Urinary system

1. Urinary system Lab 7

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 functions • Filter 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 function • Erthropoeitin – stimulates RBC production from marrow. • Metabolism of Vitamin D to active form.

4. Urinary System • Two Kidneys • Perform all functions except actual excretion. • Two Ureters • Convey urine from Kidneys to Urinary Bladder • Urinary Bladder • Holds Urine until excretion • Urethra • Conveys urine from bladder to outside of body

5. Complete System

6. Kidney general info • 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 Hilus • Inside hilus is Renal sinus • Where kidneys receive renal vessels and nerves.

7. Kidney External Anatomy • Average size – 12cm x 6cm x 3 cm • Weights 150 grams or 5 oz • Surrounded 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.

8. Kidney Anatomy • Renal arteries and veins • Renal cortex • Renal medulla • Nephron • Renal pyramids (6-10) • Renal papilla • Calyx (ces) • Renal pelvis • Ureter

9. Kidney- External Anatomy • Lateral surface- convex • Medial is concave- • Renal Hilum • Opening to Kidney • Renal Sinus • Space within hilus • Kidneys receive blood vessels and nerves.

10. Kidney Internal Anatomy I • Renal arteries and veins • Bring blood in and out of kidney • Renal cortex • Outer layer of Kidney • Renal medulla • Inner layer of Kidney • Nephron

11. Kidney Internal Anatomy II • Renal Pyramids • Renal Columns • Space between pyramids within the medula • Renal Papilla • Narrow end of pyramid • Calyx (ces) • Collecting tubes • Renal Pelvis • Collecting vessel prior to ureter

12. Human Kidney

13. Nephron • Blood processing unit which serves to produce urine • 1 million per kidney • Consists of a glomerulus and tubules

14. Nephron: Vascular System • Afferent arteriole • Glomerulus • Efferent arteriole • Peritubular capillaries • Capillary beds reabsorb in cortex • Vasa recta • Capillary beds reabsorb in medulla

15. Nephron • Tubular system • Glomerular Capsule • Proximal convoluted tubule • Loop of Henle (nephron loop) • Descending limb • Ascending limb • Distal convoluted tubule • Collecting duct

16. Nephron

17. Dynamic Human Gross Anatomy Urinary system Kidney Nephron

18. Urine Formation I • Glomerular filtration • Water, ions, amino acids, and glucose get into capsular space from blood • Proteins stay in blood – too big to leave capillaries.

19. Urine Formation II • Proximal convoluted tubule and Peritubular capillary • Na+ goes down gradient and brings glucose, amino acids, etc. back into blood stream (cotransport). • Reabsorbs about 65% of filtrate.

20. Descending limb Goes into medulla - increasing salt gradient Water leaves Fluid concentrates Ascending limb Goes up toward cortex - decreasing salt gradient Na+ pumped out Fluid relatively diluted Urine Formation III Countercurrent Multiplication in the Nephron Loop

21. Nephron Loop

22. Urine Formation IV • Collecting duct • Travels down into medulla • Water leaves tubule and enters blood • Urine becomes concentrated and enters renal papilla • ADH controls water channel • ADH – Antidiuretic hormone

23. Collecting duct

24. Dynamic Human Urine Formation

25. Micturition • Ureters • 25 cm long • Enters on the floor of bladder • Urinary Bladder • Muscular sac on floor of pelvic cavity • Muscle layer formed by detrusor muscle • Average bladder volume is 500 ml • Max capacity is 700-800 ml

26. Micturition • Urethra • Conveys urine out of body • Female urethra – 3 - 4 cm • Opens into external urethral oriface • Lies between vaginal oriface and clitoris • Male urethra – 18 cm • 3 regions • Prostatic urethra – 2.5 cm • Membranous urethra – 0.5 cm • Penile urethra – 15 cm

27. Micturition Reflex Bladder with >= 200 ml of urine Sensory input to parasympathetic system Contraction of detrusor muscle and relaxation of internal urethral sphincter Relaxation of external urethral sphincter

28. Micturition

29. Kidney stones • A 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. Dynamic Human Visualizing the Urinary System Intravenous pyelography Ultrasound

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 BreakWeek After - Practical II • Material over lymphatic, respiratory, and urinary systems • Review Sunday (end of break) at 3-5pm • Remember – some questions will be based on identifying structures on the cats.