Musculoskeletal system

Question 1

Define the MSK system

Answer 1

A human body system that provides the body with movement, stability, shape and support

Question 2

What does the muscular system contain?

Answer 2

Muscles- help generate force

Tendons- help transmit the force to bones

Question 3

What does the skeletal system contain?

Answer 3

• Bone
• Cartilage
• Ligaments

All of these combine to form joints

Question 4

Define bone tissue

Answer 4

Hard, dense connective tissue, forms most of adult skeleton

Question 5

What are the functions of the skeletal system?

Answer 5

• Support/ posture
• Movement
• Protection
• Hematopoiesis
• Storage

Question 6

How does the skeletal system allow movement?

Answer 6

Bones provide surfaces for muscles to attach, bones form joints, muscles able to pull on them, causing movement

Question 7

How does the skeletal system provide protection?

Answer 7

Bones are very strong, and therefore prevent damage to underlying viscera by significant force. For example, cranium protects brain, ribs protect heart and lungs

Question 8

How does the skeletal system allow hematopoiesis?

Name some bones that are able to do this

Answer 8

Produce blood cells due to certain bones containing red bone marrow, which produce red blood cells, white blood cells and platelets. Some bones that have red bone marrow include: femur, pelvis, sternum

Question 9

How does the skeletal system provide storage?

Answer 9

Bone tissue acts as reservoir for minerals such as calcium, phosphorous. These can be released when needed, so calcium released for nerve transmission, muscle contraction etc.

Bones also store and release fat from yellow bone marrow that is present.

Yellow bone marrow is made mostly of fat, and contains stem cells that can become cartilage, fat or bone

Question 10

What is the axial skeleton?

Answer 10

Bones of head and trunk

Question 11

How is the axial skeleton split up?

Answer 11

-Skull - neurocranium and viscerocranium
- Ossicles (inner ear)
- Thorax (ribs and sternum)
- Vertebral column

Question 12

How is the vertebral column split?

Answer 12

• Cervical vertebrae (7)
• Thoracic vertebrae (12)
• Lumbar vertebrae (5 fused)
• Sacral (5 fused)
• Coccyx (4 fused)

Question 13

What is the appendicular skeleton?

Answer 13

Bones of the limb girdles and limbs

Question 14

What are the bones of the limb girdles and limbs split into?

Answer 14

• Upper limb
• Lower limb

Question 15

What is the upper limb composed of?

Name the limbs and bones

Answer 15

• Shoulder girdle - clavicle and scapula
• Arm- humerus
• Forearm- radius and ulna
• Wrist- carpals
• Hand- metacarpals and phalanges

Question 16

What is the lower limb composed of?

What does each compartment contain?

Answer 16

• Pelvic girdle- ilium, ischium, pubis (these make up the hip bone)
• Thigh- femur and patella
• Leg - tibia (thicker bone), fibula
• Ankle - tarsals
• Foot- metatarsals and phalanges

Question 17

What are the 5 groups bones can be classified into? Describe the groups

Answer 17

• Flat - Protect vital organs
• Long- Cylindrical, longer than they are wide, facilitate movement
• Short- Cube-like. Length, width and height are similar, provide stability
• Irregular- Provide protection and movement, have no distinctive shape
• Sesamoid- Small round bones within tendons, protect tendons from excessive forces and allow leverage for effective muscle function

Question 18

Define joints

Answer 18

Connection between 2 bones in body.

Every bone, bar hyoid bone in neck, is connected to at least one other bone

Question 19

How can joints be classified?

Answer 19

By type of tissue
By degree of movement

Question 20

What are the 3 categories by which joints are classified by type of tissue?

Answer 20

• Fibrous
• Cartilaginous
• Synovial

Question 21

Describe a fibrous joint

Answer 21

Bones connected by fibrous tissue, results in strength and stability, but very little movement, if any at all

Question 22

What can fibrous joints be further divided into?

Answer 22

• Sutures
• Gomphosis
• Syndesmosis

Question 23

Describe suture joints

Answer 23

Synarthrosis joint,- means immovable joints. Only found between bones of skull

Question 24

Describe Gomphosis joints

Answer 24

Synarthosis joint, immovable. Joint involves anchoring of root of a tooth into its bony socket within the maxilla or mandible, numerous short bands of dense connective tissue called periodontal ligaments which can aid in anchoring

Question 25

Describe Syndesmosis joints

Answer 25

Amphiarthroses,- means slightly movable. Joints involve 2 parallel bones joined to each other by fibrous connective tissue called interosseous membrane e.g. radius and ulna joined together by interosseous membrane

Question 26

Describe a cartilaginous joint

Answer 26

Bones connected by hyaline cartilage or fibro cartilage

Question 27

Describe the 2 divisions that cartilaginous bones can be further divided into

Answer 27

- Synchondroses (primary cartilaginous)- Bones joined together by hyaline cartilage, synarthrosis joint, therefore immovable, example includes epiphyseal plates (growth plates) - Symphyses ( secondary cartilaginous)- Bones joined by fibrocartilage, amphiarthrosis, therefore slightly movable, example is intervertebral discs that unite adjacent vertebrae

Question 28

Describe a synovial joint

Answer 28

Involve articulating surfaces surrounded by a joint cavity filled with a lubricating fluid called synovial fluid. Defining features are joint cavity, synovial fluid and articular (hyaline) cartilage

Question 29

How can synovial joints be further divided?

Answer 29

- Plane joint - Hinge joint - Condylar joint - Ball and socket joint - Saddle joint - Pivot joint

Question 30

Describe plane joint

Answer 30

Bones are flat or slightly curved, allows bones to slide over each other, this is found in carpals of hand

Question 31

Describe Hinge joint

Answer 31

Involve a convex and a concave surface, articulating together that allow movement in a single axis. For example, the elbow joint allows on flexion and extension

Question 32

Describe condylar joint

Answer 32

Has a shallow depression and an oval rounded articulating surface, cannot rotate but can flex, extend, abduct and adduct and slightly circumduct, example is radiocarpul joint of wrist

Question 33

Describe a ball and socket joint

Answer 33

Have greatest range of movement, and involved rounded end of one bone (or the ball) articulating with the concave socket of another bone. Only 2 ball and socket joints in body, which are the knee joint and should joint. these are multiaxial joints allowing lots of movement, allow flexion, extension, abduction, adduction, rotation and circumduction.

Question 34

Describe saddle joint

Answer 34

Both articulating surfaces are saddle shaped, meaning they’re concave in one direction and convex in the other, allows them to be bi-axial joints, allowing movement in two planes. Example is joint at base of thumb, the first carpo metacarpal joint

Question 35

Describe pivot joint What is it usually held in place by?

Answer 35

Rotate around a single axis, usually held in place by ligaments, e.g proximal radioulna joint allows for pronation and supanation of radius over ulna

Question 36

What are the 3 main functions of cartilage?

Answer 36

Has 3 main functions: - Support/posture - Articular surfaces- provides smooth surface for bones to join with each other - Template for skeleton- hyaline cartilage is precursor to bone in utero, and osscifies to form foetal skeleton, and is present in growth plates

Question 37

Describe the 3 types of cartilage

Answer 37

- Hyaline cartilage- Most common form, weakest form, can be precursor for bone formation, also found at articulating surface of bones, termed articular cartilage e.g. head of femur. This articular cartilage has a slightly different structure and organisation than that of epiphyseal growth plates. - Fibrocartilage- Strongest form of cartilage, found in areas that need to withstand lots of force such as joint capsules, tendon insertions and intervertebral discs, usually attached to hyaline cartilage, tendons or ligaments -Elastic cartilage- Abundance of elastic fibre, flexible, resilient, found in commonly deformed structures such as outer ear or larynx.

Question 38

What do articulation ligaments do?

Answer 38

- Connect bones to bones

Question 39

What are the 3 main functions of articulation ligaments?

Answer 39

- Dense connective tissue so stabilise joints and limit movement - Increase muscle attachment area - Hold tendons down during movement, preventing them from bowing out .(Bowed tendon refers to swelling in the superficial or deep digital flexor tendon)

Question 40

Describe the 3 types of articulation ligaments

Answer 40

- Capsular- form part of joint capsule e.g. hip capsule. They reinforce the strength of the articular capsule - Extracapsular- Outside of the joint capsule, these hold the bones in place and provide stability - Intracapsular- Within joint capsule- provide stability but permit a far larger range of motion than extracapsular ligaments

Question 41

What is a joint capsule?

Answer 41

A dense fibrous connective tissue that is attached to the bones via specialised attachment zones at the end of each involved bone.

Question 42

What do peritoneal ligaments do?

Answer 42

- Connect viscera (organs) to viscera OR connect viscera to the abdominal wall

Question 43

What do periodontal ligaments do?

Answer 43

Connect teeth to alveolar bone

Question 44

Describe skeletal muscle

Answer 44

- Also called striated (due to long thin parallel streaks) - Most abundant muscle tissue in body - Attaches to bone - Voluntary movement- we can usually choose to contract them - Rapid contraction- allows us to exert force and move quickly - Fast twitch- Contracts quickly but for a short duration. Anaerobic, less blood supply, mitochondria and myoglobin. Used for explosive forces such as jumping or sprinting - Slow twitch- Contracts slower, but for longer durations, aerobic, richer blood supply, more mitochondria and myoglobin. These are needed for maintaining posture, running long distances

Question 45

Describe smooth muscle

Answer 45

- Forms contractile components of digestive, urinary, reproductive systems as well as airways and arteries - No striations, instead spindle shaped (wide in middle, tapers at both ends) with a single nucleus per cell - Involuntary control - Slow contraction

Question 46

Describe cardiac muscle

Answer 46

- Only in heart - Striated, but has a single nucleus per cell - Has specialised cell junctions called intercalated discs, allows cells to synchronise actions - Involuntary movement, contract myogenically iva stimulation of SAN and AVN.

Question 47

How can muscles be classified?

Answer 47

- Microstructure (skeletal, smooth, cardiac) - Orientation of muscles fibres

Question 48

Describe the types of ways muscle fibres can be orientated

Answer 48

- Circular muscles- striated muscles where fascicles (a group of bundled muscle fibres) are arranged in concentric rings e.g. orbicularis oris, muscle surrounding mouth - Parallel muscles- long, thin muscles that don't have much strength e.g. sartorius muscle, runs down thigh to knee. Fascicles run down long axis of muscle. Can be divided into 2 groups: --> Fusiform- spindle shaped (extended belly and narrow origins e.g. biceps) --> Non-fusiform- narrow belt-like muscles e.g. sartorius muscles -Convergent- muscle has a widespread expansion over a sizeable area and the fascicles come to a single, common attachment point -Pennate- resembles shape of a feather, muscle fibres approaching a central tendon that runs the whole length of the muscle at an oblique angle, maximises muscle's force potential. Can be divided into 3 groups: --> Unipennate- fascicles insert from only one side of tendon --> Bipennate- fascicles insert from opposite sides of tendon --> Multipenate- lots of central tendons, fascicles on either side all converting onto large tendon E.g. deltoid muscle of shoulder ALL pennate muscles are skeletal, so they'll be facilitating movement etc

Question 49

What is fascia?

Answer 49

Thin connective tissue, surrounds muscles, organs, blood vessels, nerves, provides structure + support throughout body AND provides smooth surface for structures (muscles, joints, organs) to slide against each other without creating friction or tears

Question 50

What is a muscle compartment?

Answer 50

Groupings of muscle, nerves and blood vessels in upper and lower limbs Usually muscles within same compartment supplied by same nerves and arteries/blood vessels and the muscles usually have a similar function

Question 51

What are muscles and nerves wrapped in?

Answer 51

Deep fascia

Question 52

What separates the muscle compartments?

Answer 52

Special bands of fascia called intermuscular septa

Question 53

What are the muscle compartments of the arm?

Answer 53

- Anterior: - Elbow flexion - Musculocutaneous nerve -Posterior: - Elbox extension - Radial nerve

Question 54

What are the muscle compartments of the forearm?

Answer 54

- Anterior - Wrist and digit flexion and pronation - Median and ulnar nerves -Posterior - Wrist and digit extension and supination - Radial nerve

Question 55

What are the muscle compartments of the thigh?

Answer 55

- Anterior - Knee extension - Femoral nerve - Posterior - Knee flexion - Sciatic nerve - Medial - Hip adduction - Obturator nerve

Question 56

What are the muscle compartments of the leg?

Answer 56

- Anterior - Ankle dorsiflexion and inversion - Deep fibular nerve - Lateral - Ankle eversion and plantarflexion - Superficial fibular nerve - Deep posterior - Plantarflexion - Tibial nerve - Superficial posterior - Knee flexion - Plantarflexion - Tibial nerve

Question 57

What 4 other ways can muscle be classified?

Answer 57

- Action- agonist (muscle that is contracting) , antagonist (muscle that is relaxing, or extending_ - Shape- deltoid, trapezius, rhomboids - Position in the body - e.g. tibialis anterior muscle has its name as its anterior of the tibia - Number of heads (proximal attachments- e.g. biceps has 2 heads, a long head and a short head

Question 58

What are tendons?

Answer 58

Dense connective tissue attaching muscle to bone made of type 1 collagen, giving it high tensile strength

Question 59

What is a thin flat tendon called?

Answer 59

Aponeurosis

Question 60

What are the functions of tendons?

Answer 60

- Transmits mechanical force of muscle to bone, efficient at this as they're much stiffer than muscles, high tensile strength allows them to withstand large loads with minimal deformations and minimal loss of energy. - Allow muscle bulk to be situated away from site of action. Reduces force and energy required for movements. - Allow muscles to pull 'round corners' so force can be transmitted around corners.

Question 61

What is the function of skeletal muscle

Answer 61

Operates the skeleton, links bones + tendons, allows movement and respiratory mechanisms (diaphragm) and maintaining posture and balance Rapid contraction of muscle but subject to fatigue, voluntary control

Question 62

What is the function of cardiac muscle

Answer 62

- Response for contractility of the heart, therefore pumping action - Muscle contracts quite rapidly, resists fatigue, can contract regularly for 90+ years - Involuntary control (for most people)

Question 63

What is the function of smooth muscle?

Answer 63

Used in vessels to maintain blood pressure and flow, in lungs it opens and closes airways, in GI system it helps motility and nutrition collection, however smooth muscle is found in many more internal organs such as uterus, bladder etc. Muscles contract slower but contractions are very powerful and energy-efficient with little fatigue. They are able to stretch further than cardiac + skeletal, and usually involuntary control, e.g. uterus, gut

Question 64

What is muscle surrounded by?

Answer 64

Epimysium- thick, outermost sheath of dense connective tissue

Question 65

What are fascicles surrounded by?

Answer 65

Perimysium- Supporting connective tissue, carries nerves, blood vessels.

Question 66

What does actin do for a muscle cell?

Answer 66

Thin filaments that transmit the forces generated by myosin to the ends of the muscle Form a network (beneath the plasma membrane) that provides mechanical support, determine cell shape, allows movement of the cell to the surface

Question 67

What does myosin do for a muscle cell?

Answer 67

This is a protein that converts ATP to mechanical energy, generating force and movement