A & P

Question 1

One of the chief differences amid the lymph vessels and the blood vessels is that the blood vessels together with the entire circulatory system constitute a closed system while the lymph vessels together with the lymph system does not constitute a closed circulatory system (Földi & Strössenreuther, 2005). Another difference between the two is that the flow of blood through the blood vessels is usually uninterrupted while the flow of lymph fluid via the lymph vessel system is usually interrupted by the lymph nodes. Besides, the blood vessels carry blood while the lymph vessels transport lymph fluid (Wingerd, 2005). Despite having differences, the lymph vessels and blood vessels also have similarities. One of the similarities is that they are both involved in the transportation of fluids. Besides, the transport of lymph in the lymph vessels is fostered by similar factors, which favor the transports of blood through the blood vessels.

Question 2

The thymus gland is remarkably crucial to the immune system since it processes lymphocytes, which fight infections in the body. The gland is vital to young adults and children as it programs lymphocytes in attacking antigens such as the viruses. Therefore, the thymus gland has a chief role in nurturing the lymphocytes through secreting a hormone. Hence, lack of the thymus gland in the immune system can lead to failure of the immune system processing lymphocytes, which help in the fight of cancerous cells and viral infections (Lavini, 2008). Therefore, there will be decreased immunity, when there is a lack of the thymus gland in the immune system. Besides, lack of the thymus gland in the immune system may affect the functions of the hormonal tissues; for example, lack of the thymus gland from birth is usually associated with alterations of the adrenal gland, pituitary gland, ovaries and thyroid.

Question 3

The arteries comprise of three layers, which are Tunica Interna, Tunica Media, and Tunica Adventitia. Tunica Adventitia is the outermost layer of the arteries and has collagen fibers, which are loosely woven (Wingerd, 2005). The function of the Tunica adventitia is holding vessels in place and preventing tearing of vessels in instances of body movements. The Tunica Media is the middle layer of the arteries. The layer has smooth muscle tissue having sheets of elasin. This layer has the function of allowing vasodilation and vasoconstriction. On the other hand, Tunica Interna is the innermost layer of the arteries (Wingerd, 2005). This layer has an endothelium lining and is usually continuous with the endocardium. The role of the Tunic Interna is preventing the adhesion of blood cells to the vessel wall and preventimg thrombosis; in case the endothelium becomes disrupted, fatal thrombosis can occur.

Question 4

The continuous flow of the blood is remarkably essential for the transport of various substances, thus facilitating their removal and exchange. In order for the blood to keep flowing, it requires enough pressure that forces it to continue flowing through the blood vessels. The pressure required to keep the blood flowing to the capillaries is generated by the arteries. The arteries are elastic allowing them to accept large volumes of blood and contract squeezing back to their usual size after they release pressure (Wingerd, 2005). The elasticity property of the arteries maintains the pressure of the blood allowing blood to transport various substances through the capillaries. Therefore, the continuous flow of blood facilitates the exchange of substances through the capillaries. In case there was less pressure, the flow of blood carrying different substances to the capillaries would not be facilitated implying that exchange of substances may not be feasible.

References

Földi, M., & Strössenreuther, R. H. K. (2005). Foundations of manual lymph drainage. St. Louis: Elsevier Mosby.

Lavini, C. (2008). Thymus gland pathology: Clinical, diagnostic, and therapeutic features. Milan: Springer.

Wingerd, B. (2005). The Human Body: Concepts of Anatomy and Physiology. New York: Wolters Kluwer Health.