Musculoskeletal System Notes

Musculoskeletal System

Components:

  • Muscle
  • Tendon
  • Ligament

Bone Diseases:

  • Rickets: Softening and weakening of bones, potentially leading to bandy legs.
  • Arthritis: Cartilage between bones wears away, causing bones to rub against each other.
  • Osteoporosis: Bones weaken and become fragile, increasing the risk of fractures. May lead to a stooped posture in older individuals.

Exercise 4: Musculoskeletal System - page 37

1.1 Muscles and Skeleton
1.2 Function
  • Enables body movement (muscles and skeleton).
  • Protects the body (skeleton).
1.3 Support and Movement
  • Body support.
  • Protection.
  • Movement.
  • Locomotion.
  • Contraction and relaxation of muscles.
1.4 Components
  • Muscles
  • Bones
  • Cartilage
  • Tendons
  • Ligaments
1.6 Diseases
  • Rickets
  • Arthritis
  • Osteoporosis

Skeletal System

Bone Structure
  • Skull
  • Cervical vertebrae
  • Clavicle
  • Scapula
  • Sternum
  • Spine
  • Pelvis
  • Ulna
  • Radius
  • Femur
  • Knee cap
  • Shin (tibia)
  • Fibula
Axial Skeleton:
  • Supports and protects vital organs.
  • Consists of the spine, ribs, and skull.
Appendicular Skeleton:
  • Responsible for movement.
  • Consists of bones of the arms and legs and the bones that connect them to the axial skeleton.
Functions of Bones:
  • Provides shape and rigidity.
  • Protects internal organs.
  • Storage place for minerals such as Calcium (Ca).
  • Produces blood.
  • Plays an important role in movement.
Cartilage:
  • Tough, flexible tissue at the end of bones.
  • Prevents friction between bones.
Ligaments:
  • Strong tissue found between joints.
  • Attach bones to other bones.
  • Prevent bones from moving away from each other and getting out of joint.
  • Example: Anterior Cruciate Ligament (ACL) joins the femur and shin bone (tibia).
Tendons:
  • Also known as sinews.
  • Connect muscle to bone.
  • Can withstand a lot of tension.
  • Example: Achilles tendon.

Muscle Types

Skeletal Muscle:
  • Voluntary muscle.
  • Composed of long cells (fibers) that appear striated.
  • Fibers are organized in bundles.
  • Can stretch, contract, and return to their original shape.
Smooth Muscle:
  • Involuntary, unstriated muscle.
  • Found in walls of hollow organs (bladder, eye, digestive tract, etc.) throughout the body.
Cardiac Muscle:
  • Found in the middle layer (myocardium) of the heart.
  • Responsible for pumping of the heart.
  • Striated but shorter and thicker than skeletal muscles.

Muscle Pairs

3.1 Muscles that work in pairs
  • e.g., biceps and triceps
3.2 Elbow Joint
  • The elbow joint lets the forearm move up or down.
  • Controlled by two muscles: biceps on the front of the upper arm, and triceps on the back of the upper arm.
    • To lift the forearm, the biceps contracts and the triceps relaxes.
    • To lower the forearm again, the triceps contracts and the biceps relaxes.