The inherent leakiness of the sinus nodal fibers to sodium and calcium ions causes their self-excitation.

TLS Online TPP Program

#Id: 2669

#Unit 7. System Physiology – Animal

The thick ascending limb has a sodium-hydrogen counter-transport.

TLS Online TPP Program

#Id: 2670

#Unit 7. System Physiology – Animal

In the thick segment of the ascending loop of Henle, paracellular reabsorption of cations, such as Mg++, Ca++, Na+, and K+ occur.

TLS Online TPP Program

#Id: 2671

#Unit 7. System Physiology – Animal

Paracellular reabsorption of cations causes slight positive charge of the tubular lumen relative to the interstitial fluid.

TLS Online TPP Program

#Id: 2672

#Unit 7. System Physiology – Animal

A slight backleak of potassium ions into the lumen, creating a positive charge of about +8 millivolts in the tubular lumen.

TLS Online TPP Program

#Id: 2673

#Unit 7. System Physiology – Animal

Positive charge forces cations such as Mg++ and Ca++ to diffuse from the tubular lumen through the paracellular space and into the interstitial fluid.

TLS Online TPP Program

#Id: 5527

#Unit 7. System Physiology – Animal

In early proximal convoluted tubule sodium is reabsorbed by co-transport along with glucose, amino acids, & other solutes.