Unit 7 — Muscular System Quiz Review

Functions of Muscle

• Movement, posture, joint stabilization, organ volume, heat

• Skeletal muscle -- Moves body 

• Smooth muscle -- moves blood 

• Cardiac muscle -- moves blood 

Criterium for naming muscle

• Location

• Shape

• Size

• Action

• Direction of fibers 

  • Oblique (diagonal), transverse (perpendicular) , rectus (parallel)

• # of origins

• Origin and insertion

Prime Mover (Agonist)

• The main muscle responsible for producing a specific movement. For example, the biceps brachii is the prime mover for elbow flexion.

Antagonist

• A muscle that opposes the action of the prime mover. It relaxes while the agonist contracts. For elbow flexion, the triceps brachii is the antagonist.

Point of Origin

• The fixed, typically proximal attachment of a muscle to a bone. It does not move during contraction. For the biceps, the origin is the scapula.

Point of Insertion

• The moveable, typically distal attachment of a muscle to a bone. It moves when the muscle contracts. For the biceps, the insertion is the radius.

Fascia

• muscle to muscle

Tendon

• muscle to tissue

Flexion

• Decreasing the angle between two bones (e.g., bending the elbow).

Extension

• Increasing the angle between two bones (e.g., straightening the knee).

Abduction

• Moving a limb away from the midline of the body (e.g., raising arms sideways).

Adduction

• Moving a limb toward the midline (e.g., lowering arms to your sides).

Rotation

• Movement of a bone around its longitudinal axis (e.g., turning the head).

Circumduction

• Circular movement combining flexion, extension, abduction, and adduction (e.g., arm circles).

Supination

• Turning the palm upward (holding a bowl of soup).

Pronation

• Turning the palm downward.

Dorsiflexion

• Lifting the foot so the toes move toward the shin.

Plantar Flexion

• Pointing the toes downward (like pressing a gas pedal).

Inversion

• Turning the sole of the foot inward.

Eversion

• Turning the sole of the foot outward.

Muscles that help knee flexion

• popliteus, sartorius 

Why does flexing help the healing of muscles

• brings the fibers close together

Biceps Brachii

• Location: Front of the upper arm

• Action: Flexes the elbow (bends the arm)

Triceps Brachii

• Location: Back of the upper arm

• Action: Extends the elbow (straightens the arm)

Deltoid

• Location: Covers the shoulder

• Action: Abducts the arm (lifts it away from the body); also helps with flexion and extension

Hamstrings

• Location: Back of the thigh

• Muscles: Biceps femoris, semitendinosus, semimembranosus

• Action: Flex the knee and extend the hip

Quadriceps

• Location: Front of the thigh

• Muscles: Rectus femoris, vastus lateralis, vastus medialis, vastus intermedius

• Action: Extend the knee (rectus femoris also flexes the hip)

Abdominals (Abs)

• Location: Front of the torso

• Muscles: Rectus abdominis, external obliques, internal obliques, transverse abdominis

• Action: Flex the trunk, rotate the torso, compress the abdominal cavity

Back Muscles (Main ones)

• Location: Posterior torso

• Muscles: Latissimus dorsi (pulls arms down/back), trapezius (moves scapula), erector spinae (extends spine)

• Action: Extend, rotate, and stabilize the back; move shoulders

Lower Leg Muscles

• Front (e.g., Tibialis anterior): Dorsiflexes the foot (pulls toes up)

• Back (e.g., Gastrocnemius, Soleus): Plantar flexes the foot (points toes down, like standing on tiptoes)