E. coli SSB is a tetramer of 74 kD that binds single-stranded DNA cooperatively

TLS Online TPP Program

#Id: 5566

#Unit 7. System Physiology – Animal

Assume first a condition in which osmolality is 300 mOsm/kg of H2O throughout the descending and ascending limbs & medullary interstitium

TLS Online TPP Program

#Id: 5567

#Unit 7. System Physiology – Animal

Assume first a condition in which osmolality is 300 mOsm/kg of H2O throughout the descending and ascending limbs & medullary interstitium

TLS Online TPP Program

#Id: 5568

#Unit 7. System Physiology – Animal

Assume in addition that the pumps in the thick ascending limb can pump 100 mOsm/kg of Na+ & Cl– from the tubular fluid to the interstitium, increasing interstitial osmolality to 400 mOsm/kg of H2O 

TLS Online TPP Program

#Id: 5569

#Unit 7. System Physiology – Animal

Meanwhile, hypotonic fluid  flows into the distal tubule, andisotonic and subsequently hypertonic fluid flows into the

ascending thick limb

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#Id: 5570

#Unit 7. System Physiology – Animal

The process keeps repeating & the final result is a gradient of osmolality from the top to the bottom of the loop

TLS Online TPP Program

#Id: 5571

#Unit 7. System Physiology – Animal

In juxtamedullary nephrons with longer loops and thin ascending limbs, the osmotic gradient is spread over a greater distance and the osmolality at the tip of the loop is greater.