CHAPTER 4 THE MUSCULAR SYSTEM

ANSWER THESE QUESTIONS AS YOU WATCH THE VIDEO CLIP What are the 3 types of muscles? What attaches muscle to bone? What are the 2 chemicals within a sarcomere? What molecule provides the muscles with energy? What happens when the myosin heads pull on the actin?

ANSWER THESE QUESTIONS AS YOU WATCH THE VIDEO CLIP What are the 3 types of muscles? Skeletal/Striated, smooth, cardiac What attaches muscle to bone? Tendon What are the 2 chemicals within a sarcomere? Myosin and actin What molecule provides the muscles with energy? ATP What happens when the myosin heads pull on the actin? Muscle contracts

FUNCTIONS OF THE MUSCULAR SYSTEM Hold the body upright Makes movement possible Walking Aid flow of blood through veins on its return to the heart Moves fluids through ducts and tubes of other body systems 85% of body heat comes from muscles

STRUCTURE OF MUSCULAR SYSTEM Muscle fibers : long slender cells that make up muscles Fascia : band of connective tissue that envelops, separates or binds together groups of muscles Tendons : narrow band of non-elastic, dense fibrous connective tissue that connects muscle to bone Fasciae are similar to ligaments and tendons as they are all made of collagen except that ligaments join one bone to another bone, tendons join muscle to bone and fasciae surround muscles or other structures.ligamentstendons

TYPES OF MUSCLES Skeletal – attached to bones to make movement possible Called “voluntary” because you have voluntary control over them AKA striated b/c they looked striped under a microscope Smooth – Move and control the flow of fluids in the digestive tract, blood vessels, and ducts leading from glands. Called “involuntary” because they are not under voluntary control Myocardial – AKA myocardium or cardiac muscles Form the muscular walls of the heart Like striated muscles in appearance, but like smooth muscle because it is involuntary

MUSCLE CONTRACTION/RELAXATION Muscle innervation ( in -err- VAY -shun): stimulation of a muscle by an impulse transmitted by a motor nerve. Neuromuscular – pertaining to the relationship between a nerve and a muscle All muscles are arranged in antagonistic pairs Antagonistic means working in opposition to each other So… When one muscle contracts, its opposite muscle relaxes Contraction : Tightening of a muscle – gets shorter and thicker Relaxation : Muscle returns to its original form

TERMS FOR MUSCLE MOVEMENT Abduction : movement of a limb away from the midline Ab- away from, duct to lead, -ion action Adduction : movement of a limb toward the midline -ad toward Flexion : decreasing the angle between two bones (bend at the joint) Flex to bend Extension : increasing the angle between two bones (straighten at the joint) Ex- away from, tens stretch out *Hyperextension – overextension of a limb beyond its normal limit