A & P Question 1

̈ldi & 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.

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.
A & P