Week 3 - The Skeletal System Flashcards
(35 cards)
What are the main components and function of the axial skeleton?
80 bones: skull, vertebral column, rib cage
Forms the central axis of the body
Protects vital organs (brain, heart, lungs)
What are the main components and function of the appendicular skeleton?
126 bones: limbs and their girdles (shoulder, pelvic)
Enables movement and locomotion
What are the six key functions of the skeletal system?
Support
Protection
Assistance in movement
Mineral homeostasis
Blood cell production (haematopoiesis)
Triglyceride (fat) storage
How does the skeletal system provide support and protection?
Support: framework for body; anchors muscles
Protection: skull (brain), ribs (heart/lungs), vertebrae (spinal cord)
How does the skeletal system assist in movement and maintain mineral balance?
Movement: bones act as levers, muscles pull on them
Mineral homeostasis: stores/releases calcium & phosphorus
Where does blood cell production occur and what is stored in yellow bone marrow?
Red bone marrow: produces RBCs, WBCs, platelets
Yellow bone marrow: stores fat (energy reserve)
What are the five classes of bone and examples of each?
Long bones – femur, humerus
Short bones – carpals
Flat bones – skull, sternum
Irregular bones – vertebrae
Sesamoid bones – patella
What are the key features of a long bone?
Diaphysis: shaft with yellow marrow
Epiphyses: ends with red marrow
Metaphyses: growth plate (epiphyseal plate)
What are the periosteum and endosteum?
Periosteum: outer covering; supports vessels, muscle attachment
Endosteum: inner lining; active in growth & repair
Compare compact and spongy bone.
Compact (cortical): dense, contains osteons, resists stress in one direction
Spongy (trabecular): porous, trabeculae, resists stress from multiple directions
What are the four main bone cell types and their functions?
Osteoprogenitor – stem cells
Osteoblasts – form bone matrix
Osteocytes – maintain bone
Osteoclasts – break down bone
What is bone remodeling and why is it important?
Continuous process of renewal
Maintains bone strength and mineral balance
Involves osteoblasts and osteoclasts
What are the main structural components of a synovial joint?
Articular cartilage
Joint cavity with synovial fluid
Synovial membrane
Joint capsule
Ligaments and tendons
What is the function of synovial joints?
Freely movable (diarthroses)
Allow various ranges of motion
Most common joint type
What are the six types of synovial joints?
Plane – gliding (e.g. intercarpal joints)
Hinge – flexion/extension (e.g. elbow, knee)
Pivot – rotation (e.g. atlas-axis)
Condyloid – flexion/extension & abduction/adduction (e.g. wrist)
Saddle – thumb joint (e.g. carpometacarpal)
Ball-and-socket – movement in all directions (e.g. shoulder, hip)
What is the epiphyseal plate and what is its function?
It is the growth plate found in metaphyses of growing bones; allows longitudinal bone growth.
What happens to the epiphyseal plate after puberty?
It ossifies and becomes the epiphyseal line, stopping further lengthwise growth.
What is the medullary cavity and what does it contain?
The hollow center of the diaphysis; contains yellow bone marrow in adults.
What is the function of red bone marrow?
It performs haematopoiesis—producing red blood cells, white blood cells, and platelets.
What is ossification?
The process of bone formation, beginning during fetal development and continuing through growth.
What is intramembranous ossification?
Bone develops directly from mesenchymal tissue (e.g. flat bones of the skull).
What is endochondral ossification?
Bone replaces a cartilage model (e.g. long bones like the femur).
What are trabeculae and where are they found?
They are the lattice-like structures in spongy bone, supporting bone from multiple angles.
What are osteons and where are they found?
Structural units of compact bone consisting of concentric lamellae around a central canal.
