Presentation on theme: "Excretory Systems semester-2 MBBS"— Presentation transcript:
1 Excretory Systems semester-2 MBBS Dr. Kumar K.V (14/2/2011)
2 Relationship of the Kidneys to Vertebra and Ribs
3 External Anatomy of Kidney Paired kidney-bean-shaped organ4-5 in long, 2-3 in wide, 1 in thickFound just above the waist between the peritoneum & posterior wall of abdomenretroperitoneal along with adrenal glands & uretersProtected by 11th & 12th ribs with right kidney lower
4 Kidneys: Gross and Sectional Anatomy RetroperitonealAnterior surface covered with peritoneumPosterior surface against posterior abdominal wallSuperior pole: T-12Inferior pole: L-3Right kidney ~ 2cm lower than leftAdrenal gland on superior pole
5 Kidney LocationLateral to vertebral column high on body wall, under floating ribs, in retro-peritoneal position (posterior to the parietal peritoneum)The right kidney is slightly inferior to the left kidney in order to accommodate the liverSurrounded by the renal capsule with a fat pad12 x 6 x 3 cmBean shapedHilus – indentationRetroperitoneal - between the body wall and peritoneum
6 Kidney External Anatomy Average size – 12cm x 6cm x 3 cmWeights 150 grams or 5 ozSurrounded by three membranes (deep to superficial)Renal capsule – fibrous barrier for kidneys.Adipose capsule – fatty tissue designed for protection / stability.Renal fascia – dense fibrous CTP anchors kidneys/ adrenals/ membrane 1 and 2 to surroundings.
7 Kidney - general information Lie against posterior abdominal wall at level of T12-L3.Right kidney is lower than left kidney due to the shape of the liver.Lateral surface of kidney is convex while medial is concave.Concave side has a cleft – Renal HilusInside hilus is Renal sinusWhere kidneys receive renal vessels and nerves.
8 Kidneys: Gross and Sectional Anatomy Surrounding tissues, from deep to superficial:Fibrous capsule (renal capsule)Dense irregular CTCovers outer surfacePerinephric fat (adipose capsule)Also called perirenal fatCompletely surrounds kidneyCushioning and insulationRenal fasciaAnchors kidney to posterior wall and peritoneumParanephric fatBetween renal fascia and peritoneum
10 External Anatomy of Kidney Protective coverings of kidneyrenal capsule---you will see in lab over sheep kidneyadipose surrounds thatlayers of thin fascia hold everything against back body wallperitoneum over allBlood vessels & ureter enter hilus of kidneyRenal capsule = transparent membrane maintains organ shapeAdipose capsule that helps protect from traumaRenal fascia = dense, irregular connective tissue that holds against back body wall
11 Kidney- External Anatomy Lateral surface- convexMedial is concave-Renal HilumOpening to KidneyRenal SinusSpace within hilusKidneys receive blood vessels and nerves.
17 Kidneys: Gross and Sectional Anatomy Minor calyx:Funnel shapedReceives renal papilla8 to 15 per kidney, one per pyramidMajor calyxFusion of minor calyces2 to 3 per kidneyMajor calyces merge to form renal pelvisRenal LobePyramid plus some cortical tissue8 to 15 per kidney
18 a. Right renal vein enters IVC directly Detailed Anatomy, cont …2. Renal Veinsa. Right renal vein enters IVC directlyb. Left renal vein passes anterior to aorta, posterior to SMA, then into IVCc. Venous pattern complex
19 Variations in Renal Veins Note the duplication in the Left Renal VeinBranches surround aorta
20 Origin of Renal, Gonadal Arteries Note the right gonadal artery arising from the aorta, then branching to form the inferior capsular artery.R and L Renal ArteriesGonadal Arteries
21 d. R. renal artery courses from aorta posterior to IVC into hilus Detailed Anatomy, cont …d. R. renal artery courses from aorta posterior to IVC into hiluse. Left renal artery course is from aorta directly to hilusf. May see 2 or 3 pairs of renal arteriesg. Gonadal arteries:1. may arise from renal artery usually arise from aorta
22 a. arise from abdominal aorta Detailed Anatomy, cont …C. Blood supply1. Renal arteries:a. arise from abdominal aortab. Divide into 2 or 3 branches before entering kidneyc. If 3 branches, may form:1. “vascular fork”2. may constrict ureter
28 Anatomy of Urinary Bladder Hollow, distensible muscular organ with capacity of mLTrigone is smooth flat area bordered by 2 ureteral openings and one urethral opening
29 Location of Urinary Bladder Posterior to pubic symphysisIn females is anterior to vagina & inferior to uterusIn males lies anterior to rectum
30 Urinary Tract – Urinary Bladder The urinary bladder:expandable, muscular containerserves as a reservoir for urinepositioned immediately superior and posterior to the pubic symphysis.in femalesthe urinary bladder is in contact with the uterus posterosuperiorly and with the vagina posteroinferiorly.in malesit is in contact with the rectum posterosuperiorly and is immediately superior to the prostate gland.is a retroperitoneal organ.when empty exhibits an upside-down pyramidal shape.Filling with urine distends it superiorly until it assumes an oval shape.
31 Urinary Bladder Located in pelvic cavity, posterior to pubic symphysis 3 layersparietal peritoneum, superiorly; fibrous adventitia restmuscularis: detrusor muscle, 3 layers of smooth musclemucosa: transitional epitheliumtrigone: openings of ureters and urethra, triangularrugae: relaxed bladder wrinkled, highly distensiblecapacity: moderately full ml, max ml
34 Urinary Tract – Urinary Bladder Trigoneposteroinferior triangular area of the urinary bladder wallformed by imaginary linesconnect the two posterior ureteral openingsand the anterior urethral opening.The trigone remains immovable as the urinary bladder fills and evacuates.It functions as a funneldirects urine into the urethra as the bladder wall contractsfour tunicsmucosasubmucosaMuscularis: called the detrusor muscleadventitia.Internal urethral sphincter (smooth muscle)
38 Anatomy of Ureters 10 to 12 in long Varies in diameter from 1-10 mm Extends from renal pelvis to bladderRetroperitonealEnters posterior wall of bladderPhysiological valve onlybladder wall compresses arterial opening as it expands during fillingflow results from peristalsis, gravity & hydrostatic pressure
39 Urinary Tract : Ureters long, fibromuscular tubesconduct urine from the kidneys to the urinary bladder.average 25 centimeters in lengthretroperitoneal.ureters originate at the renal pelvisextend inferiorly to enter the posterolateral wall of the base of the urinary bladder.wall is composed of three concentric tunics.mucosamuscularisadventitia.
40 Urethra, MaleMale – cm1. prostatic urethra – from base of bladder through prostate gland2. membranous urethra – between prostate gland & base of penis3. penile (spongy) urethra – traverses penis to orifice
41 Male Bladder and Urethra 18 cm longInternal urethral sphincterExternal urethral sphincter3 regionsprostatic urethra receives semenmembranous urethrapasses through pelvic cavitypenile urethra
42 Urethra Fibromuscular tube conducts urine to the exterior of the body. exits the urinary bladder through the urethral openingat anteroinferior surfaceconducts urine to the exterior of the body.Tunica mucosa: is a protective mucous membranehouses clusters of mucin-producing cells called urethral glands.Tunica muscularis: primarily smooth muscle fibershelp propel urine to the outside of the body.Two urethral sphincters:Internal urethral sphincterrestrict the release of urine until the pressure within the urinary bladder is high enoughExternal urethral sphincterand voluntary activities needed to release the urine are activated.
43 Anatomy of the Urethra Females Males length of 1.5 in., orifice between clitoris & vaginahistologytransitional changing to nonkeratinized stratified squamous epithelium, lamina propria with elastic fibers & circular smooth muscleMalestube passes through prostate, UG diaphragm & penis3 regions of urethraprostatic urethra, membranous urethra & spongy urethracircular smooth muscle forms internal urethral sphincter & UG diaphragm forms external urethral sphincter
44 Urethra, Female External urethral sphincter – voluntary at pelvic floor3-5 cm – from base of bladder to vestibuleUTIs (esp. E.coli)
48 Urethra The internal urethral sphincter involuntary (smooth muscle)superior sphincter surrounding the neck of the bladder, where the urethra originates.a circular thickening of the detrusor musclecontrolled by the autonomic nervous systemThe external urethral sphincterinferior to the internal urethral sphincterformed by skeletal muscle fibers of the urogenital diaphragm.a voluntary sphinctercontrolled by the somatic nervous systemthis is the muscle children learn to control when they become “toilet-trained”
49 Female Urethra Has a single function: to transport urine from the urinary bladder to the vestibule, an external space immediately internal to the labia minora3 to 5 centimeters long, and opens to the outside of the body at the external urethral orifice located in the female perineum.
50 Male Urethra Urinary and reproductive functions: passageway for both urine and semenApproximately 18 to 20 centimeters long.Partitioned into three segments:prostatic urethra is approximately 3 to 4 centimeters long and is the most dilatable portion of the urethraextends through the prostate gland, immediately inferior to the male bladder, where multiple small prostatic ducts enter itmembranous urethra is the shortest and least dilatable portionextends from the inferior surface of the prostate gland through the urogenital diaphragmspongy urethra is the longest part (15 centimeters)encased within a cylinder of erectile tissue in the penis called the corpus spongiosumextends to the external urethral orifice