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1

organs of the urinary system

1. kidneys
2. ureter
3. bladder
4. urethra

2

kidneys

filter blood

3

ureter

transports urine to urinary bladder

4

bladder

storage tank for urine

5

urethra
-definition
-length in female
-length in male

-conducts urine to outside
- 1-2 in long
- 7-8 in long

6

3 functions of the urinary system

1. excretion
2. elimination
3. homeostatic regulation

7

excretion

removal of organic waste products from body fluids

8

elimination

discharge of waste products into the environment

9

homeostatic regulation
-5

1. regulates blood vol and pressure
2. regulates concentration of plasma ions
3. helps stabilizes blood pH
4. helps conserve valuable nutrients
5. assists liver in detoxification

10

kidney
-location
-embedded in
-___ long, ___ wide, ___ thick

-posterior abdominal wall; behind the peritoneum (retroperitoneum)
-fat
- 4 in long, 3 in wide, 1 in thick

11

9 structures of the kidney

1. renal medulla
2. renal cortex
3. renal capsule
4. renal pyramid
5. renal papilla
6. renal columns
7. calyces
8. renal lobe
9. renal pelvis

12

renal capsule

CT covering

13

renal pyramid

triangular structures that make up the renal medulla

14

renal papilla

end of the pyramid

15

renal columns

extensions of the cortex between pyramids

16

calyces

cup shaped drain near papilla

17

renal lobe
-definition
-function

renal pyramid that is part of the renal column and renal cortex; functional unit
-produce urine

18

renal pelvis

connected to the ureter

19

what is the functional unit of the kidney

the nephron

20

nephron
-aka
-site of
-how many does each kidney had

-renal tubule
-urine production
- 1.25 x 10 ^6

21

8 nephron structures

1. renal corpsule
2. bowman's capsule
3. proximal convoluted tubule (PCT)
4. distal convoluted tubule (DCT)
5. collecting duct
6. loop of henle
7. descending limb of the loop of henle
8. ascending limb of the loop of henle

22

proximal convoluted tubule

reabsorption of H2O, ions and all organic nutrients

23

distal convoluted tubule
-2 functions

-secretion of acids, ions, drugs and toxins
-some reabsorption of H2O, Na+, and Cl- ions

24

collecting duct
-2 functions

1. some reabsorption of H2O
2. some secretion of Na+, K+, H+, and HCO3- ions

25

peritubular space
-definition
-contains

-area surrounding the nephron
-contains peritubular fluid

26

loop of henle

reabsorption of H2O, Na+ and Cl- ions

27

descending limb of the loop of henle

reabsorption of H2O

28

ascending limb of the loop of henle

reabsorption of Na+ and Cl-

29

renal corpuscle
-function
-what is it

produces filtrate
-Bowman's casule and glomerulus

30

2 types of nephrons in the kidneys

1. cortical nephron
2. juxtamedullary nephron

31

cortical nephron
-___ of all nephrons
-function

-85%
-performs most of the reabsorption and secretory functions of the kidney

32

juxtamedullary nephrons

enable kidneys to produce a concentrated urine

33

blood supply to the kidney

1. renal artery
2. segmental artery
3. interlobar artery
4. arcuate artery
5. interlobular artery
6. afferent arteriole
7. glomerulus
8. efferent arteriole
9. peritubular capillaries
10. vasa recta
11. interlobular vein
12. arcuate vein
13. interlobar vein
14. renal vein
15. inferior vena cava

34

where does blood enter the kidney from

the aorta

35

interlobar artery

between renal pyramids in renal columns

36

arcuate artery

boundary between cortex and medulla

37

interlobular artery

in the cortex of the renal lobes

38

afferent arteriole

brings blood into glomerulus

39

efferent arteriole

where blood exits the glomerulus

40

vasa recta
-location
-function

-juxtamedullary nephron
-modification to supply long loops of Henle

41

interlobular vein

blood returning to inferior vena cava

42

juxtaglomerular complex
-structures

1. macula densa
2. juxtaglomedullar cells
3. juxtaglomerular apparatus

43

macula densa

modified epithelial cells of the DCT

44

juxtaglomerular cells

modified smooth muscle cells in the afferent arteriole

45

function of the JGC
-type of structure
-2 functions

-endocrine structure
-1. hormone erythropoietin
2. renin enzyme

46

renin
-part of what
-function

-part of renin angiotensin system
- increases anti diuretic hormone and aldosterone release

47

what does increase antidiuretic hormone and aldosterone release do

-restricts H2O and salt loss at the kidneys, stimulates thirst and increase BP

48

factors stimulating renin release

1. sympathetic stimulation
2. decline in renal blood flow
3. decline in osmotic concentration of tubular fluid at macula densa

49

glomerular filtration
-definition
-driving force

movement of fluid across the wall of the glomerulus and into the capsular space
-BP

50

composition of filtrate

1. glucose
2. AA
3. Salts
4. H2O
5. dissolved gases
7. vitamins
8. urea
9. other drugs

51

3 layers for the filtration of plasma

1. capillary epithelium
2. basement membrane
3. filtration slits

52

filtration slits

allows only ions, nutrients, and AA to pass

53

glomerular filtration rate (GFR)
-definition
-average

-amount of filtrate the kidneys produce each min
-125 ml/min

54

controlling glomerular filtration rate
-3 mechanisms

1. autoregulation
2. hormonal regulation
3. autonomic regulation

55

auto regulation
-response to
-constriction of the efferent arteriole =
-constriction of the afferent arteriole =

-response to local changes in BP and flow to the glomerulus; changes in the diameters of the afferent arteriole, efferent arteriole and glomerular capillaries
-increase in BP in glomerulus
-decrease in BP in glomerulus

56

hormonal regulation
-2 components

-renin-angiotensin system
-atrial natiuretic peptide (ANP)

57

renin angiotensin system
-enzyme released in response to
-results in

-renin is released in response to decreased GFR
-activation of angiotensin

58

angiotensin

increases BP and blood vol

59

atrial natiuretic peptide
-secreted in response to

-increased blood vol in right atrium

60

increased blood vol in right atrium causes

dilation of afferent arteriole and constriction of efferent arteriole = increased GFR and decreased blood vol (bc of urine output)

61

autonomic regulation
-type of response
-causes

-sympathetic response
-causes
-constriction of afferent arterioles= decreased GFR

62

reabsorption at the PCT
-osmolarity
-1 mole of dissolved particles =
-body fluids =

-total number of solute particles in 1 liter
-1 osm/L = 1000 mosm/l
-300 mosm/l = isotonic

63

reabsorption at the PCT
-enter:
-osmolarity of filtrate entering the PCT
-osmolarity of tubular fluid exiting the PCT
-PCT will reabsorb ____ of filtrate vol

-filtrate from Bowmans's capsule
- 300 mosm/L
-300 mOsm/L
-60-70%

64

reabsorption in the loop of henle: descending limb
-definition
-enter
-osmolarity of tubular fluid entering the descending limb
-osmolarity of tubular fluid exiting the descending limb
-lumen of the nephron

-permeable to H2O but impermeable to solutes
-tubular fluid from PCT
- 300 mOsm/L
-1200 mOsm/L (at the bottom of the limb)
-contains tubular fluid from PCT

65

reabsorption in the loop of henle: ascending limb
-definition
-enter
-osmolarity of tubular fluid entering the ascending limb
-osmolarity of tubular fluid exiting the ascending limb
-lumen of the nephron

-impermeable to water and solutes contains active transport mechanisms to pump Na+ and Cl- of tubular fluid
-tubular fluid from the descending limb
-1200 mOsm/L
-100 mOsm/L
-tubular fluid from descending limb

66

the countercurrent mechanisms
-definition
-why does exchange occur
-2 functions

-mechanism for absorption along the loop of henle
-occurs because fluids are moving in opposite direction
-1. reabsorbs solutes and water before tubular fluid reaches DCT and CD
2. establishes a concentration gradient that helps reabsorbs H2O in DCT and CD

67

the countercurrent mechanisms
-descending limb
-ascending limb

-water moves out, solutes do not move
-solutes move out, water does not move

68

the countercurrent mechanisms
-where is Na+ Cl- pumped
-what does this do

-pumped into medulla
-helps establish a concentration gradient and used to concentrate urine in DCT and CD

69

reabsorption in the DCT and CD
-definition
-controlled by what
-osmolarity of tubular fluid entering the DCT/CD
-osmolarity of tubular fluid exiting the DCT/CD

-make final adjustments to composition and vol of urine
-hormones
-100 mOsm/L
-~800-1000 mOsm/L (largely through removal of water and retention of urea)

70

producing a concentrated urine
-what cannot be adjusted
-vol of H2O loss is dependent upon what
-controlled through
-what does ADH do
what does the hypothalamus do

-water reabsorption in PCT and descending limb
-upon reabsorption in DCT and CD
-ADH
-increases the permeability of DCT and CD to H2O
-secreates ADH through the posterior pituitary gland, continuosly at low levels

71

effects of ADH on urine concentration
-absence of ADH
-presence of ADH

-water is not reabsorbed in DCT and CD
-water is reabsorbed in DCT and CD

72

secretion at the PCT
-ions
-function

-primarily H+ ions
-helps to regulate pH of body fluids

73

secretion at the DCT
-ions/substances

1. K+
2. H+
3. creatine
4. ammonium ions
5. drugs
6. toxins

74

secretion at the CD
-ions

H+ and HCO3-

75

micturition reflex and urination
-function
-stimulus
-reflex begins
-response

-controls the process of urination
-stretch receptors in wall of urination
-begins when bladder has ~200 ml of urine
-voluntarily relax of external sphincter which causes relaxation of internal urethral sphincter

76

micturition reflex and urination
-where is sensation delivered to

cerebral cortex and become aware of fluid pressure in bladder

77

incontinence

inability to control urination voluntarily