CH23 urinary Flashcards
1
Q
What are the primary functions of the kidney ?
A
- Regulating total water volume and total solute concentration in water
- Regulating ECF ion concentrations
- Ensuring long-term acid-base balance
- Removal of metabolic wastes, toxins, drugs
- Endocrine functions
2
Q
What are the endocrine functions of the kidney?
A
–Renin - regulation of blood pressure
–Erythropoietin - regulation of RBC production
3
Q
What is the structure marked A?
A
Adrenal Gland
4
Q
What is the structure marked B?
A
Iliac Crest
5
Q
What is the structure marked C?
A
Renal Artey
6
Q
What is the structure marked D?
A
Renal Hilum
7
Q
What is the structure marked E?
A
Renal Vein
8
Q
What is the structure marked F?
A
Kidney
9
Q
What is the structure marked G?
A
Ureter
10
Q
What is the structure marked H?
A
Urinary Bladder
11
Q
What is the structure marked I?
A
Urethra
12
Q
What are the Kidneys?
A
major excretory organs
13
Q
What is the function of the ureters?
A
transport urine from kidneys to urinary bladder
14
Q
What is the urinary bladder?
A
temporary storage reservoir for urine
15
Q
What is the function of the Urethra?
A
transports urine out of body
16
Q
Which Kidney sits lower in the body?
A
The right
17
Q
Why is the right kidney lower than the left?
A
Because it is crowded by the liver
18
Q
Which gland sits atop each kidney?
A
Suprarenal adrenal gland
19
Q
Ureters, renal blood vessels, lymphatics, and nerves enter and exit the kidney where?
A
Renal hilum
20
Q
How many lobes do you ususally have per kidney?
A
7-8
21
Q
Name the Layers of surrounding supportive tissue of the kidney
A
- Renal fascia
- Perirenal fat capsule
- Fibrous capsule
- Renal cortex
- Renal medulla
- Pyramids
22
Q
Describe the renal fascia of the kidneys
A
•Anchoring outer layer of dense fibrous connective tissue
23
Q
What is the function of the kidney’s perirenal fat capsule
A
fatty cushion
24
Q
What is the function of the Fibrous capsule of the kidney?
A
•Prevents spread of infection to kidney
25
What is the Renal cortex?
Granular-appearing superficial region
26
What is the renal medulla made up of?
cone-shaped medullary (renal) pyramids separated by renal columns
27
What are the structures of the internaal anatomy of the kidney?
* Papilla
* Lobe
* Renal pelvis
* Minor calyces
* Major calyces
28
What are renal papilla?
Tip of pyramid; releases urine into minor calyx
29
What is a renal lobe made up of?
Medullary pyramid and its surrounding cortical tissue
30
What is the renal pelvis?
–Funnel-shaped tube continuous with ureter
31
What is the function of the Minor calyces
Drain pyramids at papillae
32
What is the function of the Major calyces
–Collect urine from minor calyces
–Empty urine into renal pelvis
33
What is the pathway of urine?
* Renal pyramid
* minor calyx
* major calyx
* renal pelvis
* ureter
34
What is Pyelitis?
–Infection of renal pelvis and calyces
35
What is Pyelonephritis ?
–Infection/inflammation of entire kidney
36
What is the structure Labelled A?
Renal Cortex
37
What is the structure Labelled B?
Renal medulla
38
What is the structure Labelled C?
Major Calyx
39
What is the structure Labelled D?
Papilla of Pyramid
40
What is the structure Labelled E?
Renal Pelvis
41
What is the structure Labelled F?
Minor Calyx
42
What is the structure Labelled G?
Ureter
43
What is the structure Labelled H?
Renal Pyramid in renal medulla
44
What is the structure Labelled I?
Renal Column
45
What is the structure Labelled J?
Fibrous capsule
46
Which element of blood do the kidneys filter?
Blood Plasma
47
What is the structure labelled A?
Corticol radiate vein
48
What is the structure labelled B?
Corticol Radiate Artery
49
What is the structure labelled C?
Arcurate Vein
50
What is the structure labelled D?
Arcurate Artery
51
What is the structure labelled E?
Interlobar Vein
52
What is the structure labelled F?
Interlobar Artery
53
What is the structure labelled G?
Segmental arteries
54
Name the Nephron-Associated blood vessels?
Afferent Arteriole
Glomerulus (Capillaries )
Efferent arteriole
Peritubular capillaries/Vasa recta
55
what is the path of blood in to the nephron?
1. Aorta
2. Renal artery
3. segmental artery
4. interlobar artery
5. arcurate artery
6. cortical radiate artery
56
What is the path of blood out of the nephron ?
1. cortical radiate vein
2. Arcurate Vein
3. Interlobar Vein
4. Renal Vein
5. Inferior Vena Cava
57
What are Nephrons?
Structural and functional units of the kidney that form urine
58
What ae the two main parts of the nephron?
–Renal corpuscle
–Renal tubule
59
what are the two parts of the renal corpuscle?
Glomerulus
Glomerular capsule (Bowmans capsule)
60
What is the Glomerular capsule (Bowman's capsule)
•Cup-shaped, hollow structure surrounding glomerulus
61
What is the glomerulus?
Tuft of capillaries; highly porous fenestrated endothelium allows filtrate formation
62
What is the section marked A?
Proximal Convoluted tube
63
What is the section marked B?
Thin section
64
What is the section marked C?
Descending Limb
65
What is the section marked D?
Ascending Limb
66
What is the section marked E?
Thick Segment
67
What is the section marked F?
Distal convoluted Tubule
68
What is the section marked G?
Collecting Duct
69
Describe the anatomy of the Glomerular capsule
–Parietal layer - simple squamous epithelium
–Visceral layer - branching epithelial podocytes
* Extensions terminate in foot processes that cling to basement membrane
* Filtration slits between foot processes allow filtrate to pass into capsular space
70
What are the three main sections of the Renal Tubule?
–Proximal convoluted tubule (PCT)
–Nephron loop
–Distal convoluted tubule (DCT)
71
Describe the anatomy of the Proximal convoluted tubule (PCT)
–Cuboidal cells with dense microvilli (brush border) large mitochondria
72
Describe the anatomy of the Nephron Loop
–Distal descending limb, descending thin limb; simple squamous epithelium
–Thick ascending limb; Cuboidal to columnar cells;
73
Name the two cell types found in the collecting duct
–Principal cells
* Sparse, short microvilli
* Maintain water and Na+ balance
–Intercalated cells
•Cuboidal cells; abundant microvilli; 2 types:
–A and B; both help maintain acid-base balance of blood
74
What is the primary function of collecting ducts?
* Receive filtrate from many nephrons
* Run through medullary pyramids
* Fuse together to deliver urine through papillae into minor calyces
75
Name the two types of nephrons and where they are found.
Cortical Nephrons - Found almost entirely in renal cortex
Juxtamedullary nephrons - Long loops that deeply invade the medulla
76
What are Cortical nephrons
* Short nephron loop
* Glomerulus further from the cortex-medulla junction
* Efferent arteriole supplies the peritubular capillaries
77
What are Juxtamedullary nephrons?
Long nephron loop
Glomerulus closer from the cortex-medulla junction
Efferent arteriole supplies the vasa recta
78
What type of nephron is pictured?
Cortical nephron
79
What is the most important function of a juxtamedullary nephron?
concentration of urine
80
What type of nephron is pictured?
Juxtamedullary nephron
81
Why is the Glomerulus (Capillary bed) different from other capillary beds in the body?
* specialized for filtration
* fed and drained by arteriole
82
Why is the blood pressure in the glomerulus high?
–Afferent arterioles larger in diameter than efferent arterioles
–Arterioles are high-resistance vessels
83
What type of capillary bed is the juxtamedullary nephron associated with?
Vasa Recta
84
What type of capillary beds are cortical nephrons associated with?
Glomerulus
peritubular capillaries?
85
Describe the anatomy and function of peritubular capillary beds?
–Low-pressure, porous capillaries adapted for absorption of water and solutes
–Arise from efferent arterioles
–Cling to adjacent renal tubules in cortex
–Empty into venules
86
Describe the anatomy and function of the Vasa Recta
–Long, thin-walled vessels parallel to long nephron loops of juxtamedullary nephrons
–Arise from efferent arterioles serving juxtamedullary nephrons
–Function in formation of concentrated urine
87
What is the primary function of the juxtaglomerular complex (JGC)
It is important in regulation of rate of filtrate formation and blood pressure
88
What are the three cell populations found in the JGC?
* Macula Densa
* Granular cells
* Extraglomerular mesangial cells
89
Describe the anatomy and physiology of Macula Densa Cells in the JGC?
–Tall, closely packed cells of ascending limb
–Chemoreceptors; sense NaCl content of filtrate
90
Describe the anatomy and physiology of Granular Cells in the JGC?
–Enlarged, smooth muscle cells of afferent arteriole
–Secretory granules contain enzyme renin
–Mechanoreceptors; sense blood pressure in afferent arteriole
91
Describe the anatomy and physiology of Extraglomerular mesangial cells in the JGC?
–Between arteriole and tubule cells
–Interconnected with gap junctions
–May pass signals between macula densa & granular cells
92
How many litres of fluid are procecessed through the kidney per day?
roughly 180L
93
How many litres of urine are produced per day?
1.5L
94
what are the three stages of urine production?
–Glomerular filtration
–Tubular reabsorption
–Tubular secretion
95
What is the purpose of Glomerular filtration
– produces cell- and protein-free filtrate
96
What is the purpose of Tubular reabsorption
–Selectively returns 99% of substances from filtrate to blood in renal tubules and collecting ducts
97
What is the purpose of Tubular secretion
–Selectively moves substances from blood to filtrate in renal tubules and collecting ducts
98
What is filtrate?
–Blood plasma minus proteins
99
What is Urine?
–\<1% of original filtrate
–Contains metabolic wastes and unneeded substances
100
Describe the process of glomerular filtration?
* Passive process
* No metabolic energy required
* Hydrostatic pressure forces fluids and solutes through filtration membrane
* No reabsorption into capillaries of glomerulus
101
What are the three layers of the filtration membrane in the glomerular capsule?
–Fenestrated endothelium of glomerular capillaries
–Basement membrane (fused basal laminae of 2 other layers)
–Foot processes of podocytes with filtration slits; slit diaphragms repel macromolecules
102
What is the filtration membrane in the glomerulus?
•Porous membrane between blood and interior of glomerular capsule
–Water, solutes smaller than plasma proteins pass; normally no cells pass
103
104
What do proteins in filtrate indicate?
problems with the membrane
105
What happens to macromolecules that get stuck in the filtration membrane
Engulfed by glomerular mesangial cells
106
Which molecules can pass through the filtration membrane?
–Water, glucose, amino acids, nitrogenous wastes
107
What happens to plasma proteins?
They remain in the blood
108
Why do plasma proteins remain in the blood stream?
* maintains colloid osmotic pressure
* prevents loss of all water to capsular space
109
what is the driving force behind filtrate formation?
Hydrostatic pressure in glomerular capillaries
110
What is the Chief force pushing water, solutes out of blood
55 nn HG
111
What are the forces inhibiting filtrate formation in the glomerular?
–Hydrostatic pressure in capsular space (HPcs)
•Pressure of filtrate in capsule – 15 mm Hg
–Colloid osmotic pressure in capillaries (OPgc)
•"Pull" of proteins in blood – 30 mm Hg
112
What is the Sum of forces/ Net filtration pressure (NFP) in the Glomerulae?
–55 mm Hg forcing out; 45 mm Hg opposing = net outward force of 10 mm Hg
113
Constant GFR allows kidneys to do what?
make filtrate and maintain extracellular homeostasis
114
If GFR goes up what happens to Urine out put and blood pressure?
Urine output goes up and blood pressure goes down
115
If GFR goes down, what happens to urine output and blood pressure?
Urine output goes down and blood pressure goes up
116
What is the goal of extrinsoc controls in the kidneys?
–maintain systemic blood pressure
117
What do Intrinsic controls (renal autoregulation) do ?
–Act locally within kidney to maintain GFR
118
What are the extrinsic controls for the kidneys?
–Nervous and endocrine mechanisms that maintain blood pressure; can negatively affect kidney function
119
When do extrinsoc controls take precedence over intrinsic controls of the kidneys?
if systemic BP \< 80 or \> 180 mm Hg
120
How is GFP regulated?
via glomerular hydrostatic pressure (GHP):
121
What happens if Glomerular Hydrostatic pressure ( GHP) rises?
NFP and GFR rises
122
What are the two types of renal autoregulation?
–Myogenic mechanism
–Tubuloglomerular feedback mechanism
123
Explain the myogenic mechanism
If BP rises, muscle stretch causing constriction of afferent arterioles and restricts blood flow into glomerulus
If BP is low, afferent arterioles dilate
124
How does the Tubuloglomerular Feedback Mechanism work?
* Negative feedback loop
* If GFR high, the afferent arteriole constricts
* If GFR low, afferent arterion dilates
125
how does the extrinsic/SNS function in the kidney?
•If extracellular fluid volume extremely low (blood pressure low):
–Norepinephrine released by SNS; epinephrine released by adrenal medulla à
* Systemic vasoconstriction occurs, increasing blood pressure
* GFR à increased blood volume and pressure
126
what is the : Renin-Angiotensin- Aldosterone Mechanism?
Main mechanism for increasing blood pressure
127
What are the 3 pathways to renin release by granular cells in the kidney?
–Direct stimulation of granular cells by SNS
–Stimulation by activated macula densa cells when filtrate NaCl concentration low
–Reduced stretch of granular cells
128
Which chemicals do the kidneys release that act as paracrines that affect renal arterioles?
–Adenosine
–Prostaglandin E2
–Intrinsic angiotensin II – reinforces effects of hormonal angiotensin II
129
What is the Selective transepithelial process?
–~ All organic nutrients reabsorbed
–Water and ion reabsorption hormonally regulated and adjusted
130
What are the two active and passive routes of tubular reabsorption?
–Transcellular or paracellular
131
Explain the transcellular route of reabsoprtion in the kidneys
–Apical membrane of tubule cells
–Cytosol of tubule cells
–Basolateral membranes of tubule cells
–Endothelium of peritubular capillaries
132
Explain the paracelllular route of reabsorption in the kidneys
–Between tubule cells
•Limited by tight junctions, but leaky in proximal nephron
–Water, Ca2+, Mg2+, K+, and some Na+ in the PCT
133
What is the Transport maximum (Tm)?
for ~ every reabsorbed substance; reflects number of carriers in renal tubules available
134
What happens when transport carriers reach maximum?
The excess of the given substance is excreted in the urine
135
Which is the site of most Absorption?
PCT
136
What is absorbed at the PCT?
* All nutrients, e.g., glucose and amino acids
* 65% of Na+ and water
* Many ions
* All uric acid; ½ urea
137
What filters out at the descending limb of the nephron loop?
Water, solutes cannot
138
What filters out at the ascending limb of the nephron loop?
Solutes, H20 cannot
139
What is the mechanism in the thin segment of the nephron loop?
passive Na+ movement
140
What mechanisms are in use in the thick segment of the nephron loop?
Na+-K+-2Cl- symporter and Na+-H+ antiporter; some passes by paracellular route
141
How is reabsorption regulated at the DCT and Collecting duct
Hormonal
* Antidiuretic hormone (ADH) – Water
* Aldosterone – Na+ (therefore water)
* Atrial natriuretic peptide (ANP) – Na+
* PTH – Ca2+
142
What is the effect of Antidiuretic hormone (ADH) on DCT and collecting ducts?
–Causes principal cells of collecting ducts to insert aquaporins in apical membranes increasing water reabsorption
143
What happens as levels of ADH increase in renal tubules and collecting ducts?
Water absorption increases
144
What is the function of aldosterone in renal tubules and collecting ducts
increase blood pressure; decrease K+ levels
145
What is the function of Atrial natriuretic peptide in renal tubules and collecting ducts?
Parathyroid hormone acts on DCT to increase Ca2+ reabsorption
146
Where does the majority of tubular secretion occur?
PCT
147
What substances are secreted at the PCT?
* drugs
* urea and uric acid
* excess K+
148
what is the function of tubular secretion in the PCT?
•Controls blood pH by altering amounts of H+ or HCO3– in urine
149
What is the mechanism by which the kidneys regulate urine volume and regulation?
Countercurrent mechanism
150
What is the most important factor in the regulation of urine volume and concentration?
Osmolarity
151
What is the countercurrent mechanism?
•Occurs when fluid flows in opposite directions in 2 adjacent segments of same tube with hair pin turn
152
What is the countercurrent multiplier?
interaction of filtrate flow in ascending/descending limbs of nephron loops of juxtamedullary nephrons
153
What is the countercurrent exchanger
Blood flow in ascending/descending limbs of vasa recta
154
What is the role of the countercurrent mechanisms?
–Establish and maintain osmotic gradient (300 mOsm to 1200 mOsm) from renal cortex through medulla
–Allow kidneys to vary urine concentration
155
What occurs in the descending limb as part of the countercurrent mechanism?
–Freely permeable to H2O
–H2O passes out of filtrate into hyperosmotic medullary interstitial fluid
–Filtrate osmolality increases to ~1200 mOsm
156
What occurs in the ascending limb during the countercurrent mechanism?
–Impermeable to H2O
–Selectively permeable to solutes
•Na+ and Cl– actively reabsorbed in thick segment; some passively reabsorbed in thin segment
–Filtrate osmolality decreases to 100 mOsm
157
How is the Constant 200 mOsm difference between 2 limbs of nephron loop and between ascending limb and interstitial fluid maintained?
•Difference "multiplied" along length of loop to ~ 900 mOsm
158
What is the role of the Vasa Recta in the countercurrent mechanism?
* Vasa recta
* Preserve medullary gradient
–Prevent rapid removal of salt from interstitial space
–Remove reabsorbed water
Water entering ascending vasa recta either from descending vasa recta or reabsorbed from nephron loop and collecting duct
159
Which Nephrons create an osmotic gradient within the renal medulla that allows the kidney to produce urine of varying concentration
Juxtamedullary nephrons
160
What type of feedback loop is the countercurrent mechanism?
Positive feedback loop
161
Which three properties of the nephron establish the osmotic gradient?
* Countercurent movement
* Descending limb is permeable to water and not salt
* Ascending limb is impermeable to water and pumps out salt
162
filtrate entering the nephron loop is....
isosmotic to both blood pasma and cortical interstitial fluid
163
In the descending limb filtrate is...
concentrated as water moves down the osmotic gradient into the interstitial medullar
164
filtrate reaches it's highest concentration at the
bend of the nephron loop
165
What occurs in the ascending limb
na+ and Cl- are pumped out increasing interstitial fluid osmolarity
166
filtrate is at it's most dilute (hypo-osmotic)
as it leaves the nephron loop
167
Which chemicals enhance urinary output
* ADH inhibitors, e.g., alcohol
* Na+ reabsorption inhibitors, e.g., caffeine, drugs for hypertension or edema
* Loop diuretics
* Osmotic diuretics
168
1. What factors must be assesed to examine renal function?
both blood and urine
169
How do we calculate renal clearance rate?
•C = UV/P
Clearance= concentration of substance in urinexflow rate of urine/concentration of same substance in plasma
170
Which substance is used as the standard when calsculating renal clearance rate?
Inulin(Plant polysaccharide)
171
What does GFR \< 60 ml/min for 3 months indicate?
Chronic renal disease
172
What does a GFR \< 15 ml/min indicate
Renal failure
173
What are the normal characteristics of urine?
–Clear
–Pale to deep yellow from urochrome
–Slightly aromatic when fresh
- PH 6 (slightly acidic)
- Specific gravity should be 1.001 to 1.035
- •95% water and 5% solutes
174
•Abnormally high concentrations of any constituent, or abnormal components, e.g., blood proteins, WBCs, bile pigments in the urine could indicate what?
indicates pathology
175
What is the function of ureters?
Convey urine from kidneys to bladder
176
What are the three layers of the ureter
1. Mucosa (inner)
2. Muscularis (middle layers)
3. Adventitia (external)
177
what are renal calculi?
kidney stones in the renal pelvis
178
What is the treatment for renal calculi?
shock wave lithotripsy
179
What is the urinary bladder?
•Muscular sac for temporary storage of urine
180
What is the trigone?
181
Where do urine infections tend to be most prolific?
in the trigone
182
Name the three layers of the urinary bladder
–Mucosa - transitional epithelial mucosa
–Thick detrusor - 3 layers of smooth muscle
–Fibrous adventitia (peritoneum on superior surface only)
183
What is the normal size and volume of the full bladder?
12 cm long; holds ~ 500 ml
184
What is the urethra
* Muscular tube draining urinary bladder
* Lining epithelium
* Mostly pseudostratified columnar epithelium,
185
Name the sphincters in the urethra
**–Internal urethral sphincter**
•Involuntary (smooth muscle)
**–External urethral sphincter**
•Voluntary (skeletal) muscle
186
Name the three regions of the male urethra
* prostatic
* intermediate
* spongy
187
Which three mechanisms are required for urination/voiding to occur
1. Contraction of detrusor by ANS
2. Opening of internal urethral sphincter by ANS
3. Opening of external urethral sphincter
188
What is micturition?
•Reflexive urination (urination in infants)
189
At what age to pontine control centers mature?
•between ages 2 and 3
190
What is the usual reason for incontinence?
weakened pelvic muscles
191
What is Stress incontinence?
•Increased intra-abdominal pressure forces urine through external sphincter
192
What is Overflow incontinence?
Urine dribbles when bladder overfills
193
What are the common reasons for urinary retention?
–Common after general anesthesia
–Hypertrophy of prostate
194
what are the three most common congenital abnormalities in the kidneys
Horseshoe kidney
Hypospadias
Polycyctic kidney disease
195
Which bacteria accounts for 80% of urinary tract infections?
E.coli
