Muscles, Bones and Joints

Question 1

Functions of the skeletal system

Answer 1

Supports the framework of the body

Protects vital organs

Provides ‘levers’ for the skeletal muscles to work against for movement.

Supply and storage of calcium and phosphate.

Haematopoiesis (blood cell formation)

Fat store for energy

Question 2

Features of a long bone

Answer 2

Distal Epiphysis
Proximal Epiphysis
Diaphysis
Epiphyseal line (growth plate)
Medulla cavity - filled with yellow/white marrow
Compact bone
Spongy bone in the epiphyses, site of red bone marrow
Endosteum - lines the medulla cavity
Periosteum - surrounds the diaphysis
Articular cartilage

Question 3

Two forms of osseous tissue

Answer 3

1 - Cancellous (spongy) bone - the site of haematopoiesis in the red bone marrow. Honeycombed, At the epiphyses of long bones.

2 - Compact bone - appears solid to the naked eye. Surrounds bones, below the periosteum.

Question 4

Classification of bones (by shape)

Answer 4

Flat bones - thin, flattened, a bit curved, eg skull, sternum
Long bones - longer than they are wide. eg humerus, femur, phalanges.
Short bones - cube-shaped. In the wrist (carpals) and ankle (tarsals)
Irregular bones (eg hip, vertebrae)
Sesamoid bones (eg patella)
Wormian or sutral bones (small flat bones with jagged edges in the skull)

Question 5

Classification of fractures

Answer 5

Non displaced or displaced
Complete or incomplete
Closed (simple) or open (compound)

Question 6

Types of fractures

Answer 6

Greenstick - breaks on one side, bends on the other. Frequently seen in children. Incomplete.

Spiral - ragged break due to twisting, often in sports.

Compression - bone is crushed.

Comminuted - bone fragments. Brittle bones, often in the elderly.

Question 7

Major long bones

Answer 7

Humerus (upper arms)
Radius (forearms, radiates to the thumb)
Ulna (forearms)
Femur (thighs)
Tibia (anterior lower leg - shin)
Fibula (lower leg)
Phalanges
Metacarpals
Metatarsals

Question 8

Fracture repair

Answer 8

Reduction (setting the bone back in place, re-alignment)

• Internal (surgery, wires or pins)
• External (mechanical manipulation or attached weights)

then immobilisation, usually by a cast

Question 9

Types of bone cells

Answer 9

Osteocytes - mature bone cells
Osteoblasts - constantly adding to the matrics
Osteoclasts - constantly removing from the matrix

Question 10

How do bones repair themselves?

Answer 10

• A haematoma forms
• Fibroblasts lay down collagen, chondroblasts lay down cartilage and osteoblasts lay down spongy bone and a fibrocartilaginous (soft) callus forms.
• After about 2 months the soft callus has become bony and hard.
• Bone remodelling continues as normal

Question 11

Calcium for bones

Answer 11

• In dairy and leafy greens dietary intake.
• 99% of calcium in the body is in the bones. The other 1% in the cells and blood.
• Essential for bone strength, muscle contractions, nerve impulses and heart rhythm.
• The amount of calcium in the blood/cells is regulated by the parathyroid hormone (PTH) and calcitonin.

Question 12

Osteoporosis

Answer 12

• Occurs when osteoclast action outweighs osteoblast action and calcium leeches out of the bones.
• To protect against osteoporosis, have good calcium intake, healthy sun exposure for Vit D which helps the body absorb calcium, and get weight-bearing exercise, which promotes bone growth.
• Can be caused/worsened by smoking or a reduction in sex hormones.

Question 13

Types of joints

Answer 13

• Fibrous - at skill sutures.
• Cartilaginous - at the epiphyseal plate
• Synovial joints - between the long bones of the limbs. Very broad for stability. Involves articular (hyaline) cartilage for lessening friction, ligaments connection the two bones, and synovial fluid. Exercise to promote healthy joints as it strengthens them and increased blood flow nourishes them.

Question 14

Characteristics of muscle tissue

Answer 14

• Excitable - reacts and responds to stimulus
• Contractile - contracts forcibly when stimulated
• Extendable - can be stretched
• Elastic - returns to original length after stretching
• Scars rather than regenerates
• Smooth, skeletal and cardiac
• Muscle tone = muscle tension. Opposite is flaccid.
• Muscle does NOT turn to fat.

Question 15

Skeletal muscle functions

Answer 15

• Facilitates movement by working against the skeleton, Also pumps blood.
• Maintains body posture by adjusting the position of the body.
• Stabilised joints
• Generates heat as a function of it’s cellular metabolic processes.
• Tendons attach muscle to bone.

Question 16

Electromyography

Answer 16

• Records electrical activity of contracting muscles.
• Electrodes are inserted into the muscles and records impulses.
• Determines muscle and related nerve activity.

Question 17

Intramuscular injection (IMI) sites

Answer 17

1 - Deltoid. Shoulder. Can only take a small volume.
2 - Gluteus maximus. Buttock. Aim for upper outer quadrant to avoid the sciatic nerve. Dorsogluteal
3 - Gluteus medius. Buttock. Less chance of hitting the sciatic nerve. Ventrogluteal.
4 - Rectus femoris, anterior aspect (thigh). Good for self-administration, can be very painful.
5 - Vastus lateralis, lateral aspect (thigh). Good for infants as they have under-developed deltoids and buttocks.

Question 18

Dystonia, or dystonic reaction

Answer 18

• Prolonged contraction of the skeletal muscles.
• Can be caused by antipsychotic medications.
• Reversed by another medication (IMI).

Question 19

Spinal vertebrae

Answer 19

Cervical - C1 - C7
Thoracic - T1 - T12
Lumbar - L1 - L5
Sacral - S1 (fused) 5 bones
Coccyx - Co1 (fused) 4 bones)