Properties & Functions
How many muscles are needed to frown?
43 muscles are needed to frown
What muscle is the strongest muscle by weight; closes jaw for chewing.
Masseter: Strongest muscle by weight; closes jaw for chewing.
What muscle is is the largest and heaviest muscle in the human body, making up the bulk of the buttocks?
The gluteus maximus is the largest and heaviest muscle in the human body, making up the bulk of the buttocks.
The human body contains how many skeletal muscles?
The human body contains roughly 640 skeletal muscles.
Name the 2 protein filaments found in the sarcomere.
Actin & Myosin: Thin (actin) and thick (myosin) protein filaments.
What causes Gluteal Amnesia?
Gluteal amnesia is caused by prolonged sitting
What do we call muscle's ability to respond to nerve signals?
Excitability: Ability to respond to nerve signals.
What is the name of the upper back and neck muscle? It helps move your head and shoulders, elevates and stabilizes the scapula (shoulder blade).
Trapezius (Traps): Upper back and neck muscle; helps move your head and shoulders, elevates and stabilizes the scapula (shoulder blade).
Name the longest muscle in the human body. It helps flex, abduct, and laterally rotate the hip, as well as flex the knee.
Sartorius: The longest muscle in the human body. Helps flex, abduct, and laterally
What term deals with bringing a body part inward toward the center line. Think of "adding" a part back to the body.
Adduction - Brings a body part inward toward the center line. Think of "adding" a part back to the body.
Define the sarcomere.
The sarcomere is the basic microscopic structural and functional unit of a muscle fragment.
Define rigor mortis.
Rigor mortis is the stiffening of muscles several hours after death.
Explain how muscles generate heat.
Muscles generate Heat: Cellular contractions produce body warmth.
What muscle is in the back of the upper arm; and it contracts to straighten the elbow.
Triceps Brachii (Triceps): Back of the upper arm; straightens the elbow. Fusiform shaped.
What is the name of the group of four muscles on the front of the thigh that straightens the knee?
Quadriceps Femoris (Quads): Group of four muscles on the front of the thigh; straightens the knee.
What term means when a body part moves outward or away from the center line. (Think of "abducting" or taking something away.)
Abduction: Carries a body part outward or away from the center line.
At the beginning of a contraction, a nerve signal releases what mineral?
Nerve signal releases Calcium²⁺.
Explain the difference between a strain and a sprain.
Strain vs. Sprain - A sprain is an injury to a ligament (connecting bone to bone), while a strain is an injury to a muscle or tendon (connecting muscle to bone).
What is one of the primary jobs that involves energy?
Primary job: Transform chemical energy (ATP) into mechanical energy (movement).
What is the name of the side abdominal muscles?
External Obliques: Side abdominals; assist in rotation and lateral flexion.
What do we call the wide, flat muscle in the lower leg located deep beneath the larger gastrocnemius muscle in the calf?
Soleus: A wide, flat muscle in the lower leg located deep beneath the larger gastrocnemius muscle in the calf.
What is the function of circular muscles?
Circular - ring-shaped muscle fibers that contract to close or constrict body openings and narrow internal passages.
In a contraction, what does calcium unblock?
Calcium unblocks binding sites on actin.
Explain the difference between a pulled muscle and a torn muscle.
A pulled muscle is a mild muscle strain with minor stretching or tiny fiber tears, while a torn muscle is a moderate or severe strain involving a partial or complete rupture of the tissue.
What term is given to label the following shape?
A feather-shaped skeletal muscle where multiple rows of muscle fibers approach a central tendon from several different angles along a branching internal framework.
Multipennate -a feather-shaped skeletal muscle where multiple rows of muscle fibers approach a central tendon from several different angles along a branching internal framework.
What muscle is large and in the mid-to-lower back and is used for pulling motions; also, it extends and adducts the arm.
Latissimus Dorsi: Large mid-to-lower back muscles used for pulling motions; extends and adducts the arm.
What is the thickest, strongest, and longest tendon in the human body, connecting your calf muscles to your heel bone? (Not a muscle, but a very important tendon.)
Achilles tendon: The Achilles tendon is the thickest, strongest, and longest tendon in the human body, connecting your calf muscles to your heel bone.
How do muscles stabilize joints?
Muscle tendons pull over joints for structural stability to that joint.
During a contraction, what happens after the myosin heads grab an actin thread?
Myosin heads grab an actin thread, then pulls it inward using ATP (energy), and the sarcomere shortens.
Explain the chemical reaction of rigor mortis.
Dead cells can no longer produce ATP, so muscles can not relax because relaxation requires a fresh ATP molecule. So muscles remain locked until tissue decay begins.