1. THE URINARY SYSTEM I. Introduction II
THE URINARY SYSTEM I. Introduction II. Anatomy External Internal III. Physiology Urine IV. Other Organs: Ureters, Bladder, & Urethra

2. I. Introduction & Kidney Anatomy A
I. Introduction & Kidney Anatomy A. *Urinary System Organs: Give basic description and functions Parts
*Kidneys
*Ureters
*Urinary bladder
*Urethra

3. B. Overview of Kidney Functions: Give Basic Functions of Kidney
*1. Regulate body’s ?
*2. Endocrine functions?
*3. Vitamin D?
Kidney

4. II. Kidney Anatomy A. Location & External Anatomy 1. Location
*Retroperitoneal
*Right kidney versus Left Kidney?
*Renal hilum?
Renal
hilum
Anterior
Peritoneum
Peritoneal cavity
(organs removed)
3 Supportive
tissue layers
Renal
artery
vein
• Renal fascia
anterior
posterior
Body of
vertebra L2
• Perirenal
fat capsule
• Fibrous
capsule

5. 2. Gross Regions of the Kidney: Describe
*a) Renal cortex– location?
*b) Renal medulla– location?
*Medullary pyramids
*Pyramid Papilla
*Renal columns
*Renal Pelvis?
*Major and Minor Calyces?
Contain functional units = Nephrons
Figure 15.2b

6. 3. Blood Supply 1/4th of blood per min *Renal artery = does what?
*Filtration across what vessels?
*Renal vein = does what?

7. B. Internal Kidney Anatomy
1. Conducting Path for Urine
Pyramid Papilla = tips
Minor Calyces drain to
Major Calyces
Renal pelvis
ureters
Renal cortex
Renal medulla
Major calyx
Papilla of
pyramid
Renal pelvis
Minor calyx
Ureter
Renal pyramid
in renal medulla
Renal column
Fibrous capsule
(b) Diagrammatic view
Figure 25.3

8. C. *Nephron– Microscopic Anatomy briefly define
OVERVIEW:
2. Renal Corpuscle:
a) *Glomerulus: made up of?
Afferent arteriole: does what?
Efferent arteriole: does?
*Glomerular Capsule is what?
3. *Renal tubules:
Includes: Glomerular Capsule to Collecting Duct
*Basic Function:
Histology: Single layer of epithelial cells but different types
~1 million per kidney

9. Parts of Nephron-- Details Renal Corpuscle: in what part of kidney?
C. Nephron …
Parts of Nephron-- Details
Renal Corpuscle: in what part of kidney?
*Function: filter blood produce filtrate
i) Glomerular (Bowman’s) capsule– the beginning
*Parietal layer outside or inside?
*Tissue:

10. *Visceral Layer: made up of? *Podocytes: where? *Foot processes are?
C. Nephron …
Parietal Layer
i) Glomerular (Bowman’s) capsule …
*Visceral Layer: made up of?
*Podocytes: where?
*Foot processes are?
*Filtration Slits: function
Cling to Glomerulus
*Capsular Space is what?
ii) Glomerulus
*Type of Capillaries:
Capsular Space
Capsular Space
Podocyte
Filtration Slits
Foot Processes

11. Renal Corpuscle Glomerulus Renal . Corpuscle
p = Proximal Convoluted Tube.
d = Distal Convoluted Tube.
Renal Corpuscle
Parietal Layer
Visceral Layer
Renal . Corpuscle
Glomerulus
Capsular Space

12. ii) Overall Function: Reabsorption
b. Proximal Convoluted Tubule (PCT) Location?
i) * Tissue = ?
*Microvilli = ?
*Function?
ii) Overall Function: Reabsorption

13. *c. Nephron Loop (Henle) Location?
i) Parts
*Descending Limb proximally connects to?
Proximal portion
*Thin segment mostly
-Tissue?
*Ascending Limb distally connects to?
*Thick segment is distal portion: Tissue?
ii) Primary Function: water reabsorption
Loop of Henle

14. d. Distal Convoluted Tubule Located where? Proximally connects to?
i) *Tissue: ?
*Microvilli has them?
ii) Function: Secretion & Reabsorption

15. 2. *Collecting Duct located where?
(Technically not part of nephron)
*a) Tissue: ?
b) Receives filtrate from many nephrons they then fuse together to deliver urine to Minor Calyces
c) Function: controls urine concentration  via ADH which causes reabsorption of water via aquaporins

16. Review of Epithelial Differences
Glomerular capsule: parietal layer
Renal cortex
Basement
membrane
Renal medulla
Renal corpuscle
Podocyte
Renal pelvis
• Glomerular capsule
Fenestrated
endothelium
of the glomerulus
• Glomerulus
Distal
convoluted
tubule
Ureter
Glomerular capsule: visceral layer
Kidney
Microvilli
Mitochondria
Proximal
convoluted
tubule
Highly infolded plasma
membrane
Cortex
Proximal convoluted tubule cells
Medulla
Thick segment
Distal convoluted tubule cells
Thin segment
Thick segment of loop = cuboidal/columnar
Loop of Henle
• Descending limb
• Ascending limb
Collecting
duct
Loop of Henle (thin-segment) cells
Principal cell
Intercalated cell
Collecting duct cells
Figure 25.5

17. 3. Nephron Capillary Beds– in order of pathway of filtrate/urine
a) Glomerulus - filtration
Afferent arteriole  glomerulus  efferent arteriole (smaller)
High blood pressure for capillaries (55mm) but helps to push substances in Capsular Cavity
Function: filtration
b. Peritubular capillaries – wrap around proximal and distal convoluted tubules
Function: reabsorption & secretion
c. Vasa recta – Long vessels parallel to loops of Henle
Function: helps in reabsorbing H2O

18. 4. Two types of nephrons
a) Cortical nephrons – found in cortex, most common (85%)
b) Juxtamedullary nephrons – penetrate medulla via extra long Loop of Henle (15%)
i) Function: best for reabsorbing H2O and concentrating urine; the longer the nephron loops the more concentrated the urine can get
ii) Juxtaglomerular Apparatus (JGA): Area where afferent artery meets ascending limb of loop (or first part of DCT); Function: Regulates filtration & BP

19. ii) Juxtaglomerular Apparatus …
(1) Granular cells (Juxtaglomerular Cells) of Afferent Artery
Enlarged, smooth muscle
Function: Can contract and act as Baroreceptors to sense BP; Produce renin
(2) Macula Densa cells of Ascending Limb of Loop
Tall, closely packed cells
Function: Chemoreceptors that sense NaCl & regulate release of Renin from Granular cells (Renin causes Angiotension II to be produced)
• Macula densa cells
of the ascending limb
of loop of Henle
• Extraglomerular
mesangial cells
• Granular cells of Afferent Arteriole
Juxtaglomerular
apparatus
(3) Extraglomerular Mesangial Cells are for communication

20. Extra-Glomerular Mesangial Ascending limb of Nephron Loop
JG Apparatus
Renal Corpuscle
Extra-Glomerular Mesangial
Macula Densa cells
Extra-Glomerular Mesangial
Granular cells
Macula Densa cells
Afferent Arteriole
Ascending Limb of Loop
Ascending limb of Nephron Loop

21. III. Kidney Physiology: Urine Formation
OVERVIEW
Step 1 = Glomerular Filtration
Blood filtered at glomerulus; Arteriole  Glomerulus
Step 2 = Tubular Reabsorption = nutrients moved back into blood;
PCT & DCT  Peritubular Capillaries
Step 3 = Tubular Secretion Substances actively transported into the tubules from blood;
Step 4 = Regulation Of
Loop of Henle & Vasa
Peritubular Capillaries  DCT & PCT
Water & Urine Concentration
Recta  Collecting Tubules
Figure 15.3c

22. A. Step 1: Glomerular Filtration
1. Glomerulus: Membrane is Porous
2. Fenestrated endothelium of glomerular capillaries
Visceral membrane of glomerular capsule with Podocytes
3. Gel-like basement
4. Items that pass through: glucose, amino acids, ions, water, and urea
Prevents large proteins and cells from leaving
Capsular Cavity
Proximal Convoluted Tubule
Glomerulus
Path of Filtrate
Filtration slits
Filtrate In Capsular
space
Plasma
Foot Processes
of podocyte
Fenestration

23. Glomerular capillaries
Afferent arteriole
Glomerular capillaries
Efferent arteriole
Cortical
radiate
artery
Glomerular capsule
Rest of renal tubule
containing filtrate
Peritubular
capillary
Three major
renal processes:
Glomerular filtration
To cortical radiate vein
Tubular reabsorption
Tubular secretion
Urine

24. 5. Strength of Filtration
a) Net Filtration Pressure,
= pressure for filtratIon 10 mm Hg
b) Glomerular Filtration Rate (GFR)
i) Total Volume per minute filtered across from Renal Corpuscles to Proximal Convoluted Tubule
Normally ml/min Must be > 80 ml/min
ii) Factors Effecting NFP:
Blood Pressure (important)
Total surface area
Filtration membrane permeability
NFP
Afferent
Arteriole
Glomerulus
Glomerular
capsule 10 mm Hg
Proximal Convoluted Tubule
= Net
filtration
pressure

25. afferent arterioles; GFR
6. Regulation Of Kidney Function & Systemic BP a) Intrinsic Mechanisms– Autoregulation to keep Kidneys Functional during normal BP changes
SYSTEMIC BLOOD PRESSURE
i) Purpose: keep GFR constant and > 80
ii) Myogenic mechanism in Afferent Arteriole
If ↓ BP, then: ↓Kidney arteriole stretch  afferent arteriole dilates  ↑blood flow to arteriole
Result = ↑ BP in arteriole  ↑ NFP ↑ GFR
iii) Tubuloglomerular Feedback Mechanism: NaCl detectors in Macula Densa (JG) Cells
Result:  afferent arteriole dilates  ↑ blood flow to arteriole ↑ arteriole blood flow  ↑ NFP  ↑ GFR
Conclusions for Intrinsic Controls: Both Dilate afferent arteriole  ↑ GFR
Blood pressure in
afferent arterioles; GFR
GFR
Stretch of smooth
muscle in walls of
afferent arterioles
Filtrate flow and
NaCl in ascending
limb of Henle’s loop
(+)
Targets
Vasodilation of
afferent arterioles
Macula densa cells
of JG apparatus
of kidney
Release of vasoactive
chemical inhibited
Vasodilation of
afferent arterioles
GFR
Tubuloglomerular
mechanism of
autoregulation
Myogenic mechanism
of autoregulation

26. b) Extrinsic Controls: Goal = Maintain systemic BP
during Stress/Emergency– most important i) Sympathetic Controls: (1) If BP drops due to loss of blood and other factors (2) Mechanism: ↓ Baroreceptor stretch  Medulla Vasomotor Center  ↑ Sympathetic NS stimulation  - Result 1– constriction of systemic arterioles  ↓ GFR  keeps more fluid in blood  ↑ BP - Result 2– Granular Cells of JG Apparatus Release Renin  Production of Angiotensin II 
SYSTEMIC BLOOD PRESSURE
(–)
Granular cells of
juxtaglomerular
apparatus of kidney
Baroreceptors in
blood vessels of
systemic circulation
Release
(+)
(+)
Renin
(+)
Sympathetic
nervous system
Catalyzes cascade
resulting in conversion
Angiotensinogen
Angiotensin II
(+)
(+)
(+)
Adrenal cortex
Systemic arterioles
Releases
Aldosterone
Vasoconstriction;
peripheral resistance
Targets
Kidney tubules
Na+ reabsorption;
water follows
(+)
Stimulates
(–)
Inhibits
Increase
Decrease
Blood volume
Systemic
blood pressure
Hormonal (renin-angiotensin)
mechanism
Neural controls

27. Conclusions for Extrinsic Controls: -- Constriction of Blood Vessels
 ii) Angiotensin II Effects
(1) Constricts arteriolar smooth muscle  ↑ BP to rise
(2) Stimulates reabsorption of Na+
Stimulates release of Aldosterone
Water follows salt  ↑ Blood Volume  ↑ BP
(3) Stimulates hypothalamus to
Stimulates the release ADH  Reabsorption of H2O  ↑ BP
Activates thirst center in Hypothalamus  ↑ H2O in body  ↑ BP
Conclusions for Extrinsic Controls: Constriction of Blood Vessels
-- ↑ Water In Blood ↑ Blood Volume
Increased BP

28. END OF PPT
Review Questions

29. Participating…
The functional unit of the kidney is known as the __________ . The three steps of urine formation are: 1. ______________, 2. ______________, and 3. ___________.
What cells of the JG apparatus release renin?
nephron
filtration
reabsorption
secretion
granular

30. Participating…
What are 3 things that trigger renin release by the granular cells? Low levels of NaCl ions indicates ______ flow rates in the nephron and are detected by ______ _______ cells of the J-G apparatus which signal the _________ arteriole to _________.
Very low b.p.; low filtrate flow; sympathetic stimulation
low
macula densa
afferent
dilate

31. Participating…
The __________ _________ developed in the long loops of Henle allows the body to produce __________ urine. Aldosterone targets the collecting tubules and the ______ ; it promotes ____ (and thus H2O) reabsorption by stimulating the production of what?
countercurrent multiplier
concentrated
DCT
Na+
Na+ and K+ channels and Na-K pumps

32. peripheral resistance
SYSTEMIC BLOOD PRESSURE
(–)
Granular cells of
juxtaglomerular
apparatus of kidney
Baroreceptors in
blood vessels of
systemic circulation
Release
(+)
(+)
Renin
(+)
Sympathetic
nervous system
Catalyzes cascade
resulting in conversion
Angiotensinogen
Angiotensin II
(+)
(+)
(+)
Adrenal cortex
Systemic arterioles
Releases
Aldosterone
Vasoconstriction;
peripheral resistance
Targets
Kidney tubules
Na+ reabsorption;
water follows
(+)
Stimulates
(–)
Inhibits
Increase
Decrease
Blood volume
Systemic
blood pressure
Hormonal (renin-angiotensin)
mechanism
Neural controls
Extrinsic mechanisms indirectly regulate GFR
by maintaining systemic blood pressure, which
drives filtration in the kidneys.