Skeletal System Functions and Structure

Functions of the Skeletal System

• Provides points of attachment for muscles, enabling movement of limbs.
• Supports the upper body through the backbone, holding the head upright and protecting the spinal cord.
• Protects vital organs, such as the brain (skull) and heart and lungs (ribs).
• Produces red and white blood cells in the bone marrow.
• Stores minerals like calcium and phosphorus for the body's use.

Divisions of the Skeletal System

• Axial Skeleton: Central core of the body, including the skull, spine, ribs, and sternum.
• Appendicular Skeleton: Comprises upper and lower extremities, including the shoulder girdle, arms, legs, and pelvis.

Bone Shapes

• Long Bones: Arms, legs, fingers.
• Short Bones: Wrist and ankles.
• Flat Bones: Skull and sternum.
• Irregular Bones: Spine.

Bone Structure (4 Layers)

• Periosteum: Outermost layer covering the bone.
• Compact Bone: Dense layer beneath the periosteum.
• Spongy Bone: Porous layer beneath the compact bone.
• Bone Marrow: Fills the gaps in the spongy bone, responsible for blood cell production.

Cranial Bones

• Mandible and Maxilla: Form the jaw.

Clavicle (Collar Bone)

• Holds the shoulder joint away from the upper body.
• Measures 11mm to 15mm in thickness.

Scapula

• Located on the back of the ribcage, contributing to the shoulder joint and arm movement.

Spinal Cord (Vertebral Column)

• Cervical Region (C1 - C7): Neck bones composed of 7 vertebrae.
• Thoracic Region (T1 - T12): Where ribs attach, composed of 12 vertebrae.
• Lumbar Region (L1 - L5): Lower back, consisting of 5 vertebrae.

Sacrum

• Shield-shaped bone at the base of the lumbar vertebrae, connected to the pelvis.

Coccyx

• Small triangular bone at the base of the spinal column.

Humerus (Upper Arm Bone)

• Connects to the shoulder and elbow joints.

Radius and Ulna

• Bones in the forearm, located below the humerus.

Carpal (Wrist Bones)

• Small bones forming the wrist joint.

Metacarpals (Metacarpus)

• Bones in the hand, connecting the wrist to the fingers.

Phalanges (Finger Bones)

• Small bones forming the fingers.

Sternum (Breastbone)

• T-shaped vertical bone forming the anterior portion of the chest wall.

Functions of the Skeletal System

• Movement: Bones provide points of attachment for muscles, allowing movement when muscles pull on bones.
• Support: The backbone (spinal column) serves as the main support center of the upper body, holding the head upright and protecting the spinal cord.
• Protection: The skull bones protect the brain, and the ribs safeguard the lungs and heart from injuries.
• Blood Production: Red and white blood cells are made by the bone marrow, located inside the center of bones.
• Storage: Bones store essential minerals like calcium and phosphorus for the body's use.

Major Parts of the Skeletal System

• Axial Skeleton: Forms the central core of the body and includes the skull, spine, ribs, and sternum.
• Appendicular Skeleton: Comprises the upper and lower extremities, including the shoulder girdle, arms, legs, and pelvis.

Bone Shapes

• Long Bones: Found in arms, legs, and fingers.
• Short Bones: Located in the wrist and ankles.
• Flat Bones: Form the skull and sternum.
• Irregular Bones: Make up the spine.

Bone Structure (4 Layers)

• Periosteum: Outermost layer that covers bones.
• Compact Bone: Dense layer located beneath the periosteum.
• Spongy Bone: Layer beneath the compact bone.
• Bone Marrow: Fills the gaps within the spongy bone.

Cranial Bones

• Mandible and Maxilla: Form the lower and upper jaws, respectively.
• Clavicle (Collarbone): Holds the shoulder joint away from the rest of the upper body, measuring 11mm to 15mm in thickness.
• Scapula: Found on the back of the ribcage, contributes to the shoulder joint and arm movement.

Spinal Cord (Vertebral Column)

• Cervical Region (C1 - C7): Neck bones, consisting of 7 vertebrae.
• Thoracic Region (T1 - T12): Where ribs attach, consisting of 12 vertebrae.
• Lumbar Region (L1 - L5): Lower back, consisting of 5 vertebrae.

Other Important Bones

• Sacrum: Shield-shaped bone at the base of the lumbar vertebrae, connecting to the pelvis.
• Coccyx: Small triangular bone at the base of the spine.
• Humerus (Upper Arm Bone): Longest bone in the arm.
• Radius and Ulna: Bones in the forearm.
• Carpal (Wrist Bones): Short bones forming the wrist.
• Metacarpals (Metacarpus): Long bones in the hand, connecting the wrist to the fingers.
• Phalanges (Finger Bones): Bones forming the fingers.
• Sternum (Breastbone): T-shaped vertical bone in the chest, forming the anterior part of the ribcage.
• Pelvis (Dancing Bones): Basin-shaped structure supporting the spine and protecting abdominal organs.
• Femur (Thigh Bone): Longest and strongest bone in the body.
• Tibia and Fibula: Long bones in the lower leg, with the tibia being larger on the inner side and the fibula being smaller on the outer side.
• Tarsals: Seven short bones in the foot, located at the proximal region.
• Metatarsals: Five long bones in each foot, numbered I to V from medial to lateral.
• Phalanges (Toe Bones): Bones forming the toes.
• Calcaneus (Heel Bone): Large, strong bone forming the back of the foot, responsible for transferring body weight to the ground.

Explore the essential functions and structures of the skeletal system in this quiz. Learn about the divisions of the skeleton, different bone shapes, and the layers that make up the bones. Test your knowledge on how the skeletal system supports and protects the body.