Chapter 23 The Urinary System

1. Chapter 23The Urinary System The story of your Kids

2. A sliced kidney reveals two parts: 1.) Renal cortex- outer area 2.) Renal medulla- inner area renal columns, pyramids, papilla Additional anatomy: Renal Capsule- sausage covering Hilus- pushed in center spot where blood vessels, lymphatic vessels, nerves and ureter penetrate the kidney Anatomy of Kidney

3. Anatomy of the Kidney Funnels! 1 7 8 2 3 9 4 5 10 6

4. Urinary System- Anatomy Urinary system consists of 2 kidneys (kids), each kid has a pipe called the ureter that connects to the bladder, the release hose from the bladder is called the ______ Franklin Two kidneys Two ureters Bladder Urethra

5. Kidney Location • The kidneys are kidney bean shaped, or… • About the size of your fist • Retroperitoneal-Found posterior to the peritoneum of the abdominal cavity, Right kid lower then left, Why? • Eleventh and twelfth rib partially covers them

6. The Urinary System- Physiology • The URINary system’s major job is to produce- URINe • Urine is created when the kids filter blood, the result is a sterile waste product called urine • Nephrology- is the study of the pathology of the kidneys • Urology- study of the male and female urinary system and the male reproductive system

7. Renal artery- main artery entering the renal hilus Interlobar vessels- pass through the renal columns between the pyramids Arcuate vessels- “ARC” around the distal end of the pyrimids The arcuate vessels send out interlobular vessels that go into the cortex Renal vein- main vein exiting the kidney Blood Flow to the Kidney

8. Kidney Physiology- Waste Removal • Kidneys filter blood plasma, returns useful substances to blood and eliminates waste such as: • Urea • Uric acid • nucleic acid catabolism • Renal failure • azotemia: BUN (Blood Urea Nitrogen) means increased nitrogenous wastes in blood, this could lead to: • Uremia: Literally urea in the blood, toxic effects on the body as wastes accumulate

9. Creatinine • Creatinine ( kreas = flesh) • A break-down product of muscle. • There is little-to-no tubular reabsorption of creatinine so it can be used to determine GFR. Why? • This maybe a better indication of kidney disease than BUN. • Bun may be high in dehydration. Why?

10. How Do We Get Urea? Dietary proteins break down to amino acids. Metabolized amino acids form toxic ammonia (NH3), the liverconverts ammonia to urea (NH2) which is removed from the blood by the kidneys

11. The primary kidney function is to form urine but they do other things as well: Detoxifies free radicals and drugs Gluconeogenesis- regulates blood sugar pH by regulating H+ and bicarbonate ions Electrolytes regulation in the blood - Na+, K+, Ca++ Erythropoietin secretion Blood pressure regulation- two ways by Renin hormone and Renal resistance Fluid balance- both osmolarity and blood volume by regulating water in the blood Drunk Guys pEE Behind Fences Kidney Functions

12. Urine Creation • The tissue of the kidney contains functional units (about one million) called: • Nephrons- these units form urine

13. The Nephron • The functional units of the kidneys • 3 processes: • 1.) Filtering blood • 2.) Returning useful substances • 3.) Removing non-needed substances • NEPHRONS MAINTAINS THE HOMEOSTASIS OF BLOOD AND PRODUCES URINE

14. Two Homes for Nephrons • Cortical nephrons (85%) - most of the nephrons • Lie in the cortex mostly • Has SHORT loop of Henle that dips only slightly into the medulla • Juxtamedullary nephrons (15%)- small amount of nephrons • Lie in the cortex BUT close to the medulla • Has LONG loop of Henle that go into the deepest region of the medulla

15. Parts of the Nephron • Two portion: • Renal corpuscle • Glomerulus • Glomerular capsule called Bowman’s Capsule • Renal tubule • Proximal convoluted tubule • Loop of Henle • Distal convoluted tubule

16. Renal Corpuscle is composed of: Glomerulus and Glomerular capsule (Bowman’s Capsule) Glomerular filtrate collects in capsular space, flows into renal tubule

17. Filtration Membrane • Filtration membrane = A leaky barrier, formed by glomerular capillaries • Permits: filtration of water and small solutes • Prevents: proteins, blood cells from going through

18. Filtration • Remember, ALL capillaries filter (Starling’s Law) they all have pressure in them • Principle of filtration = Forcing fluids and solutes through a membrane by pressure • But the glomerular capillaries filters more • 3 reasons: • 1.) Large surface area • 2.) Thin and leaky • 3.) High blood pressure- the efferent blood vessels are small, the afferent bigger

19. The Unique Glomerulus • The glomerulus is unique in two ways: • 1.) Glomerulus capillaries are unique- positioned between two arteries, not (like usual) between an artery and a vein • 2.) The glomerulus is part of the cardiovascular AND urinary systems

20. Glomerular Filtration Rate (GFR) • Filtrate formed per minute • Fluid that enters the capsule space of the glomerulus is called glomerular filtrate. • Filtration fraction = the portion of blood in the afferent arterioles that becomes glumerular filtrate • More then 99% of glumerular filtrate is returned to the blood by tubular reabsorption • About 1-2 quarts is excreted as urine per day

21. Effects of GFR Abnormalities • GFR, urine output rises  dehydration, electrolyte depletion • GFR  wastes reabsorbed • GFR controlled by adjusting glomerular blood pressure • autoregulation • sympathetic control • hormonal mechanism: renin and angiotensin

22. Renal Tubule- Second Part of the Nephron • PCT- Proximal convoluted tubule • Nephron loop (Loop of Henle)- U shaped; descending + ascending limbs • Distal convoluted tubule (DCT)

23. A Recycling Analogy • It's time to clean-out the garage.  It's full of "stuff".  You decide to paint the floor while you're at it.  So you move everything out to the driveway. * When the floor is dry, you move things back to the garage--but only the things you want to keep ** The "junk" is bagged-up and put out with the trash.*** • * Glomerular filtrate • ** Tubular Reabsorption • ***Urea

24. Urine Flow • Glomerulus • Bowman’s capsule • Proximal convoluted tubule • Descending limb of the loop of Henle- this part of the loop dips into the medulla • Loop of Henle- connects the proximal to the distal convoluted tubules • Ascending limb of the loop of Henle- this part takes the LOOP (hairpin curve) and returns to the renal cortex • Distal convoluted tubule • Collecting ducts- the place where the distal convoluted tubules dump • Papillary ducts- converging of many collecting ducts • Get Back! Please Don’t Look At Dairy Cows Peeing

25. Urine’s flow continues: From the Papillary ducts to the: • Minor calyces to the major calyces- funnel like structures that drain the urine to: • Renal pelvis- large basin that collects the urine and sends it to the ureter

26. Urine’s Journey Out… • Ureters- peristaltic contraction in the walls of the ureters push urine to the bladder • A foot long • At the end of the ureters is a hole that acts like a valve that shuts when the bladder gets full, preventing back flush • mucosa - transitional epithelium • lumen very narrow, easily obstructed

27. …The Journey Continues • Urinary bladder- hollow, muscular organ just posterior to the symphysis pubis. • The bladder is like a triangle pointing down, the top superior and lateral points are where the two ureters enter the bladder, mucosa: transitional epithelium • The Urethra drains the bladder at the inferior point of the triangle, rugae: relaxed bladder wrinkled • The urethra has circular muscle fibers that form the internal urethral sphincter • The urethra has another sphincter below the internal sphincter called the external sphincter, it is composed of skeletal (Hold it!) voluntary muscle • Capacity: moderately full = 2 cups, maximum = 3 ½ cups

28. Voiding Urine – Micturition • Micturition- urination, voiding, number one, peeing • When the bladder gets full, stretch receptors initiate the spinal nerves to open the sphincters • Because the external sphincter is skeletal muscle we can over ride this reflex and “Hold it!” • Valsalva maneuver • aids in expulsion of urine by  pressure on bladder • can also activate micturition reflex voluntarily • A lack of the ability to hold it is called incontinence, failure to void completely is called retention

29. Female Urethra • Short, purpose- void urine • External urethral orifice • between vaginal orifice and clitoris • Internal urethral sphincter • smooth muscle, involuntary control • External urethral sphincter • skeletal muscle, voluntary control

30. Male Urethra • Long, duo purpose = void urine & Ejaculate • Internal urethral sphincter • External urethral sphincter • 3 regions • prostatic urethra • during orgasm receives semen • membranous urethra • passes through pelvic cavity • spongy urethra in penis Males have “PMS”

32. Kidney Tests • Blood tests • BUN- blood urea nitrogen, the result of protein metabolism, increased BUN is bad • Indications are renal disease or obstruction of the urinary tract • Urinalysis (UA)- evaluation of the chemical of the urine • Microscopic and DIP-STICK is used to evaluate urine

33. Dip Stick I • (Look to your right) • A thin piece of plastic with small boxes of chemical that is placed in urine and tells: • pH- normal avg. 6 • Specific gravity- urine weight compared to water, should be 1.001-1.035, just slightly heavier then water, but not much more or the urine will have substances in it

34. Dip Stick II • Albumin- a protein in the blood, big molecule, if found in large amounts then the membranes of the kidney are damaged to let it through • Glucose- If too much glucose is in the blood (usually above 300 ppm) it will spill into the urine, no glucose should be found in the urine, suspect diabetes • Blood- if found in urine it may be due to menstrual blood, trauma to the genitals or kidney stones • Leukocytes- possible infection or not a “clean catch”, if infection is suspected must be correlated with other tests

35. Dip Stick III • Ketones- By products from fatty acid metabolism, fasting, anorexia and high fat/ low carbohydrates diets can raise ketones. Also seen in diabetes, correlate with _____ _____ and not ____ ____* • Bilirubin- excessive of RBCs being destroyed by macrophages • Urobilogen- Anemia, liver problems, mono

36. Micro/Macroscopic Urine • MACRO- Urine’s color should be yellow to amber, (red urine? Usually not blood but _____ • Turbidity- Urine should be transparent after voiding • Odor- Should not be sweet smelling • If it is sweet smelling then suspect diabetes • MICRO- Casts are tiny tubes found in the urine • Microbes- E. Coli, Candida

37. URINARY DIS-EASE I • UTI- Urinary tact infection- more common in females due to short urethra • Bright’s disease- inflammation of glomeruli of kidney, strep infection also called glomerulonephritis • Renal disease- chronic and acute, decreased glomerular filtration rate • Kidney stones- majority are calcium stones, pain more from urinary backup than stone pressing into ureter

38. Kidney Stones Treatment

39. URINARY DIS-EASE II • Urethritis- inflamed urethra from UTI usually • Cystitis- inflammation of bladder from UTI or honeymoon • Pyleonephritis- inflammation of kidneys usually from bladder infection going up commonly called Kidney infection • Polycystic kidney disease- cysts of the kidneys, inherited, causes renal failure shortly after birth

40. URINARY DIS-EASE III • Enuresis- (en-yoo-RE-sis)- bed wetting • Pyelogram (PI-e-lo-gram)- X-ray of the kids after iodine injection • Polyuria- peeing too much, a bird’s urine