutrients and oxygen occurs through blood vessels in vascular tissue. On the other hand, avascular tissue is the tissue without blood vessels and lymphatic vessels. Therefore, these tissues have a poor supply of nutrients and oxygen. Hence, the main difference between vascular and avascular tissue is the presence of vessels and the supply of nutrients and oxygen.

Reference:

1. “Epithelial Tissue.” Boundless Anatomy and Physiology, Lumen Learning, Available Here

Image Courtesy:

1. “624 Diagram of Compact Bone-new” By OpenStax College – Anatomy & Physiology, Connexions Web site, Jun 19, 2013. (CC BY 3.0) via Commons Wikimedia  
2. “501 Structure of the skin” By OpenStax College – Anatomy & Physiology, Connexions Web site, Jun 19, 2013. (CC BY 3.0) via Commons Wikimedia