Human Biology Urinary System PDF

ITBC – Course 6BM Human Biology Urinary system Nothing from this presentation may be published without explicit permission from the director of the Institute Applied Biosciences and Chemistry  Goal of the Human Biology lessons Insight and knowledge about the 4 ba...

ITBC – Course 6BM Human Biology Urinary system Nothing from this presentation may be published without explicit permission from the director of the Institute Applied Biosciences and Chemistry  Goal of the Human Biology lessons Insight and knowledge about the 4 basic tissues Epithelial tissue & skin Connective tissue Muscle tissue Nervous tissue Insight and knowledge about organs and organ systems Urinary system Digestive system & Endocrine system Respiratory system & Circulation 2 All pictures are derived from the following book (unless indicated differently): Mescher, Anthony. Junqueira's Basic Histology: Text and Atlas, Fifteenth Edition. McGraw-Hill Education This lesson: urinary system Junqueira’s basic histology Chapter 19 Useful movie (Bozeman Science, The Urinary System): https://www.youtube.com/watch?v=H2VkW9L5QSU 3 The urinary system Two kidneys Ureters Bladder Urethra 4 Functions of the urinary system Remove waste products (incl. toxins) Regulate balance between water and electrolytes (blood pressure) when you take a lot of water the pH will riase Regulate pH of the blood (acid-base balance) Secretion of various hormones Renin: blood pressure (renin-angiotensin-aldosterone-system, RAAS) Erythropoietin (EPO): erythrocyte production stimules to take more erythrocytes 5 Build-up of a kidney Cortex Medulla Pelvis Hilum; exit/entry for: Arteria renalis Vena renalis Ureter Nerves/lymph vessels 6 The nefron → the smallest functional unit of the kidney Partially in cortex, partially in medulla Glomerulus Proximal tubule Loop of Henle Distal tubule 7  Renal body (corpuscle) Glomerulus (capillary loops) → covered with podocytes Vascular pole Artery, so: blood pressure Afferent arteriole the blood come out the blood come in Efferent arteriole Macula densa cells which produce renin, regulate the blood pressure Tubular pole Produced filtrate (pre-urine) goes into proximal tubule 8  these cells are the filtration barrier Cells of the renal body Parietal epithelial cell Podocyte Endothelial cell Mesangial cell 9 Filter of the kidney Capillaries of the glomerulus → fenestrated endothelium Podocytes cover these capillaries with their many projections 10 Filter of the kidney 1 2 3 11 Filtrate (pre-urine) Ends up in Bowmans space Goes towards the proximal convoluted tubule (PCT) 12 Glomerular Filtration Rate (GFR) Surface of all glomeruli together appr. 500 cm2 GFR: appr. 180 L/day So our kidneys filter our blood 60x per day! But…… not all of this goes through our urethra……. 13 Proximal convoluted tubule Reabsorption Nutrients Proteins Water + electrolytes But also secretion Bile salts Creatinine Ammonia Drugs → Where do these substances go to?? 14 Proximal convoluted tubule cell MV? microvilli M? L? V? C? cilia 15 Loop of Henle Create salt-concentration gradient in the medulla of the kidney via “countercurrent multiplication” https://youtu.be/hjQd9nWAxQk Leads to concentration of the urine (water reabsorption) 16 Loop of Henle Located in medulla Thick and thin parts (different type of epithelium) CD = collecting ducts 17  Distal convoluted tubule Reabsorption Electrolytes Juxtaglomerular apparatus ‘near’ glomerulus 18 Proximal and distal convoluted tubules in the cortex PAS staining HE staining 19  important for regulation of the blood pressure Juxtaglomerular apparatus (JGA) Macula densa of distal convoluted tubule Cells detect amount of salts (electrolytes) in lumen high blood pressure high GFR high salt concentration decrease in blood contraction muscle cells release vasoactive pressure in glomerulus afferent arteriole compounds by MD Juxtaglomerular granular cells produce renin - increase to blood pressure low blood pressure baroreceptors in renin release by JG cells afferent arteriole increase in angiotensin: systemic vasoconstriction activation RAAS blood pressure aldosterone: extra Na+ and water reabsorption system 20 Collecting ducts In cortex and medulla Antidiuretic hormone (ADH) increases water reabsorption for more concentrated urine 21 Link between blood ↔ filtrate/urine 22 Route of the filtrate/urine Collecting ducts converge in renal pelvis Via ureters to bladder → storage Export via urethra Hypertonic fluid → special protecting epithelial layer 23 Urothelium / transitional epithelium Basal layer Intermediate layer (few cells thick, cuboidal to columnar) Superficial layer with big umbrella cells → specialized cells → aimed to protect underlying cells against the cytotoxic effects of hypertonic urine 24 Ureters Transitional epithelium (lumen) Surrounded by thick muscle layer (peristaltic contractions) Adventitia Star-shaped lumen 25 Bladder Urothelium Muscle layers Adventitia 26 Urethra Different length in male/female Transition from urothelium to stratified squamous epithelium (skin) Presence of a “sphincter” → circular muscle (tissue type?) 27 End of this lesson Are there any questions? 28 Sources Junqueira’s basic histology 15th ed., Anthony L. Mescher, McGraw-Hill Education Basicmedical Key, consulted on 12-09-2019, from https://basicmedicalkey.com/urinary-system-9/ Functionele histologie, Junqueira L.C., Carneiro J., 13th edition, Elsevier gezondheidszorg 29