9.1 - Musculoskeletal

Question 1

Describe the organisation and anatomy of the skeletal system

Answer 1

• The skeletal system consists of 206 bones, cartilage, and joints, making up approximately 20% of the body.
• The skeletal system is divided into two groups:
  1 - The axial skeleton forms the midline axis of the body. Includes the skull, thoracic cage and vertebral column.
  2 - Appendicular skeleton includes the shoulder (pectoral) girdle, upper limbs, pelvic girdle and lower limbs.

Question 2

Describe the functional properties of cartilage

Answer 2

Hyaline cartilage- functions as a shock absorber and reduces the friction between bones.
Fibrocartilage- provides rigidity and structural support to resist shear forces and compression.
Elastic cartilage- maintains the shape of these structures while allowing a lot of flexibility.

Question 3

Describe the characteristics and macro- and microscopic structure of long and flat bones

Answer 3

Microscopic- is for long bones and is made up of compact bone
and spongy/cancellous bone.

Compact bone is the dense outer layer and spongey bone is the internal portion of the bone.

Macroscopic- is for flat, short bones and irregular bones. It covers the compact bone, spongy bone.

Question 4

Briefly describe the development of the skeletal system through the lifespan

Answer 4

Over time cartilage is replaced by bone, this process is called ossification. The last part of the long bone to be ossified is the epiphyseal plates. When Ca2+ levels increase above homeostasis levels, the calcitonin stops osteoclasts from breaking down bone, to stop further release of Ca2+ into the blood

Question 5

Describe the functions of muscle tissue

Answer 5

Cardiac = pumping blood around the body
Skeletal = body movement, facial expressions.
Smooth = movement, forces substances through hollow organs, regulated passage of substances through body openings

Question 6

Briefly describe how muscles contract

Answer 6

Muscle contraction occurs when actin and myosin interact, generating force within the muscle.
Actin = thin filaments
Myosin = thick filaments
Sarcomeres are organised within the myofibrils of skeletal muscle cells and contain actin and myosin proteins involved in contraction

Question 7

Describe the movements that occur when muscles contract

Answer 7

Isotonic means that, as the muscle length changes, the same tension is maintained during the contraction. (Movement)
Isometric means that the length of the muscle is unchanged during the contraction. (No movement)

Question 8

The four bone cells are?

Answer 8

Osteogenic cells = stem cell
Osteoblast = bone growth
Osteocyte = maintains bone matrix
Osteoclasts = breakdown bone tissue