The blood vessels are one of the three major components of the circulatory system. It serves as a pathway for materials to reach their respective destinations. There are three types of blood vessels: arteries, veins, and capillaries. The walls of arteries and veins share the same histological layers. The innermost layer is the tunica intima followed by the tunica media which consists of smooth muscles and elastic fibers. The outermost layer is the tunica adventitia or tunica externa. The capillaries are the smallest of all the blood vessels. The walls are composed of a single layer of endothelial cells and a basement membrane. The urinary systems consists of a pair of kidneys, a pair of ureters, a urinary bladder, and a urethra. The kidney is a reddish, bean-shaped organ found above the peritoneum and the posterior wall of the abdomen. The right kidney is slightly lower that the left because the liver occupies considerable space on the right side above the kidney. Found in the kidneys are numerous nephrons, the functional units of the kidneys. Each nephron consists of renal corpuscle, where filtration occurs, and a renal tubule, a passageway for filtered fluid. Note: Most photos were taken from the cyberclass https://www.facebook.com/groups/314838465267544/. Credits to Ma'am Jo S. Maceda. |