(BQ) Part 2 book Color atlas of human anatomy Vol.2 - Internal organs presents the following contents: Urinary system, male genital system, fernale genital system, pregnancy and human development, endocrine system, blood and lymphatic systems, the integument.
230 Urinary System: Overview Overview Retroperitoneal The organs of the urinary and genital systems have tradiuonally been grouped (0gether as the "urogenital system: a term that reflects their common embryological origin but is less suitable lor describing morphological and funcnonal aspects of mature organ systems This book therefore presents the organs of the urinary system and the male and female genital systems III separate consecutive chapters, followed by a chapter comparing the topographtcal anatomy of the male and female pelves which house most of the organs of the un nary and genual systems, Ihe retroperitoneal space :Cllies in front of the vertebral column and behind the penioneal cavity On either side of the vertebral column Me muscles underlying each kidney i.e., the quudratus IUlllborum ((6) and psoas mujor ((7) Near these muscle, IS ,111 mdentauon alongsrde ell her side of the vertebral column referred to as the lumbar gutter The retroperitoneal space IS bounded superiorly by the diaphragm and IS connnuous inferiorly WIth the subperuoneal space of the lesser pelvis, lnllarnmation involving the retroperitoneal space can spread via the muscular span' along the psoas major to the Organization and Position of the Urinary Organs Organs in the retropentoneal space, In adduion to the organs of the urinary system the retropenroueal Sp.lCC also contains the adrenal glands ((8) the great vessels, i.e., the aorta ((9) and inferior vena cava ((10) and the 5Ympathtlic trunk ((11) Retroperitoneal organs are surrounded by loose conll!'ccive nssue and adipos(' 115511(, The organs of the urinary system consist of the paired kidneys (A-Ct) the paired renal pelves (8(2), the paired ureters (A-ClJ the unpaired urinary bladder (A84" and the urethra (AS J Functional arrangement Ihe organs of the urinary system can be diVided into those that are involved III urine formation and those mvolved in us excretion Unne IS produced and concentrated ill the kidney from an ultraliltrate of blood plasma It is collected by the renal pelvis and transported into the ureter, which empties into the unnary bladder There it IS briefly stored before being excreted via the urethra Regional arrangement The organs of the urinary system lie outside of the pentoneurn lining the abdorrunal cavity Ihey Me situated either III the retroperitoneal space or III the connective ussue of the lesser pelvis known as the subpentoneal space (see p 2) Ihc kidneys and the larger proximal parI of the ureter are situated In the retroperitoneal space while the distal part of tile ureter, the urinary bladder, and the felllale uretllra Me located in the subperitoneal space The mall' urethra leaves the lesser pelvts after a short distance and then continues in the male sex organ, the penis Space ttugh For topograptucal anat'1my of the renopentonea: space see p l4t Organization and Position of Organs of Urinary System 231 I I A Anterior aspect A B Organsof t'le unnary system I C Retropentoneal space 'I f 232 Urinary System: Kidney Kidney Gross Anatomy External I i Features The kidney may be divided Into two surfaces, an anterior surface A' ;;nd d posterior surface B l JS well as 01 wide superior pole 'AB1) and corucal inferior pole (A82l The ante I tor and postenor surfaces are hounded by the convex lateral border (AB3l which IS connnuous with the supenor and Inf"ll.or poll'S and d COHCdVl'medial border A4' On the rned 1I border IS a depression Called the hilum of kidney (AS: whuh allows passage of vessels Into and out of the organ and atso houses till' renal pelvis 1he hilum of the ktdney ' C) leads to the renal sinus {(G) a (JV Ity SUI rounded on all "des by the paren chyma, An adult kidney IS to 12[111 long • , b cm Wide and 4(m thick [-aeh kidney weighs 120· 300g and the nght kidney I usually srnalte: than the left Renal sinus The renal SJI1UScan be vlsudl izcd after removma the vessels IIClVl" fat and renal pelvis The boundary around It, entrance IS formed bv 01 lip-hke indentation on thr- medial border Projecnng mID the renal Sinus are pyrarrudal etevanons called renal papillae (C7l Ihe human kidney hilS male than one p.lplll,l (I) 121; It IS multiple because II Is developed from multiple kId· ney lones that later merge Traces Ilf the structure of the multiple kidney lobes can stili be idennfred (lobulated kidncy' Ill! the kldn('y of 01 newborn, Surface In the adult the surface of the kid· neys IS usually smooth It IS covered !)y a tough fibrous capsule :08) that contams co! Idgen fibers Mid is attached to rbe kicnev by loose connective trssue Internal Structure A (ross, section or long.tudinal secnon (If the kldney reveals two drsunct regions forming Its internal structure: the renal medulla I 09) and the outer renal cortex (010), Ihe rnacroscopu appearance of the sec troned kidnev IS produced by the orgamzanon of unniterous tubules and vessels 'see pp.234 117l Renal medulla The renal medulla IS com, posed of corneal renal pyramids (011, thaI appear pale and striated III cross section The bas('s of tit£' renal p'yramlds (012) are' directed toward the surface of the kidncv, The' rounded apices form the renal papil/ar ,OBI whr •.h project (award tile huum and rnto the renal cahces of the renal pelvrs, On I(S surface, each renal papllIJ bears a m bri/onn area of numerous perforations pro duced by the openings of papd/ar)' ducts the open-rigs of the uriniferous tubules all closer rnspecuon, 01 renal pyramid can be funher subdivided Into a reddish outer lone and I lighter inner zone Renal cortex Ihe rena: cortex lies Immediately beneath the fibrous capsule lt rs about Il m wide and III the unmounted speurnen has a reddish brown color It nverlies the pyramid; of the rena: medulla like a capsule between rhe lateral aspects of the renal pyrarruds scnd.ng extensions (all:"d renal columns (014) mto thl' mtenor of the organ Ihe renal cortex IS permeated 11Vlonguudinoll stnanons known 1S medullary rays DIS} wh It hare conunuauons of the medullary substance rdchattng from tile bases of the pvra.mds toward the capsule lht' corneal part coruarrnng rho medullarv rays IS known as the cortex corticis a lid the cortical substance between the rru-dullarv reys IS the cortical labyrinth, Kidney lobes hlCh kidnev lobe •.onusts of a renal pyramid and It< surrounding cortex (see abovcj.Indivrdual kidney lobes arc bounded by the renal co' UI11 [IS Gross Anatomy of Kidney 233 I i A Riqht kidnev, antenor dWl'CI ~ll 11 14 11 o Frontal section throuqn r.qht kidney 234 Urinary System: Kidney Microscopic Anatomy The macroscopically distinct portions of the parenchyma of the kidney (see p 232; are produced by a characrerisnc pattern of distnbution of different structural units of till' organ These structural units mcludc the numerous, densely packed uriniferous tubules, as well ,IS blood vessels and connective tissue containing nerves and lymphatic vessels Uriniferous Tubules I i The uriniferous tubules consist of two com ponent ••, a nephron and collecting ducts, which have different embryological origins l-ach nephron or basic functional Unit 01 the kidney, consists of J renal corpuscle and an associated renal tubule which IS J segment of the uriniferous tubules Renal corpuscle (A 1) E.1Ch renal corpuscle consists of a cluster of capillanes called ,1 glomerulus (Al) and ,1 surrounding glomerular capsule (A3 J Renal tubule Connected to the renal corpuscle IS ,1 continuous system of renal tubules that mav be divided into various segments The renal tubules begm with a preximal tubule which has a twisted pan known as the proximal convolwed wbule (A4; and a straight part called the proxi1lJui seraigllt cobule (AS) Following the proximal tubule IS the intermediate tubule or thin tubule (A6), which can be divided IOta the descending rilln IlIlIb (AS a) and ascending ellln limb (AS b) The mtermediate tubule tS continuous with the distal tubule, consisung of a distal stralgll! cobu/e (A7) followed by the dISCO/(Ollvo/utl'd tubule (A8) The tortuous segment of the distal I ubule IS connected by a junctional tubule (A9; With .lsdl struuons lhe cells are somewhat flatter than those ofthe proximal tubule and have only short minovilli projecung from them lhe collecting ducts (C17) are composed of about I of pale-staining epithelial cells with distinct c('11 borders and I of darkstaining intercalated cells, The cpithehal cells lining the collecnng ducts become progrl'sslwly flatter as the duct progresses toward the papitlae, Function or the kidneys Ihe renal corpuscles lorm the filter that d.lIly "squeezes" ISO liters of ullrdfillrdle (primdry urine) out of the blood Of these, 178htrrs JI~ reabsorbed In the tubule sysrem, and I.S Iuers of findl urine (secondary urine' are formed per d.lY UW1l' rs cxcrered by tbe excretory organs lhe juxtaglomerular apparatus funcuons as part of the rerun 1IlglOlenslIl system mvotved in blood pressure regul.1tion Microanatomy of Kidney cont 237 I j A RpnJIcorpusct«, orqamzaton B Section through renal corpuscle of components > C Renal tubules in crovs-secuon, appearance in light micrograph cellutar cornponems, appearance in electron micrograph ••• _- 238 Urinary System: Neurovascular Drainage Kidney Supply and lymphatic Arteries Wastl' substances are carried to the kidneys by the renal artery A 1) The ri!(llI rellol orrery springs trorn the abdominal aorta (Al) at the level of 1.1 In most people the left renal orrery anses ilt a short distance above It The left renal artery is usually shorter than the right renal artery Ihc pri mary intrarenal branches of the two rnarn artenes are end arteries and supply specific regions of the parenchyma These regions may be classified as renal segments: the superior seglllelll anterior superior segment r onrenor mIerior segment inicnor segf1leJil and the posterior se,!!f1Ielll GIVen the (0111, plex nature of kidney development these segments may vary considerably: ,1110111.1 lies In the course or the renal artery also occur Veins Venous dramage from the kidney is via the renal vein (AC3) The nght renal win is short and has ,1 straight course while the path of the left renal win is longer and curving During its course U receives the left 511prarelwl vein and the lefl teslicular win or left overinn vei" Nerves Autonomic fibers to the kidneys anse from the renal nerve plexus whrch ,1~" companies the renal artery and is mainlv formed by fibers from t h~ adjacent ce/i(l~' plexus Regional lymph nodes Lymph from kidneys drams to the lateral aortic nodes the Topography of the Kidneys Position The kidneys lie on either Side of rhe vertebral column in the lumbar groove Their long axes are directed upward and backward so that If m imagmary lme IS drawn as a cont inuauon from each ,1XIS these lines would intersect The superior pole lies at the level ofn2 and the inferior pole ,11 the level of the L3 The hilum of kidney is located ,11 the level of U The nght kidney usually lies about half a vertebra lower than the left kidney The posruon of the kidneys varies with respiration and posture Peste- rior to the kidney the 12th rill (A4l passes diagonally over the boundary between the upper ,1I1d middle thirds ot the organ CrossII1g over the kidney Ill'arly parallel to the 12th rib 111.1 cramocaudal direction arc the subcostal nen'e (AS) iliollypogastric nerve (A6) and iliomglllno/llt'rw Adjacent organs and vessels lymg anteriorly on the superior poll's ofthe kidneys are the sliprarenal/adrenal glands (A7l The anterior surface ofthe right kidney IS 111cont,lt! with the lil't'r and right colic flexure: near rhe hilum of the right kidney arc the inJaior vena COWl (A8) ,111d dllodt'num The anterior surface of (he left kidney is 111COI1tart with the stomarh pancreas and le/t colic flexure: (he (wr/a runs near the hilurrof the left kidney A9lJreter Capsules of the Kidney The capsutc-, enclosing the krdnev