DOCSLIB.ORG

SYSTEMIC HISTOLOGY URINARY SYSTEM II Mr. Babatunde

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
SYSTEMIC HISTOLOGY URINARY SYSTEM II Mr. Babatunde SYSTEMIC HISTOLOGY URINARY SYSTEM II Mr. Babatunde, D.E Descending Pars Recta (straight portion) of Proximal Tubule Is also lined by a simple cuboidal epithelium having a prominent brush border. Cells are shorter and less elaborate in shape than those of the proximal convoluted tubule, but they have the same general features. This region of the nephron is often damaged in acute renal failure and mercury poisoning. This segment constitutes the initial part (thick descending limb) of the loop of Henle. Proximal convoluted tubule and thick descending limb of Henle’s loop Distal convuloted tubule and thick ascending limb of Henle’s loop Thin limb of Henle’s loop Collecting duct Figure 19–16. Cellular ultrastructure of the nephron, represented schematically. Cells of the thick ascending limb of Henle’s loop and the distal tubule are different in their ultrastructures and functions. Thin Limb of the Loop of Henle is composed of a descending limb, a loop, and an ascending limb, all of which are lined by a simple squamous epithelium. cells in this epithelium have nuclei that bulge into the lumen, and their surfaces possess only a few short microvilli. the thin limb has separated into four distinct segment based on shape of cells, their content of organelles, the depth of their tight junctions, and their water permeability. is the region that forms the middle part of the loop Henle. Proximal convoluted tubule and thick descending limb of Henle’s loop Distal convuloted tubule and thick ascending limb of Henle’s loop Thin limb of Henle’s loop Collecting duct Figure 19–16. Cellular ultrastructure of the nephron, represented schematically. Cells of the thick ascending limb of Henle’s loop and the distal tubule are different in their ultrastructures and functions. Ascending Thick Limb (straight portion) of Distal Tubule Is the third (and final) component of the loop of Henle. Is lined by a simple cuboidal epithelium containing only a few microvilli. Its nuclei occupy an apical position in the cells. Mitochondria are compartmentalized within the interdigitations formed by the basal and lateral infoldings. Cells transport ions from the lumen into the interstitium, and since this part of the nephron has a impermeability to water, the luminal fluid becomes hypotonic to the blood. Proximal convoluted tubule and thick descending limb of Henle’s loop Distal convuloted tubule and thick ascending limb of Henle’s loop Thin limb of Henle’s loop Ascending Thick Limb of Distal Tubule Collecting duct Figure 19–16. Cellular ultrastructure of the nephron, represented schematically. Cells of the thick ascending limb of Henle’s loop and the distal tubule are different in their ultrastructures and functions. Distal Convoluted Tubule Begins at the macula densa. Has microvilli much shorter than the proximal microvilli, and their nuclei occupy an apical position in the cytoplasm. Extensive lateral interdigitations compartmentalize mitochondria in basal cytoplasmic infoldings. Cells actively transport sodium ions from the filtrate into the interstitium. Proximal convoluted tubule and thick descending limb of Henle’s loop Distal convuloted tubule and thick ascending limb of Henle’s loop Thin limb of Henle’s loop Collecting duct Figure 19–16. Cellular ultrastructure of the nephron, represented schematically. Cells of the thick ascending limb of Henle’s loop and the distal tubule are different in their ultrastructures and functions. Figure 19—19. Region of the kidney consisting mainly of distal convoluted tubules (DCT) and thin segments of Henle’s loop (asterisks). Capillaries filled with blood appear in red. PT stain. Medium magnification. Figure 19—13. Renal cortex showing proximal (P) and distal (D) convoluted tubules. One can see sections through the vascular pole of 3 renal corpuscles where juxtaglomerular renin-secreting cells appear well stained (broken lines). PT stain. Medium magnification. 1. Macula Densa Is a specific region of the distal tubule, lying near the afferent glomerular arteriole. Is one component of the juxtaglomerular apparatus. Cells are tall, narrow, and lined up closely together to form a row of nuclei that appear as a “dense spot” by light microscopy. Cells are thought to monitor the fluid in the distal tubule and send a signal to the juxtaglomerular cells (modified smooth muscle cells) located in the afferent arteriole. Signaling could occur via gap junctions present between these two cells types. Figure 19—3. The renal corpuscle. The upper part of the drawing shows the vascular pole, with afferent and efferent arterioles and the macula densa. Note the juxtaglomerular cells in the wall of the afferent arteriole. Podocyte processes cover the outer surfaces of the glomerular capillaries; the part of the podocyte containing the nucleus protrudes into the urinary space. Note the flattened cells of the parietal layer of Bowman’s capsule. The lower part of the drawing shows the urinary pole and the proximal convoluted tubule. Figure 19—9. Photomicrograph of a renal cortex showing parts of 2 renal corpuscles, macula densa, and distal and proximal convoluted tubules. The collagen type IV of the basement membrane of the glomerular capillaries is clearly visible (arrows). The collagen of the parietal layer of the Bowman’s capsule and basal membrane of a distal tubule are shown by the arrowhead. Picrosirius stain. Medium magnification. Figure 19—21. Photomicrograph of renal cortex. A macula densa is clearly seen (arrow) at the vascular pole of a renal corpuscle. Picrosirius-hematoxylin (PSH) stain. Medium magnification. 2. Juxtaglomerular (JG) Apparatus is located at the vascular pole of the renal corpuscle. consists of four structures: modified smooth muscle cells of the afferent arteriole, of the efferent arteriole, the macula densa (of the distal tubule) and the extraglomerular mesangial cells. Function of Juxtaglomerular Apparatus in response to a decrease in extracellular fluid volume (perhaps detected by the macula densa) the JG cells release renin (an Enzyme). Figure 19—3. The renal corpuscle. The upper part of the drawing shows the vascular pole, with afferent and efferent arterioles and the macula densa. Note the juxtaglomerular cells in the wall of the afferent arteriole. Podocyte processes cover the outer surfaces of the glomerular capillaries; the part of the podocyte containing the nucleus protrudes into the urinary space. Note the flattened cells of the parietal layer of Bowman’s capsule. The lower part of the drawing shows the urinary pole and the proximal convoluted tubule. Figure 19—24. Photomicrograph of an afferent arteriole entering a renal corpuscle. The wall of this arteriole shows the renin-producing juxtaglomerular (JG) cells (broken line). At the upper right is a distal convoluted tubule (DCT) with many elongated mitochondria. PT stain. High magnification. Renin acts on angiotensinogen in the plasma, converting it to angiotensin I. in capillaries of the lung, angiotensin I is converted to angiotensin II, which causes release of aldosterone from the zona glomerulosa cells in the adrenal cortex. Aldosterone stimulates distal tubule cells to retain sodium ions. water follows the sodium, and the fluid volume is increased in the extracellular compartment (thus correcting the initial problem. Angiotensin II is also a potent vasoconstrictor, which acts to elevate the blood pressure. Distal tubule Macula densa Afferent arteriole Juxtaglomerular cells (modified smooth muscle) Juxtaglomerular cells Efferent arteriole Bowman’s capsule Vascular pole (Parietal layer) Bownan’s capsule (Visceral layer Podocytes) Parietal layer Urinary space Urinary pole Brush border Proximal convoluted tubule Figure 19—24. Photomicrograph of an afferent arteriole entering a renal corpuscle. The wall of this arteriole shows the renin-producing juxtaglomerular (JG) cells (broken line). At the upper right is a distal convoluted tubule (DCT) with many elongated mitochondria. PT stain. High magnification. 3. Collecting Tubules have different functions, depending on their location in the kidney. in the cortex and medulla they respond to antidiuretic hormone (ADH), also known as vasopressin. in the medulla they play a primary role in producing a concentrated urine (by establishing a gradient due to the transport of urea from the tubular fluid into the renal interstitium). Figure 19—22. Photomicrograph of renal medulla with 2 collecting ducts consisting of cuboidal cells resting on a basement membrane. In this hypertonic region of the kidney, because of the action of the hypophyseal antidiuretic hormone, water is reabsorbed, controlling the water balance of the body. PT stain. Medium magnification. Figure 19—23. Electron micrograph of a collecting tubule wall. M, mitochondria; NU, nucleolus. x15,000. C P Collecting tubule (C) Proximal tubule (P) C P Cortical Collecting Tubules are located primarily within the medullary ray, although a few arched collecting tubules exist with the cortical labyrinth. have two cell types, a light (principal) cell and a dark (intercalated) cell. 1) Light Cells are simple cuboidal in shape and have round centrally located nuclei. a single central cilium (flagellum) extends into the lumen from the surface of each light cell. 2) Dark Cells are fewer in number and have microplicae (folds) on their surface. apical cytoplasm of the dark cell contains many vesicles. Glomerulus Collecting tubule Medullary Collecting Tubule is similar in structure to the cortical collecting tubule. dark cells
Load more

Recommended publications
  • Excretory Products and Their Elimination
    290 BIOLOGY CHAPTER 19 EXCRETORY PRODUCTS AND THEIR ELIMINATION 19.1 Human Animals accumulate ammonia, urea, uric acid, carbon dioxide, water Excretory and ions like Na+, K+, Cl–, phosphate, sulphate, etc., either by metabolic System activities or by other means like excess ingestion. These substances have to be removed totally or partially. In this chapter, you will learn the 19.2 Urine Formation mechanisms of elimination of these substances with special emphasis on 19.3 Function of the common nitrogenous wastes. Ammonia, urea and uric acid are the major Tubules forms of nitrogenous wastes excreted by the animals. Ammonia is the most toxic form and requires large amount of water for its elimination, 19.4 Mechanism of whereas uric acid, being the least toxic, can be removed with a minimum Concentration of loss of water. the Filtrate The process of excreting ammonia is Ammonotelism. Many bony fishes, 19.5 Regulation of aquatic amphibians and aquatic insects are ammonotelic in nature. Kidney Function Ammonia, as it is readily soluble, is generally excreted by diffusion across 19.6 Micturition body surfaces or through gill surfaces (in fish) as ammonium ions. Kidneys do not play any significant role in its removal. Terrestrial adaptation 19.7 Role of other necessitated the production of lesser toxic nitrogenous wastes like urea Organs in and uric acid for conservation of water. Mammals, many terrestrial Excretion amphibians and marine fishes mainly excrete urea and are called ureotelic 19.8 Disorders of the animals. Ammonia produced by metabolism is converted into urea in the Excretory liver of these animals and released into the blood which is filtered and System excreted out by the kidneys.
    [Show full text]
  • Nitric Oxide Synthase in Macula Densa Regulates Glomerular Capillary
    Proc. Nati. Acad. Sci. USA Vol. 89, pp. 11993-11997, December 1992 Pharmacology Nitric oxide synthase in macula densa regulates glomerular capillary pressure (kidney/tubuloglomerular feedback response/glomerular ifitration rate/afferent arteriole) CHRISTOPHER S. WILCOX*t, WILLIAM J. WELCH*, FERID MURADf, STEVEN S. GROSS§, GRAHAM TAYLOR¶, ROBERTO LEVI§, AND HARALD H. H. W. SCHMIDTII** *Division of Nephrology, Hypertension and Transplantation Departments of Medicine, Pharmacology and Therapeutics, University of Florida College of Medicine and Department of Veterans Affairs Medical Center, Gainesville, FL 32608; I'Department of Pharmacology, Northwestern University School of Medicine, Chicago, IL; tAbbott Laboratories, Abbott Park, IL 60064-3500; iDepartment of Pharmacology, Cornell University Medical College, New York, NY 10021; and IDepartment of Clinical Pharmacology, The Royal Postgraduate Medical School, Hammersmith Hospital, London, England W12 OHS Communicated by Robert F. Furchgott, September 3, 1992 ABSTRACT Tubular-fluid reabsorption by specialized Previous studies have established that L-arginine-derived cells of the nephron at the junction of the ascending limb of the nitric oxide (NO) is produced by several cells within the loop of Henle and the distal convoluted tubule, termed the kidney, including isolated glomerular mesangial (6) and en- macula densa, releases compounds causing vasoconstriction of dothelial cells (7), and a renal epithelial cell line (8), but its the adjacent afferent arteriole. Activation of this tubuloglo- integrative role in the control ofrenal function is not yet clear merular feedback response reduces glomerular capillary pres- (9). In the vessel wall, the endothelium can mediate vasodi- sure of the nephron and, hence, the glomerular filtration rate. lator responses to agents such as acetylcholine (10) and can The tubuloglomerular feedback response functions in a nega- blunt the actions of certain vasoconstrictors (11).
    [Show full text]
  • Basic Histology (23 Questions): Oral Histology (16 Questions
    Board Question Breakdown (Anatomic Sciences section) The Anatomic Sciences portion of part I of the Dental Board exams consists of 100 test items. They are broken up into the following distribution: Gross Anatomy (50 questions): Head - 28 questions broken down in this fashion: - Oral cavity - 6 questions - Extraoral structures - 12 questions - Osteology - 6 questions - TMJ and muscles of mastication - 4 questions Neck - 5 questions Upper Limb - 3 questions Thoracic cavity - 5 questions Abdominopelvic cavity - 2 questions Neuroanatomy (CNS, ANS +) - 7 questions Basic Histology (23 questions): Ultrastructure (cell organelles) - 4 questions Basic tissues - 4 questions Bone, cartilage & joints - 3 questions Lymphatic & circulatory systems - 3 questions Endocrine system - 2 questions Respiratory system - 1 question Gastrointestinal system - 3 questions Genitouirinary systems - (reproductive & urinary) 2 questions Integument - 1 question Oral Histology (16 questions): Tooth & supporting structures - 9 questions Soft oral tissues (including dentin) - 5 questions Temporomandibular joint - 2 questions Developmental Biology (11 questions): Osteogenesis (bone formation) - 2 questions Tooth development, eruption & movement - 4 questions General embryology - 2 questions 2 National Board Part 1: Review questions for histology/oral histology (Answers follow at the end) 1. Normally most of the circulating white blood cells are a. basophilic leukocytes b. monocytes c. lymphocytes d. eosinophilic leukocytes e. neutrophilic leukocytes 2. Blood platelets are products of a. osteoclasts b. basophils c. red blood cells d. plasma cells e. megakaryocytes 3. Bacteria are frequently ingested by a. neutrophilic leukocytes b. basophilic leukocytes c. mast cells d. small lymphocytes e. fibrocytes 4. It is believed that worn out red cells are normally destroyed in the spleen by a. neutrophils b.
    [Show full text]
  • Claudins in the Renal Collecting Duct
    International Journal of Molecular Sciences Review Claudins in the Renal Collecting Duct Janna Leiz 1,2 and Kai M. Schmidt-Ott 1,2,3,* 1 Department of Nephrology and Intensive Care Medicine, Charité-Universitätsmedizin Berlin, 12203 Berlin, Germany; [email protected] 2 Molecular and Translational Kidney Research, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany 3 Berlin Institute of Health (BIH), 10178 Berlin, Germany * Correspondence: [email protected]; Tel.: +49-(0)30-450614671 Received: 22 October 2019; Accepted: 20 December 2019; Published: 28 December 2019 Abstract: The renal collecting duct fine-tunes urinary composition, and thereby, coordinates key physiological processes, such as volume/blood pressure regulation, electrolyte-free water reabsorption, and acid-base homeostasis. The collecting duct epithelium is comprised of a tight epithelial barrier resulting in a strict separation of intraluminal urine and the interstitium. Tight junctions are key players in enforcing this barrier and in regulating paracellular transport of solutes across the epithelium. The features of tight junctions across different epithelia are strongly determined by their molecular composition. Claudins are particularly important structural components of tight junctions because they confer barrier and transport properties. In the collecting duct, a specific set of claudins (Cldn-3, Cldn-4, Cldn-7, Cldn-8) is expressed, and each of these claudins has been implicated in mediating aspects of the specific properties of its tight junction. The functional disruption of individual claudins or of the overall barrier function results in defects of blood pressure and water homeostasis. In this concise review, we provide an overview of the current knowledge on the role of the collecting duct epithelial barrier and of claudins in collecting duct function and pathophysiology.
    [Show full text]
  • Renal Corpuscle Renal System > Histology > Histology
    Renal Corpuscle Renal System > Histology > Histology Key Points: • The renal corpuscles lie within the renal cortex; • They comprise the glomerular, aka, Bowman's capsule and capillaries The capsule is a double-layer sac of epithelium: — The outer parietal layer folds upon itself to form the visceral layer. — The inner visceral layer envelops the glomerular capillaries. • As blood passes through the glomerular capillaries, aka, glomerulus, specific components, including water and wastes, are filtered to create ultrafiltrate. • The filtration barrier, which determines ultrafiltrate composition, comprises glomerular capillary endothelia, a basement membrane, and the visceral layer of the glomerular capsule. • Nephron tubules modify the ultrafiltrate to form urine. Overview Diagram: • Tuft of glomerular capillaries; blood enters the capillaries via the afferent arteriole, and exits via efferent arteriole. • The visceral layer of the glomerular capsule envelops the capillaries, then folds outwards to become the parietal layer. • The capsular space lies between the parietal and visceral layers; this space fills with ultrafiltrate. • Vascular pole = where the arterioles pass through the capsule • Urinary pole = where the nephron tubule begins • Distal tubule passes by the afferent arteriole. Details of Capillary and Visceral Layer: • Fenestrated glomerular capillary; fenestrations are small openings, aka, pores, in the endothelium that confer permeability. • Thick basement membrane overlies capillaries • Visceral layer comprises podocytes: — Cell bodies — Cytoplasmic extensions, called primary processes, give rise to secondary foot processes, aka, pedicles. • The pedicles interdigitate to form filtration slits; molecules pass through these slits to form the ultrafiltrate in the 1 / 3 capsular space. • Subpodocyte space; healthy podocytes do not adhere to the basement membrane. Clinical Correlation: • Podocyte injury causes dramatic changes in shape, and, therefore, their ability to filter substances from the blood.
    [Show full text]
  • Kidney Function • Filtration • Reabsorption • Secretion • Excretion • Micturition
    About This Chapter • Functions of the kidneys • Anatomy of the urinary system • Overview of kidney function • Filtration • Reabsorption • Secretion • Excretion • Micturition © 2016 Pearson Education, Inc. Functions of the Kidneys • Regulation of extracellular fluid volume and blood pressure • Regulation of osmolarity • Maintenance of ion balance • Homeostatic regulation of pH • Excretion of wastes • Production of hormones © 2016 Pearson Education, Inc. Anatomy of the Urinary System • Kidneys, ureters, bladder, and urethra • Kidneys – Bean-shaped organ – Cortex and medulla © 2016 Pearson Education, Inc. Anatomy of the Urinary System • Functional unit is the nephron – Glomerulus in the Bowman’s capsule – Proximal tubule – The loop of Henle • Descending limb and ascending limb twisted between arterioles forming the juxtaglomerular apparatus – Distal tubule – Collecting ducts © 2016 Pearson Education, Inc. Figure 19.1b Anatomy summary The kidneys are located retroperitoneally at the level of the lower ribs. Inferior Diaphragm vena cava Aorta Left adrenal gland Left kidney Right kidney Renal artery Renal vein Ureter Peritoneum Urinary Rectum (cut) bladder (cut) © 2016 Pearson Education, Inc. Figure 19.1c Anatomy summary © 2016 Pearson Education, Inc. Figure 19.1d Anatomy summary © 2016 Pearson Education, Inc. Figure 19.1f-h Anatomy summary Some nephrons dip deep into the medulla. One nephron has two arterioles and two sets of capillaries that form a portal system. Efferent arteriole Arterioles Peritubular Juxtaglomerular capillaries The cortex apparatus contains all Bowman’s Nephrons Afferent capsules, arteriole Glomerulus proximal Juxtamedullary nephron and distal (capillaries) with vasa recta tubules. Peritubular capillaries Glomerulus The medulla contains loops of Henle and Vasa recta collecting ducts. Collecting duct Loop of Henle © 2016 Pearson Education, Inc.
    [Show full text]
  • Anatomy and Physiology of the Bowel and Urinary Systems
    PMS1 1/26/05 10:52 AM Page 1 Anatomy and Physiology of the Bowel and 1 Urinary Systems Anthony McGrath INTRODUCTION The aim of this chapter is to increase the reader’s under- standing of the small and large bowel and urinary system as this will enhance their knowledge base and allow them to apply this knowledge when caring for patients who are to undergo stoma formation. LEARNING OBJECTIVES By the end of this chapter the reader will have: ❏ an understanding of the anatomy and physiology of the small and large bowel; ❏ an understanding of the anatomy and physiology of the urinary system. GASTROINTESTINAL TRACT The gastrointestinal (GI) tract (Fig. 1.1) consists of the mouth, pharynx, oesophagus, stomach, duodenum, jejunum, small and large intestines, rectum and anal canal. It is a muscular tube, approximately 9m in length, and it is controlled by the autonomic nervous system. However, while giving a brief outline of the whole system and its makeup, this chapter will focus on the anatomy and physiology of the small and large bowel and the urinary system. The GI tract is responsible for the breakdown, digestion and absorption of food, and the removal of solid waste in the form of faeces from the body. As food is eaten, it passes through each section of the GI tract and is subjected to the action of various 1 PMS1 1/26/05 10:52 AM Page 2 1 Anatomy and Physiology of the Bowel and Urinary Systems Fig. 1.1 The digestive system. Reproduced with kind permission of Coloplast Ltd from An Introduction to Stoma Care 2000 2 PMS1 1/26/05 10:52 AM Page 3 Gastrointestinal Tract 1 digestive fluids and enzymes (Lehne 1998).
    [Show full text]
  • Urinary System
    OUTLINE 27.1 General Structure and Functions of the Urinary System 818 27.2 Kidneys 820 27 27.2a Gross and Sectional Anatomy of the Kidney 820 27.2b Blood Supply to the Kidney 821 27.2c Nephrons 824 27.2d How Tubular Fluid Becomes Urine 828 27.2e Juxtaglomerular Apparatus 828 Urinary 27.2f Innervation of the Kidney 828 27.3 Urinary Tract 829 27.3a Ureters 829 27.3b Urinary Bladder 830 System 27.3c Urethra 833 27.4 Aging and the Urinary System 834 27.5 Development of the Urinary System 835 27.5a Kidney and Ureter Development 835 27.5b Urinary Bladder and Urethra Development 835 MODULE 13: URINARY SYSTEM mck78097_ch27_817-841.indd 817 2/25/11 2:24 PM 818 Chapter Twenty-Seven Urinary System n the course of carrying out their specific functions, the cells Besides removing waste products from the bloodstream, the uri- I of all body systems produce waste products, and these waste nary system performs many other functions, including the following: products end up in the bloodstream. In this case, the bloodstream is ■ Storage of urine. Urine is produced continuously, but analogous to a river that supplies drinking water to a nearby town. it would be quite inconvenient if we were constantly The river water may become polluted with sediment, animal waste, excreting urine. The urinary bladder is an expandable, and motorboat fuel—but the town has a water treatment plant that muscular sac that can store as much as 1 liter of urine. removes these waste products and makes the water safe to drink.
    [Show full text]
  • The Urinary System Dr
    The urinary System Dr. Ali Ebneshahidi Functions of the Urinary System • Excretion – removal of waste material from the blood plasma and the disposal of this waste in the urine. • Elimination – removal of waste from other organ systems - from digestive system – undigested food, water, salt, ions, and drugs. + - from respiratory system – CO2,H , water, toxins. - from skin – water, NaCl, nitrogenous wastes (urea , uric acid, ammonia, creatinine). • Water balance -- kidney tubules regulate water reabsorption and urine concentration. • regulation of PH, volume, and composition of body fluids. • production of Erythropoietin for hematopoieseis, and renin for blood pressure regulation. Anatomy of the Urinary System Gross anatomy: • kidneys – a pair of bean – shaped organs located retroperitoneally, responsible for blood filtering and urine formation. • Renal capsule – a layer of fibrous connective tissue covering the kidneys. • Renal cortex – outer region of the kidneys where most nephrons is located. • Renal medulla – inner region of the kidneys where some nephrons is located, also where urine is collected to be excreted outward. • Renal calyx – duct – like sections of renal medulla for collecting urine from nephrons and direct urine into renal pelvis. • Renal pyramid – connective tissues in the renal medulla binding various structures together. • Renal pelvis – central urine collecting area of renal medulla. • Hilum (or hilus) – concave notch of kidneys where renal artery, renal vein, urethra, nerves, and lymphatic vessels converge. • Ureter – a tubule that transport urine (mainly by peristalsis) from the kidney to the urinary bladder. • Urinary bladder – a spherical storage organ that contains up to 400 ml of urine. • Urethra – a tubule that excretes urine out of the urinary bladder to the outside, through the urethral orifice.
    [Show full text]
  • L8-Urine Conc. [PDF]
    The loop of Henle is referred to as countercurrent multiplier and vasa recta as countercurrent exchange systems in concentrating and diluting urine. Explain what happens to osmolarity of tubular fluid in the various segments of the loop of Henle when concentrated urine is being produced. Explain the factors that determine the ability of loop of Henle to make a concentrated medullary gradient. Differentiate between water diuresis and osmotic diuresis. Appreciate clinical correlates of diabetes mellitus and diabetes insipidus. Fluid intake The total body water Antidiuretic hormone is controled by : Renal excretion of water Hyperosmolar medullary Changes in the osmolarity of tubular fluid : interstitium 1 2 3 Low osmolarity The osmolarity High osmolarity because of active decrease as it goes up because of the transport of Na+ and because of the reabsorbation of water co-transport of K+ and reabsorption of NaCl Cl- 4 5 Low osmolarity because of High osmolarity because of reabsorption of NaCl , also reabsorption of water in reabsorption of water in present of ADH , present of ADH reabsorption of urea Mechanisms responsible for creation of hyperosmolar medulla: Active Co- Facilitated diffusion transport : transport : diffusion : of : Na+ ions out of the Only of small thick portion of the K+ , Cl- and other amounts of water ascending limb of ions out of the thick from the medullary the loop of henle portion of the Of urea from the tubules into the into the medullary ascending limb of inner medullary medullary interstitium the loop of henle collecting
    [Show full text]
  • Normal Vascular and Glomerular Anatomy
    Normal Vascular and Glomerular Anatomy Arthur H. Cohen Richard J. Glassock he topic of normal vascular and glomerular anatomy is intro- duced here to serve as a reference point for later illustrations of Tdisease-specific alterations in morphology. CHAPTER 1 1.2 Glomerulonephritis and Vasculitis FIGURE 1-1 A, The major renal circulation. The renal artery divides into the interlobar arteries (usually 4 or 5 divisions) that then branch into arcuate arteries encompassing the corticomedullary Interlobar junction of each renal pyramid. The interlobular arteries (multiple) originate from the artery arcuate arteries. B, The renal microcirculation. The afferent arterioles branch from the interlobular arteries and form the glomerular capillaries (hemi-arterioles). Efferent arteri- Arcuate oles then reform and collect to form the post-glomerular circulation (peritubular capillar- artery Renal ies, venules and renal veins [not shown]). The efferent arterioles at the corticomedullary artery junction dip deep into the medulla to form the vasa recta, which embrace the collecting tubules and form hairpin loops. (Courtesy of Arthur Cohen, MD.) Pyramid Pelvis Interlobular Ureter artery A Afferent arteriole Interlobular artery Glomerulus Arcuate artery Efferent arteriole Collecting tubule Interlobar artery B Normal Vascular and Glomerular Anatomy 1.3 FIGURE 1-2 (see Color Plate) Microscopic view of the normal vascular and glomerular anatomy. The largest intrarenal arteries (interlobar) enter the kidneys between adjacent lobes and extend toward the cortex on the side of a pyramid. These arteries branch dichotomously at the corti- comedullary junction, forming arcuate arteries that course between the cortex and medulla. The arcuate arteries branch into a series of aa ILA interlobular arteries that course at roughly right angles through the cortex toward the capsule.
    [Show full text]
  • Urinary System
    Urinary System Urinary System Urinary System - Overview: Major Functions: 1) Removal of organic waste products Kidney from fluids (excretion) 2) Discharge of waste products into the environment (elimination) 1 3) Regulation of the volume / [solute] / pH 3 of blood plasma Ureter HOWEVER, THE KIDNEY AIN’T JUST FOR PEE’IN… Urinary bladder • Regulation of blood volume / blood pressure (e.g., renin) • Regulation of red blood cell formation (i.e., erythropoietin) 2 • Metabolization of vitamin D to active form (Ca++ uptake) Urethra • Gluconeogenesis during prolonged fasting Marieb & Hoehn (Human Anatomy and Physiology, 8th ed.) – Figure 25.1 1 Urinary System Renal ptosis: Kidneys drop to lower position due Functional Anatomy - Kidney: to loss of perirenal fat Located in the superior lumbar “Bar of soap” region 12 cm x 6 cm x 3 cm 150 g / kidney Layers of Supportive Tissue: Renal fascia: Peritoneal cavity Outer layer of dense fibrous connective tissue; anchors kidney in place Perirenal fat capsule: Fatty mass surrounding kidney; cushions kidney against blows Fibrous capsule: Transparent capsule on kidney; prevents infection of kidney from local tissues Kidneys are located retroperitoneal Marieb & Hoehn (Human Anatomy and Physiology, 8th ed.) – Figure 25.2 Urinary System Functional Anatomy - Kidney: Pyelonephritis: Inflammation of the kidney Pyramids appear striped due to parallel arrangement of capillaries / collecting tubes Renal cortex Renal medulla Renal pyramids Renal papilla Renal columns Renal hilum Renal pelvis • Entrance for blood vessels
    [Show full text]