1. Anatomy and Physiology Chapter 15
The Urinary System
Anatomy and Physiology Chapter 15

2. Vocabulary Slide 1 Renal cortex Loop of Henle Renal medulla
Distal convoluted tubules
Medullary pyramids
Collecting duct
Renal pelvis
Peritubular capillaries
Hilus
Urethra
Glomerulus
Ureter
Afferent arterioles
Sphincter
Efferent arterioles
Incontinence
Bowman’s capsule
Hyperplasia
Proximal convoluted tubules
Aldosterone
Diabetes insipidus 516

3. Answer these Slide 2 What is the job of the kidneys? List 3. p502
What 2 other parts of the body aid in excretion? 502
Approximately how many nephrons does each kidney contain? 505
What are the 2 main structures of the nephron? 505
Put these in the correct order. proximal convoluted tubule, distal convoluted tubule, loop of Henle 505
Which part of the kidney are the nephrons located?
What causes fluids and small solutes out of the blood & into the Bowman’s capsule? 505

4. Answer these Slide 3 What 3 processes are needed to form urine? 507
What substances are typically reabsorbed by the tubules? 507
Name 4 physical features of the bladder. How much urine can the average adult bladder hold? 512-3
What causes urine to move down the ureters? 512
Tell the difference between the internal urethral sphincter and external urethral sphincter. 513
What % does water make up in female & male bodies? 514

5. Slide 4
Name 5 situations where incontinence is considered normal? 514 What is one time in life it is normal? 521
What is the difference of intracellular fluid and extracellular fluid? 515
When blood pH rises, the respiratory system is _____. What does this do for the blood? 520
What organ most controls blood pH?
What is the average adult urine output per day? 521
(T/F) Sexually transmitted diseases (STDs) may cause urinary tract infections. 521

6. Kidneys Dispose of metabolic waste products Regulate blood volume
Manufacture urine
Convert vitamin d from an Inactive to active form

7. Nephrons and Urine Formation

8. Nephrons Structural and functional units of the kidneys
Each kidney contains over one million
Responsible for forming urine

9. Nephrons

10. Nephrons Glomerulus: Renal Tubule: Knot of capillaries
Glomerular Capsule: closed end of the renal tubule that surrounds the glomerulus
Rest of the tube extends from the glomerular capsule, coils and twists (proximal convoluted tubule) before making a hairpin loop (Loop of Henle)
Then it becomes coiled and twisted again (distal convoluted tubule) and enters the collecting duct
Tubule cells contain microvilli to increase surface area

11. Nephrons Cortical Nephrons: Juxtamedullary Nephrons: Most nephrons
Located almost entirely within the cortex
Juxtamedullary Nephrons:
Few nephrons
Situated close to the cortex-medulla
junction
Loops of Henle dip into the medulla

12. Nephrons Collecting Ducts: Each receive urine from many nephrons
Run downward through the medullary pyramids
Deliver the urine to the renal pelvis

13. Nephrons Afferent Arteriole: Efferent Arteriole: Glomerulus:
Feeds blood to the glomerulus
Efferent Arteriole:
Carries blood from the glomerulus
Glomerulus:
Specialized capillary bed for filtration
Extremely high blood pressure forces fluid and solutes out of the blood
Most removed fluid and solutes are returned to the blood in the peritubular capillary beds

14. Urine

15. Urine Formation Three Major Processes: Filtration Tubular Reabsorption
Tubular Secretion

16. Urine Formation Filtration: Nonselective and passive
Filtrate = blood plasma without blood proteins
If blood cells or proteins are found in the urine = sign that glomerular filters are malfunctioning
Filtrate formation stops if blood pressure drops too low

17. Urine Formation Tubular Reabsorption:
Filtration removes many useful substances from the blood that must be reclaimed
Begins as soon as the filtrate enters the proximal convoluted tubule
Some is passive, most is active
Needed Substances in the blood: water, glucose, amino acids, and ions
Nitrogenous waste products are poorly reabsorbed: urea, uric acid, & creatinine

18. Urine Formation Tubular Secretion: Reabsorption in reverse
Gets rid of substances not already in the filtrate, such as certain drugs
Moves from blood peritubular capillaries into tubules
Additional means for controlling blood pH

19. Characteristics of Urine
In 24 hours the kidneys filter L of blood plasma and produces 1-1.8L of urine
Freshly voided urine is generally clear and pale to deep yellow
Urochrome pigment from destruction of hemoglobin causes yellow color
More solutes = deeper color
More dense than water
Typically contain ammonia
Sterile (free from bacteria or microorganisms)

20. Characteristics of Urine
When formed: urine is sterile with a slightly aromatic odor
When allowed to stand: ammonia odor due to bacteria
Some drugs, vegetables, and diseases alter the odor of urine

21. Characteristics of Urine
Usually slightly acidic – pH 6
Lots of protein and whole wheat = more acidic
Vegetarian diet = more basic

22. Characteristics of Urine
Urine is more dense than distilled water
Specific Gravity: compare how much heavier urine is than distilled water
Ranges from to (dilute to concentrated)
Generally low when a person: drinks excess fluids, uses diuretics, or has chronic renal failure
Generally high when a person: has inadequate fluid intake, fever, or kidney inflammation

23. Characteristics of Urine
Solutes Normally Found in Urine:
Sodium and potassium ions
Urea
Uric acid
Creatinine
Ammonia
Bicarbonate ions
Other ions

24. Characteristics of Urine
Substances NOT Normally Found in Urine:
Glucose
Blood proteins
Red blood cells
Hemoglobin
White blood cells (pus)
Bile

25. Fluid, Electrolyte, and Acid-Base Balance

26. Blood Composition Factors Affecting Blood Composition: Diet
Cellular Metabolism
Urine Output

27. Blood Composition
Four Major Roles of the Kidneys in Maintaining Stable Blood Composition:
Excretion of nitrogenous wastes
Maintaining water balance
Maintaining electrolyte balance
Ensuring proper blood pH

28. Body Fluids and Fluid Compartments
Three Major Fluid Compartments in the Body:
Intracellular Fluid
Contained within living cells
Interstitial Fluid
Fluid found between living cells, CSF, serous fluid, humors of the eye, lymph, etc
Plasma
Blood plasma

29. The Link Between Water and Salt
Types and amounts of solutes in body fluids are vitally important to overall body homeostasis
Very small changes in electrolyte balance cause water to move from one compartment to another
Alters blood volume and blood pressure
Can severely impair the activity of irritable cells

30. Water In and Water Out Water Intake: Water Output: 10% Metabolism
30% Food
60% Beverages
Water Output:
4% Feces
8% Sweat
28% Loss through skin and lungs
60% Urine

31. NASA recycles in space
Water recycling on the ISS
Recycling urine

32. Regulation of Reabsorption
When blood volume drops, arterial blood pressure drops, and filtrate formation drops
Osmoreceptors in the hypothalamus react to changes in blood composition by becoming more active
Antidiuretic Hormone: prevents excessive water loss in urine, causes the collecting ducts to reabsorb more water

33. Maintaining Acid-Base Balance of Blood
Blood pH must remain between 7.35 and 7.45
Respiratory System Controls
Release more carbon dioxide when blood pH drops
Release less carbon dioxide when blood pH rises
Bicarbonate Buffer System
Mixture of carbonic acid and sodium bicarbonate
Weak acid minimizes effect of bases
Conjugate base minimizes effect of acids

34. Maintaining Acid-Base Balance of Blood
Renal Mechanisms
Can rid the body of acids other than carbonic acid that are generated during metabolism
Regulate blood levels of alkaline substances
Slow-acting, but bring about changes
Means of Maintaining Acid-Base Balance:
Excreting bicarbonate ions
Conserving or generating new bicarbonate ions
Urine pH ranges from (slightly basic)