2 Announcements Urinary system Lab Practical Week after Spring Break Practical Review this Sunday 23rd at 3-5 pm
3 Functions of Urinary System Kidneys carry out four functionsFilter nitrogenous wastes, toxins, ions, etc. from blood to be excreted as urine.Regulate volume and chemical composition of blood (water, salts, acids, bases).Produce regulatory enzymes.Renin – regulates BP/ kidney functionErthropoeitin – stimulates RBC production from marrow.Metabolism of Vitamin D to active form.
4 Urinary System Two Kidneys Two Ureters Urinary Bladder Urethra Perform all functions except actual excretion.Two UretersConvey urine from Kidneys to Urinary BladderUrinary BladderHolds Urine until excretionUrethraConveys urine from bladder to outside of body
6 Kidney general infoLie 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.
7 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.
9 Kidney- External Anatomy Lateral surface- convexMedial is concave-Renal HilumOpening to KidneyRenal SinusSpace within hilusKidneys receive blood vessels and nerves.
10 Kidney Internal Anatomy I Renal arteries and veinsBring blood in and out of kidneyRenal cortexOuter layer of KidneyRenal medullaInner layer of KidneyNephron
11 Kidney Internal Anatomy II Renal PyramidsRenal ColumnsSpace between pyramids within the medulaRenal PapillaNarrow end of pyramidCalyx (ces)Collecting tubesRenal PelvisCollecting vessel prior to ureter
18 Urine Formation I Glomerular filtration Water, ions, amino acids, and glucose get into capsular space from bloodProteins stay in blood – too big to leave capillaries.
19 Urine Formation IIProximal convoluted tubule and Peritubular capillaryNa+ goes down gradient and brings glucose, amino acids, etc. back into blood stream (cotransport).Reabsorbs about 65% of filtrate.
20 Countercurrent Multiplication Urine Formation IIICountercurrent Multiplicationin the Nephron LoopDescending limbGoes into medulla increasing salt gradientWater leavesFluid concentratesAscending limbGoes up toward cortex - decreasing salt gradientNa+ pumped outFluid relatively diluted
22 Urine Formation IV Collecting duct Travels down into medulla Water leaves tubule and enters bloodUrine becomes concentrated and enters renal papillaADH controls water channelADH – Antidiuretic hormone
25 Micturition Ureters Urinary Bladder 25 cm long Enters on the floor of bladderUrinary BladderMuscular sac on floor of pelvic cavityMuscle layer formed by detrusor muscleAverage bladder volume is 500 mlMax capacity is ml
26 Micturition Urethra Conveys urine out of body Female urethra – cmOpens into external urethral orifaceLies between vaginal oriface and clitorisMale urethra – 18 cm3 regionsProstatic urethra – 2.5 cmMembranous urethra – 0.5 cmPenile urethra – 15 cm
27 Micturition Reflex Bladder with >= 200 ml of urine Sensory input to parasympathetic systemContraction of detrusor muscle and relaxation of internal urethral sphincterRelaxation of external urethral sphincter
29 Kidney stonesA hard granule of calcium, phosphate, uric acid and protein.Form in renal pelvis and get lodged in pelvis or ureter.Caused by urinary tract infections, dehydration, pH imbalances, or an enlarged prostate gland.Treated with stone dissolving drugs, surgical removal, or lithotripsy (ultrasonic vibrations)
30 Visualizing the Urinary System Intravenous pyelography Ultrasound Dynamic HumanVisualizing the Urinary SystemIntravenous pyelographyUltrasound
31 Dissection Be able to identify layers of the kidney on human material Be able to locate kidneys, ureters, urinary bladder, and urethra on cat.
32 Next Week – Spring Break Week After - Practical II Material over lymphatic, respiratory, and urinary systemsReview Sunday (end of break) at 3-5pmRemember – some questions will be based on identifying structures on the cats.