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Flashcards in Urinary System Deck (98):
1

List the functions of the kidneys

1. regulation of fluid, volume, ion concentration, and acid-base balance
2. excretion of metabolic toxins, and drugs
3. Hormone production
4. metabolic function (vitamin D to active form)

2

What are the three layer of supportive tissue in the kidney? Function of each?

1. Renal fascia- anchors
2. Perirenal fat capsule- provides cushion
3. Fibrous capsule- limits spread of infection

3

What are the 2 regions of the kidney?

renal cortex and renal medulla

4

List the sequence of urine flow

renal pyramid -> minor calcyx -> major calycx -> renal pelvis -> ureter

5

Empty into inferior vena cava

Renal veins

6

Deliver 1/4 total cardiac output to kidneys each minute

renal arteries

7

Structural and functional unit of kidney

Nephron

8

What are the main parts of a nephron?

renal corpuscle and renal tubule

9

What are 2 parts of a renal corpuscle?

glomerulus and glomerular capsule

10

Collects filtrate

glomerular capsule

11

forms filtrate

glomerulus

12

What are the 2 layers of a glomerulus capsule?

parietal and visceral layer

13

What is the parietal layer composed of in the glomeruluar capsule?

simple squamous epithelium

14

Where are podocytes located in the nephron?

in the visceral layer of the glomerular capsule

15

What are the 3 parts of the renal tubule?

PCT, loop of Henle, and DCT

16

Cuboidal epithelial cells with dense microvilli and confined to cortex

PCTq

17

Descending and ascending limbs

loop of Henle

18

Cuboidal cells with few microvilli and confined to cortex

DCT

19

Receives filtrate from many nephrons and delivers urine into minor calcyes

collecting ducts

20

What are the 2 classes of nephrons?

cortical and juxtamedullary

21

Which class of nephron extends deep into medulla?

juxtamedullary

22

Which class of nephrons is 85% of nephrons?

cortical

23

What is related to the length of the loop?

urine concentration

24

List the sequence of the nephron capillary bed?

renal artery -> afferent arteriole -> glomerulus efferent arteriole -> peritubular capillaries -> renal vein

25

How does the glomerulus differ from all other capillary beds?

fed and drained by arterioles and high BP (55 mmHg)

26

Adapted for absorption of water and solutes and low pressure

peritubular capillaries

27

Long, straight vessels that supple loops of Henle of juxtamedullary nephrons

vasa recta

28

Region where distal portion of ascending limb LOH lies against afferent arteriole

Juxtaglomerular complex (JGC)

29

What are the 2 major cell populations in the JGC?

macula densa and granular cells

30

Chemoreceptors that monitor NaCl content of filtrate in the ascending limp of LOH

macula densa

31

Mechanoreceptors that monitor BP in afferent arterioles in the walls of afferent arteriole

granular cells

32

In order what are the 3 processes of urine formation?

1. Glomerular formation
2. Tubular reabsorption
3. Tubular secretion

33

Movement of water and solutes from glomerular capillaries into glomerular capsule

Glomerular formation

34

Movement of substances from blood into filtrate

Tubular secretion

35

Movement of water and solutes from filtrate back into blood

Tubular reabsorption

36

Everything in blood plasma except proteins

filtrate

37

Water and unneeded substances

Urine

38

Hydrostatic pressure forces fluids and solutes through a?

filtration membrane

39

What are the 3 layers of the filtration membrane?

1. fenestrated endothelium of glomerular membrane
2. Basement membrane
3. foot processes of podocytes of glomerular capsule

40

What is the size molecules can be and cannot be to pass through the filtration membrane?

molecules 5 nm are not filtered (blood cells and plasma proteins)

41

Pressure exerted by filtrate in capsule

hydrostatic pressure in capsular space

42

pressure exerted by proteins in blood

colloid osmotic pressure in glomerular capillaries

43

Volume of filtrate formed per minute by both kidneys and directly proportional to NFP

Glomerular filtration rate (GFR)

44

What are the 2 controls that regulate GFR?

1. Renal autoregulation (intrinsic)
2. Extrinsic controls

45

Ability of kidney to maintain constant GFR despite fluctuations in systemic BP

Renal autoregulation

46

What are the two ways the kidneys undergo renal autoregulation?

myogenic mechanism and tubuloglomerular feedback mechanism

47

How does myogenic mechanism bring GFR back to normal?

When BP is high, vasoconstiction occurs lowering GFR

When BP is low, vasodilation occurs increasing GFR

48

Describe the tubuloglomerular feedback mechanism

when GFR increases NaCl concentration increases in filtrate due to insufficient reabsorption time

49

What detects elevated NaCl levels and release signaling molecules?

macula densa cells

50

What is the goal of the extrinsic control of the kidneys?

to maintain systemic BP

51

hWhat are the 2 ways the kidneys show extrinsic control?

sympathetic nervous system controls and renin-angiotensin-aldosterone mechanism

52

Strong sympathetic activation constricts afferent which decrease GFR which

sympathetic nervous system controls

53

When BP drops granular cells of JGC release renin

renin-angiotensin-aldosterone mechanism

54

Movement of water and solutes from renal tubule into blood

Tubular reabsorption

55

What are the 2 way tubular reabsorption occurs?

transcellular (through tubule cells)

paracellular (between tubule cells)

56

Which substances are reabsorbed by secondary active transport?

glucose, aa, some ions and vitamins

57

Active transport Na+ creates strong osmotic gradient therefore reabsorbed by osmosis via

aquaporins

58

Nearly every substance reabsorbed using a transport protein

transport maximum

59

Site of most reabsorption

PCT

60

What is the ascending and descending limo permeable and impermeable to?

Ascending: permeable to NaCl and impermeable to H20

Descending: permeable to H2O and impermeable to NaCl

61

Plays key role in kidney's ability to form dilute or concentrated urine

loop of Henle

62

Reabsorption is adjusted by which hormone in the DCT and collecting duct

ADH, ANP, PTH, and aldosterone

63

What does ADH target?

collecting duct to promotes insertion of aquaporins into apical membrane

64

What does aldosterone target?

DCT and collecting duct to promote synthesis of apical NA+ and K+ channels and NA+/K+ pumps

65

What does ANP target?

Collecting Duct to inhibit reabsorption of NA+ when BP or BV rise

66

What does PTH target?

DCT

67

Movement of selected substances from blood into filtrate

Tubular secretion

68

Concentration of solute particles

Osmolality

69

Kidneys maintain osmolality of plasma at what and how?

300 mOsm by regulating urine concentration and volume

70

Occurs when fluid flows in opposite directions in adjacent segments of same tube connected by hairpin

countercurrent mechanism

71

Interaction of filtrate flow in ascending/descending limbs of LOH of juxtamedullary nephrons

conuntercurrent multiplier

72

Blood flow in adjacent parallel sections of vasa recta

countercurrent exchanger

73

Establish and maintain osmotic gradient from cortex to medulla and allow kidneys to vary urine concentration

countercurrent mechanism

74

In conuntercurrent multiplier, in which limb does interstitial fluid osmolality increase and filtrate osmolality decreases?

Ascending limb

75

In conuntercurrent multiplier in which limb does filtrate osmolality increase?

Descending limb

76

Where does countercurrent exchanges occur?

between each section of vasa recta and surrounding interstitial fluid

77

What is vasa recta permeable to?

H2O and NaCl

78

How does the vasa recta preserve medullary gradient?

1. Preventing rapid removal of salt from interstitial space

2. Removing reabsorbed water

79

What does collecting use to raise urine concentration above 300 mOsm to conserve water?

osmotic gradient

80

What is the pathway when overhydrated?

There is no ADH available so
1. Decrease in osmolality of ECF
2. Decrease of ADH from posterior pituitary
3. Decrease number of aquaporins in collecting ducts
4. Decrease in H2O reabsorption from collecting ducts
5. Large volume of dilute urine

81

What is the pathway when dehydrated?

There is maximal amount of ADH
1. Increase of osmolality of ECF
2. Increase of ADH release from posterior pituitary
3. Increase number of aquaporins in collecting duct
4. Increase of H2O absorption from collection ducts
5. Small volume of concentrated urine

82

List the physical characteristics of urine
Color? Odor? pH?

Color: Clear, pale to deep yellow due to urochrome

Odor: slightly aromatic when fresh and develops ammonia odor upon standing

pH: average 6.0 (4.5-8)

83

Which solutes are present in urine?

urea, uric acid, and creatinine

84

What are some abnormal constituents of urine?

glucose, proteins, ketone bodies, Hb, bile pigments, RBCs, and WBCs

85

Transports urine from kidneys to bladder and run obliquely through posterior bladder wall

Ureters

86

What are the 3 layers of the ureters?

mucosa, muscularis, adventitia

87

How does urine flow through the ureters?

peristaltic waves push urine toward bladder

88

muscular sac for temporary storage of urine

urinary bladder

89

Smooth, triangular area outlines by penings for 2 ureters and urethra

trigone

90

What is significant about the trigone?

site where infections tend to persist

91

What are the 3 layers of the urinary bladder?

mucosa, detrusor muscle, and adventitia

92

What is the maximum value of urine in the bladder?

800-1000 mL

93

Muscular tube from bladder to body exterior opens to outside at external urethral orfice

urethra

94

Smooth muscle portion of the urethra

internal urethral sphincter

95

Skeletal muscle portion of the urethra

external urethral sphincter

96

What are 3 parts of the male urethra?

prostatic. membranous, and spongy

97

Which 2 events occur simultaneously during micturition?

1. Destrusor muscle contracts
2. Internal urethral sphincter relaxes
3. External urethral sphincter relaxes

98

Lack of voluntary control over micturition

incontinence