The amino group at C-2 bears a fatty acid in amide linkage.

The fatty acid is usually saturated or monounsaturated, with 16, 18, 22, or 24 carbon atoms.

Ceramide is the parent compound for this group.

TLS Online TPP Program

#Id: 5449

#Unit 7. System Physiology – Animal

Refractory period is divided into:

Absolute refractory period

Relative refractory period

TLS Online TPP Program

#Id: 5450

#Unit 7. System Physiology – Animal

The absolute refractory period overlaps with almost the entire duration of the action potential. During this period, no matter how great the stimulus, another action potential cannot be elicited.

TLS Online TPP Program

#Id: 5451

#Unit 7. System Physiology – Animal

The basis for the absolute refractory period is closure of the inactivation gates of the Na+ channel in response to depolarization. These inactivation gates are in the closed position until the cell is repolarized back to the resting membrane potential.

TLS Online TPP Program

#Id: 5452

#Unit 7. System Physiology – Animal

The relative refractory period begins at the end of the absolute refractory period and overlaps primarily with the period of the hyperpolarizing afterpotential.

TLS Online TPP Program

#Id: 5453

#Unit 7. System Physiology – Animal

During the relative refractory period, stronger than normal stimuli can cause excitation

TLS Online TPP Program

#Id: 5454

#Unit 7. System Physiology – Animal

The basis for the relative refractory period is the higher K+ conductance than is present at rest.