1. Memmler’s The Human Body in Health and Disease 11th edition
Chapter 22
The Urinary System
“It does not matter how slowly you go
as long as you do not stop.” Confucius

2. Excretion Body systems work interdependently to maintain
homeostasis by excretion
Urinary – urinate waste products
Digestive – defecate waste products
Respiratory – exhale waste products
Integumentary – perspiration of waste products

3. Organs of the Urinary System
Two kidneys
Two ureters
Single urinary bladder
Single urethra

4. Male urinary system, showing blood vessels.  
What vessel supplies blood to the kidney? What vessel drains the kidney?

5. Kidney Activities Excretion Urea (nitrogen based waste)
Water balance maintenance
Body fluid acid–base regulation
Blood pressure regulation
Angiotensin
Aldosterone
Red blood cell production regulation via erythropoietin

6. Acid Base balance Memmler page 455
Buffer System – accept or release ions to maintain H+ balance in body fluids
Bicarbonate, phosphate, and protein buffers
Respiration – alteration in breathing rate to retain CO2 or exhale CO2 (binds with water to make carbonic acid); short term regulation
Kidney function – absorbing or eliminating H+ ions; long term regulation

7. Kidney Structure Membranous renal capsule of fibrous connective tissue
Adipose capsule of fat
Fascia anchors kidney to peritoneum and abdominal wall
Located in the retroperitoneal space
Right kidney lower than left to accommodate liver
When have renal pain, it is noted as “flank pain”.

8. Blood Supply to the Kidney
Renal artery supplies blood to the kidney structures
Nephrons are functional units for filtration of blood to make glomerular filtrate
Afferent arteriole enters the glomerular knot of capillaries and exits the knot as the efferent arteriole which then becomes the peritubular capillaries
Renal vein drains blood from venous structures after the nephron complex

9. Kidney Organization
Hilum (also known as Hilus) on the medial convex aspect
Renal cortex (outer portion) contains the nephrons and convoluted tubules
Renal medulla (inner portion)
Renal pyramids contain Loop of Henle and collecting tubules
Renal pelvis
Calyces
Ureter

10. Question: The renal pelvis forms the upper end of what urinary structure? a. nephron b. ureter c. urethra

11. Answer: b. ureter

12. Longitudinal section through the kidney
Longitudinal section through the kidney. Its internal structure is shown (left), along with an enlarged diagram of nephrons (right). Each kidney contains more than 1 million nephrons. 

13. The Nephron Functional kidney unit Glomerular (Bowman) capsule
Afferent arteriole
Glomerulus
Efferent arteriole
Peritubular capillaries
Proximal convoluted tubule (PCT)
Nephron loop (Loop of Henle)
Descending limb
Ascending limb
Distal convoluted tube (DCT)
Collecting duct

14. A nephron and its blood supply
A nephron and its blood supply. The nephron regulates the proportions of water, waste, and other materials according to the body’s constantly changing needs. Materials that enter the nephron can be returned to the blood through the surrounding capillaries.  
Which of the two convoluted tubules is closer to the glomerular capsule? Which convoluted tubule is farther away?

15. Question: What vessel carries blood away from the glomerulus. a
Question: What vessel carries blood away from the glomerulus? a. afferent arteriole b. renal vein c. efferent arteriole

16. Answer: c. efferent arteriole

17. Formation of Urine - Step 1
Blood flows through an afferent arteriole into the glomerular capillary knot within Bowman’s capsule
The higher hydrostatic pressure in the afferent arteriole causes filtration of products across the filtration membrane into the capsule
water, glucose, electrolytes, waste
The more concentrated plasma flows out the efferent arteriole and through the peritubular capillaries ready to reabsorb ingredients the body may need.

18. Formation of Urine Step 2
The fluids and products filtered across the membrane become glomerular filtrate (early form of urine).
As the filtrate passes down the nephron into the proximal convoluted tubule, receptor sites will attach and reabsorb ingredients the body may wish to recycle.
Transport Maximum – the receptors are overloaded and stop recycling material IE glucose
This reabsorption may be via diffusion, osmosis, or active transport
These fluid changes may be affected by release of
Aldosterone
Antidiuretic Hormone

19. Formation of Urine Step 3
Tubular secretion occurs in the distal convoluted tubules where H+ ions may be excreted from the capillaries to the urine in order to maintain pH balance of the body; certain medications are excreted in this manner.
Countercurrent mechanism
Concentration of urine
Antidiuretic hormone (ADH) makes the walls of the DCT more permeable so that more water may be reaborsed which concentrates the urine.

20. Checkpoint 22-8: The first step in urine formation is glomerular filtration. What is glomerular filtration?

21. Summary of urine formation in a nephron.

22. Checkpoint 22-9: What are the four processes involved in the formation of urine?

23. Control of Blood Pressure
Juxtaglomerular apparatus: Specialized cells that regulate kidney function
Triggered by low blood pressure and/or low sodium content in the filtrate
Secretes renin – an enzyme that converts inactive Angiotensinogen; ACE converts Angiotensin 1 into active Angiotensin 2; the effects of Angiotensin 2 are:
Vasoconstriction (raises blood pressure),
Thirst, promotion of the release of ADH and aldosterone (raises blood volume).

24. Structure of the juxtaglomerular (JG) apparatus
Structure of the juxtaglomerular (JG) apparatus. Note how the distal convoluted tubule contacts the afferent arteriole (right). Cells in these two structures make up the JG apparatus.  
The JG apparatus is made up of cells from which two structures?

25. Checkpoint 22-10: What substance is produced by the JG apparatus and under what conditions is it produced?

26. The Ureters Long, slender, muscular tubes Epithelial cell lining
Involuntary muscle layer
Fibrous connective tissue coat
Entirely extraperitoneal
Extend from kidney to urinary bladder
Move urine by gravity and peristalsis

27. The Urinary Bladder Temporary reservoir for urine Multiple layers
Mucous membrane
Transitional epithelium
Rugae
Connective tissue
Three-layered coat of involuntary muscle tissue
Incomplete coat of peritoneum
Trigone

28. The Urethra Tube that extends from the bladder to the outside Male
Part of both reproductive and urinary systems
Female
Entirely separate from reproductive system

29. Urination Process of expelling urine from bladder (micturition)
Involuntary control
Internal urethral sphincter
Voluntary control
External urethral sphincter

30. The Urine 95% water, 5% dissolved solids and gases pH averages 6.0
Specific gravity measures amount of dissolved substances in the urine
Normal range to 1.040

31. Normal Constituents Dissolved solids normally found in urine
Nitrogenous waste products
Urea (Blood Urea Nitrogen – B.U.N. – elevation means urea is not being removed by the kidney signaling renal disease)
Uric acid
Creatinine
Electrolytes
Sodium chloride
Sulfates
Phosphates
Pigment

32. Abnormal Constituents
Urinalysis is evaluation of urine
Glucose - Glycosuria
Albumin - Albuminuria
Blood - Hematuria
Ketones
Diabetes mellitus and starvation
White blood cells
Pyuria
Casts
Nephron disease

33. Question: Which of these is NOT a normal constituent of urine. a
Question: Which of these is NOT a normal constituent of urine? a. creatinine b. albumin c. sodium chloride

34. Answer: b. albumin

35. Question: The amount of dissolved substances in urine is indicated by what measurement? a. dialysis b. turbidity c. specific gravity

36. Answer: c. specific gravity

37. Kidney Disorders Kidney disorders may be acute or chronic
Acute glomerulonephritis
Most common kidney disease
Pyelonephritis
Hydronephrosis
Polycystic kidney
Tumors
Kidney stones (calculi)
Renal failure
Leads to uremia, high levels of nitrogenous waste in the blood

38. Renal Dialysis and Kidney Transplantation
Hemodialysis
Peritoneal dialysis
Kidney transplantation
Final option for treatment of kidney failure

39. Disorders of the Ureters
Subdivision at renal pelvis
Constricted or abnormally narrow parts (strictures)
Renal ptosis – a dropped kidney (out of position)
Ureterocele – a sac of fluid at the end of the ureter in the bladder causing an obstruction
Ureteral stones (kidney calculi)

40. Checkpoint 22-14: What is the scientific name for stones, as may occur in the urinary tract?

41. Bladder Disorders Rupture Cystitis Interstitial cystitis Tumors
90% arise from epithelial lining
If bladder removed (cystectomy), ureters diverted to part of ileum in an ileal conduit
Urinary incontinence
Stress incontinence
Urge incontinence
Overflow incontinence
Enuresis

42. Disorders of the Urethra
Congenital anomalies
Narrowing of opening or urethra itself
Presence of valve-like structure at junction of urethra and bladder
Hypospadias
Urethritis
Straddle injuries

43. The Effects of Aging Loss of ability to concentrate urine
Decrease in number and size of nephrons
Increase in blood urea nitrogen (BUN)
Urinary infections
Prostate enlargement
Decreased bladder capacity
Incontinence