Skeletal System

Question 1

What are the functions of skeletal system? Give a short description for each.

Answer 1

1. Support - Provide frameworks and gives structure of the body
2. Movement (leverage) - works with muscle to enable body movement through joints and levers
3. Protection - protects vital organs (e.g. cranium protects brain/ heart&lungs are protected by ribcages)
4. Storage- minerals (calcium and phosphorus) and fats (in yellow marrow) are stored
5. Production - manufactures blood cells in the bone marrow (haematopoiesis)

Question 2

List the classification of bones according to shape. Give examples for each.

Answer 2

1. Long Bone - longer than they are wide; having cavity; forming limbs; provide support and movement/ leverage (e.g. femur, tibia, humerus)
2. Short Bone - Cubed-shape bone found in hands and feet; having no cavity; provide stability and some movements (e.g. carpus, tarsus)
3. Flat Bone - Flattered, thin, and often curved ; protect organs and serves as attachment points for muscles (e.g. cranium, scapula, sternum, facial bones)
4. Irregular Bone - Complex shape which do not fit other categories; provide supports and protection (e.g. vertebrae, ribs, ear, hip)
5. Sesamoid Bone - small round bones commonly found in the tendons of the hands, knee and feet. Protect tendons from wear and tear (e.g. patella)

Question 3

List the build-up of a long bone.

Answer 3

1. Diaphysis
   
   • Shaft
   • Composed compact bone
   • provides strength and houses yellow
     marrow
2. Epiphysis
   
   • Ends of the bone
   • Composed mostly of spongy (cancellous bone)
   • supports joints and load distribution
3. Periosteum
   
   • Fibrous connective tissue membrane covering lower epiphysis and diaphysis
   • (protects, repairs and anchors tendons/ligaments)
   • contains blood vessels
4. Articular Cartilage
   
   • smooth cartilage at joints (covers external surface of the epiphysis)
   • reduces friction and absorbs shock
   • (made of hyaline cartilage)
5. Medullary Cavity
   
   • Cavity of the shaft
   • contains yellow bone marrow (stores fats) in adults
   • contains Red bone marrow (for haematopoiesis) in fetus
6. Endosteum
   
   • inner membrane of the medullary cavity; aids in bone growth and repair

Question 4

List the build-up of the spinal column.

Answer 4

1. cervical vertebrae:
   7 = C1-C7
2. thoracic vertebrae:
   12 = T1-T12
3. lumbar vertebrae:
   5 = L1-L5
4. sacrum:
   5 = S1-S5 (fused bones)
5. coccyx:
   4 = Co1-Co4 (fused bones which make up the tailbone)

Question 5

List the composition of a joint

Answer 5

Bones

• The structural framework of the joint.
• Ends of bones are covered with cartilage to reduce friction.

2. Cartilage

• Articular cartilage: A smooth tissue covering the bone ends, preventing friction and absorbing shock.

3. Synovial Membrane

• A thin layer lining the joint capsule that produces synovial fluid for lubrication.

4. Synovial Fluid

• A thick, slippery fluid that lubricates the joint, reducing friction and nourishing cartilage.

5. Ligaments

• Tough, fibrous tissues that connect bone to bone (providing stability and preventing excessive movement).

6. Tendons

• Tough, fibrous tissues that connect muscle to bone, allowing movement when muscles contract.

7. Joint Capsule

• A tough, protective layer surrounding the joint, holding everything together and maintaining stability.

8. Bursae

• Small fluid-filled sacs that cushion and reduce friction between bones, tendons, and muscles.

Question 6

List the classification of the joints

Answer 6

1. fibrous - connected by dense connective tissue with no joint cavity , usually immovable
   or slightly movable. Examples: sutures of the skull, syndes moses (tibia+fibula)
2. Cartilaginous - connected by cartilage with no joint cavity (Example: intervertebral joints)
3. Synovial - have synovial cavity allowing free movement. Example: hinge joints (elbow or knee), ball-and-socket joints (shoulder or hip), pivot joints (neck)