Bio 252_Midterm Study Guide

Muscular skeletal system as physics (page329-331) (synovial joints) -In producing movement, bones act as levers, and joints function as the fulcrums of these levers. A lever is a rigid structure that can move around a fixed point called a fulcrum, symbolized by. A lever is acted on at two different points by two different forces: the effort (E), which causes movement, and the load or resistance, which opposes movement. The effort is the force exerted by muscular contraction; the load is typically the weight of the body part that is moved or some resistance that the moving body part is trying to overcome. -Synovial Joints : pivot (neck) hinge (fingers & toes) saddle(thumb, 1st metacarpal and trapezium) plane(wrist and ankle bones, sternum to clavicle) condyloid (between radius, scaphoid and wrist bones) ball-and-socket(hip and shoulder) Make difference between smooth muscles and cardiac muscles Cardiac Muscles  striated (lines) – many nuclei Smooth Muscles  nonstriated – involuntary – visceral muscle What happens during a depolarization event? Versus polarization event? - Depolarization is the state which the cell membrane change from positive to negative charged outside the cell and from negative to positive charge inside the cell. - Polarization-The cell membrane separates the inside of a cell (all cells, not just neurons) from the outside, and all chemicals that get into and out of the cell must go through it. As in all cells, the cell membrane of a neuron is polarized. This means that there is an electrical difference across the cell membrane.