Musculoskeletal/locomotor System

Question 1

Musculoskeletal/ Locomotor System

Answer 1

• Achieves external movement of the body
• Made up of 3 components
  1. Bones of the skeleton ( osseous system)
  2. Joints
  3. Skeletal muscles

Question 2

Osseous system

five basic groups

Answer 2

Approx 226 bones in human skeleton.

1. Long bones - made up of shaft(diaphysis) and 2 extremities( epiphysis). Longer than wide eg femur
2. Short bones- same basic structure but smaller scale eg bones of hands and feet.
3. Flat bones - eg sternum, ribs, skull
4. Sesamoid- weight bearing eg patella
5. Irregular-anything else eg vertebrae, some skull

Question 3

Osseous system 
( 2 groups by function)

Answer 3

Axial skeleton - central bony core. Consists of skull, vertebral column, ribs, sternum.

Appendicular skeleton - consists of upper and lower limbs and their attachments to the axial skeleton.

Question 4

Axial skeleton

the skull

Answer 4

Made up of 22 bones fused except mandible which is moveable. Rests on upper end up vertebral column.
Cranium( protects brain, flat and irregular): 1 occipital, 2 parietal, 1 frontal, 2 temporal, 1 sphenoid , 1 ethmoid.
Facial(13 bones, fit like jigsaw): 2 zygomatic, 1 maxilla( 2 fused), 2 palatine, 2 lacrimal, 2 nasal, 2 turbinate, 1 vomer, 1 mandible.

Question 5

Axial skeleton

vertebral column

Answer 5

Made up of 33 vertebrae , some fused. 
7 cervical vertebrae 
12 thoracic vertebrae
5 lumbar vertebrae 
1 sacrum , 5 fused
1 coccyx , 4 fused

Question 6

Characteristics of a typical vertebrae

Answer 6

Body - flattened broadest part. When vertebrae stacked in column flattened surfaces articulate with vertebrae above and below but no direct contact due to intervertebral discs. Lie to front of column and increase in size.
Vertebral(neural) arch- encloses large vertebral foramen forming vertebral canal that contains the spinal chord. Lies behind the body and forms lateral and posterior walls of foramen. Lateral made up of pedicles( plates) and posterior made from laminae. Projecting from where pedicle meets laminae is lateral prominence(transverse process) and where two laminae meet at the back is spinous process. Vertebral arch has four articulate surfaces, 2 with above and 2 with below.

Question 7

Cervical vertebrae

Answer 7

Smallest vertebrae as only support the head. Transverse processes have a foramen through which vertebral artery passes to the brain. C1=atlas , C2= axis.
Atlas consists of ring of bone which skull rests, atypical as has no spinous process or body but 2 short transverse processes. Has 2 flattened facets articulating with occipital bone(condyloid joint) .Axis sits below the atlas , has a small body with small superior projection called odontoid process. His occupies part of posterior foramen of atlas and held securely within it by transverse ligament . 7th cervical vertebrae is vertebra prominens as has long spinous process terminating in swollen tubercle.

Question 8

Axial skeleton

thoracic cage

Answer 8

Consists of:
Sternum
12 pairs of ribs: True ribs- pairs 1-7, attached directly to sternum by cartilage.
False ribs- pairs 8-10, attached to costal cartilage of rib cage.
Floating ribs - pairs 11&12, only attached to vertebral column posteriorly.
12 thoracic vertebrae

Question 9

Appendicular skeleton

Answer 9

1. Shoulder girdle, 2 clavicles, 2 scapula
2. Upper limbs( 30 bones each) , 1 humerus, 1 ulna, 1 radius, 8 carpal bones, 5 metacarpal bones , 14 phalanges.
3. Pelvic girdle- 2 hip bones = 3 fused bones , ilium, ischium, pubis and 1 sacrum( vertebral column)
4. Lower limbs( 30 bones each) , 1 femur, 1 tibia, 1 fibula, 1 patella , 7 tarsals, 5 metatarsals, 14 phalanges.

Question 10

Functions of osseous system

Answer 10

1. Acts as a rigid framework.
2. Supports the weight of the body.
3. Forms the boundaries of cavities in the body.
4. Forms a solid shield to protect delicate organs.
5. Acts as a lever for essential movement.
6. Provides an attachment for skeletal muscles.
7. Haemopoetic function due to presence of bone marrow.
8. Acts as a mineral reservoir ie Ca, Mg