Muscle overview
How many muscles in the body?
600+
Muscle fibers grouped together
Fascicles
The tension within a muscle increases while its length remains the same
Isometric contraction
Flexes and adducts the upper arm
Pectoralis major
Produces the backswing of the leg when walking, bulkiest muscle in the body
Gluteus maximus
Found in the digestive tract, blood vessels, airway and uterus
Smooth muscle
Connective tissue that surrounds the muscle outside the epimysium
Fascia
What is recruitment?
Activation of additional motor neurons to strengthen a contraction
Facial muscle that assists with chewing, smiling, blowing
Buccinator
Inserts on the calcaneus, strongest tendon in the body
Achilles tendon
Known as voluntary muscle because it can be contracted at will
Skeletal muscle
The neuron and all the fibers it stimulates
Motor neuron
Impulses reach the muscle fibers too quickly, not allowing for relaxation before the next impulse arrives, the force builds on the previous contraction. Most skeletal muscles remain in a state of this
Incomplete tetanus
Enlarges the thorax to trigger breathing in, chief muscle for breathing
Diaphragm
The longest muscle in the body
Sartorius
Non-striated muscle
Smooth muscle
The connection between a motor neuron and the muscle fiber
Neuromuscular junction
By product from breaking down glucose anaerobically, causes sore and burning muscles after strenuous exercise
Lactic acid
Prime mover when flexing the forearm
Brachialis
The most powerful muscle in the body
Quadriceps femoris (vastus intermedius, rectus femoris, vastus lateralis, vastus medialis)
Appears striated under a microscope
Cardiac muscle
Thin and thick myofibrils that slide across eachother to create muscle movement
Actin and myosin (myofilaments)
Prime movers
Synergists
Antagonists
Main muscle triggering movement
Assist
Muscles balancing the movements
Flexes the lumbar region of the spinal column to cause bending forward at the waist, extends from the sternum to the pubic bone
Rectus abdominus
Name the 3 muscles on the front of the lower leg
Tibialis anterior, extensor digitorum longus, soleus