Locomotion

Question 1

What is the function of the musculoskeletal system?

What are its components?

Answer 1

The musculoskeletal system allows movement and interaction with our environment.

Its components are:

1. Bones
2. Joints
3. Muscles

Question 2

List the functions of bones, joints and muscles

Answer 2

Bones:

1. Structural support
2. Protection
3. Calcium store
4. Haematopoiesis (parts of the bone invovlved in RBC production)

Joints

1. Facilitate movement: (they dont generate movement)
2. Allow growth
3. Stability

Muscles

1. Generate movement
2. Generate heat

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Question 3

Label the diagram

Answer 3

Question 4

List the characteristics of the outer cortex and inner medulla

Answer 4

Outer cortex

1. Compact (cortical) bone
2. Dense
3. Strong
4. Heavy

Inner medulla

1. Spongy (trabecular/cancellous) bone
2. Light
3. Weaker
4. More porous

Question 5

What is the function of the medulla (and which specific bones are involved in this)?

Answer 5

1. The medulla MAY contain bone marrow
2. In some bones the marrow is the site of hematopoiesis: RBC and WBC protection
   
   1. skull
   2. vertebrae
   3. Sternum
   4. ribs
   5. hip bone
   6. in the proximal cancellous ends of the long bones femur and humerus

Question 6

Label the diagram

Answer 6

Question 7

Describe the bone’s neurovascular supply

Answer 7

Periosteum (fibrous connective tissue “sleeve”):

1. Vascularised: has neurovascular bundles in it - vein, artery, nerve, lymphatics
2. Supplies the compact bone around the outside of the bone (not spongy bone)
3. It is very well innervated, very sensitive to sensation: during fractures most of the pain is actually from the periosteum tearing

Nutrient vessels (nutrient artery & vein). Supplies medullary cavity:

1. Bone marrow
2. Spongy bone
3. Deep compact bone

Question 8

Label the diagram

Answer 8

NB. Epiphysis and epiphyseal growth plate conected. Metaphysis comes after

Metaphysis = neck of bone

Diaphysis = shaft of bone

Question 9

How do long bones develop? Name and describe the process

Answer 9

Long bones develop via endochondral ossification:

1. process in which an initial small, hyaline cartilage version of the bone grows and turns into bone (ossifies)
2. begins to ossify via 2 ossification centers – the primary ossification centre in the diaphysis and the secondary ossificaiton cenre in the epiphysis
3. Epiphyseal growth plate remains hyaline cartilage as long as the bone continues to grow - this is where most of the growth of the bone occurs
4. Once you reach your ultimate height, the growth plates fuse

Question 10

What is the difference between tendons and ligaments?

Answer 10

Tendon = connective tissue that connects muscle to bone

Ligament = connective tissue connecting two bones

Question 11

Label the different types of bone with examples

Answer 11

Question 12

What are the 2 divisions of the skeleton?

Label them and their constituent parts

What is the seeming exception?

Answer 12

The sacrum is part of axial skeleton, but technically also part of the pelvic girldle (appendicular).

The axial classiciation overrides the appendicular

NOTE:

• coccyx not included in axial skeleton
• Appendicular = upper and lower limbs and the girdles that attach them

Question 13

How many vertebra do we have? What are their subdivisions?

Answer 13

Question 14

How many curvatures does our vertebral column have?

Label them

What causes their development?

Answer 14

Every adult has 4 curves intheir vertebral column

The curves that are the same as the fetus – primary curvature

Secondary curvature = develops as a result of bipedalism and weight bearing

Question 15

Where are spinal nerves found?

What kind of joint occurs between the articular processes of vertebrae?

What can it be affected by?

Answer 15

In the intervertebral foraminae (which form between adjacent vertebrae - only appear when the vertebrae are stacked together)

Vertebral facets (on processes) joined by:

• Facet joint: synovial plane joint
• Between inferior/superior articular processes of 2 adjacent vertebrae
• Affected by arthritis

Question 16

Which part of the body do the spinal nerves supply?

How do they connect with that body part and with the spinal cord?

Answer 16

The spinal nerves supply the soma (body wall)

They connect with the soma via anterior and posterior rami (branches)

They connect with the spinal cord via roots and rootlets

Question 17

What is a common feature/characteristic identifying feature of cervical vertebrae?

Why is this feature in place?

Are there any exceptions?

Answer 17

Any vertebra with little holes in the transverse processes (in each transverse process) = cervical vertebrae: has transverse foramen

Transverse foraminae are for the passage of vertebral arteries

Except C7 = transverse foraminae much smaller since only smaller veins go through them. Sometimes missing in C7

Question 18

Which are the atypical cervical vertebrae?

Name them and describe their features

Answer 18

C1, C2, C7 = completely atypical

C1 - Atlas:

• does not have a body
• does not have a spinous process
• has a posterior arch and an anterior arch instead

C2 - Axis:

• has an odontoid process which projects superiorly from body (has stolen C1’s body)

C7:

• vertebrae prominens - long spinous process
• first palpable spinous process in 70% of people: palpated in the midline of the posterior aspect of the neck
• small or missing transverse processes: for passage of small veins instead of arteries

Question 19

Identify the bone

Answer 19

C7: vertebrae prominens

Question 20

Identify the bone

Answer 20

C1: Atlas

Question 21

Identify the bone

Answer 21

C2: Axis

Question 22

What are the two girdles of the body? What are their functions?

Answer 22

The two girdles of the body are:

Pectoral girdle (2 scapulas and 2 clavicles): attaches upper limb to trunk

Pelvic girdle (Sacrum and 2 hip bones): attaches lower limb to trunk

Question 23

Label the diagram

What does meta mean?

Answer 23

Meta = beyond or after

Question 24

What are the two parts of the skull?

What is their dividing line and where does it run?

Answer 24

The two parts of the skull are

Neurocranium: bones of the cranial vault

Viscerocranium: bones of the facial skeleton

They are divided by the base of the skull (most inferior part of the neurocranium), which runs from superior to the orbits to inferior to the ears

Question 25

What are the 3 types of muscle? Describe their characteristics

Answer 25

1. Skeletal Muscle 1. Striated: actin & myosin filaments in sarcomere 2. Voluntary 3. Function: Mainly skeletal movements 2. Cardiac Muscle 1. Striated: actin & mysoin filaments in sarcomere 2. Involuntary 3. Function: Heart beating 3. Smooth Muscle 1. Unstriated: does not need to contract 2. Tube 3. Function: viscera

Question 26

What are the descending units of skeletal muscle?

Answer 26

1. Skeletal muscle 2. Muscle fascicle (bundle of muscle fibres) 3. Muscle fibre (bundle of myofibrils) 4. Myofibril (bundle of myfilaments) 5. Myofilaments (bundle of sarcomeres) 6. Sarcomeres: Z line of actin to next Z line of actin 1. Actin filaments: thin (light stripe) 2. Myosin filaments: thick (dark stripe)

Question 27

What is straining of skeletal muscle? What does grade 3 strain indicate?

Answer 27

Strained = tearing some of the fibers 3 is the most severe: ruptured = completely torn

Question 28

What are the types of skeletal muscle? List with examples

Answer 28

1. Sphincter muscles: circular e.g. orbicularis oris 2. Quadrate: 4-sided or square looking e.g. abdominus rectus 3. Fusiform: spindle shaped (big belly that tapers on either end) e.g. biceps brachii 4. Pennate: feather-like e.g. deltoid 5. Flat with aponeurosis: flattened tendon instead of tube-shaped e.g. external oblique

Question 29

What determines skeletal muscle contractility and range of motion?

Answer 29

Length of the muscle longer muscle fibres: * greater potential range of shortening * greater potential range of movement produced at joint

Question 30

Describe skeletal muscle attachment to bone What is the exception?

Answer 30

Muscles attach to bone by tendons (usually) usually at least 2 points of attachment to bone * the “origin(s)” on one side of a joint: usually more proximal to the body (not always the case) * the “insertion(s)” on the other side: usually more distal (not always the case) * Muscles have to cross a joint to be able to move it by contraction Tendons (connective tissue) usually connect muscle to bone. One area where this is not the case is the face. Muscles of facial expression Attach from bone to skin and soft tissue (of the superficial fascia)

Question 31

What is the function of facial muscles?

Answer 31

* Muscles of facial expression allow for communication without words: Convey emotion * protect entrance into the body

Question 32

Where are skeletal muscles found? How are they compartmentalized? What is the exception?

Answer 32

skeletal muscles usually found deep to deep fascia - deep fascia: tough fibrous connective tissue covering - deep fascia separates muscle into different compartments by forming intermuscular septae Facial muscles are an exception (not deep to deep fascia)

Question 33

Label the diagram with the characteristic of each layer

Answer 33

Question 34

Are the muscles that perform reflexes skeletal or smooth? Do we have control over reflexes? Where do muscles transition between types?

Answer 34

muscles that perform the protective reflexes of coughing, sneezing, gagging, swallowing & vomiting are all skeletal muscles of the proximal respiratory/alimentary tracts NB We don’t have control of reflexes, but generally have control over the muscles that perform reflexes * approximate level of transition to smooth muscle: around C6 (the trachea & the middle third of the oesophagus) * Upper 3rd of oesophagus = skeletal muscle * Lower 3rd = smooth muscle * Middle 3rd = both, transition zone * approximate level of transition back to skeletal muscle: the perineum muscles that control micturition & defecation are skeletal muscles

Question 35

What are the different types of joints? Describe their compromise profile

Answer 35

Different types and subtypes of joints 1. Fibrous 2. Cartilaginous 3. Synovial Each is a compromise between **mobility** and **stability:** * Fibrous is more stable and less mobile * Cartilaginous is in the middle * Synovial is less stable and more mobile

Question 36

What are the subtypes of fibrous joints? Give examples

Answer 36

Fibrous joints: * Generally limited mobility * Quite stable Types **1. Syndesmoses** * Unites bones with fibrous sheet/fibrous membrane * Quite stable * Partially movable * e.g. interosseous membranes: a fibrous sheet between fibula and tibia **2. Sutures** * Between bones of skull * Interlocking: Highly stable * Can sometimes completely fuse together so we don’t even see joint anymore * e.g. coronal suture **3. Gomphosis** * Dento alveolar syndesmosis * Very little movement * Peridontal ligament: is a gomphotic joint - attaches tooth to the alveolar bone in which it sits

Question 37

What are the types of cartilaginous joints? Describe them with examples

Answer 37

**1. Primary cartilaginous** * **Synchondroses:** bones joined by hyaline cartilage * e.g. long bone epiphyseal growth plate * permit growth in length of bone * Growth until ossification and fusion **2. Secondary cartilaginous** * **Symphyses:** fibrocartilaginous fusion between two bones * Fibrocartilage very strong * Slightly movable individually (we get big movements collectively across little movements of individual vertebra) * e.g. intervertebral discs

Question 38

What is a disadvantage of cartilaginous joints?

Answer 38

Since slightly less stable/with a bit more mobility than fibrous joints, both types of cartilaginous joints (primary and secondary) can ‘slip’ (generally backwards) e.g. primary – slipped femoral epiphysis secondary – slipped disc

Question 39

What are the different types of synovial joints?

Answer 39

1. Ball and socket 2. Pivot 3. Hinge 4. Plane 5. Saddle 6. Condyloid

Question 40

Label the diagram

Answer 40

Question 41

Label the diagram

Answer 41