Skeletal system

Question 1

Describe the anatomical position?

Answer 1

• All standard pictures and text are referred to the body in the anatomical position.
• Legs slightly apart.
• Feet flat on floor.
• Head and eyes looking to the front.
• Arms straight by side, palms forward.

Question 2

Describe the lateral view?

Answer 2

-A view from the side of body.

Question 3

Describe the anterior view?

Answer 3

-The view when looking at the front of the person.

Question 4

Describe the anatomical directions?

Answer 4

• Superior is at the top.
• Inferior is at the bottom.
• Medial is towards the middle.
• Lateral is towards the outside of the body.
• Proximal is close to the root of the limb (e.g. shoulder)
• Distal is towards the end of the limb (e.g. fingers)

Question 5

What is the axial skeleton composed of?

Answer 5

• Skull, thoracic cage, vertebral column.

- Surface area for attachment of muscles, joints permit limited movement.

Question 6

What is the appendicular skeleton composed of?

Answer 6

• Shoulder girdle, upper + lower limbs, pelvic girdle.

- Surface area for muscles, joints permit a greater amount of movement.

Question 7

Describe the components of bone?

Answer 7

Consists of:

• Lamellae = thin plates of calcium salts between collagen fibres.
• Osteocytes = most of the bone cells.
  
  • Osteoblasts = immature cells producing the matrix (build).
  • Osteoclasts = absorb and remove bone matrix (clean).

Question 8

Describe the 2 types of bone?

Answer 8

• Compact bone = dense, in shafts of long bones, strength as lamellae laid down in rings.
• Cancellous bone = spongy, found in bone with lightness and strength, lamellae laid down to form a mesh.

Question 9

Describe the periosteum?

Answer 9

• Surrounds bone, it is a connective tissue membrane.

- Fibres of ligaments, tendons, joint capsule merge with periosteum.

Question 10

How do blood vessels enter the bone?

Answer 10

• Large vessels and nerves enter through foramina.

- Small vessels enter through epiphysis.

Question 11

Describe the functions of bone?

Answer 11

• Support = framework of body.
• Storage of minerals, e.g. calcium + lipids.
• Blood cell production = RBC + WBC.
• Protection = surround internal organs.
• Assisting in movement = muscles attached to bone.
• Leverage = with muscles.

Question 12

What is ossification?

Answer 12

• The formation of bone.

- Collagen fibres are laid down with calcium salts.

Question 13

What happens to bone during aging?

Answer 13

• Hormones change; oestrogen helps maintain bone, bone loss occurs.
• Cancer causes bone loss as cancerous tissues stimulates osteoclasts and causes osteoporosis.
• Immobility reduces bone strength.

Question 14

What happens after a fracture?

Answer 14

-Broken ends of bone are joined by the laying down of new bone.

Question 15

What happens before the 5 stages of healing?

Answer 15

• Haemorrhage = local bleeding,

- Haematoma forms around ends of bone. (a swelling filled with blood).

Question 16

Describe the healing process in stages?

Answer 16

• Over 5 days = osteoclasts remove tissue debris, necrotic bone and haematoma.
• 2 to 6 weeks = osteoblasts lay down collagen fibres, callus forms around fracture.
• 6 to 12 weeks = ossification occurs, ca salts laid down, bony bridge crosses gap. (bone regains strength).
• Next few months = osteoclasts remodel the bone, remove callus.