Ch 45.3 Muscular System

Overview of Muscle Tissue All skeletal and

smooth muscle cells are elongated and are referred to as muscle fibers

Contraction of muscles is due to the movement of microfilaments

Overview of Muscle Tissue Muscle contraction depends on two types

of myofilaments: actin (thin) and myosin(Thick)- proteins

anchored at their endpoints and create a structure called the Z line

Contraction

ActinMyosin

When actin slides over myosin

https://www.youtube.com/watch?v=Cjx3vSm54N8

ActinMyosin

Skeletal Muscle Tissue

Skeletal muscle has obvious striations It is a voluntary muscle under conscious control

Skeletal muscle – can contract rapidly – tire easily and must be rested– contractions vary in force

depending on use

Producing MovementMovement results from

skeletal muscle contractionSkeletal muscle are responsible

for all locomotion and manipulation

Allows you to interact or react with your external environment

Attachments Most muscles span joints and have at least two

attachments an origin and an insertion Origin

– Attachment of a muscle that remains relatively fixed during muscular contraction

– Generally a more proximal or axial location

Insertion–Attachment of a muscle that moves during muscular contraction–Generally a more distal or appendicular attachment

Tendons – attach muscles to bones.