Science: Muscles

• Flexion-decreases the angle between bones
• Extension-increases the angle between bones
• Abduction-moving away from the midline
• Adduction-moving toward the midline
• Rotator-produces turning or rotation
• Levator-produces upward upward movement
• Depressor-produces downward movement
• Sphincter-decreases the size of an opening
• Tendon-connects muscle to bone
• Muscle-contractual tissue that produces movement across a joint
• Myofibril-a contractual fiber made up of actin & myosin-yo-filament
• Sarcomere-the functional unit of the Myofibril
• Actin Filament-the moving filament of the Myofibril
• Myosin Filament-the stationary filament of the Myofibril
• Origin-the muscle attachment to the stationary bone of a joint
• Insertion-the muscle attachment to the moving bone of a joint

• Isometric-the muscle contracts with no joint movement
• Isotonic-the muscle contracts producing movement at the joint
• Tonic-the muscle partially contracts producing firm muscle with no joint movement

• Skeletal Muscle-strait
• Visceral Muscle-smooth
• Cardiac Muscle-strait

Muscles contract when a motor neuron stimulates a muscle fiber causing the action myofilament to slide over the myosin myofilament. This action shortens and thickens the muscle causing joint movement.

When muscles loss all there sugar and oxygen, they are not able to continue there action. This is fatigue.

Nerve endings are attached to muscle fibers which stimulate muscle contractions at impulse from the brain spinal cord.

• Epicranius-raises eyebrows
• Sternocleidomastoid-flexes neck & rotates head
• Trapezius-raises and lowers shoulders
• Latissimus Dorsi-adducts arms
• Forearm Extensors-extends hand
• Gluteus Maximus-extends thigh
• Semitendinosis-extends thigh & flexes leg
• Biceps Femoris-extends thigh & flexes leg
• Gastrocnemius-extends foot & flexes leg
• Soleus-plantar flexes foot
• Deltoid-abducts arms
• Triceps Brachii-extends forearm
• Pectoralis Major-adducts arms
• Serratus Anterur-pulls scapula down and forward
• External Oblique-rotates and compresses obdomen
• Rectus Abdominuis-compresses abdomen and flexes trunk
• Rectus Femoris-flexes thigh & extends leg
• Vastus Lateralis-extends leg
• Vastus Medialis-extends leg
• Tibialis Anterior-dorsiflexes foot
• Biceps Brachii-flexes forearm
• Brachioradialis-flexes wrist & rotates arm
• Forearms Flexors-flexes hand
• Sartorius-abducts and rotates thigh
• Pectoralis Minor-pulls shoulders down & forward