Kidney Anatomy, Embryology and Physiology Flashcards Preview

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Flashcards in Kidney Anatomy, Embryology and Physiology Deck (137)
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1

which horizontal plane crosses both kidneys?

Transpyloric plane

2

at which vertebral level does the transpyloric plane lie?

L1

3

what vertebral levels do the kidneys occupy?

T12-L3

4

at which vertebral level do the renal arteries come off the abdominal aorta?

L1-L2

5

what are the relations of the R kidney from top to bottom?

- R adrenal gland
- liver
- duodenum
- ascending colon
- jejunum/ileum

6

what are the relations of the L kidney from top to bottom?

- L adrenal gland
- spleen
- stomach
- pancreas
- small intestine
- descending colon

7

what are some of the main structures that the transpyloric plane passes through?

- kidney hilum (L and R)
- pylorus of stomaach
- neck of pancreas
- start of duodenum and duodenal flexure
- start of superior mesenteric artery
- end of spinal cord

8

what are the posterior relations of both kidneys?

- psoas major muscle
- quadratus lumborum muscle
- diaphragm

9

what are the 5 segments of each kidney?

- A: apical
- AS: antero-superior
- AI: antero-inferior
- I: inferior
- P: posterior

10

what are the different layers and coverings around the kidney, in their exact order?

- renal capsule
- perirenal fat
- renal fascia
- pararenal fat

11

what is the renal fascia made up of and what is its purpose?

fibrofatty tissue, attaches the kidneys to the anterior body wall

12

what is the purpose of the peri and pararenal fat?

protection for kidneys

13

what are the main structural areas in the kidney?

cortex and medulla

14

what structures are found in the cortex of the kidney?

renal corpuscles, proximal and distal convoluted tubules

15

what are the renal corpuscles composed of?

glomerulus + Bowman's capsule

16

histologically, how can the kidney cortex be identified?

through the presence of renal corpuscles and convoluted tubules

17

what structures are found in the medulla of the kidney?

Loops of Henle and collecting ducts

18

what constitutes a nephron?

collection of renal corpuscles and convoluted tubules (+loop of Henle)

19

why is the right kidney lower than the left kidney?

because the liver takes up the space higher up

20

in what order do the main structures enter and exit the hilum of the kidney?

- renal vein
- renal artery
- renal pelvis/ureter

21

how are the kidneys peritonised?

retroperitoneal, but covered by peritoneum in the areas which come into contact with peritonised structures (eg liver, small intestine, stomach and spleen)

22

what is another name for the renal fascia?

Gerota's fascia

23

what are two common congenital anomalies in the kidneys?

- double ureter
- horseshoe kidney

24

in the kidney, what is the name for the areas of cortex that project towards the hilum of the kidney?

renal columns

25

what are the areas of renal medulla in between renal columns called?

pyramids

26

what structures are contained in renal pyramids?

loops of Henle and collecting ducts

27

what is the course of waste products from the collecting ducts in the kidney to the ureters?

- pyramids to minor calyces (through papillae)
- minod calyces to major calyces
- major calyces to renal pelvis
- renal pelvis to ureter

28

how is the renal medulla arranged structurally?

in pyramids containing loops of Henle and collecting ducts, sitting in between renal columns

29

what are the layers of Bowman's capsule?

parietal and visceral layers of Bowman's capsule

30

what is found between the visceral and parietal layers of Bowman's capsule, and what is contained in it?

Bowman's space - contains filtered plasma from the blood in the glomerulus

31

what is found inside each Bowman's capsule in the kidney?

glomerulus

32

what are the important areas of narrowing in the course of the ureters, and why are they relevant?

1. narrowing at renal pelvis; 2. crossing over the iliac arteries; 3. narrowing at urinary bladder
- common areas of obstruction for renal calculi

33

which blood vessel coming from the kidney passes in front of the abdominal aorta?

left renal vein

34

what are the four main structures in the urinary system?

- kidneys
- ureters
- urinary bladder
- urethra

35

what are the 5 main functions of the urinary system?

- excretion of waste products through plasma filtration
- reabsorption of important molecules
- plasma electrolyte and BP control (through RAAS)
- pH control
- erythropoietin production

36

which nerves are closely related to the posterior aspect of the kidney?

- 12th subcostal nerve
- iliohypogastric nerve
- ilioinguinal nerve

37

which blood vessel coming up from the pelvis drains into the left renal vein?

left testicular vein

38

where do the testicular veins drain?

R into IVC
L into L renal vein

39

what structures pass over the ureter in males and females?

males: vas deferens
females: uterine/ovarian vein

40

what is the blood supply to the kidneys?

renal arteries

41

what happens to the renal artery once it reaches the hilum of the kidney?

it divides in 5 segmental branches

42

how are the segmental branches of the renal artery arranged in the kidney?

interlobar branches, arcuate branches and interlobular branches

43

what is the name for the branches of the renal arteries that supply individual nephrons?

interlobular branches

44

what blood vessels drain the kidneys?

renal arteries

45

where does the nerve supply for the kidneys come from?

sympathetic: T12-L1
parasympathetic: S2-S4
afferent sensory: T12-L2

46

which lymph nodes drain the kidney?

left lateral aortic lymph nodes
right lateral caval lymph nodes

47

what type of tissue makes up the majority of the urinary bladder wall?

smooth muscle

48

what is the name of the smooth muscle found in the urinary bladder?

detrusor muscle

49

what is the trigone of the urinary bladder?

a flat area of the bladder found between the openings of the ureters and the opening of the urethra

50

what type of epithelium covers the urinary bladder and the ureters?

transitional epithelium

51

what is the characteristic of transitional epithelium?

it's able to expand as necessary whilst being very tightly arranged to keep urine in

52

on which aspect of the bladder are the ureteric and urethral openings found?

ureteric - posterior
urethral - inferior

53

what attaches the apex of the bladder the anterior body wall?

median umbilical ligament

54

what is the embryonic derivation of the median umbilical ligament?

embryonic urachus (remnant of allantois)

55

how is the urinary bladder peritonised?

only superior surface peritonised

56

what is the recto-uterine pouch, other names for it and what is its clinical significance?

aka Douglas' pouch;
lowest fold of peritoneum, found between the bladder and the rectum;
common spreading site for pus, infection and tumours, and can be used in peritoneal dialysis

57

which sex has a longer urethra?

males have a longer urethra

58

what are the four sections of the male urethra?

- preprostatic (intramural)
- prostatic
- membranous (intermediate)
- spongy (penile)

59

what is the longest section of the male urethra?

the spongy/penile part

60

what is the widest section of the male urethra?

the prostatic part

61

what is the narrowest section of the male urethra?

the membranous part

62

in the female urethra, what is the nerve supply of the internal and external urethral sphincter?

external urethral sphincter: somatic control, S2-S4
internal urethral sphincter: sympathetic control, T12-L1

63

what is the nerve supply of the detrusor muscle?

parasympathetic control: pelvic splanchnic nerves (S2-S4)
sympathetic control (T10 - L2)

64

what is found at the beginning of the spongy part of the male urethra?

opening of the ejaculatory duct

65

what is the average length of the male urethra?

18-20cm

66

what fibres carry pain sensation from the urinary bladder?

parasympathetic fibres (S2-S4)

67

what is the name of the somatic nerve supply to the urinary bladder?

pudental nerve (S2-S4)

68

what is the blood supply and drainage of the urinary bladder?

branches of the internal iliac arteries and veins

69

where does the lymphatic drainage of the urinary bladder go to first?

internal and external iliac lymph nodes

70

why does the sympathetic system control the internal urethral sphincter?

because it also controls ejaculation, therefore in males it can block off the bladder from the urethra to allow for ejaculation from the ejaculatory duct

71

what happens to the male urethra in the prostatic part?

it is joined by the ejaculatory duct

72

what is the ejaculatory duct made up of?

vas deferens + seminal vesicle

73

which nerve causes detrusor muscle contraction during urination?

parasympathetic nerves from S2-S4

74

what is the uriniferous tubule made up of?

nephron + collecting duct

75

which types of cells make up the parietal and visceral layers of Bowman's capsule?

parietal layer: simple squamous epithelium
visceral layer: podocytes

76

on a histological slide, how can a ureter be identified?

it looks like a circular tube with a star-shaped lumen with transitional epithelium and smooth muscle

77

what are the main physiological processes involved in the kidneys?

- filtration
- reabsorption
- secretion
- excretion

78

what is the average percentage of blood volume that is distributed to the kidneys?

20-25%

79

what is the average GFR for kidneys?

125ml/min

80

what percentage of renal blood flow is filtered through the glomeruli into Bowman's capsule?

19%

81

what basic physical principles govern the glomerular filtration rate?

Starling forces: hydrostatic and oncotic pressure

82

how does each Starling law affect the movement of plasma in and out of the nephron?

hydrostatic forces - promote filtration
oncotic forces - promote reabsorption

83

what are the three layers in the glomerulus which assist the highly controlled filtration of substances?

- fenestrated endothelium of capillary
- basal lamina of capillary
- slit membrane of podocyte

84

what are the structural and functional characteristics of the afferent and efferent arterioles in the glomerulus?

afferent arteriole: wide and short (high pressure, low resistance)
efferent arteriole: narrow and long (low pressure, high resistance)

85

which Starling force is highest at the glomerular capillaries?

hydrostatic pressure

86

how does the shape/size of the glomerular afferent and efferent capillaries affect filtration?

increased resistance of the efferent arteriole, added to the high pressure from the wide/short afferent arteriole, contribute to maintaining increased hydrostatic pressure in the glomerular capillaries, promoting filtration into Bowman's space

87

what is the only physical mechanism which occurs at the glomerulus of the kidney?

filtration

88

what are the extrinsic factors that affect GFR?

- sympathetic system
- circulating catecholamines
- angiotensin II

89

how does the sympathetic system affect GFR?

constricts afferent and efferent arterioles
has higher sensitivity for afferent arterioles

90

how do circulating catecholamines affect GFR?

constrict mainly afferent arterioles

91

how does angiotensin II affect GFR?

- constricts efferent arterioles if glomerular pressure too low
- constricts efferent and afferent arterioles if glomerular pressure too high

92

what is the intrinsic action of the kidneys to autoregulate the GFR?

automatic afferent arteriole constriction if MAP rises too much, and dilatation if MAP drops

93

at which range of MAP does autoregulation of GFR work best?

between 60-130mmHg

94

why is autoregulation of GFR important?

because it acts independently of neural or hormonal input

95

below what blood pressure does GFR stop altogether?

below 50mmHg

96

how would a haemorrhage affect GFR?

during a haemorrhage, extrinsic control of GFR would override autoregulation of the glomerular activity, therefore reducing blood flow to the kidney and redirecting it to more immediately important organs

97

how do peritubular capillaries promote reabsorption?

through being long and narrow they maintain high resistance, therefore causing a drop in hydrostatic pressure which then becomes lower than oncotic pressure, driving molecules back into the capillaries

98

why is oncotic pressure higher in peritubular capillaries?

because 20% of plasma has been filtered into Bowman's capsule, therefore there is a higher concentration of plasma proteins in the peritubular capillaries drawing fluid back in

99

what are the two main forces causing reabsorption in the nephron, and how do they achieve it?

- reduced hydrostatic pressure due to long narrow peritubular capillaries
- increased oncotic pressure due to filtered plasma causing high plasma protein concentration left over in capillaries

100

what facilitates reabsorption of substances from the renal convoluted tubules?

through carrier mediated transport mechanisms (eg ion channels and carrier proteins)

101

what determines the amount of particles that are reabsorbed from the kidney tubules?

the maximum transport capacity (Tm)

102

what is the renal threshold?

plasma threshold at which saturation of transport molecules occurs

103

how do the kidneys ensure that valuable molecules (eg glucose and amino acids) are always reabsorbed in full?

Tm threshold for that molecules is higher than its average plasma concentration

104

how do the kidneys regulate the amount of plasma phosphate and potassium?

they have a Tm threshold equal to the normal plasma concentration of potassium and phosphate, therefore any excess amount is not reabsorbed after filtration

105

where does the majority of sodium transport occur in the kidney?

in the proximal convoluted tubule

106

what mechanisms are used for sodium reabsorption from the kidney tubules?

active transport out of tubular cells
passive transport from tubule into tubular cells

107

how does PTH reduce reabsorption?

through reducing the amount of available transport channels

108

what happens to other molecules as a result of active sodium transport out of the tubules?

chloride and water follow out of the tubule

109

how is glucose transport dependent on sodium transport out of the renal tubules?

glucose is transported into the tubule cells through SGLT, which is a symport molecule which only transports glucose in presence of sodium

110

how are the kidneys able to excrete drug and toxic metabolites?

because the carrier transporters in the tubule cells are not very specific, so drugs and toxins fit into the same transporters that allow other organic molecules through

111

where in the nephrons does secretion of toxic metabolites occur?

in the proximal tubule

112

how is the reabsorption of sodium in the proximal tubule of the nephron increased?

by increasing surface volume with lots of villi, and large numbers of sodium channels

113

where is the majority of potassium reabsorbed from the nephron?

in the proximal tubule

114

where does most secretion of electrolytes occur in the nephron?

in the distal tubule

115

what does the secretion of potassium depend on in the tubule?

depends on the levels of potassium in the tubular cells

116

what is the basic principle of the counter current multiplier in the loop of Henle?

removal of sodium from ascending limb
removal from water at descending limb

117

what is the range of osmolarity in the renal medullary interstitium from the top of the loop of Henle to the deepest part?

300mOsm - 1200-1400mOsm

118

where is the loop of Henle permeable to water in the loop of Henle?

in the descending part

119

how does loss of sodium at the ascending limb of the loop of Henle affect the filtrate?

renders it more diluted

120

what is the osmolarity of filtrate when it reaches the distal tubule?

it's hypo-osmotic - 100mOsm

121

what is the overall purpose of the counter current multiplier in the loop of Henle?

it maintains a steep osmotic gradient for concentration of filtrate

122

what is the maximum osmotic difference achieved as the filtrate progresses down the loop of Henle?

200mOsm difference at a time

123

what types of channels are present or lacking in the descending limb of the loop of Henle?

lots of aquaporin channels, few sodium chloride channels

124

what types of channels are present or lacking in the ascending limb of the loop of Henle?

lots of sodium chloride channels, very few aquaporin channels

125

what is the main determinant of the counter current multiplier system?

sodium chloride reabsorption at the ascending limb

126

where in the hypothalamus is ADH secreted?

supraoptic (SO) and paraventricular (PVN) nuclei

127

what controls the release of ADH from the posterior pituitary?

osmoreceptors with stretch-sensitive ion channels in hypothalamus

128

what triggers the release of ADH from the posterior pituitary?

increase in plasma osmolarity

129

how does ADH promote reabsorption of water from the collecting duct of the nephron?

through increasing expression of aquaporins on the lumen surface of the tubular cells

130

why is urea reabsorption important along with ADH secretion in the collecting duct?

because it helps the body retain more water by being reabsorbed and further concentrating the urine in the collecting duct

131

where are the low pressure baroreceptors located?

in the atria and great veins

132

where are the high pressure baroreceptors located?

in the carotid sinus and aortic arch

133

how do low pressure baroreceptors in the atria and great veins trigger ADH secretion?

by reducing their inhibitory firing to ADH neurons

134

what is the effect of alcohol on ADH?

suppresses its secretion, causing more water to be kept in collecting duct

135

how is continence maintained by neural controls?

sympathetic system maintains detrusor relaxation and internal urethral sphincter contraction; voluntary contraction of external urethral sphincter

136

how is voiding of urinary bladder achieved?

parasympathetic system causes detrusor contraction and internal urethral sphincter relaxation; voluntary relaxation of external urethral sphincter

137

where in the CNS is continence maintained from? (be specific)

the micturition centre in the pons