Physiology of the Kidney Flashcards

Question

Answer 1

Distal connective tubule (CNT)

Answer 2

Distal convoluted tubule (DCT)

Answer 3

Thick ascending limb (TAL)

Answer 4

Ascending thin limb (ATL)

Answer 5

Cortical collecting duct (CCD)

Answer 6

Medullary collecting duct (MCD)

Answer 7

* Simple filtration * Selective/Passive reabsorption * Excretion

Answer 8

* Fenestrated endothelium * Glomerular basement membrane (_GBM_ ) * Slit diaphragms

Answer 9

* Size * Shape * Charge

Answer 10

negative \< neutral \< positive

Answer 11

* Collagen * Laminin * Nidogen * Proteoglycans

Answer 12

* Collagen and Laminin form two independent networks * Nidogen links these networks * Adhesion of collagen and laminin to podocytes and endothelial cells

Answer 13

Proteoglycan: Anionic filtration barrier

Answer 14

Adhesion to podocytes

Answer 15

Adhesion to endothelial cells

Answer 16

Large plasma proteins

Answer 17

* Pedicules of the podocytes * _Contains slit diaphragm_

Answer 18

Zipper-like

Answer 19

Between the foot processes of the podocytes

Answer 20

Slit area can increase with _increased intraglomerular pressure_

Answer 21

Glomerular proteins | (Exclusive to the slit diaphragm)

Answer 22

_Congenital Nephrotic Syndrome (NPHS1)_ model Leading to heavy proteinuria

Answer 23

* Persistent oedema * Recurrent infections

Answer 24

Immunoglobulin

Answer 25

* 8 x Ig-like modules (C2) * 1 x Fibronectin (type-3-like) module

Answer 26

Cell-cell interactions

Answer 27

9 x tyrosine residues ## Footnote *Used for ligand binding*

Answer 28

C-terminus: Intracellularly N-terminus: Extracellularly

Answer 29

Non-real capillaries

Answer 30

Real capillaries

Answer 31

Glomerulus

Answer 32

Peritubular capillary

Answer 33

Cortical nephron

Answer 34

Juxta Medullary Nephron

Answer 35

Peritubular capillary

Answer 36

Vas _aferent_

Answer 37

Vas _efferent_

Answer 38

Venules, *v.* *renalis*

Answer 39

Vasa Recta

Answer 40

* Enters renal medulla * Henle's loop * Countercurrent exchange * Concentration of urine

Answer 41

* Runs to α-adrenergic receptors (on v. afferent) * Leads to vasoconstriction of the afferent arteriole * GFR reduced * Rest: minimum AP * Physical activity: Intensive AP

Answer 42

Cholinergic-mediated reaction ## Footnote *(Function not understood)*

Answer 43

Sense of capsule stretching

Answer 44

Analysis of urine and plasma

Answer 45

* Tubule puncture * Clearance technique * X-ray * Scinthgraphy * Ultrasound

Answer 46

Examination of the fluid composition ## Footnote *(Kidney structure is too fine to examine histologically)*

Answer 47

* Using a fine glass capillary * Retrieval of samples from different sections of the tubules * Examination of samples under a microscope

Answer 48

* Labelled substance (isotope) administered intravenously * Isotope appears in the kidney, reaching a maximum conc. * This is detected with a detector on the body surface

Answer 49

* Anatomical details * Blood supply

Answer 50

* Measures volume of plasma which all test substances have been removed from * Shows the ability of the kidney to remove substances from the blood plasma

Answer 51

**(U x V)/P = *Clearance* ml/min** * U= Conc. in urine* * P= Conc. in plasma* * V= Produced urine (per minute)*

Answer 52

* Glucose * Inulin * PAH

Answer 53

125ml/min couldn't be filtered Therefore: _Clearance = 125 ml/min_

Answer 54

Plasma concentration

Answer 55

* Functional standards of the kidney * Quantitative values of functional disorders

Answer 56

Glomerular filtration rate (GFR)

Answer 57

Renal plasma flow (RPF)

Answer 58

Reabsorption

Answer 59

0 ml/min ## Footnote *(Totally reabsorbed)*

Answer 60

Constant at low plasma concentration

Answer 61

The _secretory capacity_ of renal tubules _decreases_

Answer 62

Transport maximum

Answer 63

Inulin's clearance Even under extremely high values

Answer 64

* Freely filtered * Passively moves along tubules * A portion remains in the interstitium * Clearance of urea is always smaller than that of inulin

Answer 65

* Urea recirculation damaged * Urea conc. increases in blood * Uraemia

Answer 66

* Filtered freely * Doesn't reach descending limb of Henle's loop * Entirely reabsorbed in the proximal tubule * Normally: clearance of glucose is 0

Answer 67

* Glucose plasma so high * Tubular cells unable to reabsorb it * Transfer maximum (Tm_gluclose) is therefore reached * Glucose appears in the urine

Answer 68

Filtration + Resorption

Answer 69

Filtration + Redfiffusion

Answer 70

Filtration only

Answer 71

Filtration + Secretion

Answer 72

**E = (Pa - Pv)/Pa** * Pa = arterial conc. of substance* * Pv = venous concrentration of substance*

Answer 73

The ability of the kidney to eliminate a substance from the organism

Answer 74

Clearance of a substance that is: * Filtered * Excreted So that none remains in the outgoing renal vein

Answer 75

PAH ## Footnote *Completely cleared (E=1)*

Answer 76

* Cortex = 90% * Outer medulla = 8-9% * Inner medulla = 1-2%

Answer 77

Glomerular filtration rate Amount of filtrate produced per unit time

Answer 78

under 80-250mmHg

Answer 79

Inulin and Creatine

Answer 80

120 ml/min

Answer 81

_Mass_ of substance that is _ultrafiltered per unit time_ _mg/min_

Answer 82

Clearance value GFR = (UxV)/P Substance such as _Inulin_

Answer 83

* Human = 120 * Cow = 75 * Pig = 70 * Horse = 60 * Dog = 50

Answer 84

Physiological by-product of muscle metabolism

Answer 85

C_creatinine

Answer 86

No substantial influence

Answer 87

Change in GFR similar to GP change

Answer 88

Reduce GFR

Answer 89

Decrease of GFR

Answer 90

Decrease GFR

Answer 91

Decreased GFR

Answer 92

Capillary wall

Answer 93

Capillary fenestrations

Answer 94

Basement membrane

Answer 95

Glomerular filtrate

Answer 96

Outer wall of Bowman's capsule

Answer 97

Glomerular (Bowman's) capsule

Answer 98

Glomerular ultrafiltrate

Answer 99

55-60 mmHg

Answer 100

15-20 mmHg

Answer 101

Filtration pressures

Answer 102

The upper limit of reabsorption

Answer 103

350 mg/min

Answer 104

If the filtered load/Tm_glucose is \> 350mg/min

Answer 105

Maximum transport

Answer 106

Normal filtered load range

Answer 107

Glucose loss: Excretion

Answer 108

Reabsorption

Answer 109

* Diabetes mellitus * Pregnancy

Answer 110

The point where above a certain plasma conc., secretion becomes constant (all secreting nephrons reach their maximum)

Answer 111

Filtration + Secretion

Answer 112

* Linear phase * SDL phase * Saturation phase

Answer 113

Filtration

Answer 114

Linear phase

Answer 115

SDL phase ## Footnote *Self-depression limit phase*

Answer 116

Saturation phase

Answer 117

* Cells become unable to secrete * Secretion capacity is reached * Excretion decreases

Answer 118

* Curve is parallel with filtration * No more secretion * Excretion depends on filtration

Answer 119

* Cortical vessels innervated by sympathetic nerves * No sympathetic innervation to the medulla

Answer 120

* Pressor reflex * Redistribution of blood

Answer 121

1. Decrease of blood pressure 2. Depressor centre activity decreases 3. Pressor activity increased 4. Periperal vasoconstriction 5. Renal ischemia

Answer 122

Increased sympathetic tonicity 1. Increased muscular activity/shock/pain 2. Renal ischaemia 3. Redistribution of blood

Answer 123

Juxtaglomerular apparatus | (JGA)

Answer 124

Bowman capsule

Answer 125

* Afferent arteriole * Glomerulus * Efferent arteriole

Answer 126

Mesangial Cells

Answer 127

Macula densa cells

Answer 128

Epithelial cells of the distal tubule

Answer 129

Juxtaglomerular cells

Answer 130

* Macula densa * Mesangial cell * Swollen smooth muscle * + myoepithelial of vas. aff/eff

Answer 131

* Renin production * A sensor of salt + water metabolism * Baroreceptor * Hormone production * Angiotensin-II

Answer 132

In the renin-angiotensin system

Answer 133

* Baroreceptor threory * Macula densa theory

Answer 134

* Triggered by EC hypovolemia * Vas. aff pressure decrease * Transmural pressure decrease * Arterial smooth muscle relax * _JGA-__baro__-R_ stimulated * Renin secretion

Answer 135

* Triggered by reduced Na-content of distal tubule * Stimulation of macula densa cells * Stimulation of myoepithelium of juxtaglomerular cells * Renin secretion

Answer 136

Renin-angiotensin system

Answer 137

* Pressor effect * Salt retention * Direct * Indirect * Nervous system effect

Answer 138

* Increase arterial pressure * Dipsogenic effect * Increase catecholamine synthesis * Increased intrarenal vasoconstriction * ADH stimulation

Answer 139

* Pressor effect 50% lower than Angiotensin II * Stimulation of aldosterone secretion is equivalent to Angiotensin II

Answer 140

Angiotensinogen

Answer 141

Angiotensin-I

Answer 142

Angiotensin-converting enzyme ## Footnote *Found mainly in the lungs*

Answer 143

Angiotensin-II

Answer 144

* ADH Stimulation * Salt appetite * Thirst * GFR, RFB decrease

Answer 145

* Aldosterone production * Vasoconstriction

Answer 146

Increased salt + water intake

Answer 147

Increased salt + water conservation

Answer 148

Hypovolemia counterregulated

Answer 149

Stimulates intake

Answer 150

Renin-angiotensin system

Answer 151

Increase of BP

Answer 152

* Increase of Na⁺/ H⁺ exchange * Increase HCO₃^- reabsorption in the proximal tubule

Answer 153

* Vas efferent constriction * GFR + RPF diminishes * RPF redistribution to the cortex * Urine formation decrease

Answer 154

* Pressor centre stimulation * Dipsogenic effect → Increased water intake * Sympathetic stimulation * Increased ADH release

Answer 155

* Synthesised in the kidney * _Strong vasodilator_ * Effects v. aff + v. eff

Answer 156

* Stimulates hepatic kininogen * Causing _bradykinin production_ (Vasodilator)

Answer 157

Adaptive contraction *of the afferent arteriole*

Answer 158

Sodium excretion

Answer 159

Bayliss-effect

Answer 160

* Afferent arteriole: Vasodilation * Efferent arteriole: Vasoconstriction

Answer 161

* Macula densa of juxtaglomerular apparatus senses volume change * Secretes signals to adjust GFR

Answer 162

GFR autoregulation

Answer 163

1. GFR Decrease 2. Fluid flow Decrease 3. Na/Cl reabsorption Increase 4. Macula Densa Activated 5. _V. afferent dilation_ 6. RBF Increase 7. GP Increase 8. GFR returns to normal

Answer 164

1. GFR Decrease 2. Na/Cl reabsorption Increase 3. Tubular Na⁺ Decrease 4. Macula densa Activated 5. RAS activated 6. Angiotensin II produced 7. V. efferent constrictor release 8. GP Increase 9. GFR returns to normal

Answer 165

* BP increase * Kidney vessel resistance Increase * Vasoconstriction * No change in RBF _Bayliss-effect_

Answer 166

Medullary vessels

Answer 167

Autoregulation of renal circulation

Answer 168

Adaption range

Answer 169

* Na⁺/K⁺ ATPase pump * Cell → interstitium * The decrease of Na⁺ draws more Na⁺ into the cell * Excess IC K⁺ leaves the K⁺ channel

Answer 170

* Na⁺ entry into the cell *via* _Secondary active transport_ * H⁺ secretion * Ensures the removal of metabolic hydrogen

Answer 171

* Cell is impermeable to HCO₃^- * HCO₃^- + H⁺forms carbonic acid * H₂CO₃ → _H₂O + CO₂_ * Catalysed by _carbonic anhydrase_ * CO₂ can diffuse through the cell membrane

Answer 172

* CO₂ → H⁺ + HCO₃^- * *Catalysed by carbonic anhydrase* * H⁺ reaches lumen *via* secondary active transport * HCO₃^-+ Na⁺ ion → Interstitium * *Via Na/3HCO₃^- cotransporter* * (Indirect HCO₃^- transport)

Answer 173

High loss of Na⁺ and water | (Diuresis = Increased urine formation)

Answer 174

* _Prerequisite:_ pH_lumen \< pH_cell * Cl^--acidic anion antiporter: * Cl^- → Cell * Acid ion → Lumen * Acidic ion binds H⁺→ Free acid * Free acid → Cell: *Dissociation* * Transport from cell to interstitium: * Cl^- channel * K⁺/Cl^- cotransporter * *HCO₃^- reabsorption increased Cl^- gradient*

Answer 175

* Movement by increased peritubular oncotic pressure * From Lumen → Interstitium * Water transport by: Aquaporin-1 (AQP-1)

Answer 176

* Glucose * Amino acids * Na⁺

Answer 177

Approximately half

Answer 178

High permeability

Answer 179

* _Furosemide sensitive Na⁺/K⁺/2Cl^- synporter_ * Na⁺/K⁺/2Cl^- → Cell * Utilises energy from _basolateral Na⁺/K⁺-ATPase pump_ * Electroneutral transport * TAL is impermeable for H₂O + Urea * K⁺ + Cl^- passively leaves cell → Interstitium * Na⁺ eliminated by ATPase pump

Answer 180

* Na⁺/Cl^- symport protein reabsorb additional 5% of filtrate at luminal side * Na⁺/K⁺ ATPase pump: * Reabsorbed Na⁺→ Interstitium * K⁺/Cl^-cotransporter: * Cl^- → Interstitium * Ca²⁺ transport begins

Answer 181

* Permeability depends on hormonal effects * _Hormonally regulated_ urine formed here * CNT + CCT → _Mineralocorticoid_ dependent Na⁺ reabsorption * CCT → _ADH_-dependent water reabsorption * MCT → * ADH-dependent water reabsorption * _ANP_ dependent Na⁺ excretion * _Intercalar cells_: * Regulation of acid/base K⁺ balance

Answer 182

* In distal + collecting tubules * K⁺ excretion + reabsorption * Na⁺ reaborption

Answer 183

* Distal connective tubule * Collecting tubule

Answer 184

* Secretion of K⁺ * Regulated by mineralocorticoids * Regulate water reabsorption * By expressing AQP-2 * As a result of ADH

Answer 185

* Maintenance of acid/base balance * Secreting H⁺ * Forwarding of HCO₃^-

Answer 186

* HCO₃^- changes place with Cl^-(*via* antiporter) * HCO₃^- forwarded onto the blood * Acidic component forwarded onto the lumen * Works as an effective defence against acidosis * The reverse is observed in alkalosis

Answer 187

Electrogenic luminal H⁺ pump (ATPase)

Answer 188

Microsomes inside the principal cells

Answer 189

To the luminal pole Facilitates water movement according to osmotic conditions

Answer 190

ADH-mediated H₂O transport

Answer 191

* HCO₃^- release into the lumen * H⁺ release into the interstitium

Answer 192

* Goal: R_emove metabolically formed hydrogen ions_ * NH₃ binds to H⁺→ NH₄⁺ * Excreted as _salt_: * Ammonium phosphate * Ammonium sulphate * _pH of urine doesn't fall to an extremely low value_

Answer 193

* In thick ascending limb (TAL) * NH₄⁺ taken up by cells by K⁺/NH₄⁺ exchange * NH₄⁺ cannot leave on the luminal side _(impermeable)_ * NH₄⁺ → interstitium → descending limb (_countercurrent multiplier_) * Medullary NH₄⁺ increase * Active uptake of NH₄⁺by collecting tubule cells

Answer 194

Neurohypophysis

Answer 195

* Hyperosmosis of plasma → Osmoreceptors * Stress * Pain

Answer 196

* Baroreceptors → BP increase * Stress, volume receptors * ANP production → Central + atrial

Answer 197

* AQP-2 expression → Water retention * Extrarenal * Renal * DCT * Collecting duct * Vessel contraction (If bleeding) * Corticoid production increase

Answer 198

Atrial natriuretic peptide

Answer 199

* Atrial stretch → pre-pro-ANP * Salt load * Fluid load

Answer 200

* Na⁺ excretion increase * cGMP production increase * Na⁺/H⁺ exchange decrease

Answer 201

* _Hyperkalemia (Plasma [K⁺] increase)_ * BP fall * Hypophysis: ACTH

Answer 202

* Triggered by K⁺ increase in the blood * Measured by _z._ _glomerulosa_ _cells_ * Aldosterone considered to be the single regulator of K⁺ excretion

Answer 203

* Parathormone * Calcitonin * Glucocorticoids

Answer 204

* 1,25-OH-D3 hormone * Erythropoietin * Prostaglandin

Answer 205

* Fluid consumption * Intermediary metabolism * Food

Answer 206

* Sweat * Lungs * Urine * Faeces * Milk/saliva

Answer 207

0.35 l/day

Answer 208

0.35 l/day

Answer 209

* Blocking of tubular H₂O reabsorption * Leads to osmotic diuresis

Answer 210

Low volume production of _hyperosmotic urine_

Answer 211

High volume production of hypoosmotic urine

Answer 212

The shift of isovolaemia

Answer 213

* A substance that cannot be reabsorbed * Mannit * Glucose * A substance that can be reabsorbed after filtration * Sodium

Answer 214

* Hypothalamic osmoreceptors *_(_**_nucl_**_.*_ _*supraopticus_**_)_* stimulated * ADH release → Water retention

Answer 215

Osmotic diuresis Osmotically active substance → removes water from the body Compensated for by water uptake (e.g diabetes)

Answer 216

* Volume + urine osmolality change in a wide range * 2-5ml/kg bwt/kg - 200-229ml/kg bwt/kg * 1400 mosmol/l - 50 mosmol/l

Answer 217

* Rapid changing of the quantity + osmolarity of the urine * Low energy requirement * High capacity

Answer 218

* Countercurrent multiplier mechanism * Countercurrent exchanger mechanism

Answer 219

* The IC space is full of 'inert' _osmoliths_ * No metabolysis

Answer 220

C_osm = U_osm x V/P_osm

Answer 221

Isosmotic urine

Answer 222

Hyperosmotic urine

Answer 223

Hyposmotic urine

Answer 224

U_osm/P_osm

Answer 225

* Human = 4 * Dog = 5-6 * Desert animals = **20**

Answer 226

The number of Juxtamedullary glomeruli

Answer 227

* Na-pump * Repetitive reabsorption of Na⁺ of the TAL * Recirculation of urea

Answer 228

Interstitial hyperosmosis ## Footnote *(creates a suction force)*

Answer 229

* Na⁺ pump increases interstitial osmolality * H₂O: descending limb → interstitium * Urea/Na⁺ cannot follow the same path

Answer 230

Countercurrent _exchanger_

Answer 231

* Maintains the status quo * Doesn't create temperature differences between

Answer 232

Vasa recta

Answer 233

* Slow blood flow * Fluid + solute exchange between 2 arms * Diffusion equilibrium between interstitium + blood * Isoosmotic blood leaves interstitium

Answer 234

* Lumen osmolality * Quantity of urine * Composition of urine

Answer 235

* Salt leaves the tubule * Salt enters the tubule * Water leaves the tubule * Water enters the tubule * Combination of the above

Answer 236

Maintain Isosmosis

Answer 237

Hyposmotic urine (Diabetes)

Answer 238

Blood ADH increase

Answer 239

Connecting part of Distal tubule + Collecting duct

Answer 240

* ADH receptor → cAMP release * AP-2 → H₂O * AP-1 → H₂O reabsorbed

Answer 241

* Dehydration → [Salt] in blood increases * Osmotic pressure increase * Receptors in hypothalamus detect this * ADH release * Thirst centre in hypothalamus also responds

Answer 242

* Dog drinking → diuresis occurs * ADH/NaCl applied → diuresis stops * The electrical stimulus of *n**ucl.* *supraopticus* → diuresis stops

Answer 243

Via CNS * AV3V of the third ventricle stimulated * ADH secretion * Thirst

Answer 244

* EC + IC balance → Hyperosmotic isovolemia * Hypothalamus: Osmoreceptor activity increase * ADH in blood increase * Distal tubule: AP-2 expression increase * Free water clearance decrease, water retention * _Isosmotic_ hypervolemia

Answer 245

1. ADH inhibition 2. No H₂O retention 3. Hypovolemic isosmosis

Answer 246

* Anteroventral wall of the 3rd ventricle * Anterolateral part of the preoptic hypothalamus * AV3V region of 3rd Ventricle

Answer 247

Extreme water intake

Answer 248

* IC-dehydration * Losing blood * Food intake * Angiotensin-II

Answer 249

* Stops unnecessary drinking * Water → Oesophagus/stomach * Relieves thirst for 30 mins

Answer 250

* 1-2 days * Verney-mechanism activated * Extra salt and water stay in the EC space * EC space is extended → hypervolemia

Answer 251

* Volume increase → BP increase * Baroreceptors stimulated → Peripheral vasodilation + oncotic pressure decrease * Fluid leaves circulation → Interstitium

Answer 252

Cardiac Atrium

Answer 253

Increase Na⁺ excretion ## Footnote *by inhibiting Na⁺reabsorption*

Answer 254

* Stretch receptors * Centre of volume regulation * Around diencephalon

Answer 255

* BP increase → Diuresis increase

Answer 256

* RAS inhibition * ANP stimulation * Na⁺excretion * RAS + ADH inhibition * Isovolemia

Answer 257

* Exhibit reflex relaxation * Plasticity → Allows uptake of large volumes * Filling → Sympathetic differentiation of bladder * Bladder loosened, sphincter contracted * Urination → Parasympathetic dominance * Bladder contracted, sphincter dilates

Answer 258

Contraction of the calix

Answer 259

* Urinary bladder * Urethra

Answer 260

Filling of bladder → Increase of mechanoreceptor activity

Answer 261

Maximal stretch and mechanoreceptor activity

Answer 262

Stimulus of urination

Answer 263

Reflex-relaxation

Answer 264

* Lumbar → Sympathetic * Sacral → Parasympathetic * Somatic → *M. abd*., perineum, outer sphincter

Answer 265

* Parasympathetic activity inhibited by sympathetic activity * Sympathetic Tone * → M. detrusor relaxes * → Contracts smooth muscle of bladder neck * Outer urethral muscles contract *(n.* *pudendus**)*

Answer 266

Alpha1 receptors

Answer 267

* Increased mechanoreceptor activity → Pons * Increased parasympathetic activation * Inhibits somatic and sympathetic activity * Bladder wall contracts, sphincters relax

Answer 268

Animals can be trained to retain urine

Answer 269

* Cattle: **9** * Horse: **5.5** * Swine: **2.5** * Dog: **1.2** * Cat: **0.1**

Answer 270

* Cattle: **1 - 3** * Horse: **0.2 - 1.3** * Swine: **0.5 - 2.2** * Dog: **0.4 - 1.2** * Cat: **0.7 - 1.4**

Answer 271

500-600 mosmol/l

Answer 272

Urea is almost absent in the medullary interstitium

Answer 273

Henle's loop | (_reptilian-type nephron_)

Answer 274

Cloaca and Large intestine

Answer 275

* Salt glands * Secreted nasaly

Answer 276

* 800-1000 mosmol/l