Chapter 12 - The Musculoskeletal System

Question 1

List 5 functions of the skeleton

Answer 1

1. Firm frame work that gives shape to the body
2. Allows movement to take place
3. Protects vital organs
4. Storage organs for minerals and salts
5. Has a role in blood cell production

Question 2

Label the skeleton

Answer 2

Skull 
- cranium 
- mandible 
Shoulder girdle 
- clavicle 
- scapular 
Sternum 
- sternum 
Vertebral column 
- Cervical vertebrae 
- thoracic vertebrae 
- lumbar vertebrae 
- sacram 
- coccyx 
Pelvic girdle 
- pelvis 
Upper limb 
- humerus 
- radius 
- ulna 
- carpals 
- metacarpals 
- phalanges 
Lower limb 
- femur 
- patella 
- tibia 
- fibula 
- tarsals 
- meta tarsals 
- phalanges

Question 3

Label a diagram of the long bone and describe the function of each component

Answer 3

Diaphysis

• the shaft, the middle bit of the bone
• outer layer or periosteum
• made of compact bone
• fat storage site ; filled with yellow bone marrow

Epiphyses

• the enlarged ends of the bone
• outer layer of articular cartilage
• made of an outer layer of compact bone and inner layer of cancellous bone
• cancellous is very porous and filled with red bone marrow. Red bone marrow can be used in the production of blood cells.

Epiphyseal line

Question 4

Describe and label an osteon

Answer 4

An osteon is a compact bone unit

Central canal
Layers of lamellae
Lacunae
Canaliculi

Question 5

What is a collagen

Answer 5

Collagen are the units that make up cartilage. Also known as protein fibres.
Collagens are embedded in a firm matrix of a protein-carbohydrate complex called chondrin.

Question 6

What are the three different types of cartilage?

Answer 6

Hyaline cartilage

• contains closely packed collagenous fibres
• fine fibres but give it strength and flexibility.
• found at the end of bones where they meet to form a moveable joint.

Elastic cartilage

• clearly visible elastic fibres
• collagenous fibres are not so tightly pack together
• provides flexible, elastic support
• found in the ear

Fibrocartilage

• course appearance
• fibres are not as compact as those in hyaline cartilage and are therefore able to be compressed slightly.
• needs to withstand heavy pressure
• found in the intervertebral discs of the spinal column.

Question 7

What is perichondrium?

Answer 7

A fibrous membrane of connective tissue that covers the external surface of cartilage, except she. The cartilage forms the articulate surface of a joint.

Question 8

What are the three different types of joints?

Answer 8

Fibrous or Fixed joints

• no movement occurs.
• held in place by fibrous connective tissue
• very difficult to damage
• examples are skull, between the teeth and the jaw

Cartilaginous or slightly moveable joints

• held in place by cartilage
• slight movement
• examples are pelvic bones, joints between the ribs and sternum.

Synovial or freely moveable joints

• most joints are freely moveable
• limited by ligaments, tendons, muscles or adjoining bones
• most commonly injured
• examples are the shoulder, wrist, fingers, hip, knee, ankle and toes.

Question 9

What are the 5 types of movement at a joint?

Answer 9

1. Flexion - also known as bending
2. Extension - also known as straightening
3. Abduction - moving away from the body and the midline
4. Adduction - moving towards the body to resting position
5. Rotation - also known as a swivel

Question 10

What are the 6 types of synovial joints?

Answer 10

1. Ball and socket joints - the head of the humerus fits into the scapula, the femur into the pelvis
2. Hinge joints - elbow, knee, ankle, between the bones of the phalanges
3. Pivot joints - head, radius, ulna
4. Gliding joints - between carpal bones, tarsal bones, the sternum and the clavicle, the scapular and the clavicle.
5. Saddle joints - thumb
6. Condyloid joints - radius + carpal bones, meta carpals and phalanges, metatarsals and phalanges.

Question 11

What are the specialised parts of a synovial joint?

Answer 11

1. Articular capsule - surrounds the joint and is made up of 2 layers ;
   - fibrous capsule ; outer layer consisting of dense, fibrous connective tissue attached to the periosteum.
   - synovial membrane ; makes up the inner layer of the capsule consisting of loose connective tissue. Well supplied with blood.
2. Synovial fluid - fills the synovial cavity. It lubricates the joint and provides nourishment for the cells. Contains phagocytic cells and prevents the articulating surfaces from making contact with one another. Only a small amount of fluid is normally present.
3. Articular cartilage - covers the articulating surfaces of the bones at the joint
4. Articular discs - occur in some synovial joints. Menisci divide the synovial joint into two. A tearing of the meniscus is also known as a torn cartilage.
5. Bursae - little sacs of synovial fluid positioned to prevent friction between a bone and a ligament of a tendon, or bone and skin.
6. Accessory ligaments hold the bones together in a joint.

Question 12

What are the three factors that keep articular surfaces of synovial joints together?

Answer 12

1. The fit of the bones
2. The strength of the joint ligaments
3. The tension provided by muscles around the joint.

Question 13

What is osteoporosis and osteoarthritis?

Answer 13

Osteoporosis occurs when the loss of bone mass with aging becomes sufficient to impair normal functioning. As bone density decreases, the risks of fractures increases. To avoid osteoporosis people require an adequate calcium and vitamin D intake and plenty of exercise.

Osteoarthritis is a gradual change in joints that occur over time. The cartilage deteriorates meaning the bone surfaces are no longer protected causing growths to develop and decrease the amount of room in the joint. Ultimately restricting movement.