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Glomerular Filtration
Published in Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal, Principles of Physiology for the Anaesthetist, 2020
Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal
In the renal corpuscle, fluid filters from the glomerular capillaries into Bowman's space by the balance of hydrostatic and osmotic pressures acting across the thin diffusion barrier of the capillary endothelium fenestrae, basement membrane and slit diaphragms between podocytes. The glomerular capillary hydrostatic pressure is determined by renal blood flow, which is autoregulated for a range of arterial blood pressures, and the resistance of afferent and efferent arterioles. The fluid in Bowman's space is a protein-free filtrate of plasma.
Familial Wilms Tumor and Related Syndromes
Published in Dongyou Liu, Handbook of Tumor Syndromes, 2020
The kidneys are a pair of bean-shaped organs (of 10–12 cm in length, 5–7 cm in width, 2–3 cm in thickness, and 135–150 g in weight) that are located along the posterior muscular wall of the abdominal cavity. Covered by a thin layer of fibrous connective tissue (the renal capsule), the kidneys comprise an outlayer of soft, dense, vascular renal cortex, and an inner renal medulla, the latter of which is composed of seven cone-shaped renal pyramids separated by the cortical tissue (called renal columns of Bertin). Each kidney contains around 1 million individual nephrons (the functional units), which are made of renal corpuscle and renal tubule. The renal corpuscle comprises the capillaries of the glomerulus that is surrounded by the glomerular capsule (or Bowman's capsule, a cup-shaped double layer of simple squamous epithelium with a hollow space between the layers). The glomerulus consists of podocytes and a basement membrane allowing water and certain solutes to be filtered across. Podocytes form a thin filter with the endothelium of the capillaries to separate urine from blood passing through the glomerulus. The outer layer of the glomerular capsule keeps the urine separated from the blood within the capsule. At the far end of the glomerular capsule is the mouth of the renal tubule, which carries urine from the glomerular capsule to the renal pelvis.
Clinical anatomy of the newborn
Published in Prem Puri, Newborn Surgery, 2017
Mark D. Stringer, S. Ali Mirjalili
At birth, the kidneys are about 4–5 cm in length compared to a mean length of 11 cm in adults. Fetal lobulation of the kidneys is still present at birth. Individual nephrons consist of a renal corpuscle with (i) a central glomerulus concerned with plasma filtration and (ii) a renal tubule that produces urine by selective reabsorption of the filtrate. At birth, there are about 1 million renal corpuscles in the cortex of each kidney. Postnatally, cortical nephron mass increases but no new nephrons are made. The glomerular filtration rate (GFR) is low in newborns, particularly in the premature, but in the term infant, the GFR doubles by 2 weeks of age and reaches adult values (120 mL/min per 1.73 m2) by 1–2 years.47
Impact of intrauterine exposure to the insecticide coragen on the developmental and genetic toxicity in female albino rats
Published in Egyptian Journal of Basic and Applied Sciences, 2022
Amel Ramadan Omar, Ahmed Emam Dakrory, Marwa Mohamed Abdelaal, Heba Bassiony
Histopathological examination of renal tissue of control pregnant rats revealed normal histological appearance. The renal corpuscle was made up of a glomerulus surrounded by the Bowman’s capsule and normal urinary space. There were proximal convoluted tubules with narrow lumens among the renal tubules, and distal convoluted tubules with wide lumen (Figure 10a). Pregnant rats treated with LD of coragen showed some histopathologic changes including; shrunken of glomeruli, urinary space dilation and basement membrane of Bowman’s capsule deterioration, shredded nuclei into the lumen of the tubule, hypertrophy and hyperplasia of the tubular epithelial lining in addition to disappearance of the lumen of renal tubules (Figure 10b). Pregnant rats treated with HD of coragen exhibit inflammatory infiltration, fragmentation in tubular epithelial lining and hemorrhage (Figure 10c&d).
Ameliorative role of alpha-lipoic acid in renal cortical structural damage, induced by limb ischemia-reperfusion injury in the rat
Published in Ultrastructural Pathology, 2022
Manal A. Othman, Heba A Mubarak, Manal M. Sayed
Group I: Histological examination of semithin sections, stained with toluidine blue, from control rats, revealed proximal convoluted tubules (PCT) demonstrating normal cytoplasmic features, and typical vesicular nuclei. The distal convoluted tubules (DCT) appeared with their wider lumen. The renal corpuscles, with its Bowman’s capsule, had a parietal layer of simple squamous epithelium, and inner layer of podocytes. The glomerular capillaries appeared normal with normal spaces (Figure 1A). Examination of group II (ischemia-reperfusion after 1 day) revealed that PCT had variable cytoplasmic vacuolizations. DCT showed vacuolated cytoplasm and dark nuclei. Renal corpuscle showed atrophic glomeruli, wide urinary spaces (Figure 1B). In group III (ischemia-reperfusion after 7 days) the PCT had marked vacuolizations and loss of brush border. DCT revealed dark pyknotic nuclei and cytoplasmic vacuolizations. Renal corpuscle showed marked glomerular atrophy, wider urinary space, and darker cellular nuclei (Figure 1C). On the other hand, examination of group IV (ischemia-reperfusion after lipoic acid treatment) revealed improvement in the cellular architecture; most PCT and DCT were within near normal morphology but few of them showed vacuolated cytoplasm. The renal corpuscle showed more or less normal appearance (Figure 1D).
Suppression of glomerular damage and apoptosis and biomarkers of acute kidney injury induced by acetaminophen toxicity using a combination of resveratrol and quercetin
Published in Drug and Chemical Toxicology, 2022
Mohammad Dallak, Amal F. Dawood, Mohamed A. Haidara, Dina H. Abdel Kader, Refaat A. Eid, Samaa S. Kamar, Asmaa M. Shams Eldeen, Bahjat Al-Ani
To determine whether APAP can induce damage to the glomerulus ultrastructure, and whether combined resveratrol and quercetin administration can protect kidney structures against injury induced by APAP, we assessed the integrity of the glomeruli (Figure 2) in the model and treated groups using TEM analysis. Representative TEM images of glomerular sections obtained from the control group (Figure 2(A,B)) showed normal kidney architecture as demonstrated by a glomerular renal corpuscle with capillary loops lumen (CL) lined with fenestrated endothelium (En) and the presence of red blood cells (Rbc). The visceral layer of the Bowman’s capsule is formed of podocytes (Ep) lining the urinary space (U), sending their foot processes (Fp) to the glomerular basement membrane (Bm). Mesangium between the capillary loops is filled with mesangial cells (Mc) with a characteristically moderate dense cytoplasm. Minor processes of podocytes are regularly spaced and separated by filtration slits that are covered by diaphragms (arrows). Whereas, the TEM images that represent glomerular sections of APAP treated rats (Figure 2(C,D)) display a glomerular basement membrane (Bm) with focal thickening and hump-like deposits (H). Foot processes (Fp) of podocytes (Ep) show large areas of fusion and obliteration of filtration slits. In addition, the vacuolations (V) and dense deposits (asterisk) within the capillary lumen (CL) are lined by mildly hypertrophied endothelial cells (En). Also, widening of the Bowman’s space with distortion and vacuolation of the cells lining the parietal layer were observed (data not shown).