Urinary (Basics) Flashcards
1
Q
What is the main function of the renal cortex?
A
Filtration (to form urine)
2
Q
What is the main function of the medulla?
A
Collection & excretion of urine
3
Q
What happens in the renal papilla?
A
Medullary pyramids empty urine into major/minor calyces
4
Q
Where are the glomeruli located in the kidney?
A
Cortex
5
Q
what % of cardiac output may pass through the kidneys at any one time?
A
25%
6
Q
Where is the capillary network found in the glomerulus?
A
Between TWO arterioles
7
Q
What is the functional unit of the kidney?
A
The nephron
8
Q
What are the 3 main section of the renal tubule?
A
PCT
Loop of Henle
DCT
9
Q
What is the glomerulus?
A
Afferent arteriole divisions forming a capillary network at the Bowmans Capsule
10
Q
Which type of nephron are present in dogs and cats? Clinical significance?
A
Juxtamedullary ONLY - urine very concentrated
11
Q
Where do JM nephrons recieve their blood supply from?
A
Vasa Recta - runs parallel to LoH
12
Q
What are the3 major functions of the kidney?
A
Regulates fluid/electrolyte balance
Extretes waste
Produces hormones
13
Q
Which two hormones are produced in the kidney?
A
EPO
Renin
14
Q
Describe how the peritubular capillaries promote reabsorption.
A
High oncotic pressure
15
Q
What does the renal corpuscle consist of?
A
Bowmans Capsule
Glomerulus
16
Q
What are the 3 major functions of the nephron?
A
Glomerular Filtration
Tubular reabsorption
Tubular secretion
17
Q
What is the GFR?
A
Amount of filtrate formed in all renal corpuscles of both kidneys in each minute.
18
Q
What is the aim of tubular reabsorption?
A
Returning important substances to the body FROM the filtrate
19
Q
What is the aim of tubular secretion?
A
Movement of waste from body TO the filtrate
20
Q
Where does filtration take place?
A
Glomerulus (Renal corpuscle)
21
Q
Where does bulk, unregulated reabsorption take place?
A
PCT
22
Q
Where does secretion take place?
A
PCT
23
Q
How much filtrate doe shte kidney produce per day?
A
60x plasma volume
24
Q
Which process in the nephron is indiscriminate?
A
Filtration
25
Which process in the nephron is extensive and selective?
Tubular reabsorption
26
Where does fluid filtered from the glomerulus enter?
Bowmans space (lumen of urinary tract)
27
Why is it important to maintain glomerular capillary BP?
GFR is directly related to CBP
28
what cannot be filtered at the glomerulus?
Proteins
29
What are the 3 factors affecting GFR?
capillary HSP
capillary flow rate
capillary SA
30
Desrcibe the link between vasoconstriction and GFR.
Vasoconstriction decreases GFR.
| Vasodilation increases GFR
31
Which cells detect increases in GFR and where are they?
Macula Densa Cells
In JM apparatus.
AUTOREGULATE
32
A massive increase in sympathetic tone has what effect on GFR?
Vasoconstriction
Dec renal blood flow
Dec GFR
33
What effect does sympahtetic drive have on blood volume and how?
Conserves fluid via dec GFR and stimulation of renin
34
What effect does Ang II have on GFR?
Decreases
35
What effect does ANP have on GFR?
increases it
36
Why is ANP released?
stretching of atria
37
Where is angiotensinogen made?
Liver
38
Where is aldosterone secreted from?
Adrenal Cortex
39
Where is ADH secreted from?
Hypothalamus to Posterior Pituitary and blood
40
What are the two routes of tubular reabsorption?
PAracellular (passive)
| Transcellular (active)
41
The asymmetrical distribution of which ion pump is key to tubular reabsorption?
Na/K
42
In which direction does Na move in reabsorption and how?
Active transport of Na OUT of tubular cells towards capillaries
43
How does Na reabsorption drive reapsorption of H20?
Anions follow electrochemical gradient made by Na+ active transport.
Water moves via osmosis following solute.
44
How is glucose reabsorbed?
secondary active transport - facilitated via Na symport.
45
How do other Cations become reabsorbed?
Follow water down diffusion gradient (passive)
46
What is transamination?
conversion of amino acid to glutamate
47
What is deamination?
conversion of glutamate to urea
48
How is urea transported?
Passively
49
How does the body get rid of urea?
continuous high GFR required to prevent high blood concentration
50
What are the 3 key principles of secretion in the PCT?
Always active
Non-selective
Substances must be ionised
51
What substances are secreted in the PCT?
Hormones
Drugs
Environmental Pollutants
52
How does the PCT affect acid-base balance?
Secretes H+
| Reabsorbs HCO3
53
What is the key membrane transporter in the LoH?
Ka+-K+2Cl- symporter
54
What is the descending loop of henle permeable to?
water
55
What is the descending loop of henle NOT permeable to?
Na
56
What is the ascending loop of henle permeable to?
Na/K/Cl (active)
57
What is the ascending loop of henle NOT permeable to?
water
58
Was is the osmolarity of the water leaving the LoH?
Hyposmotic
59
How does ADH cause water retention in the kidney?
Insert aquaporins onto apical memberane to promote absorption
60
What 2 things cause ADH release?
Hypovolaemia
| Hyperosmolarity
61
What is the role of the DCT?
Regulated reabsorption/secretion
62
What are the two epithelial cell types in the DCT?
Principal Cells
| Intercalated cells
63
What pumps/channels do principal cells in the DCT contain?
Na/K pump on basolateral membrane
| Na/K leak channels on apical membrane
64
What is the role of intercalated cells in the DCT?
H+ secretion
65
What is the role of H+ ATPase in the DCT?
Active pump of H+ into filtrate in DCT
66
What is the role of H+ K+ ATPase in the DCT?
Active pump of H+ into urine in EXCHANGE for K+
67
What is the role of Type A intercalated cells?
work in ACIDOSIS.
Secrete H+
Reabsorb HCO3
68
What is the role of Type B intercalated cells?
work in ALKALOSIS.
Secrete HCO3
Reabsorb H+
69
How does PTH stimulate the nephron?
Stimulates Ca reabsorption in DCT
70
Which hormone inhibits Ca reabsorption in the DCT?
Calcitonin
71
What is the role of aldosterone in the DCT?
stimulates principal cells to reabsorb more Na and Cl and secrete K
72
What stimulates aldosterone secretion?
Hyperkalaemia
73
What is the difference in H20/Na balance in the PCT vs DCT?
Separate regulation in DCT, water follows Na in PCT
74
Which area reabsorbs the greatest volume of water ; PCT or DCT?
PCT
75
what is the key principle of K reabsorption in PCT/LoH?
ALL K+ reabsorbed here regardless of body's status.
76
Which is more important for K+ regulation; absorption or secretion?
Secretion in DCT/collecting duct
77
What stimulates the release of EPO?
Hypoxia
78
Where is EPO produced?
Peritubular capillaries in renal cortex
79
What is the MOA of EPO?
Increases speed of maturation/release of RBCs at bone marrow
80
What is the role of ANP?
Na and H20 excretion
81
Which ions are absorbed in the DCT?
Na, Cl, Ca
82
Which ions are excreted in the DCT?
K+ and H+
83
Describe the ANS effects on bladder filling.
SYMPATHETIC
Relaxes detrusor
Contracts internal sphincter
84
Describe the ANS effects on bladder emptying.
PARASYMP
Contracts detrusor
Relaxes internal sphincter
85
Which receptors are responsible for detrusor relaxation?
Beta2
86
Which receptors are responsible for intrnal sphincter contraction?
alpha 1
87
Which receptors are responsible for detrusor contraction?
Muscarinic
88
Which receptors are responsible for internal sphincter relaxation?
Muscarinic
89
What is the normal blood pH for a mammal?
7.35-7.45
90
What are the 2 intracellular buffer systems?
Phosphate
| Protein
91
What are the 2 extracellular buffer systems?
Protein
| Carbonic Acid
92
How can you tell the difference between pre-renal and renal azotaemia?
Pre-renal CAN concentrate urine.
93
Kidney dysfunction will increase what in the blood?
Urea
Creatinine
K+
H+
94
What may be found in the urine during kidney dysfunction which is nor usually present?
Glucose
| Protein
95
What are the 3 drivers of ADH secretion?
increase osmolarity
hypotension
hypovolaemia
96
What is a commonly used osmotic diuretic in veterinary practice & how is it given?
Mannitol (IV)
97
How do osmotic diuretics work?
Filtered in kidney but NOT reabsorbed - maintain osmotic pressure in filtrate
98
Which patients are CIed for use of mannitol?
Pulmonary Oedema
CHF
(may cause initial inc in ECF)
99
Name two carbonic anhydrase inhibitors used in veterinary medicine.
Acteazolamide
| Dichlofenamide
100
What is the MOA for carbonic anhydrase inhibtors in the PCT?
Inhibit CI enzyme - reduced H+/HCO3 production so reduced Na/H+ exchange
101
Which patients would be CIed for CA inhibitors?
Liver disease - NH4 in circulation would increase
102
Name 2 loop diuretics used in vet med.
Furosemide
| Torasemide
103
what is the MOA of loop diuretics?
Inhibit NaKCl cotransporter to keep ions in UT
104
What are loop diuretics used to treat?
Oedema
CHF
Hypercalcaemia
105
what are CAIs used to treat?
Glaucoma
| Metabolic Alkalosis
106
What are osmotic diuretics used to treat?
Poisoning
Oliguric renal failure
cerebral oedema
Glaucoma
107
What effect would a long/high dose of loop diuretics have?
Dehydration
Hypovolaemia
Weakness
108
Name 3 thiazides used in vet med.
Chlorothiazide
Hydrochlorothiazide
Trichloromethiazide
109
What are thiazides used to treat?
Oedema
Ca oxalate uroliths
nephrogenic diabetes insipidus
110
What is the MOA for thiazides?
inhibit Na/Cl- co-transport before Na/K+ exchange
| Inc Na/Cl/Mg/K excretion
111
What side effects/CIs are associated with thiazides?
Hyperglycaemia
| CI in renal failure
112
Name 3 K+ sparing diuretics.
Spironolactone
Amiloride
Triamterine
113
What is the MOA of spironolactone?
Aldosterone competitive inhibitor
114
What is the MOA of Amiloride/Triamterine?
Inhibit Na/K+ATPase activity
115
Which drugs may be used to directly stimulate the SYMP system for increased urethral sphincter activity?
Phenylpropanalamine
| Ephedrine
116
How does Phenylpropanalamine work?
Release of noradrenaline
| Direct receptor activation (alpha)
117
How does ephedrine work?
Increases noradrenaline activity at alpha and beta receptors
118
Which drugs may be used to INDIRECTLY stimulate the SYMP system for increased urethral sphincter activity?
Estriol - estrogen increases alpha adrenoreceptor sensitivity
119
Which drug may be used to decrease the detrusor activity?
Propantheline (antimuscarinic)
120
which drug increases detrusor activity via parasymp stimulation?
Bethanecol - Muscarinic Agonist
121
which drugs decrease urinary sphincter activity?
Alpha antagonists - phenolxybenzamine or prazosin
122
How can we inhibit the voluntary sphincter from maintaining urinary retention?
Central inhibition - diazepam
| Peripheral inhibition - dantrolene
123
what is the MOA of dantrolene with regard to urine retention?
Prevents Ca release form SR - uncouples muscle contraction (NOT SMOOTH)
124
What are the 4 types of urolith commonly found?
Struvite
Ca Oxalate
Urate
Cystine
125
How would you cure a struvite urolith?
Acidify urine
| Low Mg/P in diet
126
How would you prevent a struvite urolith?
Alkalinise urine
127
How would you prevent a urate urolith?
low protein diet
| alkalinise urine
128
Which drug can be given to aid urate urolithiasis?
Allopurinol (dec uric acid production)
129
Which drug can be given to aid cystine urolithiasis?
Penicillamine - binds to cystine to make soluble complex
130
Name 2 drugs used to decrease the pH of urine
Methionine
| Ammonium Chloride/sulphate
131
Name 2 drugs to increase the pH of urine
NaHCO3
| Na/K citrate
132
What class of drugs may be used in UTIs as an alternative to antibiotics?
Urinary Antiseptics i.e. Methanamine
133
Whatis the range for isosthenuria?
1.008-1.012
134
What does isosthenuria mean?
SG of plasma = SG urine
135
What is the normal urine conc of a cat?
>1.035
136
What is the normal urine conc of a dog?
>1.030
137
What does hyperphosphataemia lead to?
hyperP inhibits VitD --> NO neg feedback on PTH --> unabated PTH release
138
What are 5 potential causes for increased urea?
```
High protein diet
Recent meal
Catabolism (fever)
GI haemorrhage
Dehydration
```
139
What are 3 potential causes for decreased urea?
Severe Liver Dz
Low protein diet
Aggressive IVFT
140
Which solute can be used to measure GFR?
Creatinine - reliable mesaure of kidney fct
141
Name 2 causes of AKI
Acute poisoning
| Infection
142
What effect may AKI have on urine output?
Anuria OR
| Oliguria
143
What may you notice on biochem of an AKI patient?
Azotaemia
Inc P & K
Metabolic Acidosis
144
How is AKI treated?
IVFT
| Supportive Therapy
145
What may you notice on biochem of an CKD patient?
```
Azotaemia
Inc P
Metabolic acidosis
BUT...
Inc OR dec K!!
```
146
Common Cx of CKD include....
```
PUPD
Anorexia
Hypertension
Anaemia
Hyperphosphataemia
```
147
How does renal Dz cause bottle jaw?
Secodary hyperparathyrodism --> inc PTH & demineralisation of bone
148
HOw should CKD be managed?
fluids
low protein & P diet
Drugs: EPO and dec BP
149
Name 3 different phosphate binders.
Calcium Acetate
Lanthanum Carbonate Octahydrate
Sevelamer
150
Which drugs are used to reduce systemic BP in CKD cats?
Ace inhibitors
151
Which drug is used to reduce glomerular BP in CKD cats?
Telmisartan
