Muscular System HESI

Function of muscular system

Posture & thermoregulation

Cardiac muscle

Striated fibers with a single nucleus that join at intercalated discs

Skeletal muscle

Striated multinucleated cylindrical fibers under voluntary control

Smooth/vascular muscles

Spindle-shaped, involuntary, nonstriated fibers with a single nucleus

Where are smooth muscles found?

GI tract, walls of blood vessels, uterus, bladder, ureter & urethra

Tendon

Connects muscle to bone

Ligament

Connects bone to bone

Joint

Where two bones meet

Myofibril

Rod-like structure that makes up muscle fibers

sarcomere

Functional unit of myofibril

Adduction

Movement towards the midline

Abduction

Movement away from the midline

Flexion

Decreases the angle of a joint

Extension

increases the angle of a joint

What is NOT part of a THIN filament?

Myosin

Myosin

Cleaves ATP to generate energy for muscle contraction

What does calcium bind to for muscle contraction?

Troponin which uncovers the active site of actin

Where are calcium molecules released from during muscle contraction?

Sarcoplasmic reticulum

Contraction occurs because of cross bridges between what?

Myosin & actin

Process of a muscle contraction

Action potential

release of calcium

calcium binds to proteins

cross bridges between actin & myosin use energy from ATP to slide together

contract

What movement can skeletal muscle do?

Pronate & supinate

Synergist muscle

Muscles that produce similar movement as the primary mover

Antagonist muscle

Muscles that oppose the prime movers