W16 Muscoskeletal system

Question 1

What are the 6 roles of the skeleton?

Answer 1

1. Support (of the body)
2. Movement
3. Protection (of inner organs)
4. Storage (of ions such as Ca, P, Fe)
5. Haemoporesis (bone marrow synthesising RBC’S & WBC’s)
6. Endocrinology (osteocytes release hormones to regulate glucose/metabolism)

Question 2

In which bones can you find bone marrow?

Answer 2

Long bones, skull, vertebrae, pelvis, sternum

Question 3

Name the 5 types of bone
Where can they be found?
Name a function of each

Answer 3

1. Long bone - femur/humerus - longer than it is wide
2. Short bone - wrists/ankles - wider than it is long
3. Flat bone - skull/sternum - sheilds organs
4. Irregular bone - pelvis bones - specialised to allow passage of nerves/vessels
5. Sesamoid bone -

Question 4

Which are the 2 major components of any bone?

What function do they serve?

Answer 4

1. Cortical - Stiff, gives rigidity to bone

2. Tubercular - Flexible, gives bone ability to withstand dynamic loading. Cavities hosts bone marrow.

Question 5

Explain the terminology:
Epiphysis
Diaphysis
Metaphysis

Answer 5

1. The end of a bone
2. The shaft of a bone
3. Section between the end and the shaft

Question 6

Which 2 parts is the skeleton divided into?

What are their consitutent parts?

Answer 6

Axial skeleton: skull, spine, ribcage

Appendicular: Limbs, pelvic girdles

Question 7

What are the two major parts of the cranium, separating the “face” and the “skull”?

Answer 7

Skull: Neurocranium
Face: Visceral cranium

Question 8

Describe the main effects that exercise has on the skeleton in terms of mineralisation, porosity, bone density, and trabaculae.

Answer 8

The sites of muscle attachement to bone become stronger.
Increased mechanical loading = increased bone strength.
Mineralisation (Ca, P) increases
Porosity decreases
Bone density increases
Trabaculae is alligned in the direction of stress.

Question 9

What do we mean by dynamic loading?

Why is it important for a strong skeleton?

Answer 9

Dynamic loading = loading with rest periods in between where load is taken off

Bone growth relies on dynamic loading - constantly having pressure on bones is as bad as not using them at all.

Question 10

What are the 4 main roles of muscles?

Answer 10

1. Support
2. Movement
3. Producing body heat
4. Vital functions (digestion, movement of blood, contractions of sphincters of the eye…)

Question 11

Describe the typical muscle structure

Answer 11

Proximal attachments (made of tendons)
Muscle belly (skeletal muscle tissue)
Distal attachments (made of tendons)

Question 12

Describ the muscle hierarchy as 5 parts

Answer 12

Muscle-> Fascicle (groups of muscle cells)-> Muscle cell -> Myofibril (many filaments)-> myofilament (actin and mysoin proteins)

Question 13

What are aponeurosis?

Answer 13

Broad, flat sheets connecting muscle to bone (such as the one covering the abdominal muscles)

Question 14

What is sarcopenia?

Answer 14

Age related loss of skeletal muscle mass.
The muscle decreases in size and and quality
Happens twice as fast in lower limbs compared to upper limbs

Question 15

Catgories the different types of joins, and where to find them

Answer 15

Joints-> Cavitated + Solid
Cavitated-> Synovial (wrists/ankles)
Solid-> fibrous + cartilagenous

Question 16

Describe the two mechanisms of skeletal growth

Answer 16

Hypertrophy (overnourishment) - cells increase in size, but not number
most abundant in humans

Hyperplasia (hyper cell-multiplication) - cells increase in numbers, but not size

Question 17

What is bone growth called?

Describe the two main forms of bone growth

Answer 17

Ossification
Intramembranous (starts as connective tissue, eventually replaced by bone)
+ Endochondral (Starts as hyaline cartilage, then replaced by bone matrix)

-> Interstitial (grows in one direction, bone elongates) + Appositional (bone grows in

Question 18

Imagine doing bicep curls with a dumbell:
Muscle contraction can be either _____ or _____ which in turn can be _____ and ______.
Describe what happens at each stage.

Answer 18

Isometric (holding weight still - change in tension, not length)
or Isotonic (during movement - change in length, not tension)

Concentric (muscle shortens) and Eccentric (muscle lengthens)

Question 19

What are the 2 muscle fibre types, and what are their characteristics?

Answer 19

Fast twitch (the sprinter): fast contractions, quick to fatigue)
Slow twitch (the marathon runner): slow contractions, resistant to fatigue

Question 20

What are the 2 major hormones controlling the muscoskeletal system?

Answer 20

GH: acts on liver cells to release insulin-like growth factor 1 (IGF-1), which drives longitudinal growth of bones (and increases metabolism)

PTH:Regulates distribution of Ca and P in the body. INcreasing osteoCLAST activity and DEcreasing osteoBLAST mov

Question 21

Describe the 5 other hormones related to muscoskeletal regulation

Answer 21

Calcitonin - released from thyroid, opposes PTH. INcreases osteoBLAST act. and DEcreases osteoCLAST = Ca move from blood plasma to bone.
Vit D- also stimulates reabsorption of Ca and P
Vit C - imp. for collagen synthesis
Oestrogen - can reduce bone absorp

Question 22

Describe briefly the 5 types of biomedical imaging

Answer 22

X-ray: image shows density of different tissues
CT: still x-ray, but provides 3d image from rotating scanner
MRI: protons from H20 molecules affected by magnetic field to produce image
Ultrasound: High frequency sound waves
Contrast studies: “density” can

Question 23

Why is imaging so important?

Answer 23

It allows us to examine structures in a living individual and relationships between organs.
In a surgical environment, the body should only be opened up as a last resort.