The Skeletal System Quiz

The Skeletal System

• The skeleton provides a frame of support to the human body.
• An adult human has 206 bones, while a newborn has 304.
• Some bones fuse together as we grow.
• The skeleton, along with muscles, enables movement like walking and running.
• Internal organs, like the hearth and lungs, are protected by the skeletal system.
• The skeletal system shapes our face, produces red blood cells, and stores calcium and phosphorus.

The Structure of Bones

• Bones are composed of calcium, phosphorus, and collagen.
• Although strong, bones are lightweight due to their hollow interiors.
• The inner part of bones is spongy.
• Long bones contain bone marrow in a central cavity.

Bone Marrow

• Bone marrow is a jelly-like substance that produces blood cells.
• It contains living cells and blood vessels.

Parts of the Skeletal System

• The human skeletal system comprises the skull, ribcage, backbone, and limbs.

Skull

• The skull consists of 22 bones that protect the brain.
• It contains holes for organs like eyes, ears, and the spine.
• All skull bones are fixed except the lower jaw, which allows us to eat and speak.

Ribcage

• The ribcage protects the heart and lungs.
• It is composed of 12 pairs of thin, curved bones.
• Ribs are attached to the backbone in the back and the sternum (breastbone) in the front.
• The two bottom pairs of ribs are "floating ribs" and are not attached to the sternum.

Backbone

• The backbone, called the spine or vertebral column, is a sturdy column made of 33 vertebrae.
• It supports the body, protects the spinal cord, and enables us to stand straight.
• The spine curves to provide flexibility.

Limbs

• Humans have two pairs of limbs: forelimbs (arms) and hindlimbs (legs).

Forelimbs (Arms)

• Attached to the spine by shoulder girdles, composed of shoulder blades and collarbones.
• The upper arm has a bone, the humerus, and the lower arm has two bones, the radius and ulna.

Hindlimbs (Legs)

• Made up of the upper leg and lower leg, joined at the knee.
• The upper leg contains the powerful femur, which bears the weight of our body.
• The lower leg has two bones, the tibia and fibula. The tibia is the longest bone in the body.

Joints

• A joint is the point where two or more bones meet.
• Joints allow bending, twisting, and turning movements.
• Cartilage, a thin layer of elastic substance, covers the ends of bones in a joint to prevent friction and pain.
• Ligaments, stretchy bands of tissue, hold the joint together and prevent dislocations.
• Tendons connect muscles and bones.

Types of Joints

• Movable joints allow movement.

  • Hinge joint: Moves in one direction, such as in the elbow, knees, fingers, and toes.
  • Ball and socket joint: Allows movement in all directions, such as in the shoulder and hip.
  • Pivot joint: Enables the head to turn, as in the neck.
  • Gliding joint: Allows gliding movements, such as in the wrist and ankles.

• Immovable joints do not allow movement.

  • Examples include the skull and ribcage.

Muscles and Movement

• Muscles are soft, stretchy bands of tissue that contract and relax to help us move.

Voluntary Muscles

• Controlled by our will (skeletal muscles).
• Examples include muscles in the arms, neck, shoulders, and legs.
• They have stripes on them and are called striated muscles.

Involuntary Muscles

• Not under our control.
  • Muscles in the stomach, intestines, and blood vessels are examples.
  • They don't have stripes and are called smooth muscles.

Cardiac Muscles

• Found only in the heart.
• Pump blood to all parts of the body.
• Involuntary.

How Muscles Work

• Muscles can only pull on bones, not push.
• At least two muscles are needed to move a joint.
• Examples include the biceps and triceps. The biceps contract when you pull your arm up, and the triceps contract when you lower your arm.

Healthy Bones and Muscles

• Strong bones and muscles are essential for good health.
• Calcium and vitamin D are crucial for strong bones.
• Milk, curd, fish, and green leafy vegetables are good calcium sources.
• Sunlight helps produce Vitamin D.
• Protein is essential for muscle building.
• Good sources of protein include meat, fish, eggs, chickpeas, cottage cheese, nuts, and curd.

Posture

• Posture refers to the way we hold our body while standing or sitting.
• Good posture is vital for a healthy skeletal system.

Good posture guidelines:

• Standing: Stand straight with shoulders straight, not slouching.
• Sitting: Sit up straight, with back supported by the chair. Do not slouch. Maintain a proper distance between your eyes and the book.
• Sitting on the floor: Maintain a straight posture with shoulders straight.
• Sleeping: Avoid using a very high pillow, as it can affect the backbone.

Problems with Poor Posture

• Back pain, neck pain, headaches, and digestive issues are potential consequences of poor posture.

Key Scientists

• Andreas Vesalius (1514-1564) is recognized as the founder of modern human anatomy.
• His dissections revealed the skeletal structure and muscular system of the human body.

Test your knowledge about the skeletal system in humans. This quiz covers the structure of bones, the functions of the skeletal system, and the role of bone marrow. Discover how the human skeleton supports movement and protects vital organs.