![]() ![]() There are about 1.3 million nephrons in each kidney and they function to filter the blood. The afferent arterioles deliver blood into a modified capillary bed called the glomerulus which is a component of the “functional unit” of the kidney called the nephron. The interlobar arteries, in turn, branch into arcuate arteries, cortical radiate arteries, and then into afferent arterioles. Once in the kidney, each renal artery first divides into segmental arteries, followed by further branching to form interlobar arteries that pass through the renal columns to reach the cortex ( Figure 25.1.3). Blood enters the kidney via the paired renal arteries that form directly from the descending aorta and each enters the kidney at the renal hila. The kidneys are well vascularized and receive about 25 percent of the cardiac output at rest. Each renal papilla drains into a collecting pool called a minor calyx several minor calyces connect to form a major calyx all major calyces connect to the single renal pelvis which connects to the ureter. In the medulla, 5-8 renal pyramid s are separated by connective tissue renal columns. Each pyramid creates urine and terminates into a renal papilla. Internal AnatomyĪ frontal section through the kidney reveals an outer region called the renal cortex and an inner region called the renal medulla ( Figure 25.1.2). The medial-facing hila are tucked into the convex indentation of the kidney. Each kidney looks like the kidney bean and the renal hilum is the entry and exit site for structures servicing the kidneys: vessels, nerves, lymphatics, and ureters. ![]() On the superior aspect of each kidney is an adrenal gland. ![]() Figure 25.1.1 – Kidneys: The kidneys are slightly protected by the ribs and are surrounded by fat for protection. The fascia and, to a lesser extent, the overlying peritoneum serve to firmly anchor the kidneys to the posterior abdominal wall in a retroperitoneal position. This capsule is covered by a shock-absorbing layer of adipose tissue called the renal fat pad, which in turn is encompassed by a tough renal fascia. They are about 11–14 cm in length, 6 cm wide, and 4 cm thick, and are directly covered by a fibrous capsule composed of dense, irregular connective tissue that helps to hold their shape and protect them. Each kidney weighs about 125–175 g in males and 115–155 g in females. Upper portions of the kidneys are somewhat protected by the eleventh and twelfth ribs ( Figure 25.1.1). The paired kidneys lie on either side of the spine in the retroperitoneal space between the parietal peritoneum and the posterior abdominal wall, well protected by muscle, fat, and ribs. The left kidney is located at about the T12 to 元 vertebrae, whereas the right is lower due to slight displacement by the liver. ![]() Anthony Atala discusses a cutting-edge technique in which a new kidney is “printed.” The successful utilization of this technology is still several years in the future, but imagine a time when you can print a replacement organ or tissue on demand. Watch this video to learn about the TED (Technology, Entertainment, Design) Conference held in March 2011. There have never been sufficient kidney donations to provide a kidney to each person needing one. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |