University:
Texas A&M University
Course:
BIOL 319 | Integrated Human Anatomy and Physiology I
Academic year:

2020
Views:

311

Pages:

66
Author:

teespagmaxrtf

URINARY SYSTEM: Part 1 Kidney and nephron 36748 Objectives Part 1 Kidney and nephron • Describe the structure of the kidney and distinguish between cortical and medullary organization. • Identify and differentiate between the portions of the nephron. • Trace blood flow through the kidney. • Describe the structural organization of the ureter, urinary bladder, and urethra. hilum URINARY SYSTEM - FUNCTION IN HOMEOSTASIS RID BODY OF WASTE (UREA, URIC ACID, CREATININE, SALTS) PRESERVES CONSTANCY OF EXTRACELLULAR FLUID IN COMPOSITION, VOLUME, AND pH ENDOCRINE FUNCTION a) SECRETE ERYTHROPOIETIN - RED BLOOD CELL PRODUCTION b) PRODUCES RENIN - ALDOSTERONE RELEASE hilum Kidney (H&E) Apex of renal pyramid Renal calyx CT adventia capsule Renal pyramind and calyx Medulla Cortex Simple columnar to transitional-like epithelium of pyramid Renal pelvis Kidney (H&E) Arcuate arteries Segmental vein Copyright McGraw-Hill Companies Blood flow: Renal artery > segmental artery > interlobar artery > arcuate artery > interlobular artery > afferent arteriole > glomerulus > efferent arteriole > peritubular capillaries (assoc. with convoluted tubules) OR vasa recta (assoc. with loop of henle) > interlobular vein > arcuate vein > interlobar vein > segmental vein > renal vein. Interlobular artery Kidney (H&E) Cortex Capsule Cortex Medulla Medulla Arcuate arteries Juxtamedullary nephrons Medullary rays KIDNEY FUNCTION BASED ON COMBINATION OF cortex FILTRATION ACTIVE SECRETION PASSIVE DIFFUSION SELECTIVE ABSORPTION 32 medulla Evolution – Animals escaping predators Fresh water Salt water Evolution – Animals escaping predators Fresh water Salt water PORTAL ARTERIOLE ARTERIAL PORTAL SYSTEM = CAPILLARY  PORTAL ARTERIOLE  CAPILLARY afferent ARTERIOLE efferent ARTERIOLE, and PERITUBULAR CAPILLARIES ARTERIAL PORTAL SYSTEM = CAPILLARY  PORTAL ARTERIOLE  CAPILLARY afferent ARTERIOLE efferent ARTERIOLE, and PERITUBULAR CAPILLARIES ARTERIAL PORTAL SYSTEM = CAPILLARY  PORTAL ARTERIOLE  CAPILLARY afferent ARTERIOLE efferent ARTERIOLE, and PERITUBULAR CAPILLARIES ARTERIAL PORTAL SYSTEM = CAPILLARY  PORTAL ARTERIOLE  CAPILLARY afferent ARTERIOLE efferent ARTERIOLE, and PERITUBULAR CAPILLARIES ARTERIAL PORTAL SYSTEM = CAPILLARY  PORTAL ARTERIOLE  CAPILLARY Function of a portal system? 1st afferent ARTERIOLE efferent ARTERIOLE, and PERITUBULAR CAPILLARIES 2nd 1st 2nd ARTERIAL PORTAL SYSTEM = CAPILLARY  PORTAL ARTERIOLE  CAPILLARY Function of a portal system? 1st afferent ARTERIOLE efferent ARTERIOLE, and PERITUBULAR CAPILLARIES 2nd 1st 2nd local change in blood composition whereby the first capillary modifies and second allows the change in composition to affect local cells near it. Renal corpuscle - Cells of the GLOMERULUS and capsule PARIETAL EPITHELIUM PODOCYTE MESANGIAL CELL ENDOTHELIAL CELL PARIETAL EPITHELIUM PODOCYTE MESANGIAL CELL ENDOTHELIAL CELL MESANGIAL CELLs SECRETE ERYTHROPOIETIN - RED BLOOD CELL PRODUCTION Kidney (H&E) Urinary pole Urinary space Parietal epithelium Bowman’s capsule Podocyte Glomerulus Visceral epithelium Arteriole of vascular pole Juxtaglomerular cells Macula densa Renal corpuscle kidney Proximal convoluted tubules Glomerulus Distal convoluted tubules Proximal convoluted t ubules Kidney (H&E) Juxtaglomerular apparatus Macula densa of distal tubule Juxtaglomerular cells Distal convoluted tubules Proximal convoluted tubules Microvilli Brush border Proximal convoluted tubules 0 to 8 mg/dL protein in urine is considered normal. The brush border is involved in reabsorption of protein. Human kidney cortex Proximal convoluted tubules Adventia capsule with no mesothelium Renal corpuscle Human kidney cortex Proximal convoluted tubules Adventia capsule with no mesothelium The intense eosinophilia of the cytoplasm of cells in the proximal convoluted tubules results from the glycocalyx covering the brush border staining intensely eosinophilic and the high density of membranes within the cells. These membranes and the high density of PCTs in the cortex are responsible for the PCTs absorbing most of filtered water from the renal corpuscle. Renal corpuscle Toulidine blue kidney Proximal convoluted tubules Urinary pole PCT DCT Glomerulus Collecting ducts 36748 EM 18b Kidney (PAS/Hematoxylin) Basement membranes are PAS positive Brush border of proximal tubule Distal tubule Kidney (PAS/Hematoxylin) Basement membranes are PAS positive Distal tubule Brush border of proximal tubule stain PAS positive due to the rich the glycocalyx covering its numerous microvilli. EM 30 & 43 Components of the filtration barrier: EM 18a Components of the filtration barrier: 1. The fenestrations of the capillary endothelium, which blocks blood cells and platelets EM 18a Components of the filtration barrier: 1. The fenestrations of the capillary endothelium, which blocks blood cells and platelets 2. The thick, combined basal laminae, or GBM, which restricts large proteins and some organic anions EM 18a Components of the filtration barrier: 1. The fenestrations of the capillary endothelium, which blocks blood cells and platelets 2. The thick, combined basal laminae, or GBM, which restricts large proteins and some organic anions 3. The filtration slit diaphragms between pedicels, which restrict some small proteins and organic anions EM 18a filtrate blood GLOMERULUS - PASSIVE ULTRAFILTRATION (ball park values) ENDOTHELIAL CELL >600,000 MW BASAL LAMINA >160,000 MW FILTRATION SLITS >70,000 MW Histologic features and major functions of regions with renal tubules Region of Tubule Histological Features Locations Major Functions Proximal convoluted tubules • Simple cuboidal epithelium • Cells well-stained with numerous mitochondria • Prominent basal folds and lateral interdigitations • Long microvilli, lumens often occluded Cortex • Reabsorption of all organic nutrients, all proteins, most water and electrolytes • Secretion of organic anions and cations, H+, and NH4+ Thin limbs of Loop of Henle • Simple squamous epithelium • Few mitochondria Medulla Passive reabsorption of Na+ and Cl- Thick ascending limb (TAL) of Loop of Henle • Simple cuboidal epithelium • No microvilli Medulla and medullary rays Active reabsorption of various electrolytes Distal convoluted tubules • Simple cuboidal epithelium • Cells smaller than in proximal convoluted tubules • Short microvilli and basolateral folds • More empty lumens Cortex Reabsorption of electrolytes Principle cells of Collecting system • • • • Medullary rays and medulla • Regulated reabsorption of water and electrolytes • Regulated secretion of K+ Intercalated cells of Collecting system • Few and scattered • Slightly darker staining Medullary rays • Reabsorption of K+ (low-K+ diet) • Help maintain acid-base balance Most abundant Cuboidal to columnar Pale-staining Distinct cell membranes Kidney (H&E) - Thick ascending limb of loop of Henle Thick descending limb of loop of Henle Thin limb of loop of Henle Collecting duct kidney medulla Descending PT CD CD CD ThLH Cap TnLH Cap Cap CD Cap TnLH Kidney medulla (Lee’ s stain) – thin portion of loop of Henle Blood capillaries Loop of Henle Collecting tubule Transitions Transitions Toulidine blue kidney Ascending loop of Henle Peritubular capillaries of the vasa recta Distal tubules Transition from ascending loop of Henle to distal tubules Descending loop of Henle 36748 Transition from proximal tubules to thin descending loop of Henle Transitions from ascending loop of Henle to distal tubules 36748 Transitions from ascending loop of Henle to distal tubules Infolding of the basal cell membrane line up mitochondria in cells of the distal tubule. 36748 36748 Ascending loop of Henle Distal tubule Blood capillaries of the vasa recta Descending loop of Henle 19713 kidney CT CT TnLH CT ThLH CT Cap CT Cap 458 kidney Collecting duct 458 kidney Collecting duct cortex medulla Minor calyx 32

Urinary System Part 1 Kidney and Nephron

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