Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Histology > Urinary system > Flashcards

Urinary system Flashcards

1
Q

main function of the urinary system

A

production, storage and voiding of urine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is urine?

A

aqueous solution of excess anions and cations and breakdown products of metabolic processes (esp. toxic ones)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

location of the kidneys

A

solid bean shaped
high on posterior abdominal wall, beneath peritoneum
concave aspects face midline (aorta and IVC)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is the concave area of the kidney called?

A

hilum

entry of renal arterial supply and venous drainage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

pelvicalyceal system and ureters

A

hollow muscular tubes
specialised epithelium resistant to damage
smooth muscle - peristalsis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

zones of the kidney

A

outer cortex

inner medulla

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

cortex of kidney

A

forms an outer shell

forms columns lying between individual medullary units (columns of Bertin)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what are columns of Bertin?

A

columns lying between individual medullary units by the cortex in the kidney

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

medulla of kidney

A

series of conical structures (medullary pyramids)
base of each cone is continuous w/ inner limit of cortex
pointed peak protrudes into urine collecting system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is the papilla?

A

pointed peak of medullary pyramids in the kidney

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

how many pyramids are there in the kidney?

A

10-18

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

how does the kidney produce urine?

A

selective removal of substances from blood plasma
composition of urine is appropriate to internal environment and requirements
always has required amount of waste products and ions for homeostasis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what substances are controllingly reabsorbed by the kidney?

A

water, ions, salts, sugars, carbs, small molecular weight proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

feature of kidney failure

A

inability to produce conc./dilute urine

inadequate excretion of nitrogenous waste products/potassium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

how do the kidneys and lungs differ from other organs?

A

parenchymal components of organ are servants of the blood supply, as kidney filters/cleanses the blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what percentage of CO do the kidneys receive? what is a consequence of this?

A

25

most kidney diseases result from abnormal blood vascular component

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what hormones does the kidney produce?

A

erythropoietin and renin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

kidney arterial supply

A

single renal artery - substantial, direct branch of abdominal aorta
runs towards hilum, divides into minor posterior branch and substantial anterior branch
divide into interlobular arteries running between medullary pyramids, one to each developmental lobe

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

branching of interlobular arteries

A

at midpoint of thickness of parenchyma - corticomedullary junction
several lateral arcuate arteries running laterally

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

capillary systems in renal microcirculation

A

glomerular tuft - blood from afferent arteriole, site of filtration of waste products from plasma
second one arises from efferent arteriole, varies in structure and function according to location

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

efferent arteriole after the glomerulus structure and function

A

divides into complex capillary system
interstitial spaces between cortical tubules

takes up substances resorbed from glomerular filtrate by tubular epithelial cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what are juxtamedullary glomeruli?

A

glomeruli deep in the cortex

close to corticomedullary junction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

capillary system originating from efferent arterioles leaving juxtamedullary glomeruli

A

divide into long, thin-walled vessels (vasa recta)
run into medulla alongside medullary components

ionic and fluid exchanges

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

where may vasa recta arise from?

A

efferent arterioles leaving juxtamedullary glomeruli

directly from arcuate artery

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

differences in roles between the capillary systems in the kidney

A

glomerular tuft doesn’t transfer oxygen to tissues, or take up CO2

gas exchange in second
O2 supplied to cortical and medullary parts of parenchyma (highest demand)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

what areas of the kidney have the highest demand for oxygen, and why?

A

cortical and medullary parts

high metabolic activity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

venous drainage of kidney compared to arterial supply

A

mirrors it

no equivalent of glomerular capillary tuft

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what forms the origin of the interlobular veins?

A

subscapular arteriolar and capillary plexuses drain into subscapular venular and venous plexus of stellate veins, forming origin of interlobular veins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

what happens as the interlobular veins approach the corticomedullary junction?

A

receive venous tributaries from peritubular capillary network

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

what happens as the interlobular veins approach the juxtamedullary zone?

A

receive venous tributaries from medulla (equivalent of arterial vasa recta)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

where do arcuate veins run with?

A

run laterally w/ equivalent artery at corticomedullary junction
drain into large interlobular veins between adjacent medullary pyramids, then into major vein tributaries at hilum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

where does the major renal vein open into?

A

IVC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

what is the nephron?

A

functional unit of the kidney parenchyma serving the blood supply

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

components of the nephron

A

glomerulus

cortical and medullary tubular systems

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

function of nephron components

A

glomerulus - initial blood filtration

tubular systems - conc. and chemical content of blood is controlled

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

what are the components of the medullary ray?

A

midpoint between adjacent interlobular arteries
vertically running arrangement of tubules and ducts
centre: main collecting duct which collects largely conc. urine from nephrons on either side
straight collecting tubules carrying urine from end of distal tubule to main cortical collecting duct

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

how do the duct systems of the medullary ray run?

A

vertically downward into medulla

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

what is the renal lobule?

A

subunit of the cortex
centrally placed medullary ray and nephrons on either side
each interlobular artery runs upward in cortex between adjacent lobules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

afferent vs efferent arterioles

A

afferent is branch of interlobular artery, enters the glomerulus at vascular hilum
efferent arteriole emerges from glomerulus, divides into peritubular capillary network

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

where do arcuate veins and arteries run?

A

corticomedullary junction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

example of injection showing renal microvasculature

A

carmine-gelatin injection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

what is the first functional component of the nephron encountered by the microcirculation? what does it do?

A

glomerulus

initial filtration of blood arriving by afferent arterioles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

division of afferent arteriole

A

enters glomerulus
divides into 5 main branches
each branch subdivides into its own capillary network

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

what is the short main branch (and its capillaries) of the afferent arteriole supported by?

A

own strip/stalk of mesangium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

what is the consequence of the branching of the glomerular capillary network?

A

divides into 5 independent segments

implicit lobulation rarely apparent by light microscopy in health - evident in primary glomerular disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

when may lobulation of glomerular tuft be seen?

A

light microscopy in some primary glomerular disease
esp. when mesangial component is enlarged
independence of each segment seen by disease affecting only one segment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

what is an example of a renal disease only affecting one segment of the glomerulus?

A

segmental glomerulonephritis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

glomerulus structure

A

globular capillary network intruding into hollow sphere of epithelial cells (Bowmann’s capsule)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

what is Bowmann’s capsule?

A

sphere of epithelial cells

bulbous, distended closed end of long hollow tubular system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

epithelial cells of Bowmann’s capsule

A

flat and simple
become more cuboidal and acquire some organelles of proximal convoluted tubule epithelial cells near opening of tubular system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

epithelial cells of glomerular capillary

A

lined internally by endothelial cells
ones lining capillary tuft are larger and have specialised and unusual structure
podocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

urinary space

A

epithelium-lined space between coated glomerular capillary network and parietal shell of Bowman’s capsule
continuous w/ lumen of long tubular system of nephron

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

passage of blood

A

blood enters glomerular capillary network from afferent arteriole
ultrafiltration
filtrate passes into urinary space, passes down the tubular system
partly filtered blood leaves glomerulus via efferent arteriole and provides oxygenation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

basement membrane in glomerular capillary network

A

unusually thick

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

glomerular filtration barrier

A

barrier between circulating blood and urinary space

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

components of glomerular filtration barrier

A

capillary endothelial inner layer
thick BM
podocyte (outer epithelial) layer

high polyanionic charge on some components

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

thickness of glomerular BM

A

310-350 nm

thicker in males

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

what contributes to the glomerular BM?

A

inner endothelial and outer epithelial cells contribute to its production

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

layers of glomerular BM

A

central electron-dense lamina densa
electron-lucent lamina rara interna on endothelial side
electron-lucent lamina rara externa on epithelial podocyte/urinary space side

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

development of layers of BM

A

clearly seen in rodents and children

less apparent in adults

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

lamina densa layer of glomerular BM

A

type IV collagen

fibril network acts as physical barrier to large molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

polyanionic sites in glomerular BM

A

lamina rara layers and surfaces of some podocyte secondary foot processes contain negative sites composed of GAG
BM: heparan sulfate
foot process: sialic acid-rich substance, podocalyxin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

GAG in BM and podocyte foot processes

A

heparan sulfate

sialic acid-rich substance (podocalyxin)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

demonstrating polyanionic sites in glomerular BM

A

ultrastructurally
using cationic substance e.g. ruthenium or polyethylenimine
form regular lattice, spacing of 60nm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

what may polyanionic sites act as?

A

charge barrier

prevent passage of cationic molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

structure of glomerular capillary endothelial cells

A

small circular fenestrations 70 nm diameter

attenuated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

where are the nuclei of the fenestrations located?

A

near the mesangium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

what is the podocyte layer composed of?

A

specialised epithelium continuous at hilum w/ epithelium at Bowman’s capsule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

why is the podocyte named so?

A

main body of the cell hovers above the external surface of glomerular capillary and sends down cytoplasmic extensions (foot processes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

foot processes of podocytes

A

cytoplasmic extensions that contact the BM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

what is between adjacent foot processes?

A

consistent gap
30-60nm
filtration slit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

what is the filtration slit membrane? what does it contain?

A

bridges gap between adjacent foot processes

cell adhesion molecule: nephrin

73
Q

what is nephrin?

A

cell adhesion molecule

connects actin filaments within adjacent foot processes

74
Q

what are the components of mesangium?

A

mesangial cells and extracellular mesangial matrix

75
Q

mesangial cells structure

A

round/oval nucleus, larger than endothelial nucleus
dense rim of chromatin in nuclear membrane
small chromatin clumps throughout nucleoplasm

76
Q

how do mesangial cell processes run?

A

haphazardly through extracellular mesangial matrix

77
Q

what does the mesangial cell cytoplasm contain?

A

myosin-like filaments

angiotensin-II receptors

78
Q

mesangial matrix structure

A

encloses mesangial cells, permeated by their cytoplasmic processes
variable electron density
in continuity w/ glomerular BM where capillary and BM meet
acellular

79
Q

what is the mesangial matrix produced by?

A

mesangial cell

80
Q

functions of the mesangium

A

support of glomerular capillary loop system
control of blood flow through glomerular loop by myosin-angiotensin mechanism
phagocytosis
maintenance of glomerular BM

81
Q

which parts of the tubules are close to the glomeruli?

A

convoluted parts of proximal and distal tubules

82
Q

which parts of the tubules are in parts devoid of glomeruli?

A

straight parts of tubular system and cortical parts of collecting duct system

83
Q

what is the first part of the tubular system?

A

proximal tubule - continuation of Bowman’s capsule

84
Q

path of proximal tubule

A

initially has convoluted course, remains close to Bowman’s capsule
straightens and descends toward medulla
merges w/ thin limb of loop of Henle
runs down in cortex, then in medulla, toward papillary tip (descending thin limb)
loops back on itself and forms distal straight tubule

85
Q

path of distal tubule

A

comes from ascending thin limb from proximal tubule, as a thick straight tubule
close to the glomeruli, becomes convoluted
empties into collecting tubule
empties into collecting duct within medullar ray

86
Q

path of collecting ducts

A

descend into medulla

converge to form large diameter ducts in papillae (papillary ducts/ducts of Bellini)

87
Q

where do capillary ducts open into?

A

calyces at tips of papillae

88
Q

what is the area cribosa? what is it produced by?

A

sieve-like surface appearance of the capillary tip

concentration at the openings

89
Q

main variation in length in the tubular system

A

thin ascending and descending loops of Henle

proximal convoluted tubule is longer than the distal convoluted tubule

90
Q

what is the function of the proximal tubule?

A

reabsorption of components of the glomerular filtrate

91
Q

structure of proximal tubule cells

A

cuboidal/columnar
centrally placed nucleus
well-developed luminal brush border
microvilli, closely packed

92
Q

what is the structure of the luminal brush border in proximal tubule cells?

A

microvilli, closely packed, 1mm

pinocytotic vesicles close to lysosomes

93
Q

BM of each tubule cell

A

extensive basal interdigitation and some lateral interdigitation
lateral border is irregular and difficult to define

94
Q

what is the purpose of the microvilli and mitochondria in proximal convoluted tubule cells?

A

immense SA for absorption

mitochondria are numerous and prominent in the convoluted section
energy for active transport of substances against gradients

95
Q

substances going into proximal convoluted tubule cells

A

Na+, H20, Cl-, amino acids, glucose, proteins, polypeptides, carbs

96
Q

transport of Na+ into proximal convoluted distal tubule cell

A

ATPases bring Na+ into cell
other ions, H+/K+ may leave the cell
membrane pumps in basolateral membrane push Na+ into intercellular space - creates high osmotic force

97
Q

what does passage of Na+ ions into the intercellular space cause?

A

high osmotic force

98
Q

what is the paracellular route?

A

the high osmotic force caused by Na+ pulls H20 and Cl- into intercellular space

99
Q

what happens to H20 and Cl- once in the cell?

A

pass through BM into interstitium

hydrostatic pressure forces them into adjacent peritubular capillaries

100
Q

transport of protein, polypeptides and some carbohydrates

A

reabsorbed into cell by endocytosis
broken down by lysosomal enzymes into amino acids and small molecular sugars
pass into intercellular space, then the interstitium and capillaries

101
Q

transport of glucose and amino acids into proximal convoluted distal tubule cells

A

specific transport systems at the microvillar surface

102
Q

arrangement of mitochondria in lower half of each proximal tubule cell

A

elongated mitochondria are closely associated w/ basal interdigitations from adjacent cells
arranged in parallel w/ interdigitating basal cytoplasmic membranes

103
Q

variations in specialisations in cells

A

membrane and cytoplasmic specialisations most developed in convoluted part
microvilli become smaller and less numerous as thin loop of Henle is approached
basal and lateral interdigitation less marked
mitochondria and lysosomes fewer
cells more cuboidal

104
Q

why is the thin-walled part of the loop of Henle considered a distinct functional and structural entity?

A

thick descending and ascending components are ultrastructurally identifiable with the proximal and distal convoluted tubules

transitions between thick and thin tubules are abrupt - thick ascending and descending parts merge gradually with proximal and distal tubules

105
Q

length of thin limbs of loop of Henle

A

those associated w/ juxtamedullary glomeruli are long, extend deep into medulla towards papillary tip

those associated w/ midcortical or subscapular glomeruli extend halfway into medulla

106
Q

epithelium lining thin limbs of loop of Henle

A

flat lining
little cytoplasmic specialisation

like a dilated capillary

107
Q

function of the thin limb of loop of Henle

A

creates osmotic gradient of hypertonicity

108
Q

where does the gradient of hypertonicity in the thin limb extend?

A

from the corticomedullary junction to the top of papilla

109
Q

what is the gradient of hypertonicity in the thin limb affected by?

A

variable passage of sodium and chloride ions between the lumen and the interstitium

110
Q

what does this gradient of hypertonicity do?

A

allows conc. of the urine in collecting duct system

111
Q

what is the explanation for the gradient mechanism?

A

countercurrent multiplier hypothesis

112
Q

what is the macula densa?

A

distal tubule runs close to hilum at the junction between the straight and convoluted parts

113
Q

what is the countercurrent multiplier hypothesis?

A

descending thin limb of loop of Henle is freely permeable to water, Na+ and Cl- ions
ascending thin limb is impermeable to water, actively pumps Cl- ions out of lumen into interstitium, which Na+ ions follow to maintain neutrality. retains water
produced hypotonic tissue/fluid

114
Q

cells lining the distal tubule

A 
cuboidal epithelial cells
basal and lateral interdigitations
microvilli less formed and scanty (to proximal tubule)
numerous, close to interdigitations
no invaginations or vesicles
115
Q

control of acid-base balance in the distal tubule and what this function depends on

A

Na+ ions reabsorbed from dilute urine in lumen, K+ ions excreted
bicarbonate ions reabsorbed, H+ excreted -> acidic urine

dependent on aldosterone (secreted by adrenal cortex)

116
Q

function of ADH

A

antidiuretic hormone
secreted by posterior pituitary
acts on last part of distal convoluted tubule
absorption of water -> conc. urine

collecting ducts - absorption of water from lumen into hypertonic intersitium, into vasa recta
dependent on countercurrent exchange system

117
Q

what does the tubular and duct system depend upon for its oxygen supply?

A

glomerular capillary network and arteries supplying glomeruli

118
Q

hypoxia of tubular epithelial cells

A

reduced blood flow
enzyme systems and pumping mechanisms stop functioning
biochemical abnormalities

119
Q

features of renal failure

A

acidosis (high conc. of H+ ions)
hyperkalemia (high conc. of K+ ions)
retention of nitrogenous waste material

120
Q

connecting segment

A

where convoluted distal tubule opens into collecting system

epithelial lining contains both cell types randomly

121
Q

what are the collecting tubules lined by?

A

clear cells

intercalated dark cells

122
Q

clear cells

A 
cuboidal/flat in proximal segment
light, poorly staining cytoplasm
few organelles
basal membrane infoldings, become less apparent
microvilli short and sparse
123
Q

intercalated dark cells

A

many mitochondria
well developed microvilli
vesicles at base of microvilli
no basal infoldings

124
Q

epithelium and BM of collecting ducts

A

initially identical to tubules
pass down medullary rays and into medulla
decreased intercalated dark cells
clear cells taller and more prominent
regular straight sided columnar clear cells

progressively thicker BM as it nears papillary tip

125
Q

countercurrent exchange system

A

dilute urine in collecting tubule is progressively conc. by osmotic transfer of water from lumen into the hypertonic medullary interstitial tissue
reabsorbed into vasa recta

126
Q

high vs low ADH levels

A

high: water lost from collecting duct lumen into interstitium
low: water remains within lumen, lost in form of dilute urine

127
Q

vasa recta and the conc. of urine

A

on the descending (arterial) side, the walls are permeable to water and salts
water passes into interstitium, and salts into lumen
on the ascending (venous) side, vice versa

128
Q

variation of the interstitial space in the kidney

A

cortex: small, small blood vessels and lymphatics
medulla: significant in bulk and function
tip of papilla: increases in size and importance

129
Q

what is the medullary interstitium composed of?

A

loose electron-lucent acellular material
protein and GAGs
scattered collagen fibres, lipid droplets and basal lamina material
interstitial cells

130
Q

what is the most common interstitial cell in humans?

A

irregular in outline

narrow, stellate cytoplasmic processes extending in all directions into matrix

131
Q

what does the cytoplasm of interstitial cells contain?

A

mitochondria, lysosomes, lipid droplets, small RER

132
Q

function of juxtaglomerular apparatus

A

maintaining BP and volume by producing renin

adaptation of vascular and tubular tissues allowing blood flow to affect renin output

133
Q

what are the components of the juxtaglomerular apparatus?

A

renin-producing cells
lacis cells
macula densa

134
Q

where are renin-producing cells located?

A

walls of afferent and efferent arterioles at vascular hilum of glomerulus

135
Q

what are the features of renin-producing cells?

A

highly specialised myoepithelial cells, with some contractile filaments

136
Q

what do renin-producing cells contain?

A

type 1 and 2 granules

137
Q

what do type 1 granules contain?

A

irregular in shape

rhomboidal crystalline bodies (protogranules) - precursors of other granules

138
Q

what are protogranules? where are they founde?

A

rhomboidal crystalline bodies, precursors of other granules

type 1 granules in renin-producing cells

139
Q

what are type 2 granules?

A

larger, spherical, uniformly electron dense, ill-defined membrane
mature renin-secreting granules

140
Q

what is the structure of lacis cells?

A

network of interwoven processes separated by acellular matrix of BM like material

141
Q

where are lacis cells located?

A

triangular region bordered by macula densa at base and afferent and efferent arterioles at the sides
apex is formed by base of glomerular mesangium

142
Q

what is the macula densa?

A

specialised zone of distal tubule where it’s in close contact w/ vascular hilum
specialised adaptation of its epithelium

143
Q

epithelium of the macula densa

A

taller
tightly packed
nuclei closer to luminal surface
Golgi between nucleus and BM

144
Q

what is the function of renin?

A

catalyses conversion of inactive angiotensin

145
Q

what is angiotensin?

A

alpha2 globulin produced in the liver, converted by renin to decapeptide angiotensin I.

146
Q

conversion of angiotensin I to II

A

by ACE in lung

stimulates secretion of aldosterone by zona glomerulosa of adrenal cortex

147
Q

what is aldosterone and its action?

A

mineralcorticoid hormone
regulates Na+ and K+ levels by effect on pump mechanism
promotes resorption of ions in distal tubules

148
Q

mechanisms for feedback control of renin synthesis and release

A

macula densa cells monitor Na+ conc. in distal tubule, affect renin release by granulated cells

juxtaglomerular cells monitor arteriolar stretching

149
Q

secretion of erythropoietin

A

kidney, not sure where exactly

150
Q

lymphatic systems in kidney

A

main ones run with interlobular, arcuate and interlobar vessels and emerge at hilum
minor runs in renal capsule and receives some tributaries from cortex

some communication between them in cortex

151
Q

nerve supply to kidney

A

autonomic

adrenergic and cholinergic fibres

152
Q

components of lower urinary tract

A 
calyceal collecting system - large collecting ducts of Bellini discharge urine into this
renal pelvis 
ureter
bladder
urethra
153
Q

calyceal collecting system

A

part of lower urinary tract

large collecting ducts of Bellini in papillae discharge urine into here

154
Q

renal pelvis

A

reservoir at hilum into which calyces pass urine

155
Q

ureter

A

long muscular tube which conducts urine down into bladder

156
Q

bladder

A

reservoir, holds urine until voiding

157
Q

urethra

A

urine stored in bladder is voided to exterior through here

158
Q

sphincters in lower urinary tract

A

close off parts of tract to act as reservoir

one at junction between bladder and urethra is under voluntary control

159
Q

urothelium

A

multilayered epithelium in lower urinary tract

160
Q

variation of urothelium

A

in calyces, only 2-3 layers thick

empty bladder, 5-6 layers

161
Q

distention of urothelium

A

ability to stretch, shift and flatten
distended: stretched, flat cells, fewer layers
non-distended: compact, cuboidal basal layer, polygonal celled middle layers, surface layer of tall columnar cells (binucleate)

162
Q

surface layer of urothelium

A

specialised
luminal aspect is convoluted
deep clefts run down to cytoplasm
fusiform vesicles lined by cell membrane identical to luminal surface

163
Q

BM of urothelium

A

thin, indistinct

supported by dense subepithelial tissue of mainly collagen (lamina propria)

164
Q

surface cells during distension

A

flattened
lose convex apical bulge
deep clefts and vesicles disappear

165
Q

what is the urothelium supported by?

A

lamina propria and layers of smooth muscle

166
Q

arrangement of smooth muscle in ureter

A

loose spiral muscle (longitudinal)

tight spiral muscle (circular - outer)

167
Q

what prevents urine reflux during micturition?

A

functional valve

168
Q

innervation of the bladder

A

ANS
sensory fibres from bladder transmit signals to sacral spinal cord i.e. its distension
parasymp. fibres ending in muscles and adventitia of bladder act as effector muscle for micturition
symp. fibres innervate blood vessels to bladder

169
Q

female urethra - length, opening

A

short
5cm long
runs from bladder, opens to exterior in midline of genital vestibule between clitoris and superior border of vaginal introitus

170
Q

what is the urethra lined by?

A

stratified squamous epithelium

lamina propria has vascular channels and small mucus-secreting glands

171
Q

what is the urethral muscle wall?

A

continuation of the involuntary smooth muscle of the bladder

172
Q

what is the external sphincter? where is it? what is it composed of?

A

striated muscle
voluntary control
midportion of urethra as it passes through striated muscles of pelvic floor

173
Q

male urethra - length

A

20-25cm long

174
Q

what are the segments of the male urethra?

A

prostatic, membranous, penile

175
Q

prostatic urethra

A

begins at bladder neck
runs through prostate gland
periurethral glands open into it through short ducts
openings of ejaculatory ducts

176
Q

membranous urethra

A 
short segment
1cm long
runs through pelvic floor muscles
voluntary control
external sphincter
177
Q

penile urethra

A

runs through corpus spongiosum
opens to exterior at external meatus of glans penis
small mucous glands open into this

178
Q

what is the male urethra lined by?

A

transitional epithelium -> non-specialised pseudostratified -> stratified squamous as it merges with that of glans penis

Histology (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions