Excretory Products and Their Elimination

Ammonia

Urea

Uric acid

Water

Mammals

Amphibians

Insects

Echinoderms

Carbohydrates

Lipids

Proteins

Vitamins

Ammonia

Uric acid

Nitrites

Hydrogen sulfide

To reduce the toxicity of nitrogenous waste.

To allow the waste to be transported in the blood safely.

To conserve water by requiring less of it for excretion.

To increase the pH of the blood.

It excretes urea which is stored in the yolk.

It excretes ammonia which diffuses through the shell.

It excretes uric acid which is stored in the allantois as a non-toxic solid.

It does not produce any nitrogenous waste until hatching.

Through urine concentrated in the bladder.

Through the skin by active transport.

By diffusion through the gill membranes as ammonium ions.

By converting it to uric acid pellets.

Accumulation of Citrulline in the blood

Inability to form Arginine from Argininosuccinate

Accumulation of Ammonia and Carbamoyl Phosphate

Excessive production of Uric acid

10 times

100 times

10,000 to 100,000 times

1,000,000 times

2:1 in urea; 4:5 in uric acid

1:2 in urea; 5:4 in uric acid

2:1 in urea; 1:1 in uric acid

1:1 in urea; 4:5 in uric acid

Bowman's capsule

Henle's loop

Vasa recta

Glomerulus

Columns of Bertini

Major and minor calyces

Ureters

Afferent arterioles

Renal vein

Renal artery

Hepatic portal vein

Pulmonary artery

Glomerular pores

Filtration slits

Calyx channels

Medullary pores

Fenestrations

Slit pores

Villi

Microvilli

It is a layer of neurons covering the kidney

It is a tough, fibrous connective tissue covering of the kidney

It is the functional unit of the kidney

It is the same as the Bowman's capsule

Smooth

Cardiac

Skeletal

Involuntary

2 times

4 times

10 times

100 times

Between the levels of the last thoracic and third lumbar vertebra.

Between the levels of the first cervical and seventh thoracic vertebra.

Within the pelvic cavity attached to the dorsal wall.

Between the levels of the fifth thoracic and tenth thoracic vertebra.

$K^+$ and water

$Na^+$ and water

Glucose and amino acids

$H^+$ and $NH_3$

Calyx

Hilum

Pelvis

Cortex

$Na^+$ and $Ca^{2+}$

$H^+$ and $K^+$

$Cl^-$ and $HCO_3^-$

$Mg^{2+}$ and $Fe^{2+}$

Production of dilute urine

Faster filtration of blood

Increased water conservation

Increased salt excretion

PCT

DCT

Collecting duct

Bowman's capsule

It creates the medullary osmotic gradient.

It maintains the medullary osmotic gradient by removing reabsorbed water and solutes.

It filters the blood in the medulla.

It secretes $H^{+}$ ions into the medullary interstitium.

More urea in urine

Less urea in urine

No urea in urine

More glucose in urine

Secrete Renin

Sense $NaCl$ concentration in the DCT

Constrict the efferent arteriole

Filter the blood

Because water is added to the filtrate from the vasa recta

Because solutes ($NaCl$) are removed while water is retained in the tubule

Because urea is actively reabsorbed into the blood

Because the tubule diameter increases, diluting the contents

Insertion of Aquaporin-2 channels into the apical membrane

Decrease in the permeability of the duct to urea

Active transport of water into the lumen

Inhibition of $Na^{+}$ reabsorption

Only filtered but not reabsorbed

Filtered and then partially reabsorbed

Filtered and also actively secreted by the tubules

Not filtered at all

Atrial blood pressure

Glomerular blood flow

Blood glucose level

Body temperature

Renin

ADH

ANF

Insulin

Dilation of renal arteries

Release of ANF

Stimulation of Adrenal Cortex

Inhibition of Renin

Aldosterone

Atrial Natriuretic Factor

ADH

Renin

X: ANF; Y: Hunger

X: ADH; Y: Thirst

X: Aldosterone; Y: Sleep

X: Renin; Y: Thirst

1: Renin; 2: Angiotensinogen; 3: Aldosterone

1: Angiotensinogen; 2: Renin; 3: Aldosterone

1: Angiotensin I; 2: Renin; 3: ADH

1: Angiotensinogen; 2: ACE; 3: ANF

Blood volume and body fluid volume only

Ionic concentration only

Blood volume, body fluid volume, and ionic concentration

Blood pressure in the atria only

The Macula Densa is a part of the afferent arteriole that releases Renin.

The Macula Densa is a specialized region of the distal tubule that monitors filtrate composition and communicates with JG cells.

The Macula Densa consists of modified podocytes that regulate the size of filtration slits.

The Macula Densa releases Aldosterone in response to low sodium levels.

$↑$ Renin, $↑$ ANF

$↓$ Renin, $↓$ ANF

$↑$ Renin, $↓$ ANF

$↓$ Renin, $↑$ ANF

By activating RAAS to constrict the efferent arteriole more than the afferent arteriole.

By releasing ANF to cause systemic vasodilation.

By inhibiting ADH to reduce the volume of the filtrate.

By increasing the resistance of the afferent arteriole.

By secreting sebum

By the evaporation of sweat

By increasing blood flow to the heart

By storing fat

Lungs

Liver

Kidneys

Pancreas

It removes large amounts of water

It removes small amounts of nitrogenous waste

It removes bile pigments

It removes sterols

1.2 Liters

12 Liters

120 Liters

2 Liters

Only kidneys are responsible for all metabolic excretion

Lungs, liver, and skin assist in removing specific metabolic wastes

The liver's only excretory function is to remove $CO_{2}$

Sweat and sebum are identical in their excretory composition

Urea and salts

Hydrocarbons and waxes

Bile pigments

Water vapor

Liver and Lungs

Sweat glands and Saliva

Sebaceous glands and Liver

Lungs and Sebaceous glands

They are highly hydrophilic proteins.

They are hydrophobic lipids like waxes and hydrocarbons.

They are ionic salts like NaCl and KCl.

They are volatile organic acids.

60-90 mg

600-900 mg

10-15 mg

120-180 mg

The liver excretes only organic compounds, while the lungs excrete only inorganic ones.

The lungs remove volatile wastes ($CO_{2}$), while the liver removes non-volatile metabolic byproducts (bile pigments).

Both organs are primarily responsible for $NaCl$ homeostasis.

The liver's excretory products enter the blood, while the lungs' products enter the lymph.

Plasmolysis

Hemolysis

Hemodialysis

Diffusion

Gallstones

Renal calculi

Tonsilloliths

Phleboliths

Heparin

Anti-heparin

Insulin

Adrenaline

Infectious disease of the bladder

Inflammatory condition of the kidney

Inherited disorder of the liver

Autoimmune reaction in the lungs

Same position as the original kidney

Iliac fossa of the pelvis

Chest cavity

Abdominal cavity near the liver

To increase the solubility of urea

To slow down metabolic reactions and prevent clotting

To kill any viruses present

To prevent the cellophane from melting

Antibiotics

Hemodialysis

Increased salt intake

Liver transplant

Bilirubin

Urochromes and carotenoids

Melanin

Hemofuscin

Hemolysis (bursting) of Red Blood Cells

Crenation (shrinking) of Red Blood Cells

No effect on blood cells

Sudden increase in blood urea

Bowman's Capsule

Proximal Convoluted Tubule and Thick Ascending Limb

Distal Convoluted Tubule

Descending limb of Loop of Henle

There will be no urine formation

Urine will be more concentrated

Urine will be more dilute

There will be no change in urine concentration

Reabsorption and Secretion

Only filtration

Storage of urine

Synthesis of urea

Always zero

Minimal

Large and helps in concentrating urine

Only active transport

PCT

DCT

Glomerulus

Bowman's capsule

The PCT

The DCT

Henle's Loop

The Bowman's capsule

Glomerulus

Loop of Henle

PCT and DCT

Descending limb only

Descending limb of Henle's loop

Ascending limb of Henle's loop

PCT

Collecting duct

Simple diffusion

The $Na^+-K^+-2Cl^-$ cotransporter

Exchange with $HCO_3^-$

Secondary active transport with glucose

At the end of the PCT

At the bottom of the Loop of Henle

At the end of the Collecting Duct

In the Bowman's Capsule

Proximal Convoluted Tubule

Descending limb of Henle

Distal Convoluted Tubule

Thin Ascending limb of Henle

Henle's loop

Vasa recta

Interstitial fluid

Proximal Convoluted Tubule

Active secretion of water

Passive reabsorption of water

Active reabsorption of urea

Filtering blood at the glomerulus

Passive

Active

Against the gradient

Through the vasa recta

Oxytocin

ADH (Vasopressin)

Insulin

Adrenaline

Active transport of $Na^{+}$ in the thick ascending limb

Permeability of the descending limb to water

Active transport of $Na^{+}$ in the PCT

Passive diffusion of urea from the collecting duct

Urine would be more concentrated

The medullary osmotic gradient would be washed away

Filtration would stop

Glucose reabsorption would fail

Poison bacteria in the urine

Contribute to the high osmolarity of the medullary interstitium

Decrease the work done by the vasa recta

Be converted into glucose

Hypertonic to the plasma but isotonic to the medullary interstitium

Hypotonic to the plasma

Isotonic to the cortical fluid

Pure water

Both are actively transported into the interstitium

NaCl is actively transported (thick limb) and Urea is passively transported

Both are passively transported from the cortex

NaCl is passively transported and Urea is actively transported

Total kidney failure

Inability to concentrate urine above $300\text{ mOsmol/L}$

Inability to reabsorb glucose

Formation of very concentrated urine

Sensory

Motor

Inhibitory only

No messages

Non-elastic

Stretchable

Rigid

Permeable to urea

$10-15$ grams

$25-30$ grams

$40-50$ grams

$1-5$ grams

Only voluntary

Only involuntary

Neural reflex process

Purely chemical

Urinary bladder

Urethra

Glomerular filtration membrane

Ureter

Frequency decreases because the bladder takes longer to fill

Frequency increases because the bladder fills faster with dilute urine

Frequency remains unchanged as it is only time-dependent

Frequency increases because the urea concentration increases

Vagus nerve

Pudendal nerve

Pelvic nerve

Hypogastric nerve

Glucose levels increase.

Urea levels increase significantly.

Ketone bodies become the main solute.

The urine becomes highly alkaline.

Micturition

Glomerular filtration

Ultrafiltration

Ureotely

Urea

Uric Acid

Creatinine

Hippuric acid