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Comparative Anatomy, Physiology, and Biochemistry of Mammalian Skin
Published in David W. Hobson, Dermal and Ocular Toxicology, 2020
In man, the integument is derived from two morphologically distinct layers: the epidermis from surface ectoderm and the dermis from mesoderm. The surface ectodermal cells proliferate in the second month to form the periderm (epitrichium). This cell layer consists of simple squamous epithelium with microvilli, which increases the epidermal surface area exposed to the amniotic fluid. The presence of microvilli on the amniotic surface suggests that the periderm cells are involved in the exchange of material between the fetus and amniotic fluid. The peridermal cells contain filaments and glycogen and the underside is attached by junctional complexes to the adjacent epithelial cells. The basal ectodermal cells continue to proliferate and undergo keratinization and desquamation. These exfoliative cells, along with sebum from the sebaceous glands and other cellular debris, form the vernix caseosa, a whitish protective substance that covers the fetal skin. At birth, all cell layers are present.29–32 Cells of neural crest origin migrate into the epidermis during the early fetal period. Breathnach and Wyllie33 noticed melanocytes and Langerhans’ cells at 14 weeks in human fetal epidermis.
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.
Renal Cancer
Published in Dongyou Liu, Tumors and Cancers, 2017
Structurally, 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 capsule, a cup-shaped double layer of simple squamous epithelium with a hollow space between the layers). The glomerulus contains 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.
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).
Therapeutic role of Azadirachta indica leaves ethanolic extract against diabetic nephropathy in rats neonatally induced by streptozotocin
Published in Ultrastructural Pathology, 2021
Abd El-Fattah B. M. El-Beltagy, Amira M.B. Saleh, Amany Attaallah , Reham A. Gahnem
The renal sections from control (Figure 2A&A1) and neem supplemented (Figure 2B&B1) rats appeared with normal histological architecture whereas it is differentiated into outer cortex and inner medulla. The renal cortex displayed well-organized renal corpuscles and tubules. The renal corpuscle consists of glomerulus that is surrounded by Bowman’s space and intact Bowman’s capsule that lined with simple squamous epithelium. The renal tubules represented by proximal tubules (PT), distal tubules (DT) and collecting ducts (CD). The PT is characterized by its star-shaped lumen that is lined with brush bordered cubical epithelium. Moreover, the DT has relatively rounded lumen that lined by cubical epithelium with little microvilli. The CD lined with short cubical epithelium and has a relatively wider lumen than the PT and DT. The renal medulla displayed well-organized collecting ducts and Henel,s loops.
Effects of catechin hydrate in benzo[a]pyrene-induced lung toxicity: roles of oxidative stress, apoptosis, and DNA damage
Published in Toxicology Mechanisms and Methods, 2021
Samah A. Khattab, Wafaa F. Hussien, Nermin Raafat, Eman Ahmed Alaa El-Din
In control animals, H&E-stained sections of lung tissues showed a lace appearance as most lung tissues composed of thin-walled alveoli. The alveoli are composed of a single layer of squamous epithelium. A thin layer of connective tissue and numerous capillaries also lined with simple squamous epithelium was found between the alveoli. Also, corn oil and DMSO groups showed the same appearance. While (group IV) B[a] P-treated rats showed abnormally thick alveolar walls and a markedly congested blood vessel with interstitial pneumonia in the form of thick alveolar walls. Most alveoli appeared empty air-filled alveoli, and severe mononuclear inflammatory infiltrates restricted to the alveolar walls and interstitial tissues. Lung tissue from rats treated with B[a] P + CH (group VI) revealed mild congestion of the alveolar capillaries with thickened edematous alveolar walls infiltrated but with few inflammatory cells. While group V treated with CH only appeared normal with thin-walled alveoli with normal squamous epithelium. A thin layer of connective tissue and numerous capillaries lined with simple squamous epithelium (Figure 2).