When the Ca2+ levels drop:

Myosin LC is dephosphorylated by MLC phosphatase, causing muscle relaxation.

TLS Online TPP Program

#Id: 5287

#Unit 7. System Physiology – Animal

Acetylcholine (ACh), released from parasympathetic nerve fibers, activates muscarinic (M2) receptors in the SA node.

TLS Online TPP Program

#Id: 8119

#Unit 1. Molecules and their Interaction Relevant to Biology

The triterpenes are C30 terpenes and include squalene and lanosterol, two of the precursors of cholesterol

TLS Online TPP Program

#Id: 7480

#Unit 4. Cell Communication and Cell Signaling

IgA is the principal class in secretions, the most important being those from the epithelia lining the intestinal and respiratory tracts.

Dimeric IgA operates mainly on epithelial surfaces.

This monomeric IgA is predominantly of the subclass IgA1; the ratio of IgA1 to IgA2 in the blood is 10:1.

IgA antibodies produced by plasma cells in the gut are dimeric and predominantly of subclass IgA2; the ratio of IgA2 to IgA1 in the gut is 3:2.

TLS Online TPP Program

#Id: 8523

#Unit 2. Cellular Organization

TLS Online TPP Program

#Id: 5550

#Unit 7. System Physiology – Animal

The second half of the distal tubule and the subsequent cortical collecting tubule have two distinct cell types:  principal cells and intercalated cells