Urinary and Integumentary Systems 1. Urinary system overview 2. Kidney and its excretory ducts 3. Ureters 4. Urinary bladder 5. Urethra 6. Skin – epidermis, dermis and hypodermis 7. Skin appendages SPLANCHNOLOGY Urinary system ° Urinary system, systema urinaria: V elimination of wastes from the body – urine V homeostasis – very close relationships with the circulatory, respiratory and endocrine systems ° Urinary organs, organa urinaria: V kidney, ren: renal calyces renal pelvis V ureter, ureter V urinary bladder, vesica urinaria V urethra, urethra: male urethra, urethra masculina female urethra, urethra feminina Prof. Dr. Nikolai Lazarov 2 SPLANCHNOLOGY Kidney, ren ° Kidney , ren (Gr. nephros): V a paired organ V excretory function: removal of wastes excessive water V endocrine function: renin regulation of blood pressure erythropoietin erythrocytopoiesis calcitriol increase of blood calcium levels ° Kidneys in situ: V at the rear of the abdominal cavity V in the retroperitoneum V below the diaphragm V near the vertebral column Prof. Dr. Nikolai Lazarov 3 SPLANCHNOLOGY Gross anatomy ° External morphology: V shape – bean-like two poles: o extremitas superior et extremitas inferior two surfaces and two margins: o facies anterior et facies posterior o margo lateralis et margo medialis hilum renale sinus renalis calyces renales V size : length 10-13 (~12) cm width ~6 cm thickness ~3 cm V weight – 150 g (♂); 135 g (♀); 1/240 of the body weight V color – reddish browny V consistency – parenchymal organ Prof. Dr. Nikolai Lazarov 4 SPLANCHNOLOGY Kidney topography ° Skeletotopy: V against the posterior abdominal wall V at the level of vertebrae Th 12 to L 2 V right kidney – 1-2 cm lower than the left (liver) Prof. Dr. Nikolai Lazarov 5 SPLANCHNOLOGY Renal fascias ° Fascias of the kidney: V fibrous organ capsule V adipose capsule perinephric fat, corpus adiposum pararenale V renal fascia (Gerota) fascia prerenalis fascia retrorenalis Prof. Dr. Nikolai Lazarov 6 SPLANCHNOLOGY Syntopy of kidney Prof. Dr. Nikolai Lazarov 7 SPLANCHNOLOGY Internal anatomy of the kidneys ° Renal parenchyma: V renal cortex, cortex renalis – 5-10 mm brown-red color granular appearance: o pars convoluta o pars radiata (cortex juxtamedullaris) o lobulus corticalis V renal medulla, medulla renalis: renal pyramid – 7-20 (12): o pyramid base o renal papilla renal sinus o foramina papillaria area cribrosa renal columns (of Bertin ) V 7-9 renal lobes, lobi renales Prof. Dr. Nikolai Lazarov 8 SPLANCHNOLOGY Microscopic anatomy ° Nephron, nephronum – the basic structural and functional unit of the kidney: V renal (Malpighian) corpuscle, corpusculum renale (Malpighi) V renal tubules: proximal convoluted tubule , tubulus contortus proximalis nephron loop (loop of Henle ), tubulus atenuatus (ansa nephroni) o descending limb o ascending limb distal convoluted tubule , tubulus contortus distalis collecting duct, tubulus renalis colligens o tubulus colligens arcuatus et rectus ° Types of nephrons: V cortical, nephronum breve (corticale ) V intermediate, nephronum intermedium V juxtamedullary, nephronum longum (juxtamedullare) – 1/7 of all nephrons Prof. Dr. Nikolai Lazarov 9 SPLANCHNOLOGY Microscopic anatomy ° Renal (Malpighian) corpuscle, corpusculum renale (Malpighi) – 2 million, diameter 200 µm: V cortical glomeruli (80%) and juxtaglomellular (20%) V a tuft of capillaries, glomerulus – rete capillare glomerulare (mirabile): tubular (urinary) pole, polus tubularis vascular pole, polus vascularis afferent arteriole, vas afferens efferent arteriole, vas efferens mesangium V glomerular (Bowman’s) capsule, capsula glomeruli: internal visceral layer, paries interna external parietal layer, paries externa capsular space, lumen capsulae Prof. Dr. Nikolai Lazarov 10 SPLANCHNOLOGY Blood-urine filtration barrier ° Glomerular filtration barrier – 170 l of primary urine: V fenestrated continuous endothelium, lamina fenestrata endothelial cells, endothelocyti fenestrati o pores 0.04-0.1 µm o not spanned by diaphragms V basement membrane, membrana basalis – 30 µm lamina rara interna lamina densa lamina rara externa V internal layer of Bowman’s capsule podocytes, podocyti – 20-30 µm o foot processes , primary and secondary processes (pedicels) o filtration slits – 20-30 nm o a thin diaphragm – 6 nm thick Prof. Dr. Nikolai Lazarov 11 SPLANCHNOLOGY Mesangium, mesangium ° Mesangium (Gr. mesos, middle + angeion, vessel): V intraglomerular mesangial cells, mesangiocyti in islets, insulae perivasculares masangii supporting role – production of glomerular matrix contractile and phagocytic functions receptors for angiotensin II and ANF produce chemical mediators – IL-1 and prostaglandins V extraglomerular mesangial cells – juxtaglomerular apparatus Prof. Dr. Nikolai Lazarov 12 SPLANCHNOLOGY Renal tubules ° Proximal convoluted tubule, tubulus contortus proximalis : V length 15 µm; width 50-60 nm V parts: initial portion, neck pars convoluta pars recta V cuboidal, or low columnar epithelium brush border microvilli basilar infoldings of the membrane V reabsorption of water, amino acids, sodium, proteins and glucose ° Distal convoluted tubule , tubulus contortus distalis: V shorter and wider V parts: straight portion, pars recta convoluted, pars convoluta V simple cuboidal epithelium short sparse microvilli basal membrane invaginations V absorption of Na, K and water V macula densa Prof. Dr. Nikolai Lazarov 13 SPLANCHNOLOGY Renal tubules ° Nephron loop (loop of Henle ), tubulus atenuatus (ansa nephroni): V in the renal medulla (pyramids) V parts – a long U-shaped structure descending limb – 30 nm , simple squamous epithelium ascending limb – 60 nm , simple cuboidal to columnar epithelium in the thick limb V single microvilli V involved in water retention V creates a gradient of hypertonicity ° Collecting duct, tubulus renalis colligens: V parts: tubulus colligens arcuatus tubulus colligens rectus V simple cuboidal epithelium light cells – aquaporin-1, -2 and -3 dark cells V one layer two layers (in calyces) columnar epithelium V basement membrane V water absorption (ADH), major component of the urine-concentrating mechanism Prof. Dr. Nikolai Lazarov 14 SPLANCHNOLOGY Endocrine kidney ° Juxtaglomerular apparatus: V juxtaglomerular cells : modified smooth muscle cells in the tunica media of afferent arteriole secretory granules (10-40 nm) – renin absent internal elastic membrane V macula densa: tall columnar cells o closely packed together nuclei o signaling molecules enzyme renin absence of basement membrane V extraglomerular mesangial cells [lacis, Goormaghtigh, or Polkissen (polar cushion) cells] – erythropoietin ° interstitial cells – prostaglandins Prof. Dr. Nikolai Lazarov 15 SPLANCHNOLOGY Excretory ducts of the kidney ° Minor calyces, calyces renales minores: V 8-9 in number V fornix ° Major calyces, calyces renales majores: V 2(3) in number ° Renal pelvis, pelvis renalis: V in the renal sinus V pelvis ampullaris et ramificans ° Forms of the excretory system: V embryonic V fetal V mature Prof. Dr. Nikolai Lazarov 16 SPLANCHNOLOGY Ureter, ureter ° Ureter, ureter: V muscular tube V length 30 cm V diameter 7-8 mm ° Anatomical parts: V abdominal part – – retroperitoneal position V pelvic part V intramural part ° Three anatomical constrictions: V diameter 3-4 mm Prof. Dr. Nikolai Lazarov 17 SPLANCHNOLOGY Microscopic anatomy ° tunica mucosa : V lamina epithelialis – transitional epithelium V lamina propria – 350-700 µm fibroelastic connective tissue lymphocytes and lymphatic follicles ° tunica muscularis – 750-800 µm: V stratum longitudinale V stratum circulare V stratum longitudinale – lower ⅓ ° tunica adventitia: V nerves V loose connective tissue V blood and lymph vessels Prof. Dr. Nikolai Lazarov 18 SPLANCHNOLOGY Urinary bladder, vesica urinaria ° Urinary bladder, vesica urinaria (Gr. cystis): V reservoir – collects urine, 120-230 (max. 500) ml V on the pelvic cavity floor V sphere- or pear-shaped ° Anatomical parts: V fundus, fundus vesicae V neck, cervix vesicae V body, corpus vesicae V summit , apex vesicae lig. umbilicale medianum ° Internal surface: V trigone, trigonum vesicae ostium ureteris ostium urethrae internum V plica interureterica, uvula Prof. Dr. Nikolai Lazarov 19 SPLANCHNOLOGY Microscopic anatomy ° tunica mucosa – wrinkled or folded: V lamina epithelialis – transitional epithelium V lamina propria – 350-700 µm areolar connective tissue lymphocytes and lymph follicles ° tela submucosa – mucosal rugae, mucosal stroma ° tunica muscularis – detrusor muscle V internal longitudinal layer V circular layer m. sphincter vesicae V external longitudinal layer ° tunica serosa (adventitia): V superior-posterior surface – serosa V loose connective tissue V blood and lymph vessels Prof. Dr. Nikolai Lazarov 20 SPLANCHNOLOGY Male and female urethra Prof. Dr. Nikolai Lazarov 21 Male urethra ° Urethra masculina ~20 cm: V intarmural part V prostatic part – 3 cm V membranous part – 1-2 cm V spongy (penile) part – 15 cm 22 SPLANCHNOLOGY Microscopic anatomy ° tunica mucosa : V lamina epithelialis transitional epithelium pseudostratified columnar epithelium stratified squamous nonkeratinized – in the navicular fossa V lamina propria – basement membrane; stroma urethral glands (Littre ); urethral lacunae (Morgagni) ° tunica muscularis – prostatic and membranous parts V str. circulare m. sphincter urethrae (externus) V str. longitudinale Prof. Dr. Nikolai Lazarov 23 Female urethra ° Urethra feminina: V ostium urethrae