37Excretory system

πŸ“š
EXCRETORY PARTS

Table 1: Excretory Organs

Organ
System
Excretory product
Kidney
Urinary system
Urea, uric acid, water
Lungs
Respiratory system
\(CO_2\), water
Liver
Hepatobiliary system
Cholesterol, bile pigments
Large intestine
Gastrointestinal system
Calcium salts, heavy metals
Skin
Integumentary system
Sweat β†’ urea, NaCl, lactic acid, water, waxes, fatty acids
β–’ Homeostasis: Excretory organs = organs of homeostasis
β–’ Human Urinary System:
  • β€’
    Kidneys β†’ 2
  • β€’
    Ureters β†’ 2
  • β€’
    Urinary bladder β†’ 1
  • β€’
    Urethra β†’ 1
πŸ“š
KIDNEY
β–’ Introduction:

Table 1: Kidney: Basic Features

Feature
Point
Development
Nephrotome plate of mesoderm
Mammalian kidney
Metanephric
Shape
Dark-red, bean-shaped
Size
β‰ˆ 11 cm Γ— 5 cm Γ— 3 cm
Weight
Male β‰ˆ 150 g; Female β‰ˆ 135 g
Peritoneal relation
Retroperitoneal / extraperitoneal
Ventral covering
Peritoneum
Extent
\(T*{12}\)–\(L_3\)
Blood supply
Renal artery ← abdominal aorta
Venous drainage
Renal vein β†’ inferior vena cava
Cardiac output
β‰ˆ 25% per minute
Blood filtration time
β‰ˆ 4 min
β–’ Position:

Table 1: Kidney Position

Organism
Position
Human
Right kidney lower than left β†’ liver above
Rabbit
Right kidney slightly higher than left
Frog
Both kidneys at same level
β–’ Developmental Types:

Table 1: Types of Kidney by Development

Type
Origin
Nephron feature
Examples
Pronephric kidney
Anterior nephrotome / pronephros
Simple tubular nephrons; not differentiated
Cyclostomates; tadpole of frog
Mesonephric / Opisthonephric kidney
Middle nephrotome / mesonephros
Bowman's capsule + simple tubular part
Most fishes; adult amphibians
Metanephric kidney
Posterior nephrotome / metanephros
Well differentiated β†’ Bowman's capsule, PCT, LOH, DCT
Reptiles, aves, mammals
❖ Loop of Henle:
  • β€’
    Absent β†’ frog
  • β€’
    Less developed β†’ reptiles
  • β€’
    Incompletely developed β†’ aves
  • β€’
    Most developed β†’ mammals
β–’ Gross Structure:

Table 1: Gross Anatomy of Kidney

Structure
Description
Hilum / Hilus renalis
Concave medial border β†’ renal artery, renal vein, lymphatics, ureter, nerves pass
Capsule
Thin fibrous connective tissue covering
Cortex
Outer part
Medulla
Inner part
Renal pyramids / Medullary pyramids
Conical medullary regions; composed of nephrons + blood vessels
Renal papilla
Pointed end of pyramid toward pelvis
Renal columns of Bertini
Cortical invagination between pyramids
Minor calyces
Receive renal pyramids
Major calyces
Formed by union of minor calyces
Renal pelvis
Major calyces open here; continues as ureter
❖ Human Calyces:
  • β€’
    Minor calyces β†’ 7–13
  • β€’
    Major calyces β†’ 4
❖ Rabbit Kidney:
  • β€’
    Only 1 pyramid
  • β€’
    Renal pelvis unbranched
  • β€’
    Calyces absent
  • β€’
    Renal columns of Bertini absent
β–’ Internal Structure:

Table 1: Internal Parts

Part
Feature
Capsule
Tough fibrous connective tissue envelope
Cortex
Outer β‰ˆ 1 cm thick; dotted; contains Malpighian corpuscle, PCT, DCT
Medulla
Inner striated lighter region; contains Loop of Henle + collecting tubules
Parenchyma
Renal cortex + renal pyramids = functional portion
Pyramids
6–10 medullary projections into pelvis
Pelvis
Large funnel-shaped space toward concavity
Papilla
Blunt pointed end of medulla facing sinus
Renal sinus
Hilus-expanded cavity inside kidney
πŸ“š
NEPHRON / URINIFEROUS TUBULE
β–’ Definition: Structural + functional unit of kidney
β–’ Number:

Table 1: Nephron Number

Organism
Nephrons / kidney
Human
β‰ˆ 1 million / 10 lakhs / 1.2 million
Rabbit
β‰ˆ 2 lakhs
Frog
β‰ˆ 2000
β–’ Parts:

Table 1: Nephron Parts

Part
Components
Malpighian / Renal corpuscle
Glomerulus + Bowman's capsule
Renal tubule
PCT + Loop of Henle + DCT
Collecting tubule
Not part of nephron
Uriniferous tubule
Nephron + collecting tubule
β–’ Cortex vs Medulla:

Table 1: Location of Nephron Parts

Region
Structures
Cortex
Malpighian corpuscle, glomerulus, Bowman's capsule, PCT, DCT
Medulla
Loop of Henle, collecting tubules, collecting ducts, duct of Bellini
β–’ Fluid Names:
  • β€’
    Inside nephron β†’ filtrate
  • β€’
    After reaching collecting tubes β†’ urine
β–’ Urine Flow:
  1. Nephron
  2. Collecting duct
  3. Duct of Bellini / papillary duct
  4. Renal papilla
  5. Minor calyx
  6. Major calyx
  7. Renal pelvis
  8. Ureter
  9. Urinary bladder
  10. Urethra
πŸ“š
MALPIGHIAN / RENAL CORPUSCLE
β–’ Location: Renal cortex
β–’ Components:
  • β€’
    Glomerulus
  • β€’
    Bowman's / glomerular capsule
β–’ Glomerulus:

Table 1: Glomerulus

Feature
Point
Structure
Capillary tuft
Blood entry
Afferent arteriole
Blood exit
Efferent arteriole
Pressure cause
Efferent arteriole narrower than afferent arteriole
β–’ Bowman's Capsule:

Table 1: Bowman's Capsule

Layer / Space
Epithelium / Cell
Feature
Parietal layer
Simple squamous epithelium
Outer layer
Capsular space
Between parietal + visceral layers
Filled with glomerular filtrate
Visceral layer
Podocytes
Filtration slits
❖ Podocytes: Special boot-shaped cells of visceral layer β†’ filtration slits
πŸ“š
RENAL TUBULES
β–’ Proximal Convoluted Tubule / PCT:

Table 1: PCT

Feature
Point
Epithelium
Simple columnar epithelium
Brush border
Numerous microvilli
Main site
Maximum absorption
Complete active reabsorption
Glucose + amino acids
Renal threshold for glucose
180 mg/dL
Chloride reabsorption
Passive; follows positive ions
Water reabsorption
β‰ˆ 80%; passive; obligatory water reabsorption
Bicarbonate reabsorption
β‰ˆ 80–90%
Urea
Some reabsorbed by diffusion
β–’ Loop of Henle / LOH:

Table 1: Loop of Henle

Limb
Epithelium
Permeability / Function
Descending limb
Thin squamous epithelium
Permeable to water; impermeable to salts
Ascending limb
Cuboidal epithelium
Permeable to salts; impermeable to water
❖ Longest LOH: Kangaroo rat
β–’ Distal Convoluted Tubule / DCT:

Table 1: DCT

Feature
Point
Epithelium
Cuboidal glandular epithelium
Main ions
\(Na^+\) absorption + \(K^+\) excretion
ADH effect
↑ water permeability of DCT + collecting duct
Water reabsorption
Osmosis β†’ concentrated urine
Facultative water reabsorption
Under ADH
ADH deficiency
Diuresis β†’ diabetes insipidus
Aldosterone effect
\(Na^+\) reabsorption
Urine volume regulation
ADH + aldosterone
β–’ Collecting Ducts:
  • β€’
    Lined by cuboidal + columnar epithelium in different regions
  • β€’
    DCTs of many nephrons β†’ collecting duct
  • β€’
    Collecting ducts β†’ papillary duct / duct of Bellini
  • β€’
    Duct of Bellini β†’ renal papilla / pelvis
β–’ Nephron Summary:

Table 1: Tubular Epithelium, Action & Filtrate Concentration

Part
Epithelium
Action
Concentration
PCT
Columnar
Complete absorption β†’ glucose + amino acids; water + \(Na^+\), \(K^+\), \(Cl^-\)
Isotonic
Descending limb of LOH
Squamous
Water reabsorption
Hypertonic
Ascending limb of LOH
Cuboidal
\(Na^+\), \(K^+\), \(Cl^-\), \(Ca^{2+}\), \(Mg^{2+}\) reabsorption
Hypotonic
DCT
Cuboidal
Water reabsorption under ADH; \(Na^+\) reabsorption under aldosterone
Isotonic
Collecting tubule / duct
Cuboidal / Columnar
Water reabsorption
Hypertonic
β–’ Mammalian Urine: Hypertonic
πŸ“š
VASA RECTA & TYPES OF NEPHRON
β–’ Vasa Recta:
  • β€’
    From efferent arteriole of juxtaglomerular nephron
  • β€’
    Peritubular capillary system around Loop of Henle
  • β€’
    U-turn in inner medulla
  • β€’
    Returns to venous circulation near cortico-medullary junction
β–’ Types of Nephron:

Table 1: Cortical vs Juxtamedullary Nephron

Feature
Cortical nephron
Juxtamedullary nephron
Percentage
80–90%
10–20%
Location
Renal cortex; near capsule / surface
Near cortex-medulla junction
Loop of Henle
Short; extends little into medulla; sometimes absent
Long; extends deep into medulla
Capillaries
Peritubular capillary network
Vasa recta
Presence
Common nephrons
Only birds + mammals
Function
Plasma volume control in normal water supply
Plasma volume regulation in water shortage / adverse condition
πŸ“š
URINE FORMATION
β–’ Processes:
  1. Glomerular filtration / ultrafiltration
  2. Tubular reabsorption / selective reabsorption
  3. Tubular secretion
β–’ Glomerular Filtration / Ultrafiltration:
❖ Nature: Passive process
❖ Site: Glomerulus β†’ Bowman's capsule
❖ Filtration Pores: Glomerular micropores β‰ˆ 0.1 ΞΌm
❖ Filtered Components:
  • β€’
    Urea
  • β€’
    Water
  • β€’
    Glucose
  • β€’
    Salts
  • β€’
    Non-colloidal plasma part
❖ Not Filtered:
  • β€’
    Blood cells
  • β€’
    Plasma proteins
❖ Filtration Membrane:
  1. Fenestrated capillary endothelium
  2. Basement membrane
  3. Filtration slits between podocytes
❖ Pressures:

Table 1: Filtration Pressures

Pressure
Value
Effect
Glomerular hydrostatic pressure / GHP
70 mmHg
Favours filtration; chief driving force
Blood colloidal osmotic pressure / BCOP
30 mmHg
Opposes filtration; due to plasma proteins mainly albumin
Capsular hydrostatic pressure / CHP
20 mmHg
Opposes filtration; due to filtrate in Bowman's capsule
❖ Effective Filtration Pressure:
β—‰ Formula: \(EFP = GHP - (BCOP + CHP)\)
β—‰ Calculation: \(EFP = 70 - (30 + 20) = 20\;mmHg\)
β—‰ Range: 15–20 mmHg
❖ Glomerular Filtration Rate / GFR:
  • β€’
    Total filtrate collected in Bowman's capsules of both kidneys per minute
  • β€’
    \(GFR = 125\;mL/min\)
  • β€’
    β‰ˆ 180 L/day
❖ Glomerular Filtrate:
β—‰ Formulae:
  • β€’
    Glomerular filtrate = Blood βˆ’ (blood cells + plasma proteins)
  • β€’
    Glomerular filtrate = Blood βˆ’ (RBCs + WBCs + platelets + plasma proteins)
  • β€’
    Glomerular filtrate = Plasma βˆ’ Protein
β—‰ Related Formulae:
  • β€’
    Lymph = Blood βˆ’ RBC
  • β€’
    Plasma = Blood βˆ’ Blood cells
  • β€’
    Serum = Plasma βˆ’ Clotting factors
β–’ Tubular Reabsorption:
  • β€’
    Changes composition of filtrate
  • β€’
    Reduces filtrate volume
  • β€’
    Exchange between filtrate + peritubular blood
  • β€’
    Passive + active transport
β–’ Tubular Secretion:

Table 1: Tubular Secretion

Site
Secreted substances
PCT
Creatinine, hippuric acid, pigments, drugs e.g. penicillin, \(H^+\), ammonia
DCT
\(K^+\), \(H^+\), \(NH_4^+\), \(HCO_3^-\)
Thin ascending limb of LOH
Urea by diffusion
❖ Special Note: Marine fish + desert amphibians lacking glomeruli / Bowman's capsule β†’ tubular secretion = only excretory mode
β–’ Threshold Substances:

Table 1: Renal Threshold Substances

Type
Reabsorption
Examples
High threshold
Almost fully reabsorbed
Sugar, amino acids, vitamins
Low threshold
Reabsorbed in low concentration
Urea, phosphate, uric acid
Non-threshold
Not reabsorbed
Creatinine
β–’ Diuretic Substances:
  • β€’
    Increase urine volume
  • β€’
    Examples β†’ tea, coffee, alcohol, diuretic drugs
πŸ“š
URINE

Table 1: Normal Urine

Feature
Value / Point
Volume
1.5–2 L/day
Water
96%
Urea
2%
Other solutes
Salts, uric acid, creatinine, ammonia
pH
4.5–8; average β‰ˆ 6; mildly acidic
Specific gravity
1.015–1.025
Colour
Pale yellow due to urochrome
Odour
Unpleasant; standing urine β†’ urea degraded by bacteria β†’ ammonia smell
β–’ Pathological Urine Contents:
  • β€’
    Protein / albumin
  • β€’
    Bile salts
  • β€’
    Bile pigments
  • β€’
    Ketone bodies
  • β€’
    Blood
  • β€’
    Pus
  • β€’
    Microbes
  • β€’
    More than trace glucose
β–’ Pathological Terms:

Table 1: Urine Abnormalities

Finding
Term
Glucose
Glycosuria
Protein
Proteinuria
Blood / RBCs
Haematuria
Ketone bodies
Ketonuria
Pus / WBCs
Pyuria
πŸ“š
URETERS

Table 1: Ureters

Feature
Point
Number
2
Origin
Hilum of each kidney
Length
β‰ˆ 25 cm
Wall lining
Transitional epithelium
Wall muscle
Muscle fibres around epithelium
Bladder opening
Separate but closely placed
Oblique opening
Prevents regurgitation during bladder contraction
Peristalsis
Checks urine regurgitation
πŸ“š
URINARY BLADDER

Table 1: Urinary Bladder

Feature
Point
Shape
Pear-shaped
Muscle
Smooth involuntary detrusor muscle
Neck
Lower part β†’ urethra
Trigone / Trigonum vesicae
Smooth triangular area
Lining
Transitional epithelium
Lining property
Great stretching power
Capacity
β‰ˆ 500 mL; fully stretched β‰ˆ 1000 mL
β–’ Sphincters:

Table 1: Bladder Neck Sphincters

Sphincter
Control
Inner sphincter
Involuntary; spinal reflex
Outer sphincter
Voluntary; cerebral cortex
β–’ Autonomic Control:

Table 1: Bladder Control

Action
Nervous system
Urine collection
Sympathetic nervous system
Micturition
Parasympathetic nervous system
πŸ“š
URETHRA

Table 1: Urethra

Feature
Value / Point
Female length
β‰ˆ 4 cm
Male length
β‰ˆ 16–20 cm
Female UTI
More common due to short urethra + proximity to anal opening
Common UTI organism
E. coli
β–’ Male Urethra Parts:
  1. Prostatic urethra
  2. Membranous urethra
  3. Penile / Spongy urethra
πŸ“š
EXCRETORY PRODUCTS

Table 1: Nitrogenous Excretory Products

Product
Type of excretion
Properties
Examples
Amino acids
Aminotelic / aminotelism
Excess amino acids excreted directly
Some molluscs e.g. Unio, Limnaea; echinoderms e.g. Asterias
Ammonia
Ammonotelic / ammonotelism
Highly toxic; highly water soluble; needs large water
Aquatic arthropods, bony fishes, freshwater fishes, tadpoles, turtles
Uric acid
Uricotelic / uricotelism
Non-toxic; almost insoluble; solid crystals; water conserving
Insects, land reptiles, birds
Urea
Ureotelic / ureotelism
Less toxic and less soluble than ammonia
Adult amphibians, mammals, elasmobranch fishes
β–’ Urea:
  • β€’
    Derived from 2 ammonia + 1 carbon dioxide
  • β€’
    Formed in liver
  • β€’
    Cycle β†’ urea cycle / ornithine cycle / Krebs-Henseleit cycle
  • β€’
    Amino acids involved β†’ ornithine, citrulline, arginine
  • β€’
    Final enzyme β†’ arginase
πŸ“š
FORMATION OF UREA
β–’ Urea Cycle / Ornithine Cycle:
  1. \(2NH_3 + CO_2\) --carbamyl phosphate synthetase→ carbamyl phosphate
  2. Carbamyl phosphate + ornithine β†’ citrulline
  3. Citrulline + aspartic acid --arginosuccinic synthetase + ATP→ arginosuccinic acid
  4. Arginosuccinic acid --arginosuccinase→ arginine + fumaric acid
  5. Arginine --arginase→ urea + ornithine
β–’ Urea Concentration:

Table 1: Urea in Blood Vessels

Vessel
Concentration
Reason
Hepatic vein
Highest
Urea formed in liver β†’ enters circulation
Renal vein
Lowest
Urea excreted by kidney
πŸ“š
RENIN-ANGIOTENSIN-ALDOSTERONE SYSTEM / RAAS
β–’ Trigger: ↓ Blood pressure
β–’ Pathway:
  1. ↓ BP detected by macula densa cells in DCT wall
  2. Macula densa stimulates juxtaglomerular cells of afferent arteriole
  3. Juxtaglomerular cells secrete renin
  4. Renin converts angiotensinogen from liver β†’ angiotensin I
  5. ACE from type I alveolar cells in lungs converts angiotensin I β†’ angiotensin II
β–’ Angiotensin II:
❖ Nature: Potent vasoconstrictor
❖ BP-Increasing Mechanisms:

Table 1: Actions of Angiotensin II

Mechanism
Effect
Vasoconstriction
↓ blood vessel diameter β†’ ↑ BP
Aldosterone stimulation
Adrenal cortex β†’ aldosterone β†’ ↑ \(Na^+\) + water reabsorption β†’ ↑ blood volume β†’ ↑ BP
Hypothalamus stimulation
Thirst centre β†’ ↑ water intake β†’ ↑ blood volume β†’ ↑ BP
β–’ Juxtaglomerular Apparatus / JGA:

Table 1: JGA Components

Component
Function
JG cells
Secrete renin
Macula densa cells
Detect tubular fluid / pressure / volume changes
Mesangial cells
Modified macrophage-like interstitial cells; communication support
β–’ Erythropoietin: Secreted by JGA β†’ stimulates erythropoiesis / RBC production
πŸ“š
FUNCTIONS OF KIDNEY
β–’ Homeostasis: Eliminates metabolic wastes + impurities + surplus useful materials β†’ internal environment maintenance

Table 1: Kidney Functions

Function
Mechanism / Point
Osmoregulation
Maintains ECF water balance by diluting or concentrating urine
pH regulation
Maintains ECF pH β‰ˆ 7.4 by acid-base buffer support + acidic/basic urine excretion
Electrolyte regulation
Controls total + individual electrolyte concentrations by tubular reabsorption/secretion
RBC count regulation
Hypoxia β†’ erythropoietin β†’ bone marrow stimulation β†’ ↑ RBC
Blood pressure regulation
RAAS mechanism
β–’ Acid-Base Terms:

Table 1: pH Disorders

Condition
Meaning
Acidosis
Low pH / ↑ \(H^+\)
Alkalosis
High pH / ↓ \(H^+\)
πŸ“š
IMPORTANT TERMS

Table 1: Urinary Terms

Term
Meaning
Anuria
Urine output 0–100 mL/day
Albuminuria
Albumin in urine
Azotaemia
Nitrogenous waste accumulation in blood
Bright's disease / Glomerulonephritis
Inflammation of kidney / glomeruli
Cystitis
Inflammation of urinary bladder lining
Diuretics
Chemicals increasing urine volume
Dysuria
Painful urination
Enuresis
Bed-wetting
Glycosuria
Glucose in urine; pathological in diabetes mellitus
Gout
↑ uric acid in blood
Haematuria
Blood / RBCs in urine
Haemoglobinuria
Haemoglobin in urine
Haemodialysis
Removal of accumulated wastes e.g. urea from blood by artificial kidney
Ketonuria / Acetonuria
Ketone bodies in urine β†’ acetoacetic acid, \(\beta\)-hydroxybutyric acid, acetone
Kidney stone / Renal calculi
Crystallized uric acid, calcium oxalate, calcium phosphate
Micturition
Act of passing urine
Nephrology
Study of kidney anatomy, physiology, pathology
Nephroptosis / Floating kidney
Inferior displacement / dropping of kidney
Oliguria
Urine output <500 mL/day
Polyuria / Diuresis
Urine output >2 L/day
Proteinuria
Excess protein in urine
Pyuria
WBCs / pus in urine
Shock-wave lithotripsy
Kidney stone removal by high-intensity sound waves
Uraemia
High blood urea level due to kidney failure
Urinalysis
Physical + chemical examination of urine
Urinary incontinence
Lack of voluntary control over micturition
Urology
Medicine branch β†’ male + female urinary systems + male reproductive system
πŸ“š
DISORDERS OF EXCRETION
β–’ Renal Calculi: Kidney stones / renal calculi
β–’ Nephritis: Inflammation of kidney
β–’ Renal Failure: Failure of kidney excretory function
β–’ Haemodialysis: Artificial kidney-based removal of accumulated wastes
β–’ Kidney Transplantation: Replacement of failed kidney with donor kidney
πŸ“š
EXTRA POINTS

Table 1: Comparative Urinary Facts

Fact
Answer
Functional kidney of tadpole frog
Pronephric kidney
Functional kidney of adult frog
Mesonephric kidney
Urinary bladder absent in
Fishes, snakes, crocodiles, birds except ostrich
Urinary bladder present in
Lizard, amphibians, mammals
πŸ“š
HIGH-YIELD RECALL

Table 1: Excretory System One-Liners

Fact
Answer
Mammalian kidney
Metanephric
Kidney origin
Nephrotome plate of mesoderm
Kidney position
Retroperitoneal
Human kidney extent
\(T*{12}\)–\(L_3\)
Right kidney in human
Lower than left
Right kidney in rabbit
Higher than left
Kidney functional unit
Nephron / uriniferous tubule
Malpighian corpuscle
Glomerulus + Bowman's capsule
Cortex contains
Malpighian corpuscle + PCT + DCT
Medulla contains
Loop of Henle + collecting ducts
Bowman's capsule visceral cells
Podocytes
Maximum reabsorption
PCT
Glucose renal threshold
180 mg/dL
Obligatory water reabsorption
PCT
Facultative water reabsorption
DCT + collecting duct under ADH
ADH deficiency
Diabetes insipidus
Aldosterone effect
\(Na^+\) reabsorption
Descending LOH
Water permeable; salt impermeable
Ascending LOH
Salt permeable; water impermeable
Longest LOH
Kangaroo rat
Vasa recta
Juxtamedullary nephron capillary
Cortical nephrons
80–90%
Juxtamedullary nephrons
Water shortage regulation
GFR
125 mL/min = 180 L/day
Glomerular filtrate
Plasma βˆ’ Protein
EFP formula
\(GHP - (BCOP + CHP)\)
Normal urine volume
1.5–2 L/day
Urine pH
Average 6
Urine colour
Urochrome
Ureter length
25 cm
Bladder muscle
Detrusor
Bladder lining
Transitional epithelium
Micturition
Parasympathetic
Urine collection
Sympathetic
Female urethra
4 cm
Male urethra
16–20 cm
Common UTI organism
E. coli
Urea cycle site
Liver
Final urea cycle enzyme
Arginase
Highest urea concentration
Hepatic vein
Lowest urea concentration
Renal vein
Renin source
Juxtaglomerular cells
Angiotensinogen source
Liver
ACE source
Lungs
Angiotensin II
Potent vasoconstrictor
JGA components
JG cells + macula densa + mesangial cells
Q1.
In kidney of mammals, malphigian capsule is situated in [IOM 2008]
πŸ“…IOM 2008
Q2.
Urinary bladder is lined by [IOM 2007]
πŸ“…IOM 2007
Q3.
Uricotelism is found in [IE 2010]
πŸ“…IE 2010
Q4.
Muscle controlling the passage of urine from the bladder to the urethra in vertebrates [KU 2012]
πŸ“…KU 2012
Q5.
The conversion of protein waste, the ammonia into urea occurs mainly in [KU 2012]
πŸ“…KU 2012
Q6.
Kidneys of frog and rabbit are: [BPKIHS 2012]
πŸ“…BPKIHS 2012
Q7.
Which of the following is not absorbed from proximal convoluted tubule? [BPKIHS 2012]
πŸ“…BPKIHS 2012
Q8.
Duct of Bellini is associated with [KU 2012]
πŸ“…KU 2012
Q9.
Reptiles and birds are [BPKIHS 2010]
πŸ“…BPKIHS 2010
Q10.
What is the correct order of urine formation? [BPKIHS 2010]
πŸ“…BPKIHS 2010
Q11.
Which of the following parts of the nephron is least permeable to water? [IE 2009]
πŸ“…IE 2009
Q12.
Transitional epithelium is found in: [IE 2008]
πŸ“…IE 2008
Q13.
GFR stands for [IOM 2007]
πŸ“…IOM 2007
Q14.
Chemical responsible for increase in BP due to renin action is [BPKIHS 2009]
πŸ“…BPKIHS 2009
Q15.
Homeostasis occurs in: [IE 2007]
πŸ“…IE 2007
Q16.
Which is not absorbed from the filtrate to the blood of the proximal tubules? [IE 2007]
πŸ“…IE 2007
Q17.
The maximum reabsorption of water takes place in [BP 2007]
πŸ“…BP 2007
Q18.
The mammalian urine is [BP 2007]
πŸ“…BP 2007
Q19.
Ultrafiltration takes place in [KU 2006]
πŸ“…KU 2006
Q20.
Uriniferous tubules is found in [MOE 2060]
πŸ“…MOE 2060
Q21.
Urea is mainly excreted by
Q22.
In Rabbit [IOM 2001]
πŸ“…IOM 2001
Q23.
Uriniferous tubule is found in [MOE-2060]
πŸ“…MOE 2060
Q24.
Portal system of rabbit differs from that of frog in that rabbit has [IOM 1997]
πŸ“…IOM 1997
Q25.
Diuresis is a condition characterized by [BP 2004]
πŸ“…BP 2004
Q26.
Haemodialysis especially as performed by an artificial kidney [IOM 2003]
πŸ“…IOM 2003
Q27.
The blood leaving the liver & joining towards the heart is rich in [IE 2001]
πŸ“…IE 2001
Q28.
Which of the following organs maintains the acidbase balance in the body? [IOM 2000]
πŸ“…IOM 2000
Q29.
The right kidney is usually slightly lower than the left, probably due to the presence of [IOM -1995]
πŸ“…IOM -1995
Q30.
Kidney of adult rabbit is [IOM 1998]
πŸ“…IOM 1998
Q31.
Muscle controlling the passage of the urine from the bladder to the urethra in vertebrates [KU 2012]
πŸ“…KU 2012
Q32.
The conversion of protein waste, the ammonia into urea occurs mainly in [2017]
πŸ“…2017
Q33.
Most common nitrogenous waste in blood is: [KU 2011]
πŸ“…KU 2011
Q34.
Ascending limb of loop of Henle is permeable to: [MOE 2014]
πŸ“…MOE 2014
Q35.
A single structural and functional unit in the kidney of mammal is called: [KU 2015]
πŸ“…KU 2015
Q36.
Podocytes cells are used in [KU]
πŸ“…KU
Q37.
Condition in which blood present in urine is [KU ]
πŸ“…KU