Urinary System Flashcards
(100 cards)
1
Q
General functions of the kidney are:
A
Fluid balance, electrolyte balance, acid-base balance, blood pressure regulation via renin-angiotensin aldo system, endocrine organ via release of renin and erythropoeitin, and vitamin D activation by stimulating absorption of vitamin D by the small intestine
2
Q
Renal Lobe
A
Basic subunit of the kidney, may fuse together differently depending on the species
3
Q
The cortex is what layer of the lobe?
A
Outer
4
Q
The renal pyramid of the kidney is also known as the?
A
Medulla
5
Q
What are the two components of the renal pyramid (medulla)?
A
The base (towards the cortex) and the papilla (apex).
6
Q
The term papilla in context to the renal lobe refers to?
A
The apex of the renal pyramid (medulla).
7
Q
What are renal columns?
A
Cortical tissue located along the sides of the pyramids.
8
Q
What is unique about pig kidneys?
A
Papillae are present in the kidneys of pigs. This is because cortical portions fuse, but medullary portions do NOT fuse so pyramids are still visible.
9
Q
What is unique about the kidney of the dog, cat, horse, and small ruminants?
A
The papillae fuse to form the renal crest.
10
Q
What is the area of cribrosa?
A
They are located on the surface of the renal crest and are the openings of papillary ducts on the renal crest.
11
Q
Unilobar kidneys are also called?
A
Unipyramidal kidneys
12
Q
What are unilobar kidneys?
A
They consist of many lobes where the papillae of the pyramids have fused together to form a singel renal crest.
13
Q
What species have unilobar kidneys?
A
Domestic species like the dog and cat, the sheep and horse.
14
Q
Multilobar kidneys are also called:
A
Multipyramidal kidneys
15
Q
What species have multilobar kidneys?
A
The pig
16
Q
What are multibobar kidneys?
A
They have visible, individual papillae because there was little to no fusion of the papillae on the medullary pyramids.
17
Q
The fibrous capsule of the kidney contains:
A
An outer layer consisting of dense, irregular collagenous connective tissue and an inner layer consisting of smooth muscle except the cat.
18
Q
Which species does not contain smooth muscle in the inner layer of the fibrous capsule?
A
The cat
19
Q
Define the different between the parenchyma and the stroma of glandular organs like the kidney.
A
The parenchyma is the epithelial component while the stroma is the connective tissue, supportive component.
20
Q
The parenchyma of the kidney is composed of:
A
uriniferous tubules
21
Q
What structures make up the uriniferous tubules?
A
The nephron and the collecting duct.
22
Q
Why is the collecting duct considered a separate structure from the nephron?
A
While the two structures appear to be continous, they are derived from two different sources during embryonic development and connect later on in development.
23
Q
What two structures does the cortex contain?
A
The medullary rays and the cortical labyrinth.
24
Q
What is located in the cortical labyrinth and where is it located?
A
The cortical labyrinth is part of the cortex of the lobule and consists of convoluted tubules.
25
List the 6 segments of the nephron:
Glomerular capsule, proximal convoluted tubule, proximal straight tubule, thin tubule, distal straight tubule, and distal convoluted tubule.
26
Proximal straight tubule is also known as:
Descending thick limb of the Loop of Henle
27
Distal straight tubule is also known as:
Ascending limb of the loop of Henle
28
What segments of the nephrone make up the loop of Henle?
Proximal straight tubule, thin tubule, and distal straight tubule
29
Where is glomerular (bowman's) capsule located?
In the cortical laybyrinth between the medullary rays of the cortex.
30
What two layers make up the glomerular capsule?
Parietal layer and the visceral layer
31
What is the visceral layer of the glomerular capsule composed of?
Podocytes (simple squamous epithelial cells) that have primary processes and secondary processes called pedicels.
32
What are pedicels?
Secondary processes of the podocytes of the glomerular capsule that contain filtration slits, which are the space in between the interdigitating pedicels.
33
What is the renal corpuscle?
It consists of the glomerulus and the glomerular capsule.
34
What is the vascular pole of the renal corpuscle?
Where afferent and efferent arterioles leave.
35
What is the tubular (urinary) pole of the renal corpuscle?
where the proximal convoluted tubule begins.
36
Where is the lumen (urinary space) of the renal corpuscle located?
It is the space in the renal corpuscle between parietal and visceral layers of the glomerular capsule.
37
List the three components of the filtration barrier between the lumen of the capillary and the tubule in the kidney:
1. Fenestrated endothelium of the vessel (porous, no diaphragm, allows everything to go through besides cells)
2. Basement membrane (very thick)
3. Filtration slit membrane (space between pedicils - continous monoloayer membrane)
38
What are mesangial cells and where are they located?
The are located between the glomerular capillaries and have contractile elements to help regulate the glomerular filtration rate (GFR). They are also phagocytic and help filter from getting clogged by phagocytosing old cells that cannot get through the fenestrated endothelium.
39
What is the proximal convoluted tubule (PCT)?
It is the longest segment of the nephron that is located only in the cortex (cortical labyrinth). Its function is to absorb 100% of the glucose, amino acids and proteins that pass through, and ~85% of ions in the tubule fluid that are followed by water.
40
Describe the course of the loop of Henle:
It starts in the cortex as the proximal straight tubule and runs to the medulla to become the thin tubule which bends and forms the loop. Then the tubule runs back up to the cortex and the thin tubule transitions back to the distal straight tubule.
41
What is the function of the loop of Henle?
To create a hypertonic environment in the interstitium in order to create concentrated urine in the end.
42
What is the macula densa?
It is a group of cells of the distal straight tubule located next to the renal corpuscle at the vascular pole where efferent and afferent arterioles are located. These cells function as chemoreceptors and maintain the concentration of ions and regulate the release of renin of JG cells from the afferent arterioles.
43
What is the function of the the distal convoluted tubule (DCT)?
Its function is the active recovery of sodium in exchange for potassium and hydrogen ions. Sodium is taken out of the tubular fluid and potassium goes in. This process is dependent on the hormone aldosterone. DCTs are located in the cortex and are the last segment of the nephron.
44
What is the light microscopic appearance of the distal convoluted tubule?
Cells are less acidophilic, and are smaller so you can see more nuclei. The luminal border is relatively smooth compared to the proximal convoluted tubule because they don't have a brush border.
45
How does number of nephrons relate to species?
Usually, the relationship is size dependent. The bigger the mammal, the more nephrons they have. This does not apply to birds however.
46
What are collecting tubules and what are their course?
Their cells are classic simple cuboidal. The collecting tubules connect with the distal convoluted tubule located in the medullary ray. The arched collecting tubules become the straight collecting tubules as they descend into the medulla and unite with other straight collecting tubules to form papillary ducts that will open up on the renal crest.
47
What is the last segment of the nephron?
the distal convoluted tubule
48
Is the collecting duct part of the nephron?
No, it is the next segment following the nephron, and is continuous with the distal convoluted tubule.
49
What kind of arteries are in the kidney?
They are muscular arteries and all of them are end arteries. There is no collateral circulation and therefore if you cut off one of these arteries, the surrounding tissues will die.
50
The renal artery is a branch of what elastic artery?
The aorta
51
Interlobar arteries are:
branches of the renal arteries that pass between the renal pyramids.
52
Arcuate arteries are:
Branches of the interlobar arteries, located at the corticomedullary junction.
53
Interlobular arteries are:
branches of the arcuate arteries that go from the corticomedullary junction towards the surface of the kidney
54
Afferent arterioles are:
branches of the interlobular arteries and go the the glomerulus.
55
The glomerulus is drained via:
efferent arterioles
56
What is the peritubular plexus?
It is formed by the efferent arteriole of the outer cortical nephrons and is a network of capillaries that supply blood to the proximal and distal convoluted tubules.
57
What is the arteriolae rectae spuriae?
They are formed by the efferent arteriole of the deep cortical nephrons (juxtamedullary), meaning they are located in the cortex but closer to the medulla. Their function is to supply blood to the medulla.
58
What is the arteriolae rectae verae?
They are branches arising from arcuate arteries that go down into the medulla. They are the vasa recta (straight vessels in the the medulla).
59
List the 8 veins associated with the kidney:
1. Coritical venous plexus
2. Stellate V.
3. Interlobular V.
4. Arcuate V.
5. Venulae rectae
6. Interlobar V.
7. Renal V.
8. Caudal vena cava
60
Cortical venous plexus
number of small veins in the cortex that drain peritubular capillaries and drain into interlobular veins or arcuate veins
61
Stellate Vein
Located just beneath the capsule of the kidney and drain into interlobular veins
62
Interlobular Vein
drains into arcuate vein
63
Arcuate Vein
drains into interlobar V
64
Venulae rectae
"straight" venules that drain blood into the arcuate vein
65
Interlobar Veins
located between pyramids and drain into the renal vein
66
Renal vein
drains into caudal vena cava
67
Vasa recta
The main function of the vasa recta is to maintain hypertonisity in the interstitium created by the loop of henle.
68
Vasa recta consists of three structures:
1. Arteriolae rectae verae
2. Arteriolae rectae spuriae
3. Venulae rectae
69
Where is the medullary ray found?
Only in the cortex
70
What does the medullary ray contain?
Proximal and distal straight tubules of the loop of henle and arched collecting tubules and sttraight collecting tubules
71
What is the renal lobule?
Cortical tissue between two interlobular arteries. The medullary ray is located in the center of the lobule. All nephrons that drain into single medullary rays are called the renal lobule.
72
What three components make up the juxtaglomerular apparatus (complex)?
1. Macula Densa
2. Juxtaglomerular (JG) cells
3. Mesangial cells
73
What are JG cells?
Baroreceptors that are modified smooth muscle cells in the afferent arteriole with secretory granules containing the enzyme renin which regulates blood pressure.
74
When do JG cells release renin?
When blood pressure is low in the afferent arteriole. This causes an increase in angiotensin II which causes vasoconstriction and an increase in alodsterone which will increase the reabsorption of sodium and water causing an increase in renal arterial pressure/volume.
75
Where are mesangial cells located?
Between afferent and efferent arteioles at the vascular poles of the renal corpuscles.
76
What is the function of mesangial cells?
The regulate GFR, but no one knows exactly their main function.
77
What is unique about the feline kidney?
1. Capsular veins found on the surface of the kidney (called subcapsular veins in anatomy) that drain toward the hilus, into the renal vein.
2. Lipid droplets found in the proximal tubule cells.
78
What is unique about the equine kidney?
Instead of the macula densa being a single layer of cells in the distal straight tubule it is a stratified layer in the equine kidney.
79
How does the renal corpuscle produce an ultrafiltrate of plasma?
The capillary bed located between the afferent and efferent arteriole has a high pressure because the efferent arteriole has a smaller diameter. This high pressure in the glomerular capillaries allows for an ultrafiltrate of plasma.
80
Function of the fenestrated endothelium of the renal corpuscle:
to hold back cells
81
Function of the basement membrane of the renal corpuscle:
hold back molecules of 160,000 MW or greater
82
Function of filtration slit membrane of the renal corpuscle:
to hold back molecules of 60,000 MW
83
What part of the nephron has microvilli and what is this referred to as?
The proximal convoluted tubule contains microvilli that is referred to as the brush border, and is there for absorption where glucose is taken up via transporters.
84
What do pinocytotic vesicles fuse with in the proximal convoluted tubule?
they fuse with primary lysosomes and their contents are degraded and recycled
85
Why do we see increased number of mitochondria and basal membrane infoldings in the proximal convoluted tubule?
The mitochondria are required to provide ATP pumps to provide energy for the active reabsorption of sodium and chloride.
The basal membrane infoldings increase surface area to keep up with the large amount of ion transport via ion pumps in the membrane.
86
What part of the nephron actively secretes creatine?
Proximal convoluted tubule. Creatine is a non-toxic byproduct of muscle metabolism. If creatine is high, the GFR is low.
87
The ascending limb is _____ to water.
Impermeable
88
Does the loop of henle concentrate urine?
No, it just sets the conditions to allow urine to be concentrated further down.
89
Main function of distal convoluted tubule?
active ion exchange, and therefore have increased amount of mitochondria in their cells just like the proximal convoluted tubule. The Na+/K+ ATPase pumps are located in the basal membrane.
90
Why don't the distal convoluted tubules contain basal membrane infoldings like the proximal convoluted tubules do?
There is no brush border in the distal convoluted tubule because absorption is NOT their main function.
91
What is the renal pelvis?
The expanded end of the ureter that sits in the renal sinus.
92
What is unique about the bovine kidney?
The ureter branches into two main calices which branch into minor calices which cover the renal papillae.
Each minor calix invests in an individual papillae.
There is no real renal pelvis in the bovine kidney.
93
What is unique about the procine kidney?
The renal pelvis branches into major calices which branch into minor calices which cover the renal papillae. Here, the ureter has an expanded renal pelvis.
94
Describe the tunica mucosa-submucosa of the ureter and urinary bladder:
This is the inner most tunic that rests on loose or dense irregular collagenous connective tissue.
There is no lamina muscularis here so the mucosa and submucosa blend, hence "t. mucosa-submucosa"
95
Describe the tunica muscularis in the ureter and urinary bladder, and what characteristic of this layer distinguishes the ureter from the urinary bladder?
Consists of a thick layer (usually three) of smooth muscle. The bladder has a very thick T. muscularis, more than half its wall thickness while the ureter has a thinner layer, consisting of less than half its wall thickness.
96
Is there a tunica adventitia or a serosa in the ureter and urinary bladder?
this depends on the species and level of section. Horses have mucous glands surrounding the ureter causing secretion of mucous into the urine and causing cloudy urine.
97
Describe the T. mucosa-submucosa of the female urethra:
Does not contain lamina muscularis just like the male ureter and bladder. Consists of transitional-stratified columnar and cuboidal epithelium.
Loose connective tissue in propria mucosa contains large vascular sinuses equivalent to the erectile tissue surrounding the urethra in the male.
98
Describe the T. muscularis in the female urethra:
may contain smooth and skeletal muscle (urethralis muscle)
99
what is different about the outer layer of the female urethra compared to the male ureter and the bladder?
The female urethra only has a T. adventitia, but never serosa.
100
How are vascular complexes in the female urethra different from vessels from the bladder?
These vascular complexes are much larger than vessels in the bladder and can be seen on low power.
