Ward Round Notes

Skeletal muscles contain muscle fibres which span the whole length of the muscle. These are made up of subunits called sacromeres containing thick myosin filaments and thin actin filaments. Thick and thin filaments slide towards each other during contraction, the total effect of multiple sacromeres contracting leads to the shortening of the muscle. 

Membrane potential Membrane potential refers to the net difference in charge on each side of a selectively permeable membrane  due to an imbalance of cations and anions. This difference has the potential to become electrical energy (current) which is produced when ions move down an electrochemical gradient.  In the body, a membrane potential exists between the intracellular fluid and the extracellular fluid (ie almost all cells and the extracellular fluid surrounding it). Membrane potential is measured in milivolts (mV) in the body. It is always measured with the inside (ICF) relative to the outside (ECF).