The urinary tract and male reproductive system
C. Simon Herrington in Muir's Textbook of Pathology, 2020
The urinary tract comprises: The kidneys (see Chapter 14).The renal pelvis, the ureters, the bladder, and urethra. These structures form a continuum that collects the urine from the kidneys and conveys it to the exterior. The renal pelvis is funnel-shaped and situated in the medial aspect of each kidney. The ureters are two hollow tubes that link the pelvises with the urinary bladder; a hollow muscular organ situated in the pelvis. The ureters transport the urine from the pelvis to the bladder with the aid of peristaltic contractions where it is stored until it is passed through the urethra during the voluntary act of micturition. This collecting system formed of different organs is seamlessly lined by highly specialized epithelium known as urothelium. Its histological appearance was deemed transitional between non-keratinizing squamous and pseudostratified columnar epithelium and ‘transitional epithelium’ has been widely used in the past to refer to the epithelium lining the urinary tract. Urothelium is currently the preferred term.
Renal System
David Sturgeon in Introduction to Anatomy and Physiology for Healthcare Students, 2018
Both types of nephron produce urine by three precisely regulated processes: filtration, reabsorption, secretion. Once this has taken place, urine drains from the nephron into a collecting duct (tubule) which transports it through the renal pyramids to the papilla (‘nipple’) and gives them their striped (striated) appearance (Figure 10.3). Urine eventually drains from the papilla into a number of cup-shaped structures known as calyces (singular: calyx). These form the distal part of a larger funnel-shaped structure known as the renal pelvis. The walls of the renal pelvis are lined with transitional epithelium (urothelium) and contain smooth muscle. This allows it to propel the urine into the ureters using peristaltic waves of muscular contraction. The final part of the kidney is known as the hilus (or hilum) and describes the area where the ureter, nerves and blood enter and exit the organ. It comes as a surprise to many people that urine is essentially filtered blood plasma that contains variable quantities of waste material depending on the time of day and environmental conditions. Consequently, without an adequate supply of blood (and blood pressure) the kidneys cannot produce urine and the body is unable to maintain chemical or fluid balance (homeostasis).
The patient with acute renal problems
Peate Ian, Dutton Helen in Acute Nursing Care, 2020
There are three specific areas in the kidney. There is an outer section called the renal cortex, which contains all of the glomeruli and portions of the tubule. The inner section is known as the renal medulla, and this contains the straight segments of the proximal and distal tubules and the collecting ducts. Renal pyramids are found here, and these cone-shaped areas have their apices ending in the papillae, which open into the minor calyx. Urine passes from the collecting ducts in the pyramid to two small cavities, the minor calyces and the major calyces, and, from here, it enters the renal pelvis. Finally, the renal pelvis is formed from the expanded upper section of the ureter and it acts as a collecting space.
Temperature profiles during ureteroscopy with thulium fiber laser and holmium:YAG laser: Findings from a pre-clinical study
Published in Scandinavian Journal of Urology, 2022
M. S. Æsøy, P. Juliebø-Jones, C. Beisland, Ø. Ulvik
We used an ex-vivo porcine model for our experiment. A porcine kidney is recognized as the most accurate comparative model for human renal anatomy. It has a multipapillate system with associated major and minor calyces. Furthermore, both the kidney, renal pelvis, and ureters are of similar size to that of human renal anatomy [32]. However, the ex-vivo porcine model used in our study differs from a clinical scenario in several aspects and caution should be taken when drawing clinical recommendations from benchtop studies. First, the URS procedure itself was different from the actual surgery performed in clinical practice. As we used ex-vivo kidneys there was no muscle tone in the renal pelvis or ureter, which could affect outflow and irrigation rates. Also, the porcine kidneys had a baseline room temperature and there was no blood perfusion. However, it is noteworthy that in previous in-vivo porcine studies, baseline intrapelvic temperatures were 23–25 °C as continuous room tempered irrigation lowers the intrapelvic temperature to that of the irrigation fluid when the laser is not activated [12]. Nevertheless, the absolute temperatures found in our ex-vivo model are not necessarily accurate for a clinical setting and future clinical studies are therefore needed. Another limitation was that the kidneys used in this study were gradually warmed up during the experiments due to accumulation of laser energy. This caused a slight rise in the baseline temperature throughout the experiment. As a result of this, comparing changes in temperature rather than absolute temperature was determined to be more appropriate.
Twelve tips for interpreting abdominal CT scans
Published in Medical Teacher, 2021
Sailantra Sivathasan, Jakub Nagrodzki, David McGowan
Initially, identify the kidneys and note any asymmetry in size or location and any anatomical variations. Look for the bladder and any signs of obvious pathology such as cysts, tumours or gross dilatation. Then identify the collecting system of one of the kidneys and follow the ureter closely from the renal pelvis to the bladder. Repeat this for the opposite side. Look for any obvious dilatation and/or asymmetry in size or location of the kidneys and ureters, potentially indicating polycystic kidneys, a tumour or obstructive uropathy. Also look for signs of calculi, such as bright white signal in the lumen of the renal pelvis, ureter or bladder. If stone disease is suspected clinically and there is contrast present within the lumen of the ureter it can make the test difficult to interpret, unless there are signs of absolute blockage with no contrast after a certain point.
The feasibility of one-stage flexible ureteroscopy lithotripsy in solitary kidney patients with 1–3 cm renal stones and risk factors of renal function changes
Published in Renal Failure, 2021
Yang Pan, Han Chen, Hualin Chen, Xiaoxiang Jin, Yunxiao Zhu, Gang Chen
Flexible ureteroscopy lithotripsy for renal stones in solitary kidney patients was performed under general anesthesia and standard lithotomy position. For patients with prior stenting, the stent was removed using forceps through ureteroscopy firstly. The subsequent procedures were the same for patients in two groups. A guidewire was inserted from the ipsilateral ureterovesical opening. Along the guidewire, the ureter was checked and expanded using ureteroscopy retrograde until reaching the renal pelvis. After ureteral stenosis or ureteral stone was excluded, a ureteral access sheath (UAS) with an inner/outer diameter of 12/14-Fr (Cook Urological, Bloomington, IN, USA) was placed into the ureter. A flexible ureteroscope was put into the renal pelvis and stones were searched during the pelvicalyceal system. After finding the stones, a 200-µm holmium laser at a power of 0.8–1.5 J and a pulse frequency of 10–20 Hz was used to crush the stones into fragments of less than 2 mm. The large fragments were removed by a nitinol stone basket under the vision of flexible ureteroscopy. At last, the pelvicalyceal system was examined again to ensure no large remaining stones. The post-ureteroscopic lesion scale (PULS) grading system [11] was used to assess the degree of ureteral lesions after withdrawing the UAS. If there were no severe complications such as fever and urinary sepsis, patients were discharged 1 day postoperatively.