Exam 4 Review:  Chapter 25:  Kidney Anatomy

renal capsule - The thin, tough, inelastic dense fibrous connective tissue sheath which surrounds the kidney and is continuous with the outer coat of the ureter at the hilus of the kidney.

adipose capsule - A layer of fatty tissue of variable thickness located external the the fibrous capsule of the kidney; this fatty tissue also extends into the renal sinus as filler between the blood vessels and the major calyces which merge to form the renal hilus; during starvation, this fat is the last adipose tissue to be metabolized

renal fascia - The thin layer of dense irregular fibrous connective tissue which anchors the kidney, the renal vessels and their connections to the inferior vena cava and aorta, and the adjacent adrenal glands to the abdominal wall and other surrounding structures.

renal hilus - The opening on medial side of the kidney which leads into the renal sinus and through which the renal vessels enter/leave the kidney; it is the point where renal pelvis leaves the kidney to become the ureter.

renal sinus - The potential hollow space on the medial side of the kidney which opens at the renal hilus; it contains the renal blood vessels, the major calyces and the renal pelvis and adipose tissue as filler between these tubular structures.

renal cortex - The outer layer of kidney which contains the majority of the glomeruli in the renal corpuscles and major parts of the associated nephrons.

renal medulla - The inner layer of the kidney which contains some portions of the renal tubules and most of the collecting duct tubules of the kidney which are organized as renal pyramids; in the medulla between the renal pyramids are the renal columns which consist of cortex-like tissue.

renal pyramid - Any of the triangular or cone-shaped arrangement of various renal tubules within the medulla; the tip of each renal pyramid  (its papilla) projects into a minor calyx where urine is collected from the tubes draining this portion of the medulla; in gross specimens, the pyramids are darker, a purple-brown shade, compared to the lighter (red if fresh, tan if preserved) cortical tissue and give the appearance of being striated because at the microscopic level, the tubules are running in parallel.

renal papilla - The tip of each renal pyramid which projects into a minor calyx where urine is collected from the tubes draining this portion of the medulla; it is covered by a stratified cuboidal epithelium.

renal column - Any of the columns of renal tissue which are histologically identical to tissue found in the cortex, but which are located in the medulla between the renal pyramids; interlobar arteries pass from the renal sinus to the renal cortex within the renal columns.

papillary ducts - The largest and distal portions of the collecting duct system within each renal pyramid which deliver urine by peristalsis to the surface of the renal papillae and into the minor calyces; they are lined by a simple columnar epithelium.

minor calyx - Any of the initial cuplike collection chambers for receiving urine released from the papillary ducts at the renal papillae in the medulla of the kidney; their walls consist of a mucosal lining of transitional epithelium, a submucosa of loose fibrous connective tissue, a muscularis for persistalsis, and an adventitia; they merge to form the major calyces.

major calyx - Any of the cuplike collection chambers for receiving urine flowing through the minor calyces in the renal medulla of the kidney; their walls consist of a mucosal lining of transitional epithelium, a submucosa of loose fibrous connective tissue, a muscularis for persistalsis, and an adventitia; they merge to form the renal pelvis.

renal pelvis - The large collecting chamber for receiving urine which is formed by the union of the major calyces and it is the dilated origin of the ureter; it is located at the renal hilus and is surrounded by the renal sinus.

parenchyma - The main functional cell type(s) and tissue(s) characteristic of an organ, as distinguished from associated connective or supporting tissues, such as the vasculature; in the kidney, the cells forming the nephrons, renal tubules, and collecting duct system.

nephron - The structural and functional unit of the kidney which is responsible for urine formation and contributes to homeostasis of water balance and acid-base balance; there are more than one million of them in each kidney and they comprise the majority of the parenchymal tissue in the renal cortex and renal pyramids; it consists of a renal corpuscle (a capsule containing the glomerular capillary tuft and podocytes) where glomerular filtration occurs and the renal tubule which consists of the proximal covoluted tubule, loop of the nephron [loop of Henle], and distal convoluted tubule where renal tubular reabsorption and secretion occur; urine from each nephron drains into the collecting duct system to pass to the renal medulla and beyond.

cortical nephron - Any of the majority (~80-85%) of the nephrons in the kidney; its renal corpuscle and glomerulus, which are relatively small, and its convoluted tubules are located in the outer portion of the cortex and its short loop, which lacks a thin portion of the ascending limb, penetrates only to the outer portion of the medulla; it plays the major role in adjusting the concentrations of various solutes in the urine by the mechanisms of tubular reabsorption and tubular secretion.

juxtamedullary nephron - Any of the minority (~15-20%) of the nephrons in the kidney; its renal corpuscle and glomerulus, which are relatively large, and its convoluted tubules are located in the inner portion of the cortex near the border with the medulla and its long loop, which has a thin portion of the ascending limb, penetrates deep into the pyramid of the medulla; it plays the major role in adjusting the concentration of water in the urine by the mechanism of tubular reabsorption of water in response to ADH increase.

afferent arteriole -- glomerular capillaries -- efferent arteriole -- renal corpuscle -- proximal convoluted tubule -- loop of the nephron (of Henle) -- distal convoluted tubule -- collecting duct system -- papillary ducts -- papilla of renal pyramid -- minor calyx

Sketch and label:

1. a simple diagram of a longitudinal section through the kidney and label its structures.

2. a simple sketch of the nephron and label its structures.