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Flashcards in Downing: Urinary System Deck (83):
1

What are the components of the urinary system?

Kidneys
ureters
urinary bladder
urethra

2

What are the functions of the urinary system?

1. Eliminate UREA and NITROGENOUS waste
2. Maintain FLUID blance
3. Maintain SALT balance
4. Control acid-base balance
5. ENDOCRINE fxn

3

How mechanisms does the kidney use to carry out its functions?

1. filtration of blood plasma
2. passive diffusion
3. active secretion
4. selective reabsorption
5. exchange of hydrogen ions/formation of ammonia through acid-base regulation

4

What are the three layers of the capsule? What are their characteristics?

Innermost- capsule covers surface of kidney
middle- thick layer of fat
outermost- ct which binds kidney to surface structures

5

What passes through the hilus?

Renal artery
renal vein
nerves and lymphatics

6

What does the cortex contain?

renal corpuscles
medullary rays

7

What does the medulla contain?

6-18 pyramids (base lies adjacent to cortical tissue; tips (renal papillae) point towards minor calyces of renal pelvis

8

What is the area cribrosa?

Tip of the papilla
Perforated by 10-25 small openings where hte terminal segments of the uriniferous tubules open into the minor calyx

9

What are the renal columns?

Cortical substance that extends BETWEEN the medullary pyramids

10

What is the renal sinus?

Cavity/potential space occupied by:
Renal pelvis
major and minor calyces
AVNL
LCT/fat

11

What does a kidney lobe consist of?

Medullary pyramid and surrounding cortical tissue

GROSSLY visible

12

What does a kidney lobule consist of?

Straight tubules in a medullar ray and the cortical substance immediately surrounding the tubules.

MICROSCOPICALLY visible

13

What does the parenchyma consist of?

uriniferous tubules and blood vessels

14

What does a nephron do?

forms urine

15

What are the two layers of bowmans capsule?

Parietal layer (capsular epithelium)
Visceral layer (glomerular epithelium)

16

Where is the parietal layer in bowmans capsule and what is it composed of?

Simple squamous

Begins where visceral layer is reflected at the vascular pole and is continuous with the proximal convoluted tubule at the urinary pole

17

What ishte visceral layer composed of?

PODOCYTES that are closely applied to the GLOMERULAR endotehlium (separated only by a thick basal lamina)

18

What are the two distinct poles of bowmans capsule?

1. vascular (eff and aff arterioles enter and exit)
2. Urinary (parietal epith is continuous with cuboidal epith of prox CT)

19

What is the capsular space in bowmans capsule?

Lumen of hte tubule between the visceral and parietal epithelial layers.

20

Where does glomerular filtrate originally enter?

Capsular space (continuous with lumen of the proximal convoluted tubule)

21

What is the glomerulus?

Arterial vascular aparatus

Aff arterioles> fenestrated capillaries> capillaries reunite and form the eff arteriole

22

What composes the visceral epithelial layer of bowmans capsule?

Podocytes

23

What are hte components of a podocyte?

1. Primary processes
2. Secondary processes- interdigitate w/ elements of corresponding processes and surround the basal lamina of capillary endotehlium. Creates slit pores).

24

What are the components of the filtration apparatus?

1. Capillary endotehlium (fenestrated capillaries)
2. Basal lamina (find proteins and glycoprotein matrix)
3. Slit pores (between adjacent interdigitating foot processes of podocytes)

25

How do the endothelial pores act as a barrier in the filtration apparatus?

Stop CELLULAR components of blood and large particles of plasma

26

How does the basal lamina act as a barrier in the filtration apparatus?

1. holds back LARGE molecules
2. Hold back some CHARGED molecules

27

What are mesangial cells?

Similar to a pericyte--occur where adjacent capillaries are close together so that podocytes can't totally surround them

28

What do mesangial cells do?

1. keep glomerular filter free of debris
2. provide support where basement membrane is lacking
3. basement membrane turnover

29

What makes up the bulk of the renal cortex?

Proximal convultuted tubule and proximal straight tubule

30

What are tubules comprise of?

Simple high cuboidal OR
two columnar epitheliium

31

How is the cytoplasm of cells comprising the tubules unique?

More acidophilic than other tubules

32

What is seen on electron microscopy of proximal tubules?

1. BRUSH BORDER (closely packed microvilli)- FUZZY
2. Apical canaliculi
3. Lateral cell membranes are highly folded
4. MITOCHONDRIA in basal half of cell
5. Basal processes of cells undermine each other and make it look like there is extensive infolding (striations)

33

What percent of water and NaCL is reabsorbed from the tubule?

65%

Na is ACTIVELY transported out, Cl and water follow

34

What else is reabsorbed in the tubule?

Glucose and amino acids
Proteins via pincocytosis

35

What happens to the epithelium in the thin segment of the loop of Henle?

1. APRUPT change from simple cuboidal to SIMPLE SQUAMOUS
2. Brush border stops
3. Nuclei bulge into lumen of the tubule

36

What surrounds the thin segment of the loop of Henle?

Capillares- vasa recta
Efferent vessels of the juxtamedullary glomeruli

37

What happens to the epithelium of the distal straight tubule (thick segment)?

1. EpithelIum becomes SIMPLE CUBOIDAL
2. LESS acidophilic
3. LARGE LUMEN than proximal
4. MORE NUCLEI seen around circumference of tubule.

38

What is the macula densa?

Eliptical disc of elongated cells in wall of ascending limb where it contacts the afferent arteriole

39

Where does the distal convoluted tubule begin?

At the vascular pole of the renal corpuscle

40

How does the distal convoluted tubule differ from the proximal tubules?

Less acidophilic

(similar to ascending thick segment)

41

What does ADH do in the distal convoluted tubule?

INCREASES permeability of cells to water>
forms concentrated urine

42

What does hte arched region of the collecting tubule do? Where is it?

Cortical location

Receives urine from distal convoluted tubule

43

What does the straight region of the collecting tubule do? Where is it?

Medullary rays and medulla

Unites with adjacent tubules as they run toward hte renal papillae>
form larger collecting ducts called papiallry ducts

44

What do papillar ducts do?

Open on the area cribrosa at the apex of each papila

45

What is the epithelium of the collecting tubules?

Simple cuboidal to low columnar

46

What are the two types of cells in the epithelium of collecting tubules?

1. Light cells (CD cells)
2. Dark cells (IC cells)

47

Which cells of the collecting tubules play a role in acid base balance by resorption/secretion of bicarbonate and acid?

Dark cells

48

Describe the nuclei and cytoplasm of a collecting tubule.

Nuclei- one level
cytoplasm- clear/light staining

49

What is the function of the collecting tubule?

Water resorption (ADH)
Acid base balance

50

What are the juxtaglomerular cells?

Specialized cells
Wall of AFF arteriole (among smth muscle cells)

51

What do juxtaglomerular cells contain?

renin

52

What is the macula densa?

Densely packed cells of the distal tubule

53

Where is the macula densa located?

Adjacent to juxtaglomerular cells at the vascular pole

54

Where are extraglomerular mesangial cells located?

In the angle between aff and eff arterioles at vascular pole of the glomerulus

55

What is the function of the juxtaglomerular apparatus?

Maintain BP

56

How does the JGA maintain bp

Decrease in BP>
less stretch>
JG cells secrete renin

Jg cells respond to FALLING bp

57

What does the macula densa do in the distal tubule?

Monitors the NA concentration

58

What happens to Na when there's low BP?

Decrease BP>
Decrease in plasma Na conc>
low plasma Na>
renin release

59

What does angio II do directly?

Constricts arterioles> increased BP

60

What does angio II do indirectly?

Stimulates zona glomerulosa of adrenal cortex> release aldosterone> distal kidney tubles> Na/Water resorption> increased BP

61

Describe the arterial blood supply.

Renal artery>
interlobar aretery>
arcuate artery>
interlobular artery>
aff arteriole>
glomerular capillaries>
eff arteriole

62

Describe the path from the juxtamedullary glomeruli to the renal vein.

Juxtamedullary glomeruli>
vasa recta>
arcuate vein>
interlobar vein>
renal vein

63

Describe the path from the juxtacapsular or mid cortical glomeruli to the renal vein.

Juxtacapsular glomeruli>
cortical peritubular capillary network>
justacapsular region>
stellate veins>
interlobular veins>
arcuate veins>
interlobar vein>
renal vein

64

What are the two types of vasa recta?

1. Arteriolae rectae (descending vessels, CONTINUOUS epithelium)

2. Venae rectae (ascending vessels, FENESTRATED epithelium)

65

What is the nerve supply to the kidneys?

SNS> vasoconstriction

66

How does constriction of afferent arterioles affect filtration rate/urine production?

REDUCES filtration rate and DECREASES urine production

67

How does constriction of efferent arterioles affect filtration/urine prodution?

INCREASES filtration and INCREASES urine production

68

What does a loss of SNS innervation do?

Leads to increased urinary output

69

Is extrinsic nerve supply essential for normal renal function?

NO- transplanted kidneys function normally

70

What are the characteristics of the mucosa of the ureter?

1. Epithelium (transitional)
2. Basement membrane
3. lamina propria- well developed

71

What are the 4 layers of the ureter?

Mucosa
submucosa
muscular coat
adventitia

72

Describe the muscular coat of the ureter.

Upper 2/3- two layers of smooth muscle (inner-longitudinal, outer- circular)

Lower 1/3 (outer, longitudinal)

73

How do peristlatic waves affect the ureter?

Move urine down from renal pelvis to bladder

74

What is the adventitia of the ureter composed of?

Fibroelastic CT
Rich blood supply/lymphatic vessels
nerve plexuses (some sensory fibers)

75

What are the 4 layers of the urinary bladder?

Mucosa
submucosa
uscular wall
adeventitia

76

What are the 3 layers of the mucosa?

1. Epithelium (transitional)
2. basement membrane
3. lammina propria

77

What are the three distinct layers of the muscular coat of the bladder?

1. inner longitudinal
2. middle circular
3. outer longitudinal

78

What forms the internal urethral sphincter?

The middle circular layer of hte muscular coat ( thickened around orifice of the urethra)

79

What forms the adventitia of the bladder?

fibroelastic tissue

80

What plexus innervated the bladder?

Sympathetic

Sends numerous fibers into muscular coat

81

HOw long is the female urethra?

short (2-3 cm)

82

What are the components of the female urethra?

1. Mucosa (transitional near bladder and stratified squamous the rest of hte way)
2. muscular wall (primarily smooth muscle w/ some mixing with skeletal at end)

83

What are the three parts of the male urethra?

LONG 18-20 cm

1. Prostatic portions (transitional epi)
2. membranous portion (stratified columnar)
3. Cavernous portion (stratified columnar but becomes stratified squamous at end)