Human Anatomy and Physiology
II
Biology 1414
Unit 1
The Urinary System
Objective 1

List the functions of the urinary
system and explain how they
contribute to homeostasis.

Unit 1 - Objective ...
Functions of the Urinary System
• Filtration of the blood
– Occurs in the glomerulus of the kidney
nephron
– Contributes t...
Functions of the Urinary System
• Reabsorption of vital nutrients, ions
and water
– Occurs in most parts of the kidney
nep...
Functions of the Urinary System
• Secretion of excess materials
– Assists filtration in removing material
from the blood
–...
Functions of the Urinary System
• Activation of Vitamin D
– Vitamin D made in the skin is converted
to Vitamin D3 by the k...
Functions of the Urinary System
• Release of Erythropoietin by the
kidney
– Erythropoietin stimulates new RBC
production
–...
Functions of the Urinary System
• Release of Renin by the kidney
– Renin stimulates the formation of a
powerful vasoconstr...
Functions of the Urinary System
• Release of Prostaglandins
– Prostaglandins dilate kidney blood
vessels
– Dilated blood v...
Functions of the Urinary System
• Secretion of H (+1) and reabsorption
of HCO3 (-1)
– Eliminates excess hydrogen ions and
...
Objective 2
Given a diagram of the Urinary
System, you will recognize and
label the following parts: kidney,
ureters, blad...
Urinary System

Renal Vein

Renal artery
Kidney
Ureter

For
sphincters,
see next slide

Urinary Bladder
Urinary System
Female Sphincters

Male Sphincters

Internal urethral
External Urethral
sphincter
Sphincter
Objective 3
Given a diagram of the kidney you
will label and give the functions
of the following structures: renal
vein, r...
Kidney Diagram

Medulla
Papilla
Pyramid
Cortex
Nephron
Column

Calyx
Renal Vein
Renal Artery
Pelvis

Capsule
Ureter
Functions of Kidney Structures
Examine the kidney structures
in the following slides and note
the particular functions.

U...
Functions of Kidney Structures
• The Renal Artery
– Transports oxygenated blood from the
heart and aorta to the kidney for...
Functions of Kidney Structures
• Renal Vein
– Transports filtered and deoxygenated
blood from the kidney to the posterior
...
Functions of Kidney Structures
• Renal Column
– A passageway located between the renal
pyramids found in the medulla and u...
Functions of Kidney Structures
• Nephron
– The physiological unit of the kidney used
for filtration of blood and reabsorpt...
Functions of Kidney Structures
• Capsule
– The outer membrane that encloses,
supports and protects the kidney

Unit 1 - Ob...
Functions of Kidney Structures
• Cortex
– The outer layer of the kidney that contains
most of the nephron; main site for
f...
Functions of Kidney Structures
• Medulla
– inner core of the kidney that contains the
pyramids, columns, papillae, calyces...
Functions of Kidney Structures
• Renal Pyramids
– Triangular shaped units in the medulla that
house the loops of Henle and...
Functions of Kidney Structures
• Renal Papilla
– The tip of the renal pyramid that releases
urine into a calyx

Unit 1 - O...
Functions of Kidney Structures
• Calyx
– A collecting sac surrounding the renal
papilla that transports urine from the
pap...
Functions of Kidney Structures
• Renal Pelvis
– Collects urine from all of the calyces in
the kidney

Unit 1 - Objective 3
Functions of Kidney Structures
• Ureter
– Transports urine from the renal pelvis to
the bladder

Unit 1 - Objective 3
Objective 4
Given a diagram of a Nephron you will
label and give the functions of the
structures: afferent arteriole, effe...
Diagram of Kidney Nephron
Efferent arteriole
Afferent arteriole
Bowman’s
capsule
Distal convoluted
tubule

Collecting
duct...
Functions of Nephron Structures
• AfferentArteriole
– Transports arterial blood to the
glomerulus for filtration

Unit 1 -...
Functions of Nephron Structures
• Efferent Arteriole
– Transports filtered blood from the
glomerulus , through the peritub...
Functions of Nephron Structures
• Glomerulus
– The site for blood filtration
– operates as a nonspecific filter; in that, ...
Functions of Nephron Structures
• Bowman’s Capsule
– A sac that encloses Bowman’s Capsule and
transfers filtrate from the ...
Functions of Nephron Structures
• Proximal Convoluted Tubule (PCT)
– A thick, constantly actively segment of the
nephron t...
Functions of Nephron Structures
• Decending Limb of the Loop of Henle
– A part of the counter current multiplier
– freely ...
Functions of Nephron Structures
• Ascending Limb of the Loop of Henle
– a part of the counter current multiplier
– imperme...
Functions of Nephron Structures
• Distal Convoluted Tubule (DCT)
– receives dilute fluid from the ascending
limb of the Lo...
Functions of Nephron Structures
• Collecting Duct
– receives fluid from the DCT
– variably active portion of the Nephron
–...
Functions of Nephron Structures
• Peritubular Capillaries
– transport reabsorbed materials from the
PCT and DCT into kidne...
Objective 5
Identify the parts of the Nephron
responsible for Filtration, Reabsorption
and Secretion, and describe the
Mec...
Site of Filtration
• Glomerulus
– the Glomerulus is the site of filtration
– the filtration mechanism is sieve-like and
co...
Location of the Glomerulus
Efferent
Arteriole

Afferent
Arteriole

Bowman’s
Capsule
Glomerulus

Proximal
Convoluted
Tubule
Glomerular Filtration Mechanism
Podocyte with
Basement
Membrane
Glomerulus
Bowman’s Capsule
Fenestrated Capillary
Objective 6
Describe the Juxtaglomerular Apparatus
and how it maintains renal blood pressure

Unit 1 - Objective 6
The Juxtaglomerular Apparatus
• Description
– the juxtaglomerular apparatus consists of
specialized macula densa cells tha...
The Juxtaglomerular Apparatus
Bowman’s Capsule

PCT

Efferent Arteriole

DCT

Macula
Densa Cells
Granular Juxtaglomerular ...
The Juxtaglomerular Apparatus
• Used in maintaining blood pressure
– if the blood pressure drops, the granular JG
cells re...
The Juxtaglomerular Apparatus
• Used in maintaining blood pressure
continued:
– Angiotensin II also stimulates the release...
The Juxtaglomerular Apparatus
• Used in maintaining blood pressure
continued:
– salt reabsorption attracts water to the bl...
The Juxtaglomerular Apparatus
• Used in maintaining blood pressure
continued:
– the macula densa cells monitor the salt
co...
The Juxtaglomerular Apparatus
• Used in maintaining blood pressure
continued:
– suppression of renin acts as a negative
fe...
The Juxtaglomerular Apparatus
• Use in maintaining blood pressure
continued:
– eventually the blood pressure will come
bac...
Objective 7
Discuss the functioning of the counter
current mechanism through which the
kidneys excrete a concentrated urin...
The Counter Current Mechanism
Compare to the Nephron and recall parts

?
?
?

Unit 1 - Objective 7

?
The Counter Current Mechanism
Were you able to locate the decending limb
of the Loop of Henle, the ascending limb
of the L...
The Counter Current Mechanism
We will begin our discussion of the
counter current mechanism with the
ascending limb of the...
The Counter Current Mechanism
As salt (NaCl) leaves the ALLH, the
osmolarity of the fluid decreases from 1,200
to 100 mill...
The Counter Current Mechanism
The accumulated salt in the interstitium of
the medulla acts as an osmotic force which
can b...
The Counter Current Mechanism
As the DLLH gives up water to the
medullary interstitium, the osmolarity of the
fluid change...
The Counter Current Mechanism
The hyperosmotic interstitium of the
medulla will also “pull” and conserve water
from the co...
The Counter Current Mechanism
The availibility of Antidiurectic Hormone
(ADH) is determined by dehydration and
thirst. Und...
The Counter Current Mechanism
As water leaves the collecting duct, the
urine becomes progressively more
concentrate. The o...
The Counter Current Mechanism
The vasa recta is made up of a group of
capillary like vessels and is freely
permeable to sa...
Objective 8
Given the value for two of the following,
you will compute the value for the third:
Amount Filtered, Amount Re...
Objective 8
The relationship between the variables of
Objective 8 is as follows:
Amount Excreted = Amount Filtered Amount ...
Objective 8
If the kidneys filter 16 grams of NaCl per
day and then reabsorb 14 grams of NaCl per
day, then 2 grams of NaC...
Objective 8
Examine the following and find the missing
value:
Amount Excreted = Amount Filtered - Amount Reabsorbed
1)
?
=...
Objective 9

Given the concentration of a substance in
the plasma and the amount of the substance
excreted in the urine pe...
Plasma Clearance
Plasma clearance is defined as the amount
of plasma that is cleared or “cleansed” of
a particular substan...
Plasma Clearance
Filtration will directly affect clearance. As
filtration increases, more material will be
removed from th...
Plasma Clearance
The formula used to calculate plasma
clearance is:
C = V x U/P
C = plasma clearance rate in ml/min
V = ur...
Plasma Clearance
Let us practice calculating plasma clearance
using the clearance equation. In all your
calculations, assu...
Plasma Clearance
If you did not get 120ml/min, look at the
following calculation and recheck your
work.
120 ml/min = 2 ml/...
Plasma Clearance
Test your ability to conduct further
calculations by calculating the clearance
rate for the following sub...
Objective 10
Give the cause and describe the disease
process for the following: renal calculi
(kidney stones); cystitis; g...
Disorders of the Urinary System
• Renal Calculi (kidney stones)
– caused by the crystallization of calcium,
magnesium or u...
Disorders of the Urinary System
• Cystitis
– typically caused by bacteria from the anal
region, but, can also be caused by...
Disorders of the Urinary System
• Glomerulonephritis ( Bright’s Disease)
– caused by inflammation of the glomeruli
due to ...
Disorders of the Urinary System
• Incontinence
– caused by loss of the ability to control
voluntary micturition (releasing...
Objective 11
Describe the process involved in dialysis
therapy.

Unit 1 - Objective 11
Dialysis Therapy
Dialysis is a process that artificially
removes metabolic wastes from the blood in
order to compensate fo...
Dialysis Therapy
The most common form of dialysis is
hemodialysis which uses a machine to
transfer patient’s blood through...
Dialysis Therapy
Some key aspects of hemodialysis are:
- blood is typically transferred from an arm artery
- after dialysi...
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Unit 1 1 Urinary System

  1. 1. Human Anatomy and Physiology II Biology 1414 Unit 1 The Urinary System
  2. 2. Objective 1 List the functions of the urinary system and explain how they contribute to homeostasis. Unit 1 - Objective 1
  3. 3. Functions of the Urinary System • Filtration of the blood – Occurs in the glomerulus of the kidney nephron – Contributes to homeostasis by removing toxins or waste Unit 1 - Objective 1
  4. 4. Functions of the Urinary System • Reabsorption of vital nutrients, ions and water – Occurs in most parts of the kidney nephron – Contributes to homeostasis by conserving important materials Unit 1 - Objective 1
  5. 5. Functions of the Urinary System • Secretion of excess materials – Assists filtration in removing material from the blood – Contributes to homeostasis by preventing a build-up of certain materials in the body such as drugs, waste,etc. Unit 1 - Objective 1
  6. 6. Functions of the Urinary System • Activation of Vitamin D – Vitamin D made in the skin is converted to Vitamin D3 by the kidney – Active Vitamin D (D3) assists homeostasis by increasing calcium absorption from the digestive tract Unit 1 - Objective 1
  7. 7. Functions of the Urinary System • Release of Erythropoietin by the kidney – Erythropoietin stimulates new RBC production – New RBC’s assist homeostasis by insuring adequate Oxygen and Carbon Dioxide transport Unit 1 - Objective 1
  8. 8. Functions of the Urinary System • Release of Renin by the kidney – Renin stimulates the formation of a powerful vasoconstrictor called Angiotensin II – Angiotensin II assists homeostasis by causing vasoconstriction which increases blood pressure Unit 1 - Objective 1
  9. 9. Functions of the Urinary System • Release of Prostaglandins – Prostaglandins dilate kidney blood vessels – Dilated blood vessels contribute to homeostasis by maintaining blood flow in the kidneys Unit 1 - Objective 1
  10. 10. Functions of the Urinary System • Secretion of H (+1) and reabsorption of HCO3 (-1) – Eliminates excess hydrogen ions and conserves buffer material such as bicarbonate – Contributes to homeostasis by controlling acid/base conditions in body fluids Unit 1 - Objective 1
  11. 11. Objective 2 Given a diagram of the Urinary System, you will recognize and label the following parts: kidney, ureters, bladder, urethra, internal and external sphincters. Unit 1 - Objective 2
  12. 12. Urinary System Renal Vein Renal artery Kidney Ureter For sphincters, see next slide Urinary Bladder
  13. 13. Urinary System Female Sphincters Male Sphincters Internal urethral External Urethral sphincter Sphincter
  14. 14. Objective 3 Given a diagram of the kidney you will label and give the functions of the following structures: renal vein, renal artery, capsule, cortex, medulla, pyramids, renal papilla, calyx, pelvis, ureter, renal column and nephron Unit 1 - Objective 3
  15. 15. Kidney Diagram Medulla Papilla Pyramid Cortex Nephron Column Calyx Renal Vein Renal Artery Pelvis Capsule Ureter
  16. 16. Functions of Kidney Structures Examine the kidney structures in the following slides and note the particular functions. Unit 1 - Objective 3
  17. 17. Functions of Kidney Structures • The Renal Artery – Transports oxygenated blood from the heart and aorta to the kidney for filtration Unit 1 - Objective 3
  18. 18. Functions of Kidney Structures • Renal Vein – Transports filtered and deoxygenated blood from the kidney to the posterior vena cava and then the heart Unit 1 - Objective 3
  19. 19. Functions of Kidney Structures • Renal Column – A passageway located between the renal pyramids found in the medulla and used as a space for blood vessels Unit 1 - Objective 3
  20. 20. Functions of Kidney Structures • Nephron – The physiological unit of the kidney used for filtration of blood and reabsorption and secretion of materials Unit 1 - Objective 3
  21. 21. Functions of Kidney Structures • Capsule – The outer membrane that encloses, supports and protects the kidney Unit 1 - Objective 3
  22. 22. Functions of Kidney Structures • Cortex – The outer layer of the kidney that contains most of the nephron; main site for filtration, reabsorption and secretion Unit 1 - Objective 3
  23. 23. Functions of Kidney Structures • Medulla – inner core of the kidney that contains the pyramids, columns, papillae, calyces, pelvis and parts of the nephron not located in the cortex; used for salt, water and urea absorption Unit 1 - Objective 3
  24. 24. Functions of Kidney Structures • Renal Pyramids – Triangular shaped units in the medulla that house the loops of Henle and collecting ducts of the nephron; site for the countercurrent system that concentrates salt and conserves water and urea Unit 1 - Objective 3
  25. 25. Functions of Kidney Structures • Renal Papilla – The tip of the renal pyramid that releases urine into a calyx Unit 1 - Objective 3
  26. 26. Functions of Kidney Structures • Calyx – A collecting sac surrounding the renal papilla that transports urine from the papilla to the renal pelvis Unit 1 - Objective 3
  27. 27. Functions of Kidney Structures • Renal Pelvis – Collects urine from all of the calyces in the kidney Unit 1 - Objective 3
  28. 28. Functions of Kidney Structures • Ureter – Transports urine from the renal pelvis to the bladder Unit 1 - Objective 3
  29. 29. Objective 4 Given a diagram of a Nephron you will label and give the functions of the structures: afferent arteriole, efferent arteriole, glomerulus, Bowman’s capsule, proximal convoluted tubule, decending limb and ascending limbs of the loop of Henle, vasa recta, distal convoluted tubule, peritubular capillaries and the collecting duct. Unit 1 - Objective 4
  30. 30. Diagram of Kidney Nephron Efferent arteriole Afferent arteriole Bowman’s capsule Distal convoluted tubule Collecting duct Proximal convoluted tubule Glomerulus Peritubular capillaries Vasa recta Decending limb of loop of Henle Ascending limb of loop of Henle Unit 1 - Objective 4
  31. 31. Functions of Nephron Structures • AfferentArteriole – Transports arterial blood to the glomerulus for filtration Unit 1 - Objective 4
  32. 32. Functions of Nephron Structures • Efferent Arteriole – Transports filtered blood from the glomerulus , through the peritubular capillaries and the vasa recta, and to the kidney venous system Unit 1 - Objective 4
  33. 33. Functions of Nephron Structures • Glomerulus – The site for blood filtration – operates as a nonspecific filter; in that, it will remove both useful and non-useful material – the product of the glomerulus is called filtrate Unit 1 - Objective 4
  34. 34. Functions of Nephron Structures • Bowman’s Capsule – A sac that encloses Bowman’s Capsule and transfers filtrate from the glomerulus to the Proximal Convoluted Tubule (PCT) Unit 1 - Objective 4
  35. 35. Functions of Nephron Structures • Proximal Convoluted Tubule (PCT) – A thick, constantly actively segment of the nephron that reabsorbs most of the useful substances of the filtrate: sodium (65%), water (65%), bicarbonate (90%), chloride (50%), glucose (nearly 100%!), etc. – The primary site for secretion (elimination) of drugs, waste and hydrogen ions Unit 1 - Objective 4
  36. 36. Functions of Nephron Structures • Decending Limb of the Loop of Henle – A part of the counter current multiplier – freely permeable to water and relatively impermeable to solutes (salt particles) – receives filtrate from the PCT, allows water to be absorbed and sends “salty”filtrate on the the next segment. “Saves water and passes the salt” Unit 1 - Objective 4
  37. 37. Functions of Nephron Structures • Ascending Limb of the Loop of Henle – a part of the counter current multiplier – impermeable to water and actively transports (reabsorbs) salt (NaCl) to the interstitial fluid of the pyramids in the medulla. “Saves salt and passes the water.” – the passing filtrate becomes dilute and the interstitium becomes hyperosmotic Unit 1 - Objective 4
  38. 38. Functions of Nephron Structures • Distal Convoluted Tubule (DCT) – receives dilute fluid from the ascending limb of the Loop of Henle – Variably active portion of the nephron – When aldosterone hormone is present, sodium is reabsorbed and potassium is secreted. Water and chloride follow the sodium. Unit 1 - Objective 4
  39. 39. Functions of Nephron Structures • Collecting Duct – receives fluid from the DCT – variably active portion of the Nephron – when antidiuretic hormone (ADH) is present, this duct will become porous to water. Water from the collecting duct fluid then moves by osmosis into the “salty” (hyperosmotic) interstitium of the medulla. – The last segment to save water for the body Unit 1 - Objective 4
  40. 40. Functions of Nephron Structures • Peritubular Capillaries – transport reabsorbed materials from the PCT and DCT into kidney veins and eventually back into the general circulation – help complete the conservation process (reabsorption) that takes place in the kidney Unit 1 - Objective 4
  41. 41. Objective 5 Identify the parts of the Nephron responsible for Filtration, Reabsorption and Secretion, and describe the Mechanisms underlying each of these functional processes. Unit 1 - Objective 5
  42. 42. Site of Filtration • Glomerulus – the Glomerulus is the site of filtration – the filtration mechanism is sieve-like and consists of fenestrated glomerular capillaries, podocytes and a basement membrane that allows free passage of water and solutes smaller than plasma proteins Unit 1 - Objective 4
  43. 43. Location of the Glomerulus Efferent Arteriole Afferent Arteriole Bowman’s Capsule Glomerulus Proximal Convoluted Tubule
  44. 44. Glomerular Filtration Mechanism Podocyte with Basement Membrane Glomerulus Bowman’s Capsule Fenestrated Capillary
  45. 45. Objective 6 Describe the Juxtaglomerular Apparatus and how it maintains renal blood pressure Unit 1 - Objective 6
  46. 46. The Juxtaglomerular Apparatus • Description – the juxtaglomerular apparatus consists of specialized macula densa cells that develop in the distal convoluted tubule (DCT) and specialized granular juxtaglomerular (JG) cells that develop mainly in the afferent arteriole. See following diagram. Unit 1 - Objective 6
  47. 47. The Juxtaglomerular Apparatus Bowman’s Capsule PCT Efferent Arteriole DCT Macula Densa Cells Granular Juxtaglomerular (JG) Cells Afferent Arteriole
  48. 48. The Juxtaglomerular Apparatus • Used in maintaining blood pressure – if the blood pressure drops, the granular JG cells release renin – renin converts the blood protein angiotensinogen into angiotensin I which converts to angiotensin II – angiotensin II acts as a vasoconstrictor to raise blood pressure. Continued on next slide. Unit 1 - Objective 6
  49. 49. The Juxtaglomerular Apparatus • Used in maintaining blood pressure continued: – Angiotensin II also stimulates the release of aldosterone hormone from the adrenal cortex – aldosterone stimulates the DCT to reabsorb salt (NaCl). Continued on next slide. Unit 1 - Objective 6
  50. 50. The Juxtaglomerular Apparatus • Used in maintaining blood pressure continued: – salt reabsorption attracts water to the blood by osmosis and raises blood volume, as well as, contributing to the increase in blood pressure. Continued on next slide. Unit 1 - Objective 6
  51. 51. The Juxtaglomerular Apparatus • Used in maintaining blood pressure continued: – the macula densa cells monitor the salt content of the blood – if the blood salt content gets too high, the macula densa cells begin to inhibit the granular cells and suppress renin release Unit 1 - Objective 6
  52. 52. The Juxtaglomerular Apparatus • Used in maintaining blood pressure continued: – suppression of renin acts as a negative feedback mechanism to prevent further increases in angiotensin II, Aldosterone and blood pressure Unit 1 - Objective 6
  53. 53. The Juxtaglomerular Apparatus • Use in maintaining blood pressure continued: – eventually the blood pressure will come back down – the “push/pull” action of the granular cells and macula densa cells provide an effective mechanism for regulating blood pressure in the kidney Unit 1 - Objective 6
  54. 54. Objective 7 Discuss the functioning of the counter current mechanism through which the kidneys excrete a concentrated urine by indicating the role of the following: sodium chloride, posterior pituitary, ADH, hypothalamus, collecting duct, active transport, osmosis, interstitial fluid, vasa recta, diffusion, loop of Henle and urea Unit 1 - Objective 7
  55. 55. The Counter Current Mechanism Compare to the Nephron and recall parts ? ? ? Unit 1 - Objective 7 ?
  56. 56. The Counter Current Mechanism Were you able to locate the decending limb of the Loop of Henle, the ascending limb of the Loop of Henle, the collecting duct and the vasa recta in the previous diagram? Be able to explain these components in your discussion of this mechanism. Unit 1 - Objective 7
  57. 57. The Counter Current Mechanism We will begin our discussion of the counter current mechanism with the ascending limb of the loop of Henle (ALLH). This portion of the nephron reabsorbs chloride by active transport. As chloride moves from the filtrate it pulls along sodium into the interstitium of the medulla. The medulla then becomes very hyperosmotic Unit 1 - Objective 7
  58. 58. The Counter Current Mechanism As salt (NaCl) leaves the ALLH, the osmolarity of the fluid decreases from 1,200 to 100 milliosmoles/L (mOSM/L). This happens because the ALLH is impermeable to water. The net effect of this activity is to remove salt from the kidney filtrate and transfer it into the medulla where it can be saved for use by the body. Unit 1 - Objective 7
  59. 59. The Counter Current Mechanism The accumulated salt in the interstitium of the medulla acts as an osmotic force which can be used to “draw” and conserve water from other parts of the nephron: the decending limb of the Loop of Henle (DLLH) and the collecting duct. The DLLH is a thin passive segment that is permeable to water, but, impermeable to salt. Unit 1 - Objective 7
  60. 60. The Counter Current Mechanism As the DLLH gives up water to the medullary interstitium, the osmolarity of the fluid changes from 300 to 1,200 mOSM/L. The net effect of this process is to conserve water for the body. Thus, the loop of Henle actively transfers salt back into the kidney which can be used to save water osmotically. A remarkable process! Unit 1 - Objective 7
  61. 61. The Counter Current Mechanism The hyperosmotic interstitium of the medulla will also “pull” and conserve water from the collecting duct, but, on a variable basis depending on the availibility of ADH. As water moves from the collecting duct, urea will follow. Thus, as water is conserved at this level, a certain amount of urea is also conserved. The urea contributes to the high osmolarity of the medulla Unit 1 - Objective 7
  62. 62. The Counter Current Mechanism The availibility of Antidiurectic Hormone (ADH) is determined by dehydration and thirst. Under these conditions, the hypothalamus makes extra ADH and stores it in the posterior pituitary where it can be released. The increased release of ADH causes the “water pores” of of the collecting duct to open and allow water to move from the urine to the medulla. Unit 1 - Objective 7
  63. 63. The Counter Current Mechanism As water leaves the collecting duct, the urine becomes progressively more concentrate. The osmolarity of the collecting duct fluid will increase from about 150-300 to 1,200 mOsm/l. under these conditions. If ADH is not present, water is not conserved and is lost as part of a dilute urine (100 mOsm/l). Unit 1 - Objective 7
  64. 64. The Counter Current Mechanism The vasa recta is made up of a group of capillary like vessels and is freely permeable to salt and water. The vessels of the vasa recta roughly flow counter to the loop of Henle and acts as a counter current exchanger. As blood flows through the vasa recta it picks up water and leaves behind salt. Thus, the vasa recta returns conserved water back to the body and leaves the salt which maintains the hyperosmotic medulla. Unit 1 - Objective 7
  65. 65. Objective 8 Given the value for two of the following, you will compute the value for the third: Amount Filtered, Amount Reabsorbed and Amount Excreted. Unit 1 - Objective 8
  66. 66. Objective 8 The relationship between the variables of Objective 8 is as follows: Amount Excreted = Amount Filtered Amount Reabsorbed This equation signifies that if we take the difference between the filtration and reabsorption rate, we can determine how much of a substance the kidneys eliminate per unit of time. Unit 1 - Objective 8
  67. 67. Objective 8 If the kidneys filter 16 grams of NaCl per day and then reabsorb 14 grams of NaCl per day, then 2 grams of NaCl would be excreted or eliminated by the kidneys per day as part of the urine. Amount Excreted = Amount Filtered - Amount Reabsorbed 2 g NaCl/day = 16 g NaCl/day - 14 g NaCl/day Unit 1 - Objective 8
  68. 68. Objective 8 Examine the following and find the missing value: Amount Excreted = Amount Filtered - Amount Reabsorbed 1) ? = 100 g of glucose - 100 g of glucose 2) 100 g of glucose = ? 3) 100 g of glucose = 400 g of glucose - 300 g of glucose - ? Answers: (1)equals zero; (2) equals 400; (3) equals 300 Unit 1 - Objective 8
  69. 69. Objective 9 Given the concentration of a substance in the plasma and the amount of the substance excreted in the urine per minute, you will compute the plasma clearance rate. Unit 1 - Objective 9
  70. 70. Plasma Clearance Plasma clearance is defined as the amount of plasma that is cleared or “cleansed” of a particular substance in one minute. The kidneys will carry out this clearance process through the use of filtration, reabsorption and secretion. Unit 1 - Objective 9
  71. 71. Plasma Clearance Filtration will directly affect clearance. As filtration increases, more material will be removed from the blood plasma. Reabsorption will indirectly affect clearance. As reabsorption increases, less material will be removed from the blood plasma. Secretion will directly affect clearance. As secretion increases, more material will be removed from blood plasma. Unit 1 - Objective 9
  72. 72. Plasma Clearance The formula used to calculate plasma clearance is: C = V x U/P C = plasma clearance rate in ml/min V = urine production rate in ml/min U = the concentration of a substance in the urine in mg/ml P = the concentration of a substance in the plasma in mg/ml As you track the units in the equation, you will notice that mg/ml cancel out, leaving ml/min. Unit 1 - Objective 9
  73. 73. Plasma Clearance Let us practice calculating plasma clearance using the clearance equation. In all your calculations, assume that the urine production rate (V) is 2 ml/min. Let’s start with the substance inulin (not insulin!). If after a dose of inulin, your urine has 30 mg/ml and your plasma has 0.5 mg/ml of this substance, what is the inulin clearance rate? If you got 120ml/min, you are correct! Unit 1 - Objective 9
  74. 74. Plasma Clearance If you did not get 120ml/min, look at the following calculation and recheck your work. 120 ml/min = 2 ml/min x 30 mg/ml/ 0.5 mg/ml Unit 1 - Objective 9
  75. 75. Plasma Clearance Test your ability to conduct further calculations by calculating the clearance rate for the following substances: Substance Urine concentration Plasma concentration Urea 7.0 mg/ml 0.2 mg/ml Glucose 0.0 mg/ml 1.0 mg/ml Penicillin 298 mg/ml 0.7 mg/ml Remember that the urine production rate (2ml/min) will be the same for all of the above calculations. The clearance rate for each of the above substances will be: Urea = 70 ml/min; Glucose = 0 ml/min; Penicillin = 851 ml/min. Were you able to get the right answers? If not, go back and restudy the clearance process. Unit 1 - Objective 9
  76. 76. Objective 10 Give the cause and describe the disease process for the following: renal calculi (kidney stones); cystitis; gout; Glomerulonephritis (Bright’s Disease); incontinence. Unit 1 - Objective 10
  77. 77. Disorders of the Urinary System • Renal Calculi (kidney stones) – caused by the crystallization of calcium, magnesium or uric acid salts that precipitate in the renal pelvis. – If the calculi become large and travel down the ureter, they can cause excruciating pain which radiate from the flank to the anterior abdominal wall on the same side. Unit 1 - Objective 10
  78. 78. Disorders of the Urinary System • Cystitis – typically caused by bacteria from the anal region, but, can also be caused by sexually transmitted diseases and various chemical agents – can lead to inflammation, fever, increased urgency and frequency of urination and pain Unit 1 - Objective 10
  79. 79. Disorders of the Urinary System • Glomerulonephritis ( Bright’s Disease) – caused by inflammation of the glomeruli due to an abnormal immune response (autoimmune, streptococcal antibody complexes). – Inflammation of the glomeruli leads to faulty filtration (passage of blood cells and proteins) and possible kidney failure. Unit 1 - Objective 10
  80. 80. Disorders of the Urinary System • Incontinence – caused by loss of the ability to control voluntary micturition (releasing urine from the bladder) due to age, emotional disorders pregnancy, damage to the nervous system, stress, excessive laughing and coughing – leads to wetting of clothing, discomfort and embarassment Unit 1 - Objective 10
  81. 81. Objective 11 Describe the process involved in dialysis therapy. Unit 1 - Objective 11
  82. 82. Dialysis Therapy Dialysis is a process that artificially removes metabolic wastes from the blood in order to compensate for kidney (renal) failure. Kidney failure results in the rapid accumulation of nitrogen waste (urea, etc.) which leads to azotemia. Uremia and ion disturbances can also occur. This condition can cause acidosis, labored breathing, convulsions, coma and death. Unit 1 - Objective 11
  83. 83. Dialysis Therapy The most common form of dialysis is hemodialysis which uses a machine to transfer patient’s blood through a semipermeable tube that is permeable only to selected substances. The dialysis machine contains an appropriate dialysis fluid that produces a diffusion gradient. This gradient allows abnormal substances to diffuse from the patient’s blood and produce a “cleaning” effect. Unit 1 - Objective 11
  84. 84. Dialysis Therapy Some key aspects of hemodialysis are: - blood is typically transferred from an arm artery - after dialysis, blood is typically returned to an arm vein - to prevent clotting, blood is typically heparinized - dialysis sessions occur about three times a week - each dialysis session can last four to eight hours! - long term dialysis can lead to thrombosis (fixed blood clots), infection and death of tissue around a shunt (the blood access site in the arm) Unit 1 - Objective 11
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