Muscular System

anterior view

trapezius, pectoral, deltoid, bicep, abdominal group, hip flexors, quadriceps group, tibialis anterior

posterior view

trapezius, latissimus dorsi, tricep, adductor group, gluteus maximus, hamstring group, gastrocnemius, soleus

functions of muscular system

produce movement, maintain essential bodily functions, maintain posture, stabilise joints, generate heat

produce movement

skeletal muscles which are consciously controlled (voluntary) are attached to bones. When we want to produce movement, the CNS sends a message from brain to relevant muscles to contract, resulting in 'pulling the bone' causing movement to occur. this enables human body to respond quickly to changes in external environment

maintain essential bodily functions

those muscles which we have little or no conscious control over are regarded as involuntary muscles. these muscles are responsible for maintaining body's ongoing needs. Includes the smooth muscle of hollow organs such as gastrointestinal tract, bladder, or uterus which forces fluids (urine, bile) and other substances (food, a baby) though internal body channel. The cardiac muscle of heart and walls of blood vessels which work together to circulate blood around body.

maintain posture

through continuous contraction of muscles, making one tiny adjustment after another, the human body is able to maintain posture despite the never-ending downward pull of gravity.

stabilise joints

Skeletal muscles serve to stabilise the joints of skeleton. Muscle tendons play an important role in reinforcing and stabilising joints that have inadequately fitting articulating surfaces.

generate heat

heart is a by-product of muscular activity. As ATP is used to power muscle contraction, nearly 3/4 of its energy is released as heat, which is critical in maintaining normal body temperature. Heat released by working muscles keeps the body temp in the range required for normal functioning

origin

Bone that origin of muscle is attached to, does not move when muscle contracts. Origin is point which usually at the proximal end

insertion

bone that insertion is attached to moves more when muscle contracts. Insertion of muscle is point which is usually at distal end

how muscles help us move

when a muscle contracts it pulls on one of the two bones to which it is attached, creating movement. origin and insertion points of a muscles are its two attachment points on the skeleton. All muscles bridge a joint and when contraction occurs, movement takes place, altering the joint angle. Once a muscle contracts to move a bone, another muscle must contract to return the bone to its original position - hence muscles work in pairs.

muscle and joint movement

when muscles produce movement, they work in pairs. this is because muscles can only pull, not push. the muscle which contracts in any movement is referred to as the agonist. the muscle which relaxes to allow movement to occur passively is referred to as the agonist. the term reciprocal inhibition is used to describe the coordinated relaxing of muscles on one side of a joint to accommodate contraction on the other side of that joint.