Renal System YouTube Lecture Handouts Medical Science
Glide to success with Doorsteptutor material for competitive exams : get questions, notes, tests, video lectures and more- for all subjects of your exam.
Get video tutorial on: Examrace YouTube Channel
RENAL SYSTEM
Functions of Kidney
- Excretion
- Metabolic waste
- Foreign sub-Drugs, etc.
- Regulation of Fluid & Electrolytes
- Maintain Acid Base Balance
Functions
Hormonal Functions
- 1 Renin Angiotensin Aldosterone System
- 2 Calcitrol
- 3 Erythropoietin
KIDNEY-ANATOMY
- Functional anatomy: bean shaped st.
- Location: retroperitoneal, on post. Abdominal wall. At to Vertebrae
- Size:
- Length = 10 cm
- Width = 5 cm
- Thickness = 2.5 cm
KIDNEYS
- Weight of kidney is 150 gm
- Rt. Kidney slightly lower
- On medial side a notch, Hilum is present
- Through it passes
- Renal artery and veins
- Lymphatics and nerves
- Ureter
Renal Sy
- Microscopic structure
- Outer-cortex
- Inner-medulla
- NEPHRON: structural and functional unit
- Each kidney has about 1.2 million nephrons
Renal Sy
- Nephrons are
- Cortical
- Juxtamedullary
NEPHRONS
Differences:
Sn 1 2 | Feature No. Location of glomerulus | Cortical 85% Small loc. In cortex | JM 15% Large at corticomedullary junctions |
NEPHRONS
Sn 3 4 | Feature LH LH | lCortical Short up to outer medulla Dl thin seg Al thick | JM Long Deep into medulla Both have thin seg. |
NEPHRONS
Differences
Sn 5 6 | Feature Vascular supply Filtration rate | Cortical Vasa recta not present Slow | JM Vasa recta present high |
NEPHRONS
Differences
Sn 7 | Feature Main function | cortical Excretion of waste product | JM Concentration of urine |
NEPHRON
- Structure of nephron: has two parts
- Renal or Malpighi and corpuscle
- Tubules
- Malpighi and corpuscle has:
- Glomerulus
- Bowmans capsule
Malpighi and Corpuscle
Glomerulus (tuft of capillaries) –
- Size – 200 µm
- Afferent arteriole- short & wide, blood enters through them
- Efferent arteriole-long & narrow blood leaves, through them
- Vascular pole- afferent & eff. are close
Malpighi an Corpuscle
Bowman՚s capsule – initial dilated part of nephron. It has:
- Parietal layer — outer layer
- Visceral layer — Inner, covering the glomerular capillaries
- Bowman՚s space — between two layers
Renal System
Diagram
Glomerular Membrane
Ultrastructure of glomerular membrane
- Three layers
- Capillary endothelium: fenestrated pore diameter 70 to 90 nm
Freely permeable to water & solutes
Renal System
2. Basement membrane: matrix of glycoproteins & mucopolysaccharides lamina rara externa lamina dens lamina rara interna has no pores but permeability matches to pore size of about 8 nm
Renal System
3. Visceral epithelium of bowman՚s cap. Formed by podocytes filtration slits diameter — 25 nms slits covered by fine filaments
Renal System
- Filtration
Membrane
₹ — Tubules
- Proximal convoluted tubule
- Loop of Henle
- Distal convoluted tubule
- Collecting tubule
₹ — Tubules
Characteristics of epi. lining tubules:
- Cells have special features in different seg. & perform specific functions
- Cells are mostly cuboidal
- Apical surfaces have microvilli
- PCT has brush border on luminal side
₹ - JG Apparatus
Also called JG complex: has JG cells macula densa mesangial cells
₹ - JG Apparatus
- Diagram
₹ – JG Apparatus
- Juxtamedullary cells:
- Modified my epithelial cells
- Located in the media of aff. Arteriole
- Granular cells
- Densely innervated by sympathetic
- Secret RENIN
- Baroreceptor by function
₹ — JG Apparatus
Macula Densa Cells:
- Are in contact with mesangial & JG cells
- Not well adapted for reabsorption
- Not innervated
- Act as chemoreceptor
- Stimulated by ↓ Nacl
- ↓ Renin release
₹ -JG Apparatus
- Mesangial cells or Lacis cells
- Possibly relay signals from macula densa to granular cells
- Take up immune complexes
- In extreme hyperactivity show granules containing renin
JG-Apparatus
Functions:
- Renin secretion
- Regulation of GFR
- Mesangial cells mediate signals between Macula Densa & Afferent Arteriole
- Mesangial cells within the glomerulus communicate with cells outside
- ↓ surface Area of filtration when BP is V. low
₹ -Renal Blood Flow
- Renal circulation is portal circulation 2 sets of capillaries are present
- Amount & rate of flow
- In basal condt … 1200 ml⟋min.
- High flow is related to excretory function.
- Flow is remarkably constant due to Autoregulation
₹ -Renal Blood Flow
Internal distribution of blood flow
- Cortex … 90%
- Outer medulla … 9%
- Inner medulla … 1%
- Low blood flow through medulla helps in urinary concentration.
₹ — Renal Blood Flow
Autoregulation of renal blood flow
- Feature of cortical blood flow
- Present in denervated kidney
- Seen in transplanted kidney.
₹ — Renal Blood Flow
Autoregulation of renal blood flow:
- Myogenic Theory
- Tubuloglomerular feedback
- Cell separation Theory
- Intrarenal tissue pressure
- Intrarenal reflexes
₹ — Renal Blood Flow
Measurement, 2 methods
- Venous shunt technique
- Fick principle
Fick principle: substance used
- Con. In blood can be measured easily
- Not metabolized, stored or produced
- Does not affect blood flow
₹ — Renal Blood Flow
- Substances used are
- PAH (p-amminohippuric acid)
- Diodrast
- Usually PAH is used, it has high extraction ratio 90%
₹ — RBF
- Effective Renal plasma flow:
- ERPF = UPAHxV⟋PPAH = clearance of PAH e. g. = UPAH = 14 mg⟋ml V = 0.9 ml⟋min PPAH = 0.02 mg⟋ml
- ERPF .
₹ — RBF
- ERPF is converted to actual plasma flow Extraction ratio is 0.9
Actual Plasma flow = 630⟋0.9 = 700 ml⟋min
- Hematocrit = 45%
- RBF = RPF
- RBF ml⟋min or 1.2 L⟋min
₹ — Urine Formation
- Mechanism: includes
- Filtration … (glomerulus)
- Reabsorption … (tubules)
- Secretion … (tubules)
₹ — Glomerular Filtration
- Definition: Amount of fluid filtered by all the nephrons of both the kidneys⟋min.
- Normal value ml⟋min.
- Filtration fraction: Ratio of GFR to renal plasma flow
Filtration Fraction
Is
- FF = GFR (ml⟋min.) , RBF (ml⟋min) Normal range %
Dynamics of Filtration
NET FILTRATION PRESSURE
Forces Favoring Filtration
1. Gl. Hydro. Press. = 60 mmHg
2. Colloid osmotic pressure of Bowman՚s capsule = 0
GFR
Forces Opposing Filtration (mm Hg)
1. Capsule Hydrostatic Press. = 18
2. Gl. Cap. Colloid osmotic Pressure = 32
- NET FILTRATION PRESSURE:
60 - (18 + 32) =+ 10 mm Hg
GFR
Filtration Coefficient:
- Rate of filtration⟋mm Hg Filtration Press
- ml⟋min⟋mm Hg
- It is GFR at 1 mm Hg Effective Filtration Pressure
- It is product of permeability and filtration area
Filtration Membrane
- Permeability-
- Pores in capillary Endo. Cell -70 - 90 nm
- Podocytes Filtration Slits … 25 nm
- Glomerular Basement Mem. Has no pores but permeability corresponds to pore size of 8 nm.
Filtration Membrane
- Molecules less than 4 nm — freely filtered
- Molecules more than 8 nm-not filtered
- Pores are – vely charged due to presence of glycoproteins rich in sialic acid
- Albumin with mol. Diameter of 7 nm is negatively charged so not filtered
Filtration Membrane
- Area
- Controlled by mesangial cells
- COMPOSITION OF FILTRATE:
- Like plasma except for absence of proteins and cells
Factors Affecting GFR
- Glomerular capillary hydrostatic press.
- Glomerular capillary oncotic pressure
- Hydrostatic press. of fluid in Bow. Cap.
- Filtration Coefficient
- Permeability of membrane
- Filtration Area
GFR Measurement
- By Clearance method:
- Salient features of the substance used
- Not toxic & biologically inert
- Is freely filtered
- Has no effect on GFR
- Not absorbed or secreted by tubules
- Not stored in kidneys
GFR Measurement
Substances used:
- Inulin- A polysaccharide Mol. Wt. 5200
- Creatinine
- Sodium Ferro cyanides
- Mannitol
- Radioactive cobalt labelled vit. B12
- R. A. 51 Cr. labelled EDTA
GFR- Inulin Clearance
- C in
- Uin mg⟋ml
- V ml⟋min
- Pin mg⟋ml
- ml⟋min is GFR
Creatinine Clearance
- Endogenous Creatinine Clearance is easy to measure
- Some reabsorbed & some secreted in tubules
- Not very exact but convenient
Tubular Reabsorption
- Filtered Load: Amount of solute transported across the glomerular membrane per unit time.
- Filtered load = GFR x Plasma concentre of the solute
Glomerulotubular Balance
- Is percentage of filtered fluid that is reabsorbed in proximal tubule?
- It is constant i.e.. 70% of fluid filtered.
- Key element in PT reabsorption is Na +- K +- ATPase
Substances Reabsorbed in PT
Important substances reabs. are
- Sodium
- Glucose
- Aminoacids
- Bicarbonates
Reabs of Sodium
~65% of filtered sodium is reabsorbed
- In first half by co-transpot along with glucose, aminoacids etc.
- In second half with chloride
Glucose Reabsorption
- Essentially all is reabsorbed only few mg. appear in urine
- Secondary Active transport
- Filtered at a rate of about 100 mg⟋min.
- (Plasma concentration … 80 mg⟋dL & GFR … 125 ml⟋min)
Renal Threshold & Tm
Renal Threshold:
- Plasma glucose level at which it first appears in urine … 180 mg⟋dL
- Transport Maximum is max. Rate at which a substance is transported. Limiting factor is saturation of carrier proteins
TMG
Transport Maximum of Glucose
- Males … 375 mg⟋min Corresponding Plasma Level 300 mg⟋dL
- Females — 300 mg⟋min (Tm and Value)
- Amino acids 1.5 mg⟋min
- Plasma proteins 30 mg⟋min
Bicarbonate Reabsorption
Reabsoption of WATER
- Total fluid filtered … 180 L⟋day
- Urine output … 1 L⟋day
Reabsoption is by Two Ways
- Obligatory water Reabsoption &
- Facultative Reabsoption.
Obligatory Reabsoption
- In proximal tubules
- Secondary to solute reabs.
- Osmotic reabs.
- About 65%
- Cannot be changed according to need of body
Facultative Water Reabsorb
- In distal tubule & collecting tubule
- It changes according to need of body
- Controlled by ADH
Water Reabs. In Different Parts
- Approx. values are
- PT … 60 to 70%
- LH … 15%
- DT … 5%
- CD … C … 10
- … M … 4.7%
Mechanism of Water Reabs
- By diffusion across cell membrane
- Diffusion is through protein channels called AQUAPORIN
- Different types of Aquaporins are in human beings: 1, 2,3, 4,5 &9
- Aquaporin 1&2 play key role in water reabs
Mechanism of Water Reabs
- Aquaporin-1 is localized in proximal tubules
- Aquaporin-2 is in collecting ducts
- Stored in the vesicles in the cytoplasm of Principal Cells
- Vasopressin causes insertion of these vesicles into the apical mem. of cells
Mechanism of Water Reabs
- Effect mediated by receptors
- Cyclic AMP, Protein kinase & a molecular motor (one of dyneins) are also involved
Regulation of Urine Osmolarity and Volume
Body can produce
- Vol. of urine⟋day Osmolarity mOsm⟋L
- 500 ml … 1400
- 23.3 L … 30
- About 87% of filtered Water is always reabs.
Osmolarity
- Human … 1400 mOsm⟋kg of water
- Dogs … 2500
- Rats … 3200
- Some … 5000
Rodents
It depends on max. Osmolarity present in medulla
Mechanism of Concentration & Dilution of Urine
Principal factors:
- ANTIDIURETIC HORMONE
- GRADIENT OF OSMOLARITY IN RENAL MEDULLA
- SLUGGISH BLOOD FLOW IN MEDULLA
ANTIDIURETIC HORMONE
- ADH is required for water reabsorption
- Maximum ADH … 99% reabsorbed
- Absence of ADH … 88%
Gradient of Osmolarity in Renal Medulla
- Gradient generated by Counter Current Multiplier system
- Maintained by C. C. Exchange system
Counter Current Multiplier System
Counter Current Multiplier System
- In flow runs parallel to, counter to and in close proximity to outflow.
- It is active process
- It generates gradient of osmolarity in renal medulla
- Key role is played by LOOP of HENLE
LOOP of HENLE
- DLH is CONCENTRATING SEGMENT
- Highly permeable to water
- Relatively impermeable to solutes. Therefore
- Solute free water moves in interstitium
- Fluid in DLH becomes concentrated
LOOP of HENLE
- ALH is DILUTING SEGMENT
- Thin seg. Impermeable to water & permeable to NaCl and urea
- Thick seg.
- Impermeable to water & solutes
- ACTIVE TRANSPORT of NaCl out of lumen
LOOP of HENLE
- Sodium transported by
- Na +-K +-ATPase and
- In ALH tubular fluid becomes more & more dilute & rich in urea
- Interstitial fluid becomes hyperosmotic
- MEDULLARY HYPEROSMOLARITY Gen.
COUNTER CURRENT EXCHANGE SYSTEM
- Formed by VASA RECTA
- Cannot generate gradient
- But maintain gradient of osmolarity in medulla
- Passive mechanism
CCM
CC Exchange
- Solutes tend to recirculate in medulla
- Water tends to bypass it.
- Medullary HYPEROSMOLARITY is MAINTAINED
Sluggish Blood Flow in Renal Medulla
- Blood flow of Cortex … 90%
- Flow of Outer Medulla … 9%
- Flow of Inner Medulla … 1%
Role of Urea in Concern of Urine
- DCT & CT- Impermeable to water
- Urea concern Increases in CT
- IMCD- Permeable to urea so both water & urea are absorbed in here
- Outer Medullary interstitial Osmolarity is because of sodium
- Inner medullary by both Na + & urea
Formation of Concern Urine
↑ Osmolarity of extracellular fluid
↓
↑ Release of ADH from post. Pituitary
↓
↑ Permeability of DCT & Collecting duct
↓
↑ Increase water reabs.
Formation of Dilute Urine
- ↓ Osmolarity of ECF (excess of water) ↓
- ↓ ADH secretion ↓
- ↓ Permeability f DCT & collecting duct ↓
- Less water is reabsorbed
Water Diuresis
- If large amount of water is taken. Within 45 min. urine output increases. Due to decreased ADH. It continues until osmolarity comes back to normal.
Acidification of Urine
- pH is negative log of H ion concentration.
- pH of solutions
Normal pH
- Plasma pH- 7.4
- Urine pH … 6.0
Secretion of H Ions
- There is always an excess of H ions in body & they must be excreted
- Hydrogen ions are secreted from tubules
H Ion Secretion in PT
- In PT secretion depends on sodium reab.
- It is by Secondary Active Transport Na +-H + antiport
- For secretion of every hydrogen ion one Sodium & one Bicarbonate ions are reabsorbed
H Ion Secretion in DT
- Independent of sodium reab.
- Mainly by ATP driven PROTON PUMP
- Aldosterone acts on this pump
- Active reab.
III
H ION Secretion
- PCT (rich in CA) … 85%
- DCT … 10%
- Collecting tubule … 5%
Fate of H IONS Secreted
- LIMITING pH of urine is 4.5 so H IONS must be buffered in tubule
- BUFFER SYSTEMS IN THE KIDNEY
- Bicarbonate system
- Dibasic Phosphate system
- Ammonia system
Bicarbonate Buffer
- In PCT
- No change in tubular fluid pH
- Large amount of H ions are secreted here
- H Ions buffered do not add to urinary acidity
Dibasic Phosphate Buffer
- More important in DCT, as phosphates are concentrated here
- Dibasic phosphate ions are converted to monobasic phosphate
- to
- It adds to urinary acidity
II
Ammonia Buffer
- Ammonia is synthesized & secreted by DCT&CT
- Sources of Ammonia are
- 60% by deamination of Glutamine
- 30% by deamination of Glutamic acid
- 10% by deamination of other aminoacids like Glycine, Alanine etc.
Ammonia Buffer
- Important points
- Ammonium ion major urine acid
- Ammonium content increases when urine pH is below 6
- There is adaptative increase in Ammonia synthesis. In Diabetic ketosis H ion excretion may increase 10 folds.
TITRABLE ACIDITY
- Definition: Amount of Alkali that must be added to the urine, so as to bring its pH to 7.4
- H buffered by Bicarbonate not measured
- Large contribution is by Phosphate buffers
- It does not measure H ions that combine with Ammonia
Urinary Acid Excretion
- Urinary acid Normal Excretion in mEQ or mmol⟋day
- Titrable Acid (25%) … 10 - 30
- Ammonium ion (75%) … 30 - 50
- Total … 40 - 80
PHYSIOLOGY of MICTURITION
- Includes
- Structure & Innervation of bladder
- Physiology of micturition
- Filling of bladder
- Micturition Reflex
- Abnormalities of micturition
Structure of Urinary Bladder
Has
- Body of urinary bladder
- Urethra &
- Sphincters
- Internal sphincter (smooth muscles)
- External sphincter (skeletal muscle)
Urinary Bladder
- Capacity:
- At birth … 20 - 50 ml
- At one year … 200 ml
- In adult … 600 ml
INNERVATION
Is by
- Sympathetic nervous System
- Parasympathetic &
- Somatic nervous system
Motor Innervation
- Symp. Is from 2&3
- Effect of stimulation
- They relax Detrusor muscles
- Contraction of Int. Sphincter
- Retention of urine
- Prevent reflux of sperms from prostatic urethra to urinary bladder during ejaculation
Motor INNERVATION
- Parasymp. (Nervi erigentes) :
- From S 2,3 & 4
- Effect of stimulation
- Contraction of Detrusor muscle
- Relaxation of Internal sphincter
- Leads to emptying of bladder
- Somatic innervation: S 2,3 & 4 (Pudendal Nerve) to Ext. Sphincter
Sensory Inn
- For
- Bladder distension &
- Bladder pain
SENSORY Innervation
- Bladder distension:
- From Detrusor mus. Pelvic Splanchnic Nerves
- From bladder Neck & Trigone via Hypo gastric plexus
- Fibres travel in Post. column to reach spinal, pontine& supra pontine M. C.
SENSORY Innervation
- Bladder pain:
- In Hypogastric plexus
- Some in nervi erigentes
- Run in Lateral Spin thalamic Tract Urethral sensation: Pudendal nerve
Bladder Filling
- Urine flows from Renal pelvis towards bladder by peristaltic cont. of ureters
- Renal calyces have inherent Pacemaker activity
- Peristaltic cont. enhanced by Parasymp.
- Inhibited by Sympathetic
Cystometry
- Cystometrogram
- Shows changes in intravesicular pressure as the bladder fills with urine
- First urge to pass urine … 150 ml
- Marked fullness & discomfort … 400 ml
- Unbearable … 600 ml
- Anatomical capacity … about .
Micturition Reflex
- Fundamentally a spinal reflex, facilitated & inhibited by higher centres
- It is a Parasympthetic Reflex
- Higher Control:
- Faci. — Post. Hypothalamus & Pontine reg.
- Inhi. — mid brain
- Cerebral cortex — in voluntary micturation
Spinal Mic. Reflex
- Filling of bladder (Afferent nerves) ↓
- Sacral segment of spinal cord (Mic. Cen) ↓
- Efferent to motor nerves ↓
- Emptying of bladder
VOL. MICTURITION
- Impulses reach to S 234 ↓
- Dorsal column (travel upwards) ↓
- Brain (Post Central Gyrus) ↓
- Motor Cortex ↓
- Sacral Seg. (Emptying of bladder)
Desire to Hold Urine
- Cerebral Cortex ↓
- 1 Inhibit Sacral Parasy. Excitatory activity
- 2 Stimulate Symp. Activity ↓
- Desire to Micturate PASSES OFF
- Only a temporary phase
Accessory Muscles Involved
Muscles Involved during Micturition:
- Abdominal muscles Contract
- Perineal muscles Relax
- Diaphragm descends
- Breathing is hold with glottis closed
- Thus Intra-Abdominal Pressure ↑
Applied Aspects
- DEAFFERENTATION
- DENERVATION
- TRANSECTION OF SPINAL CORD
DEAFFERENTATION of URINARY BLADDER
- Cause: Tabes Dorsalis (Syphlis)
- Findings:
- Vol. mict. Is possible
- Unaware of state of bladder distension
- Periodical emptying not present
- Overflow dribbling – AUTOMATIC BLADDER
- DISTENDED, THIN, HYPOTONIC BLADDER
DENERVATED BLADDER
- Cause: Tumour or injury to Cauda Equina. Injury to both Afferent & Efferent nerv.
- Loss of vol. Micturition
- Bladder is flaccid and distended for a while
- Bladder is decentralized
- SHRUNKEN HYPERTROPHIED BLADDER
TRANSECTION of SPINAL CORD
Cause: injury, Syringomyelia, Disseminated Sclerosis
- Both facilitatory and Inhibitory fibres are damaged
- Recovery in two stages
- Early Stage (stage of spinal shock)
- Late stage
SPINAL TRANSECTION
EARLY STAGE:
- Vol. Mict. Abolished
- State of retention with overflow develops
- Bladder becomes spastic neurogenic
- Complications like cystitis and ascending urinary tract infections can develop
SPINAL TRANSECTION
LATE STAGE:
- Voiding reflex returns
- No voluntary control
- Micturition can be initiated by mass reflex
Endocrinal Functions
- Erythropoietin
- Calcitrol
- Renin a Proteolytic Enzyme
HORMONES ACTING on KIDNEY
- Aldosterone
- Antidiuretic hormone
- Parathormone
Renal Function Tests
- Performed to
- Asses the functional capacity of the kidney
- To detect the renal impairment in the early stage
Renal Function Tests
Various tests are performed
- Analysis of urine
- Analysis of blood
- Renal Clearance tests
- Radiology & Renal Imaging
- Renal Biopsy
- Other methods
Urine Analysis
Normal Colour … light yellow due to
- Pigments -Urochrome, urobilin &Uroerythrin
- Deepens on standing, oxidation of urobilinogen to urobilin
- Brownish yellow … presence of conjugated Bilirubin
- Red- Dark brown … porphyria
- Frothy in Proteinuria
Urine Analysis
Composition
- Inorganic … Na, K, Ca & phosphate
- Organic …
- Urea … 20 to 30 g⟋day
- Uric Acid … 0.6 gm⟋day
- Creatinine … 1.2 gm⟋day
Urine Analysis
- Normal vol. = Approx. 1 to 2.5 L⟋day
- Polyuria = 2.5 L⟋day (fluid intake not high)
- Oliguria = 500 ml⟋day
- Anuria < 50 ml⟋day or no urine formed
- Obligatory urine vol. = 500 ml⟋day.
- It is minimum quantity of urine that must be formed to remove waste products.
Urine Analysis
Osmolality & Specific gravity
- Normal Osmolality = 50 to 1200
- Normal Specific Gravity = 1.003 to 1.030
- Fixed Osmolarity of 300 mOsm⟋Kg (sp. gr. -1.010) = Advanced renal failure
- Persistently low Osmolality less than 100 (after 8 hr. fluid deprivation) diagnostic of Diabetes Insipidus
Urine Analysis
Approx. correlation between S. G. and osmolality
S. G. | Osmolality (mOsm⟋kg) |
---|---|
1001 | 100 |
1010 | 300 |
1025 | 1000 |
1030 | 1200 |
1040 | 1400 |
Urine Analysis
Reaction
- Normal range … 4.5 to 8, Av. 6 - 7
- After meals it becomes alkaline (postprandial alkaline tide)
- Alkaline urine turns red litmus blue
Urine Ana
- Microscopic
- normally
- 1 to 2 WBC or Pus Cells⟋HPF
- Hyaline Cast = occasional
- They are clear, colourless cast made up of high molecular weight mucoproteins
Urine Analysis
Abnormal constituents
- RBC
- Bacteria
- Granular casts
- Glucose
- Albumin
- Ketone bodies
Applied
- Isosthenuria … S. G. of urine is fixed at 1010 (Pl. 300 mOsm⟋L e. g Renal Failure)
- 12 hours water deprivation ↑ S. G. to 1025 failure to do this indicates abnormal Renal functions
- Albuminuria – Albumin excretion above 150 mg⟋day
Albuminuria
Causes
- Nephritis
- TB
- Carcinoma
Albuminuria
Orthostatic Albuminuria
- Albumin appears in urine in standing position
Blood Analysis
Normal
- Blood Urea … 20 to 40 mg %
- S. Creatinine … 0.6 to 1.5 mg %
- S. Cholesterol … 150 to 240 mg %
- Uric Acid … 2 to 4 mg %
- Protein A⟋G ratio 1.7: 1
- Nephrotic Syndrome reversal of A⟋G ratio
Clearance Tests
- Tests for Glomerular Functions
- Inulin Clearance
- Creatinine Cl.
- Tests for Tubular Functions
- PAH Clearance
- Urea Clearance
- Phenol Sulphonephthalein (PSP) test
Urea Clearance
- Standard Urea Cl. - urine flow 2 ml⟋min normally … 54 ml⟋min (40 to 60)
- Maximum Urea Cl. … flow 2 ml⟋min normally … 75 ml⟋min (60 to 90)
- It is obsolete & not used clinically
Other Methods
- Micropuncturing
- Stop Flow Tech.
- Microcryoscopic studies
Diuretics
- Are substances that cause increase in urinary flow
- They are of various types
1 | 2 | 3 | 4 | 5 | 6 |
Class of Diuretic | Site of act. | Mechanism of action | Effect | K+ depletion | pH |
HIGH EFF. LOOP DIURETICS | TAL | Inhibition of pump | ↑NaCl excret. ↑ excret | Yes | Alkal. |
1 | 2 | 3 | 4 | 5 | 6 |
MEDIUM EFFICACY THIAZIDE DIURETICS Chlorthiazide Hydrochlorthiazide | Early DT | Inhibition of symporter | Exc of ↑ ↑ Antihypertensive | Yes | Alkal |
1 | 2 | 3 | 4 | 5 | 6 |
WEAK DIURETICS 1. C. A. INHIBITORS Acetazolamide 2. Sparing Spironolactone Triamterene Amiloride | PT Late DT &CD | Inhibition of Carbonic Anhydrase Inhibition of Na+ Reabsor & Inhibition of K+ Exc. | HCO- 3 Excretion Excret & K+ Excretio | Yes No | Acidosis Acidosis |