Anatomy final

Question 1

1. List 5 Functions of the Muscular System

Answer 1

Produce movement of skeleton

Maintain posture and body position

Support soft tissues

Guard entrances and exits

Maintain body temperature

Question 2

List and Describe the 3 Types of Muscles

Answer 2

Skeletal muscles

    Striated

    Voluntary

    Move the skeleton

Cardiac muscle

    Striated

    Involuntary

    Heart muscle

Smooth muscle

    Involuntary control

    Found in internal organs (digestive system, blood vessels, lungs)

Question 3

Draw and Describe the Parts of a Sarcomere

Answer 3

Z-lines: Attach to thin filaments (actin).

M-line: Connects the central portion of thick filaments (myosin).

A-bands: Dark portion containing thick filaments (myosin).

I-bands: Light portion containing thin filaments (actin).

H-zone: Center dark area with no overlap (shrinks during contraction).

Question 4

Describe the Physiology of a Muscle Contraction

Answer 4

Neuron releases acetylcholine (ACh) at the neuromuscular junction.

Impulse travels through T-tubules to the sarcoplasmic reticulum (SR).

Calcium is released from the SR.

Calcium binds to troponin, causing tropomyosin to move and expose actin’s active sites.

Myosin cross-bridges bind to actin, pulling thin filaments toward the M-line (sliding filament mechanism).

Cycle repeats (attach, pivot, detach, return) as long as calcium and ATP are present.

Question 5

Describe the Difference Between Slow and Fast Twitch Muscle Fibers

Answer 5

Feature Fast-Twitch Fibers Slow-Twitch Fibers
Diameter Large Smaller
Mitochondria Few Many
Contraction Powerful, brief (e.g., sprinting, lifting) Slow, steady (e.g., endurance, posture)
Energy Source Anaerobic (glycolysis) Aerobic (oxygen-dependent)
Fatigue Quick Resistant
Examples Face, hands (“white meat”) Legs (“dark meat”)

Answer 6

Head & Neck

Frontalis: Raises eyebrows.

Occipitalis: Retracts scalp.

Temporalis: Closes jaw (chewing).

Orbicularis oculi: Closes eyelids.

Masseter: Chewing (elevates mandible).

Zygomaticus: Smiling (elevates corners of mouth).

Buccinator: Compresses cheeks (whistling).

Orbicularis oris: Closes lips (kissing).

Sternocleidomastoid: Rotates/flexes neck.

Trunk

Pectoralis major: Arm flexion/adduction.

External/Internal obliques: Trunk rotation.

Rectus abdominis: Flexes trunk ("abs").

Trapezius: Elevates shoulders.

Latissimus dorsi: Arm extension/adduction.

Arm

Biceps: Flexes elbow.

Triceps: Extends elbow.

Leg

Quadriceps (Rectus femoris, Vastus lateralis): Extend knee.

Gluteus maximus: Hip extension.

Hamstrings (Biceps femoris): Flex knee.

Gastrocnemius: Plantar flexion (point toes).