L08. Physiology - Cardiac Function I #2

Troponin C - helps bind calcium ions

Troponin I - Inhibit myosin and actin from binding in the absence of Ca2+

Troponin T - Bind troponin to tropomyosin

<p>Depolarization cause an AP --&gt; AP travels via T-Tubules --&gt; causes L-Type Ca2+ channels to open and a small amount of Ca2+ gets released into the cytosol --&gt; this release of Ca2+ causes the RyR2 receptors to release even more Ca2+ (CALCIUM-INDUCED-CALCIUM RELEASE) from the SR --&gt; this increase in Ca2+ is going to active the thin filaments --&gt; Ca2+ binds to troponin (TnC) --&gt; move the tropomyosin form the actin-moysin binding sites --&gt; now we are ready for myosin and actin to bind and for contraction to occur</p> <p>Hydrolyzation of ATP into ADP + Pi will get myosin in a cocked position and ready for actin --&gt; actin + myosin bind and form a cross-bridge --&gt; Power stroke = CONTRACTION --&gt; ADP + Pi leave the scene and ATP comes in --&gt; actin gets released --&gt; relaxation</p> Signup and view all the answers

<p>Phospholamban (PLB) - Phosphorylation of PLB inhibits its ability to inhibit SERCA and as such SERCA activity is ENHANCED and it is able to sequester more Ca2+ into SR</p> Signup and view all the answers

<ol> <li>alpha - MHC (Fast, MYH6 gene)</li> <li>beta - MHC (Slow, MYH7 gene) --&gt; ATPase and power stroke occur more slowly and generate more force</li> </ol> Signup and view all the answers

<p>Tension at a specific preload/length</p> Signup and view all the answers

<p>Titin + Collagen (both elastic)</p> Signup and view all the answers

<p>Force generated in a resting/hyper polarized cell. Defined by titin and collagen</p> Signup and view all the answers

<p>Myosin ATPase defines DEVELOPED tension</p> Signup and view all the answers

<p>Increases calcium dissociation rate of TnC --&gt; basically we can generate the same level of contraction in the cardiac myocyte with less Ca2+</p> Signup and view all the answers