L17 - Histology of the Urinary system Flashcards
(108 cards)
1
Q
What is the principal functions of the urinary system?
A
Maintenance of water, electrolyte and acid-base homeostasis
2
Q
What is the normal expected urine volume per day?
A
1.25 L/day
3
Q
What is Polyuria (too many) / oligouria (too little) a homeostatic disorder of?
A
Homeostasis of urine production
4
Q
What are the most important toxic metabolites that require breakdown in body?
A
Nitorgen-containing compounds as products of protein breakdown
e.g. urea and creatinine
5
Q
What actions of the urinary system do the principal functions involve? (what happens to the urine?)
A
Production, passage, storage and voiding of urine
6
Q
What is secreted by the juxtaglomerular cells that regulate blood pressure?
A
renin (angiotensinogenase): cleaves angiotensinogen > makes angiotensin I > regulate blood pressure
7
Q
What is the consequence on urine production volume by lack of ADH in Diabetes insipidus?
A
Lack of ADH > lose ability
to reabsorb water from distal convoluted tubule and collecting ducts >
large volume of urine production (up to 22 liters/day)
8
Q
What are the four structures that make up the urinary system?
A
2 kidneys
2 ureters
urinary bladder
urethra
9
Q
What is the kidneys’ function?
A
Control urine production and urine composition
10
Q
How are the ureters and urethra similar in function?
A
Both for passage of urine
11
Q
What is the function of the urinary bladder?
A
storage and voiding of urine
12
Q
How would you describe kidneys as an organ?
A
Kidneys are compound tubular glands covered by a thin capsule of dense connective tissue and embedded in a layer of fat
(renal capsule> perirenal fat >renal fascia> pararenal fat)
13
Q
What is the location and level of the kidneys?
A
T12- L3
retroperitoneal
Right kidney is inferior to left kidney
14
Q
What is the renal fascia made of?
A
thin layer of loose connective tissue
15
Q
What passes through the hilum of the kidneys?
A
renal artery / vein (more anterior), nerves, ureter
16
Q
What is the renal sinus?
A
cavity within the kidney
occupied by the renal pelvis, renal calyces, blood vessels, nerves and fat
17
Q
What are the pyramids in the kidney?
A
The pyramids made of tubules that transport urine from the cortex to the calyces
18
Q
Where and what is renal papilla?
A
where the renal pyramids in the medulla empty urine into the minor calyces
19
Q
How is renal papilla duct formed?
A
medullary collecting ducts converging to form a papillary duct
20
Q
How is the renal pelvis formed?
A
Fused major calyces
21
Q
The kidney can be divided functionally into which two sections?
A
Transport portion
Filtration portion
22
Q
What marks the start of the transport portion of the kidney?
A
major and minor calyces
23
Q
What and where are the three physiological constrictions along the ureter?
A
Pelviureteric junction- after renal pelvis
Pelvic brim- crossing with external iliac artery
Uretero-vesical junction- before entrance into bladder
24
Q
What artery does the renal artery branch from?
A
Aorta
25
What is the sequenc eof circulation from the renal artery to micro-circulation?
Renal artery > Segmental artery > InterLOBAR artery > Arcuate artery > interLOBULAR artery > microcirculation
26
What are the arteries before and after arcuate artery in kidney?
InterLOBAR is before
| interLOBULAR is after
27
What preceeds interlobar artery in kidney?
Segmental artery
28
How are interlobar arteries arranged in kidney? (where does it lead to)
ascend within renal
| columns toward cortex
29
Where are do arcuate arteries exist in kidneys?
arch over base of
| pyramids
30
Where do interLOBULAR arteries end up in the kidney?
Renal cortex
31
Is the nephron open-ended or blind-ended?
Blind-ended
32
What is the uriniferous tubule of the kidney? What structures does it consist of?
The functional unit of the kidney that collects and conducts urine
Consists of a nephron + collecting tubule
(Renal corpuscle + PCT + Loop of Henle + DCT + collecting tubule)
33
Are the two components of the uriniferous tubule from the same embryonic origin?
No
34
Where are distal and proximal convoluted tubules located relative to the renal corpuscle?
PCT and DCT are adjacent to the renal corpuscle
35
What are the two types of nephrons? How are they distributed?
80% Cortical
| 20% Juxtamedullary
36
Does the loop of Henle of cortical nephron extend into the medulla? How about juxtamedullary nephrons' loop of Henle?
Cortical nephron: Yes but not deep into medulla
Juxtamed. nephron: Yes and deep into medulla
37
What forms the peritubular capillary network?
Efferent glomerular arterioles of the CORTICAL nephron
38
What is the difference in location between the renal corpuscle of cortical vs juxtamedullary nephron?
Cortical nephrons:
Renal corpuscle nearer to periphery of cortex
Juxtamedullary nephrons:
Renal corpuscle near cortical medullary border/ in the juxtamedullary cortex
39
What is the sequence for urine drainage inside the kidney?
nephron > collecting ducts > papillary ducts >
| minor calyses > 3 major calyses > renal pelvis
40
What structures does the glomerular filtrate go through inside the uriniferous tubule?
Renal corpuscle > Proximal convoluted tubule > Loop of Henle > Distal convoluted tubule > Cortical Collecting duct > Medullary collecting duct
41
What is the Medullary Ray made of ?
Consists of Collecting tubule and segments of the loop of Henle of CORTICAL nephron
42
What is the difference between the structures formed from the efferent glomerular arteriole of the cortical and juxtamedullary nephrons?
Cortical nephron efferent glomerular arterioles form the peritubular capillary network
Juxtamed. nephron efferent glomerular arterioles form the VASA RECTA
43
What is the difference between the structures surrounded by the peritubular capillary network and Vasa Recta?
Peritubular capillary network surrounds the convoluted tubules of nephrons in the cortex
Vasa Recta surrounds the limbs of Loop of Henle
44
In which of the two types of nephrons is the Loop of Henle longer?
The juxtamedullary nephron has longer Loop of Henle
45
The cortex and medulla of kidneys is divided into which 4 sections?
Cortex- Outer cortex, juxtamedullary cortex
Medulla- Outer medulla, Inner medulla
46
What structures of nephron is prominent in the medulla?
Only Loop of Henle and Collecting duct
47
Are the renal corpuscle and convoluted tubules of juxtamedullary nephron located in the Medulla?
No, located in the juxtamedullary cortex
48
What is the sequence of venous vessels from microcirculation to inferior venan cava in the kidneys?
Microcirculation / peritubular capillaries > InterLOBULAR vein> Arcuate Vein> InterLOBAR vein> Renal Vein > Inferior VC
(No segmental vein)
49
Are the peritubular capillary networks continous with Vasa Recta?
Yes, the two capillary beds are linked
| This is called Portal Circulation
50
What is the sequence of vessels in the microcirculation of the kidney?
Interlobular artery > Afferent arteriole > glomerulus > Efferent Arteriole > then to:
1) Peritubular capillaries > Vasa Recta > either arcuate vein or interlobular vein
2) Directly to interlobular vein
3) to Peritubular caplillaries > Interlobular vein
51
Which two veins can Vasa Recta lead to?
InterLOBULAR vein
| Arcuate Vein
52
Which two vessels can Peritubular capillaries lead to?
Vasa Recta
| InterLOBULAR vein
53
Which two vessels can efferent arteriole lead to?
interLOBULAR vein
| Peritubular capillaries
54
What is the path that Vasa Recta (formed by juxtamedullar nephron efferent arterioles) takes in the kidneys?
course along with loops of Henle into the medulla > then to cortex
55
Where in the kidney are Arcuate A/V located?
Juxtamedullary cortex
56
What is located between renal pyramids?
Renal Columns
57
Is corticomedullary junction same as juxtamedullary cortex?
Yes
58
What are the epithelium types in parietal (outer) and visceral (inner) Bowman's capsule?
Parietal layer = simple squamous epithelium
Visceral layer = specialized podocytes, highly specialized simple squamous epithelium
59
What is the role of Mesangial matrix?
Produce Extra-cellular matrix for structural support of the glomerulus
60
What is glomerular tuft?
20-40 loops of fenestrated capillaries
61
In visceral epithelium, what structures does the plasma ultrafiltrate pass through from the glomerular capillary to urinary space?
Glomerular capillary endothelium > Fenetration > Basal Laminae (fused basement membrane between podocyte and endothelial > Filtration slit diaphragm between podocyte pedicels > Urinary space
62
What are pedicels of podocytes?
Finger-like projections, space between is called filtration slit
63
What 2 components make up renal corpuscle?
Glomerulus and Bowman's capsule
64
What structure faces the vasuclar pole and what faces the urinary pole?
Vascular pole: DCT, Afferetn and Efferent arterioles
Urinary pole: PCT
65
What are juxtaglomerular cells?
modified smooth
muscle cells of
AFFERENT arteriole
66
What is the role of juxtaglomerular cells?
Secretes renin
(converts angiotensinogen to angiotensin I > angiotensin II)
Act as mechanoreceptors, sensitive to BP
67
What are macula densa cells?
specialized / modified epithelial cells of distal
| convoluted tubule
68
What is the role of macula dense?
Sensitive to osmolarity (e.g. amount of NaCl in distal
convulated tubules) and volume of filtrate =
regulates glomerular filtration rate
69
What cells has gap junction with juxtaglomerular cells and lies bteween macular densa and glomerulus?
Lacis cell (extraglomerular mesangial cells)
70
What is the Proximal convoluted tubule epithelium?
| 3 special features?
Simple cuboidal
epithelium with:
1) Microvilli (at luminal
brush border)
2) Mitochondria in basal infoldings/invaginations
3) Apical tight junctions + intercellular junctions (alternating ridges along basal part of cell)
71
What microscopy features do proximal convoluted cells have?
Brushed border
Cytoplasm: more
eosinophilic than DCT
No distinctive cell border
72
Does PCT reabsorb most of water and solutes?
Yes about 70% of all reabsorption
73
What is reabsorbed in the PCT?
Actively reabsorb Na+ ,amino acid, (small) proteins,glucose
Reabsorb water by osmosis
74
What is the pathway of reabsoption of PCT?
filtrate >
tubule cell >
interstitial fluid >
peritubular capillaries
75
What is the chang ein epithelium of Loop of Henle from descending limb to ascending limb?
1. Initial part of descending limb: simple cuboidal epithelium
2. Latter part of descending limb: simple squamous epithelium
3. Initial part of ascending limb: simple squamous epithelium
4. Distal part of ascending limb: simple cuboidal epithelium
Epithelial cells interlock with each other
76
What is the role of Loop of Henle?
Create hypertonicity gradient between collecting ducts and interstitium
77
When is renin secreted? What 2 cells is it made and secreted by?
When BP is low:
1) Detected by macula densa by decreased sodium concentration in DCT due to decreased glomerular filtration rate
or
2) Detected by Juxtamedullar cells (mechano-receptors)
78
What is the difference in water and solute permeability between ascending and descending limbs of the Loop of Henle?
Descending= impermeable to salt but permeable to water
Ascending pumps of salt but impermeable to water
79
What is the pairing of vasa recta to the limbs of the loop of henle?
Descending limb coupled with ascending Vasa Recta
Ascending limb coupled with descending Vasa Recta
Interstitium in between
80
DCT epithelium? 3 sepcial features?
Simple cuboidal epithelial cells with:
1) Mitochondria in basal folding/ invagination
2) Intercellular junction (impermeable to water)
3) Sparse microvilli
81
How does DCT cells compare to PCT cells morphological?
```
Morphology:
Shorter, appear less in a section
Pale stain
Less brush border on luminal surface (few/sparse microvilli)
More distinctive border
Smaller size
Less acidophilic
```
82
What is the function of the DCT?
Achieve acid-base and water balance by:
Absorption of water, Na+, HCO3-
Excretion of K+ and H+
83
Which of the DCT's membranes are responsible for transport of which ions?
Apical membrane: countertransport (reabsorb Na+, Cl-; excrete H+, K+)
Basal membrane: active transport/symport (reabsorb Na+, Cl-; excrete K+)
84
How do the lumens of PCT and DCT compare?
PCT=Thicker wall, Smaller lumen
| DCT= Thinner wall, Bigger lumen
85
Collecting tubule/ duct function?
Controlled reabsoption of water under influence of ADH
86
What epithelium and cell types are in collecting ducts?
Simple Cuboidal epithelium
Principal and Intercalated (dark) cells
87
Function of medullary collecting tubules?
Water reabsorption
Hypothalamus synthesizes ADH > release from
posterior lobe of pituitary > collecting tubules respond to increase permeability to
water > water moves out > produce concentrated urine
88
What is the difference in function between the two types of collecting duct cells?
Principal (light) cells: mechanosensor of fluid flow and contents
Intercalated (dark) cells: Mediate acid-base transport, water impermeable
89
What are the two roles of interstitial cells?
Maintenance of renal architecture and production of erythropoietin
(Produces 1,25-dihydroxycholecalciferol/ active vitamin D to increase Calcium levels during UV exposure)
90
How does the DCT relate to renin/ angiotensin / aldosterone?
Angiotensinogen (liver) > angiotensin I > angiotensin II
Increased K+ + angiotensin II act on adrenal cortex > increase aldosterone secretion > reabsorb Na+, Cl-, excrete K+
91
Ureter epithelium?
transitional epithelium
92
How does transitional epithelium change?
Contracted (fat) and Distended (slim) states of viscus
Contracted/non-distended state of viscus:
Cuboidal basal, polygonal middle, columnar upper
93
Transitional epithelium vesicles role?
Reserve segments of surface membrane to incorporate into surface when lumen is distended
94
What are the layers and lumen of the ureter?
Transitional epithelim (urothelium) >Lamina propria >Inner spiral (longitudinal) muscle >Outer spiral (circular) muscle> Outermost longitudinal layer (in lower third) >Adventitia
Stellate-shaped lumen
95
What is the role of the ureter?
Hollow fibromuscular tubes that deliver urine from renal pelvis to urinary bladder via peristaltic smooth muscle contraction
96
What is the lamina propria of the ureter made of?
Dense collagenous and elastic connective tissue
97
What is the adventitia of ureter made of?
Loose connective tissue with autonomic nerve plexuses, clood vessels and lymphatics
98
Which muscle layer in ureter is for peristaltic movements to move urine?
Outermost longitudinal layer in lower third
99
What is the role of the urinary bladder?
Receive and stor urine until neural stimulation cause it to contract and expel urine via urethra
100
What three structures surrounding the male kidney is not found in female?
L/R ductus deferens
L/R seminal vesicle
Prostate
101
What is the lining of the bladder?
Transitional epithelium> Lamina propria > 3 layers of Detrusor muscle
102
What is the difference in neural control between the external detrusor muscle and the internal urethral sphincter?
External detrusor = Somatic NS
| Internal urethral sphincter = Autonomic NS
103
Where is the trigone?
triangular area between entry of 2 ureters and exit of urethra
104
Compare male and female urethra location and length?
Length: Female shorter
Location:
- female: opens into vestibule anterior to vaginal opening
- male: from inferior part of urinary bladder through penis
105
3 sections of male urethra and epithelium?
Prostatic > Membranous > Spongy/penile
Transitional epithelium>
(pseudo-)stratified columnar
epithelium (most) >
Non-keratinized stratified squamous epithelium (tip of penis)
106
Is the change in epithelium in female urethra the same as in male?
Yes
| Transitional > Pseudo. Col.> NKSS
107
How does urine movement change through the urinary system?
Through nephron: hydrostatic pressure
| From renal pelvis > ureters > urinary bladder: peristalsis
108
How does neural control change frequency of urine movement?
Parasympathetic stimulation: increases frequency
| Sympathetic stimulation: decreases frequency
