Musculoskeletal System LO

Question 1

Describe the growth and development of bones

Answer 1

• in early development of human foetus: skeleton is made entirely of cartilage. Soft cartilage gradually turns into hard bone via ossification. This is when mineral deposits replace cartilage
• long bones ossify and get longer as they grow and develop. These bones grow from their ends known a epiphysis, the presence of a growth plate signifies the bone is still growing
• in a persons late tweens-early twenties a person reaches skeletal maturity. Bones can still increase in thickness

Question 2

Functions of skeletal system

Answer 2

1) provide the body with framework
2) give attachment for muscles
3) allows movements by forming joints that are moved by muscles
4) Haemopoiesis - production of blood - good blood supply
5) mineral storage

Question 3

Name and give examples of different types of bones

Answer 3

Flat bones - sternum, frontal bone
Irregular bones - vertebrae, mandible
Short bones - carpel, tarsals
Long bones - femur, tibia, fibula
Sesamoid bones - patella

Question 4

Describe spongy bone tissue

Answer 4

• porous
• highly vascularised
• “honeycomb”
• reduces bone density
• allow end of long bone to compress as a result of repeated stress

Question 5

Describe compact bone tissue

Answer 5

• makes up hard outer layer, compact due to minimal gaps and spaces
• tissue gives the bones their smooth, white and solid appearance
• accounts for 80% of bone mass
• contains nerves and blood vessels

Question 6

Describe long bones

Answer 6

• shaft (diaphysis) - compact bone
• 2 extremities (epiphysis) - spongy bone
• vascular membrane (periosteum)
• outer layer is tough/fibrous to protect bone underneath
• inner layer contains bone cells for bone production and breakdown, repair and remodelling
• main arterial nutrient supply to diaphysis
• epiphysis has own blood supply
• bone is full of nerves - breaks are painful

Question 7

Define the term osteoblasts

Answer 7

Bone building cells - they deposit new bone tissue around themselves, they eventually become trapped in tiny pockets in the growing bone, and differentiate in osteocytes

Question 8

Define the term osteocytes

Answer 8

Mature bone cells - they do not divide and are responsible for bone formation and calcium homeostasis

Question 9

Define the term osteoclasts

Answer 9

Bone reabsorbing cells - breakdown bone releasing calcium and phosphate. As new bone cells are made, old ones are destroyed by osteoclasts

Question 10

Describe the process of osteogenesis

Answer 10

Step 1: osteoblast secrete osteoid (protein)
- replaces cartilage in foetus
Step 2: calcium and phosphate laid down
- progressively calcifying it, converting it to hard rigid mature bone
Step 3: osteoblasts form a matrix
- cells become trapped and become osteocytes

Question 11

Describe a synovial joint

Answer 11

• most common type of joint in the body
• freely moveable
• ends of bone held close together by a sleeve of fibrous tissue and lubricated with a small amount of fluid
• contains synovial fluid

Question 12

Identify different types of synovial joints

Answer 12

1) ball and socket joint
2) hinge joint
3) gliding joint
4) pivot joint
5) condyloid joint
6) saddle joint

Question 13

Name the 3 main types of muscle tissue

Answer 13

1) smooth
2) cardiac
3) skeletal

Question 14

Describe how antagonistic pairs work together

Answer 14

Muscles work together in pairs to perform a range of movements e.g. flexion and extension. In the pair one muscle acts as the agonist (one that contracts) and the other is the antagonist (the one that relaxes)