Each cardiac cycle is initiated by spontaneous generation of an action potential in the sinus node.

TLS Online TPP Program

#Id: 1217

#Unit 7. System Physiology – Animal

The parathyroid cell membrane contains Ca2+ sensing receptors that are linked, via a G protein (Gq).

TLS Online TPP Program

#Id: 1218

#Unit 7. System Physiology – Animal

When extracellular Ca2+ concentration is increased  Ca2+ binds to the receptor  activates phospholipase C inhibits PTH secretion.

TLS Online TPP Program

#Id: 1219

#Unit 7. System Physiology – Animal

When extracellular Ca2+ is decreased decreased Ca2+ binding to the receptor stimulates PTH secretion

TLS Online TPP Program

#Id: 1220

#Unit 7. System Physiology – Animal

When extracellular Ca2+ is decreased decreased Ca2+ binding to the receptor stimulates PTH secretion

TLS Online TPP Program

#Id: 1221

#Unit 7. System Physiology – Animal

The receptor for PTH is coupled, via a Gs protein, to adenylyl cyclase.

TLS Online TPP Program

#Id: 1222

#Unit 7. System Physiology – Animal

In bone, PTH receptors are located on osteoblasts but not on osteoclasts.