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 Ù regulation of blood pressure ‹ erythropoietin Ù erythrocytopoiesis ‹ calcitriol Ù 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 Ù hilum renale Ù sinus renalis Ù 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 Ù 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 Ù renal sinus o foramina papillaria Ù 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 Ù 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 Ù 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 Ù 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 Ù 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 Ù 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 Ù m. sphincter urethrae (externus) V str. longitudinale

Prof. Dr. Nikolai Lazarov 23 Female urethra ° Urethra feminina: V ostium urethrae internum V ostium urethrae externum V length 3-4 cm V diameter 6-10 mm ° Microscopic anatomy: V tunica mucosa – longitudinal folds, urethral crest ‹ transitional epithelium ‹ stratified squamous nonkeratinized epithelium ‹ stratified squamous keratinized ‹ lamina propria o urethral glands o urethral lacunae V tela submucosa ‹ tunica spongiosa V tunica muscularis ‹ internal layer, smooth muscle fibers ‹ external layer, striated muscle fibers 24 SPLANCHNOLOGY

The integument

1. Skin and its main functions 2. Structure of the skin: V epidermis – microscopic structure V dermis – microscopic structure V hypodermis (subcutaneous tissue) 3. Appendages of the skin: V hairs and nails V sebaceous and sweat glands

Prof. Dr. Nikolai Lazarov 25 SPLANCHNOLOGY Human skin Skin and skin functions

° the largest single organ of the body: ~16% (~4 kg) of the total body weight ° major role – a barrier between the organism and the environment V protection of the body against pathogens and damage ° some other functions: V thermal insulation and heat regulation V excretion by sweating Ù temperature regulation V control of evaporation and water resistance ‹ prevents excessive water loss and body dessication V storage and synthesis: ‹ storage center for lipids and water ‹ synthesis of vitamin D V absorption – oxygen, nitrogen and carbon dioxide, medicine V sensation – nerve endings, cutaneous receptors V aesthetics and communication NB: The adjective cutaneous literally means “of the skin" (from Latin cutis , skin ) Prof. Dr. Nikolai Lazarov 26 SPLANCHNOLOGY Human skin Structure of the skin ° two major layers – Gr. derma , skin: V epidermis ‹ epithelial layer ‹ derived from embryonic ectoderm ‹ generates skin appendages ‹ high capacity of regeneration ‹ non-vascular but richly innervated V dermis (corium) ‹ connective tissue layer ‹ mesenchymal origin ‹ highly vascularized V hypodermis (subcutis) ‹ looseirregular connectiveandfattytissue, panniculus adiposus ° two skin types – thickness of the epidermis: V thick (glabrous, hairless) skin ‹ palms and soles – 1.5 mm V thin (hairy) skin – 0.08 mm ‹ elsewhere on the body ‹ thinnest on the eyelids – 0.05 mm

Prof. Dr. Nikolai Lazarov 27 SPLANCHNOLOGY Human skin Epidermis

° stratified squamous keratinized epithelium ° main cell types: V keratinocytes – 85-95% of all epidermal cells ‹ keratin-producing cells V melanocytes ‹ neural crest cells ‹ production and storage of melanin ‹ darkening of the skin (tanning) V Langerhans cells – 2-8% ‹ macrophages ‹ dendritic cells with Birbeck granules ‹ immune, antigen-presenting cells V Merkel cells ‹ present in the thick skin ‹ "touch cells" Ù mechanoreceptors ‹ APUD cells Ù neuroendocrine function Prof. Dr. Nikolai Lazarov 28 SPLANCHNOLOGY Human skin Epidermis – microscopic structure

° 5 layers of keratinocytes: V stratum basale (germinativum) ‹ single layer of columnar cells ‹ renewal of the epidermis V stratum spinosum ‹ several layers of polygonal spiny cells Ù desmosomes V stratum granulosum ‹ 3-5 layers of flattened polygonal cells with keratohyalin granules V stratum lucidum ‹ only in thick skin ‹ flattened eosinophilic cells V stratum corneum ‹ 15-20 layers of flattened nonnucleated keratinized (horny) cells ° keratinization: V every 15-30 days V due to mitotic activity of the malpighian layer Prof. Dr. Nikolai Lazarov 29 SPLANCHNOLOGY Human skin Dermis, corium

° connective tissue – though, flexible and elastic ° variable thickness – max. 4 mm on the back ° two layers: V papillary layer – thin and superficial: ‹ dermal papillae Ù ridges ‹ loose connective tissue • collagen fibers Ù anchoring fibrils • fibroblasts, mast cells, macrophages ‹ increase and reinforce dermal-epidermal junction V reticular layer – deep and much thicker: ‹ irregular dense connective tissue • collagen type I and elastic fibers • fewer cells ° rich lymph and capillary network – 4.5% of the blood volume ° epidermal derivatives Prof. Dr. Nikolai Lazarov 30 SPLANCHNOLOGY Human skin Dermis – microscopic structure

Prof. Dr. Nikolai Lazarov 31 SPLANCHNOLOGY Human skin Hypodermis ° subcutaneous tissue – synonyms: superficial fascia, panniculus adiposus: V loose connective tissue and elastin ‹ binds the skin loosely to the subjacent organs ‹ supplying skin with blood vessels and nerves ‹ renewal of the epidermis V components: ‹ fat cells – varying in number and size, contains 50% of body fat ‹ fibroblasts, macrophages

Prof. Dr. Nikolai Lazarov 32 SPLANCHNOLOGY Human skin Skin appendages ° Appendages associated with the skin: V hairs – functions: ‹ sensation ‹ heat loss ‹ filter for breathing ‹ protection V nails – function: ‹ protection V sebaceous glands – function: ‹ secrete sebum onto hair follicle to oil the hair V sweat glands – function: ‹ produce sweat to help keep the body cool ‹ secreted with strong odour (apocrine), with a faint odour (eccrine) V arrector pilli muscle – function: ‹ smooth muscle that pulls hairs straight Prof. Dr. Nikolai Lazarov 33 SPLANCHNOLOGY Human skin Hair structure and colour ° three parts length-wise: V hair bulb – stem cells V hair root – beneath the skin surface V hair shaft – above the skin surface ° three parts in cross-section: V hair medulla – area in the core: ‹ contains loose cells and airspaces V hair cortex : ‹ contains densely packed keratin ‹ responsible for the pigmentation, shape and texture of hair V hair cuticle : ‹ single layer of cells covering the cortex ‹ last cell line to differentiate ° natural hair colours: V phaeomelanin – responsible for the yellowish-blond to red colors V eumelanin is responsible for the brown to black shades V gray hair – little or no pigment Prof. Dr. Nikolai Lazarov 34 SPLANCHNOLOGY Human skin Sebaceous glands ° small, sacculated, holocrine glands: V embedded in the dermis; 100 glands/cm2 V absent in the glabrous skin of palms and soles V 400-900/cm2 on the face, forehead and scalp V begin to function at puberty ° structure: V secretory portion: ‹ 2-5 acini of flattened epithelial cells ‹ larger fat-containing sebaceous cells ‹ basal lamina V single short duct: ‹ in the upper portion of a hair follicle ° sebum (Lat, fat or tallow ) – functions: ‹ complex mixture of lipids and waxes, triglycerides, squalene and cholesterol ‹ natural lubricant of the hair and skin ‹ antibacterial and antifungal properties ‹ no importance in preventing water loss Prof. Dr. Nikolai Lazarov 35 SPLANCHNOLOGY Human skin Sudoriferous (sweat) glands

V widely distributed in the skin V absent in the glans penis ° two types: V eccrine (merocrine) glands: ‹ most numerous ‹ simple, coiled tubular glands ‹ ducts opened at the skin surface ‹ secretory portion in the dermis, surrounded by myoepithelial cells • dark (mucoid) cells Ù glycoproteins • clear cells – no secretory granules ‹ innervated by cholinergic nerve endings V apocrine glands: ‹ in axillae, eyelids, areola and nipple, anal region, embedded in the subcutaneous tissue ‹ much larger (3-5 mm in diameter) ‹ tubular with extensive coiled secretory portion ‹ cuboidal cells with secretory granules ‹ straight ducts opened into hair follicles ‹ produce odorless viscous secretion ‹ innervated by adrenergic nerve endings ° sweat – functions: ‹ clear and not viscous, salty fluid Ù keep the body cool ‹ proteins, water, sodium chloride, urea, uric acid Prof. Dr. Nikolai Lazarov 36 SPLANCHNOLOGY Human skin Nails ° Lat. ungues , Gr. onyx, onychos ° fingernails and toenails – on the dorsal surface of each distal phalanx V tough keratin as animals' hooves and horns ° nail parts: V root – proximal part V body – exposed part V free border – distal end ° structure: V matrix – the only living part of the nail V eponychium (cuticle) V paronychium – the 'live' skin V hyponychium V nail plate – layers of keratin V nail bad – pink colour of the nail V lunula – visible whitish crescent part of the matrix ° nail fold – overlaps the base and sides of nails ° nail groove – guide the direction of nail growth Prof. Dr. Nikolai Lazarov 37 SPLANCHNOLOGY

Thank you ... NB: Human skin: the most valuable 2 mProf.2! Dr. Nikolai Lazarov