Musculoskeletal System Quiz 2 Homework Attendance

Smooth Muscle used for involuntary actions Innervated by the autonomic nervous system Found in the digestive tract, bladder, uterus, blood vessel walls, and other places. Has actin and myosin filaments No striations=no sarcomeres

Smooth Muscle Contractions Same as skeletal muscle Use actin and myosin Regulated by calcium ions Different from skeletal muscle Contractions are slower Contractions can occur for a longer amount of time Have both inhibitory and excitatory synapses Has myogenic activity: can contract without stimulation from the nervous system

Cardiac Muscle The muscle tissue of the heart has cardiac muscle fibers. Has actin and myosin filaments. Has striations, so has sarcomeres. One or two central nuclei Innervated by the autonomic nervous system, which regulates heart beat. Myogenic

Energy Reserves Can break down fatty acids, glycogen, and glucose to produce ATP Also, energy can be temporarily stored as Creatine Phosphate Exercise At Rest

Myoglobin a protein similar to hemoglobin structure unique to muscle tissue has high O2 affinity binds to O2 from blood and holds onto it.

Questions Fill in this chart: Smooth Cardiac Involuntary/Voluntary Innervated by Found in Actin and Myosin Filaments Striations Sarcomeres Myogenic

Questions Part 6-1

Strenuous Exercise During exercise: Muscle cells very quickly run out of oxygen Myoglobin gives oxygen to muscle Sometimes, extra oxygen from myoglobin is not enough. Muscle gets oxygen from anaerobic respiration. Result: lactic acid build up

Connective Tissue binds and supports other tissue. 2 kinds: loose connective tissue and dense connective tissue

Loose Connective Tissue Found throughout the body Binds epithelium to other tissues Holds organs in place

Loose Connective Tissue Has three protein fibers: collagenous fibers: Has collagen and very strong elastic fibers: Has elastin and gives strength to connective tissue. Reticular fibers: branched, tightly woven fibers that join connective tissue to adjoining tissue.

Loose Connective Tissue 2 cells: fibroblasts Secrete substances that make extracellular fibers macrophages Eat bacteria and dead cells using phagocytosis

Dense Connective Tissue Has very high amount of collagenous fibers Regular dense connective tissue is very strong Dense connective tissue forms tendons (joins muscle to bone) and ligaments (hold bones together at joints)

Muscle-Bone Interactions Movement depends on interaction between skeletal and muscular system If a muscle is attached to 2 bones, only 1 bone moves. origin: End of the muscle attached to stationary bone. Proximal end in limb muscles insertion End of the muscle attached to the bone that moves during contraction Distal end in limb muscles

Muscles work in Antagonistic Pairs

Synergistic Muscles Help principal muscles during movement.

Flexor/Extensor Muscles Contracts to decrease the angle of a joint extensor Contracts to straighten the joint

Abductor/Adductor Muscles moves a part of the body away from the body's midline adductor moves a part of the body toward the midline

Questions Part 6-2