Adult Nursing 1
Summary & Reminder UNIT 7
The left kidney is slightly longer and narrower than the right. Larger-than-usual kidneys may indicate obstruction or polycystic disease. Smaller-than-normal kidneys may indicate chronic kidney disease. Some people have more than 2 kidneys and some have only one. On the outer surface of the kidney is a layer of fibrous tissue called the capsule. This capsule covers most of the kidney except the hilum, which is the area where the renal artery and nerve plexus enter and the renal vein and ureter exit. The renal cortex is the outer tissue layer and is covered by the capsule. The medulla is the medullary tissue lying below the cortex in the shape of many fans. Each “fan” is called a pyramid, and there are 12-18 pyramids per kidney. The renal columns are cortical tissue that dips down into the interior of the kidney and separates the pyramids. The tip, or end, of each pyramid is called a papilla. A cuplike structure called a calyx collects urine at the end of each papilla. The calices join together to form the renal pelvis, which narrows to become the ureter.
The nephron is the “working” or functional unit of the kidney, and it is here that urine is actually formed from blood. There are 2 types of nephrons: cortical nephrons and juxtamedullary nephrons. The cortical nephrons are short, with all parts located in the renal cortex. The juxtamedullary nephrons are longer, and their tubes and blood vessels dip deeply into the medulla.
There are 2 segments of the ascending limb of the loop of Henle: the thin segment and the thick segment. The DCT forms the thick segment. Renin is a hormone that helps regulate blood flow, glomerular filtration rate (GFR), and blood pressure. Glomerular filtration is the first process in urine formation.
Antidiuretic hormone (ADH) is also known as vasopressin and affects arteriole constriction. There is a limit to how much glucose the kidney can reabsorb. The limit is called the renal threshold for glucose reabsorption or the transport maximum for glucose reabsorption.
**ACTION ALERT: REPORT THE PRESENCE OF GLUCOSE OR PROTEINS IN THE URINE OF A PATIENT UNDERGOING A SCREENING EXAMINATION TO THE HEALTH CARE PROVIDER BECAUSE THIS IS AN ABNORMAL FINDING AND REQUIRES FURTHER ASSESSMENT.
Prostaglandins are produced in the kidney and many other tissues. Bradykinin is released by the kidney in response to the presence of angiotensin II, prostaglandins, and ADH. Erythropoietin is produced and released in response to decreased oxygen tension in the kidney’s blood supply. Vitamin D activation occurs through a series of steps.
The ureter has 3 layers: an inner lining of mucous membrane (urothelium), a middle layer of smooth muscle fibers, and an outer layer of fibrous tissue.
In men, the urethra is about 6-8 inches long, with the meatus located at the tip of the penis. The male urethra has 3 sections. The prostatic urethra, which extends from the bladder to the prostate gland. The membranous urethra, which is extends to the wall of the pelvic floor. The cavernous urethra, which is external and extends through the length of the penis. In women, the urethra is about 1-1.5 inches long and exits the bladder through the pelvic floor.
Kidney size and function decrease with aging. GFR decreases with age, especially after 45 years of age. Hormonal changes include a decrease in renin secretion, aldosterone levels, and activation of vitamin D. in women, weakened muscles shorten the urethra and promote incontinence. In men, an enlarged prostate gland makes starting the urine stream difficult and may cause urinary retention.
A high-protein intake can result in temporary kidney problems. A patient at risk for calculi (stone) formation who ingests large amounts of protein or has a poor fluid intake may form new stones.
Past terms for kidney disease includes Bright’s disease, nephritis, and nephrosis. If tumor or aneurysm is suspected, palpitation may