Chr. 26 - The Urinary System Flashcards
(104 cards)
1
Q
[26.1] What is the urinary system composed of?
A
Two kidneys, two ureters, one urinary bladder, and one urethra.
2
Q
[26.1] List the functions of the urinary system.
A
- Excretion
- Regulation of blood ionic composition
- Regulation pH
- Regulation of blood volume
- Regulation of blood pressure
- Maintenance of blood osmolarity
- Regulation of blood glucose level.
3
Q
[26.2] Describe the kidneys
A
Paired reddish, bean-shaped organs located above the waste, between the peritoneum and posterior wall of abdomen - retroperitoneal.
4
Q
[26.2] What the renal hilum?
A
An indentation near the center of the concave border facing the vertebral column. Channel for the ureter, blood vessels, lymph vessels, and nerves.
5
Q
[26.2] List the three layers of tissue surrounding the kidney
A
- The renal capsule
- Adipose capsule
- Renal fascia
6
Q
[26.2] Describe the renal capsule.
A
Deep layer composed of smooth, transparent sheet of dense irregular connective tissue continuous with the outer coat of the ureter.
7
Q
[26.2] Describe the adipose capsule.
A
Middle layer composed of a mass of fatty tissue surrounding the renal capsule. Protection and structural stability.
8
Q
[26.2] Describe the renal fascia.
A
Superficial layer composed of a thin layer of dense irregular connective tissue anchoring the kidney to surrounding structures.
9
Q
[26.2] List the path of urine drainage, in order.
A
- Collecting duct
- Papillary duct
- Minor calyx
- Major calyx
- Renal pelvis
- Ureter
- Urinary bladder
10
Q
[26.2] What are the two distinct regions of the kidney?
A
The renal cortex and renal medulla.
11
Q
[26.2] What is the renal cortex?
A
The superficial, light red region of the kidney. Extends between renal pyramids to their base.
12
Q
[26.2] What are renal columns?
A
The portion of the renal cortex that extends between renal pyramids.
13
Q
[26.2] What is the cortical zone of the kidney?
A
The outer cortex region excluding the renal columns
14
Q
[26.2] What is the juxtamedullary zone?
A
The portion of the cortex only composed of renal columns.
15
Q
[26.2] What is the renal medulla?
A
The deep, darker reddish-brown region of the kidney, composed of renal pyramids and renal papilla.
16
Q
[26.2] What is the renal papilla?
A
The apex of the renal pyramids pointing towards the renal hilum.
17
Q
[26.2] What is the parenchyma?
A
The functional portion of the kidney composed of the renal cortex and renal pyramids.
18
Q
[26.2] What is a nephron?
A
The function unit of the kidney found within the parenchyma.
19
Q
[26.2] What are papillary ducts?
A
Ducts draining filtrate from nephrons.
20
Q
[26.2] What are the minor and major calyces?
A
Singular, calyx. Cuplike structures collecting urine from papillary ducts.
21
Q
[26.2] What is the renal pelvis?
A
A singular, large cavity draining the minor and major calyces. Drains into the ureter.
22
Q
[26.2] What is the renal sinus?
A
A cavity, expanded from the hilum, containing a portion of the renal pelvis, calyces, and branches of renal blood and lymph vessels.
23
Q
[26.2] What are the renal arteries?
A
Arteries within the kidney, left and right, receiving 20-25% of resting cardiac output.
24
Q
[26.2] What is renal blood flow?
A
The flow of blood through the kidneys, ~1200mL / min.
25
[26.2] What are afferent arterioles within kidneys?
Branches of blood vessels within the renal cortex, stemming from cortical radiate arteries and forming glomeruli.
26
[26.2] What is the glomerulus?
Branches of afferent arterioles forming ball-shaped capillary network supplying nephrons.
27
[26.2] What is an efferent arteriole?
Reuniting of glomerular capillaries to form arterioles carrying blood out of the glomerulus
28
[26.2] What are peritubular capillaries?
Divisions of efferent arterioles surrounding a portion of the nephron in the cortex.
29
[26.2] What are vasa recta?
Long, loop-shaped capillaries extending from efferent arterioles supplying tubular portions of the nephron in the medulla.
30
[26.2] What is a renal vein?
The single vessel transporting all blood out of the kidney.
31
[26.2] Where do renal nerves originate?
The renal ganglion.
32
[26.2] Which division of the ANS innervate renal nerves?
The sympathetic nervous system.
33
[26.3] What are nephrons?
The functional unit of the kidney.
34
[26.3] What are the two parts of the nephron?
The renal corpuscle and the renal tubule.
35
[26.3] What is renal corpuscle?
The portion of the nephron where blood plasma is filtered.
36
[26.3] What are the components of the renal corpuscle?
The glomerulus and the glomerular capsule.
37
[26.3] What is the renal tubule?
The portion of the nephron where filtrate passes through.
38
[26.3] List the main sections of the renal tubule.
1. Proximal convoluted tubule
2. Nephron loop / Loop of Henle
3. Distal convoluted tubule.
39
[26.3] What are collecting ducts?
Ducts draining filtrate from the distal convoluted tuble.
40
[26.3] Describe the nephron loop.
Composed of the descending limb of the nephron which extend towards or into the medulla from the cortex. The loop turns back and reaches into the cortex again, known as the ascending limb.
41
[26.3] What are cortical nephrons?
Nephrons with their renal corpuscles laying in the outer portion of the cortex, with short loops remaining in the cortex. 80-85% of nephrons.
42
[26.3] What are juxtamedullary nephrons?
Nephrons which lay deep in the cortex and have nephron loops extending into the medulla. 10-15% of nephrons. Their ascending limb usually is thin followed by a thicker portion.
43
[26.3] Describe the glomerular capsule.
A double-walled epithelial structure composed of a visceral and parietal layer.
44
[26.3] Describe the visceral layer of the glomerular capsule.
A single layer of modified simple squamous epithelial cells called podocytes that wrap around the endothelial cells of the glomerular capillaries
45
[26.3] What are podocytes?
Cells of the visceral glomerular capsule featuring feet-like projections called pedicels.
46
[26.3] Describe the parietal layer of the glomerular capsule.
Simple squamous epithelium forming the outer wall of the capsule.
47
[26.3] What is the capsular space of the glomerulus?
Space between the visceral and parietal glomerulus, continuous with the lumen of the tubule.
48
[26.3] Describe the cells that compose the proximal convoluted tubule.
Simple cuboidal cells with prominent brush borders of microvilli.
49
[26.3] Describe the cells composing the descending limb and thin ascending nephron loop.
Simple squamous epithelial cells.
50
[26.3] Describe the cells composing the thick ascending limb.
Simple cuboidal or low columnar epithelial cells.
51
[26.3] Describe the cells composing the majority of the distal convoluted tubule.
Simple cuboidal epithelial cells.
52
[26.3] Describe the cells composing the last portion of the distal convoluted tubule.
Simple cuboidal cells consisting of principle and intercalated cells.
53
[26.3] What is the macula densa?
The columnar tubule cells of the thick ascending limb of the nephron loop that make contact with afferent arterioles.
54
[26.3] What are juxtaglomerular cells?
Modified smooth muscle fibers within the walls of afferent arterioles in contact with the macula densa. Located just before the glomerulus, hence the name.
55
[26.3] What is the juxtaglomerular apparatus?
A structure formed by the macula densa and juxtaglomerular cells of afferent arterioles.
56
What are principal cells?
Cells in the distal convoluted tubule with receptors for antidiuretic hormone and aldosterone.
57
[26.3] What are intercalated cells?
Cells in the distal convoluted tubule playing a role in homeostasis of blood pH.
58
[26.4] List the three basic processes of the nephron.
1. Glomerular filtration
2. Tubular reabsorption
3. Tubular secretion
59
[26.4] Describe glomerular filtration.
Water and most solutes move from blood plasma across the glomerular capillaries into the glomerular capsule, then the renal tubule.
60
[26.4] Describe tubular reabsorption.
Tubule cells reabsorb 99% of water and useful solutes, returning them to the blood through peritubular capillaries and vasa recta.
61
[26.4] Describe tubular secretion.
Secretion of wastes, drugs, and excess ions from blood into the filtrate as it flows through the tubule.
62
[26.5] What is glomerular filtrate?
Fluid entering the capsular space of the glomerulus.
63
[26.5] What is the filtration fraction?
The fraction of blood plasma in the afferent arterioles of the kidneys becoming glomerular filtrate. 16-20%
64
[26.5] What is the filtration membrane?
A leaky barrier formed by the glomerular capillaries and the podocytes surrounding the capillaries.
65
[26.5] What is the function of the filtration membrane?
Filtration of water and small solutes and prevention of filtration of plasma proteins and blood cells.
66
[26.5] List the three filtration barriers of the filtration membrane.
1. Glomerular endothelial cells
2. Basement membrane
3. Filtration slit
67
[26.5] Describe the role of glomerular endothelial cells in the filtration membrane.
Leaky cells due to large fenestrations allowing solutes from blood plasma into the glomerulus.
68
[26.5] What are mesangial cells?
Contractile cells aiding in regulation of glomerular filtration.
69
[26.5] Describe the basement membrane in the filtration membrane.
A layer of collagen fibers and negative glycoproteins between endothelium and podocytes allowing water and solutes through but repelling plasma proteins through the negative charge of glycoproteins.
70
[26.5] Describe the filtration slit of the filtration membrane.
The spaces between pedicels containing a "slit membrane" permitting passage of small molecules.
71
[26.5] List the three main pressures of net filtration pressure (NFP).
1. Glomerular blood hydrostatic pressure
2. Capsular hydrostatic pressure.
3. Blood colloid osmotic pressure.
72
[26.5] Describe glomerular blood hydrostatic pressure (GBHP).
The blood pressure within glomerular capillaries, ~55 mmHg. Promotes filtration.
73
[26.5] Describe capsular hydrostatic pressure (CHP).
The hydrostatic pressure exerted by fluid within the capsular space and renal tubule. ~15 mmHg and opposes filtration.
74
[26.5] Describe blood colloid osmotic pressure (BCOP).
Pressure within the blood exerted by proteins that oppose filtration, ~30 mmHg
75
[26.5] What is the formula for net filtration pressure?
NFP = GBHP - CHP - BCOP
76
[26.5] What is glomerular filtration rate?
The amount of filtrate formed in all renal corpuscles of both kidneys. ~125mL/min in males, 105mL/min in females.
77
[26.5] What is renal autoregulation?
The ability of kidneys to maintain constant renal blood flow and glomerular filtration rate.
78
[26.5] What are the mechanisms of renal autoregulation?
Myogenic mechanism and tubuloglomerular feedback.
79
[26.5] What is the myogenic mechanism?
A mechanism that occurs when stretching activates contraction of smooth muscle in walls of afferent arterioles. Negative feedback loop where increased blood pressure increases stretch causing contraction and stemming blood flow, and decrease in blood pressure results in relaxation and promoting blood flow.
80
[26.5] What is tubuloglomerular feedback?
Feedback from macula densa to the glomerulus when cells detect changes in solute level in filtrate. Increase in solutes means higher filtration rate, sending signals to vasoconstrict. Lower levels of solute trigger relaxation to promote blood flow and thus filtration.
81
[26.5] How is glomerular filtration rate regulated by the nervous sytem?
Autonomic nervous system activate a-1 receptors in the smooth muscle of afferent arterioles, constricting the vessels and decreasing the glomerular filtration rate. Occurs when the sympathetic nervous system is stimulated and overrides renal autoregulation.
82
[26.5] How is glomerular filtration rate regulated by hormones?
Angiotensin II reduces glomerular filtration rate, and atrial natriuretic peptide increases glomerular filtration rate.
83
[26.6] What are the reabsorption routes fluid can take into peritubular capillaries?
Paracellular reabsorption and transcellular reabsorption.
84
[26.6] What is the apical membrane of cells in the renal tubule?
The surface of a cell that contacts tubular fluid.
85
[26.6] What is the basolateral membrane of cells in the renal tubule?
The surface of a cell that contacts interstitial fluid at the base and sides of the cell.
86
[26.6] What is paracellular reabsorption?
Fluid leak that occurs between the cells of the proximal convoluted tubule despite the tight junctions that hold them together.
87
[26.6] What is transcellular reabsorption?
Movement of a substance as it passes from the tubular lumen into the apical membrane of a cell, across the cytosol, and into the interstitial fluid.
88
[26.6] What is primary active transport?
Transport of substances using energy derived from ATP.
89
[26.6] What is secondary active transport?
Transport of a substance using the energy stored in an ion's electrochemical gradient, typically moving one substance with its gradient and another against its gradient.
90
[26.6] What is the transport maximum?
The upper limit of how fast a transporter can work.
91
[26.6] What is obligatory water reabsorption?
Water reabsorbed with solutes in tubular fluid, as water is "obliged" to follow the solutes.
92
[26.6] What is facultative water reabsorption?
The reabsorption of 10% of water filtrated occurring in the collecting ducts and regulated by antidiuretic hormone.
93
[26.6] Where does the largest amount of solute and water resorption occur?
The proximal convoluted tubules.
94
[26.6] What percentages of solutes and water are reabsorbed in the proximal convoluted tubules?
Water: 65%
Na + K: 65%
Glucose + Amino acids: 100%
Cl + urea: 50%
HCO3: 80 - 90%
95
[26.6] How do Na symporters play a role in reabsorption?
The symporters reabsorb substances like glucose, amino acids, lactic acids, and vitamins through secondary active transport as they facilitate the movement of Na through primary active transport.
96
[26.6] How does the Na-H antiporter function?
The antiporter expels H ions into the lumen of the proximal convoluted tubule as secondary active transport when it uptakes Na through primary active transport.
97
[26.6] How are H ions sourced for the antiporters to function?
From the disassociation of carbonic acid into bicarbonate. The carbonic acid is sourced from CO2, either in the bloodstream or cellular metabolic waste.
98
[26.6] What is aquaporin-1?
Integral proteins in the plasma membrane that create water channels, increasing the rate of water movement across the membranes.
99
[26.6] What is the rate at which fluid enters the nephron loop?
40 - 45 mL/min
100
[26.6] What is the effect of the nephron loop being relatively impermeable to water?
It reduces osmosis of water and leads to solutes being reabsorbed at a higher rate than water, allowing for independent regulation of volume and osmolarity of body fluids.
101
[26.6] What type of symporters are found in the ascending nephron loop?
Na - Cl symporters.
102
[26.6] What is the rate of fluid entry in the distal convoluted tubes, and what are the percentage of resorption for molecules?
Rate: 25 mL / min
Water: 10-15%
Na + Cl: 5%
103
[26.6] What hormone acts on the distal convoluted tubule, and what is its action?
Parathyroid hormone, calcium resorption.
104
[26.6]
