Module 4 Review Lecture Questions

Question 1

Describe the functions of the skeletal system.

Answer 1

Support & Protection (give structure to the body and protect many of our vital organs).
Movement (articulations between bones act like levers for muscles to pull on).
Storage (minerals and fats).
Blood cell production (haematopoiesis, from bone marrow).

Question 2

List the 5 different classifications of bones and name one bone in the human body.

Answer 2

Flat (e.g., scapula)
Long (e.g., femur)
Short (e.g., carpal bones)
Irregular (e.g., vertebrae)
Sesamoid (e.g., patella)

Question 3

Explain the gross structure of a long bone.

Answer 3

Comprised of an outer layer of compact bone and an inner layer of spongy bone.
Either side of the compact bone layer is a connective tissue membrane; periosteum on the
outside, endosteum on the inside.
The ends of the long bones are termed epiphyses, while the shaft in between is the diaphysis.

Question 4

Name the regions of the vertebral column and
how many vertebrae are in each section.

Answer 4

Cervical = 7
Thoracic = 12
Lumbar = 5
Sacral = 5*
Coccygeal = 4*

Question 5

What are the bones that make up the pectoral girdle, arm, forearm, and hand (not specific names of hand bones, but general names)?

Answer 5

Pectoral girdle = scapula & clavicle. Arm = humerus. Forearm = radius & ulna. Hand = carpals, metacarpals, phalanges (proximal, middle, distal).

Question 6

What are the bones that make up the pelvis?

Answer 6

Pelvis = 2 x hip bones, as well as sacrum & coccyx. Each hip bone = ilium, ischium and pubis.

Question 7

Name the main bones that make up the thigh, leg, and foot (not specific names of foot bones, but general names).

Answer 7

Thigh = femur. Leg = tibia and fibula. Foot = tarsals, metatarsals, phalanges (proximal, middle and distal).

Question 8

Explain the age-related changes in skeletal properties through development. How does this differ between sexes?

Answer 8

During childhood/adolescence: bone formation exceeds resorption.
During young adulthood: bone formation equals resorption.
During adulthood: bone resorption exceeds formation.
In older adults: bone mass, mineralisation and healing ability decrease with age.

In older adults, bone loss is exacerbated in women due to menopause.
In both sexes, severe bone loss may result in osteoporosis!

Question 9

Draw an (active and passive) force-length relationship for skeletal muscle. Explain why active force decreases with increasing length.

Answer 9

Active force decreases with increasing length as the sarcomeres become excessively stretched, there is not enough overlap of actin and myosin
(hence myosin cannot bind to actin).

Question 10

Describe the size principle for motor unit recruitment.

Answer 10

Motor units are recruited in a particular order, and this is based on their size. Smaller motor units (i.e., those with smaller motoneurons
innervating slow twitch muscles fibres) are recruited before larger motor units.

Question 11

Describe the two ways in which motor unit recruitment can be altered to increase muscle force output.

Answer 11

The number of motor units recruited: i.e., how many motor units are discharging (more recruited = more force).
The discharge rate of motor units: more frequent action potentials generate more force.

Question 12

What are 4 differences between Type I and Type IIB muscle fibres?

Answer 12

Contraction speed: slow for Type I, fast for Type IIB.
Fatigue rate: slow for Type I (fatigue resistant), fast for Type IIB (more rapidly fatigued).
Force generated: smaller twitch force by Type I, larger twitch force by Type IIB.
Mitochondria: many in Type I (aerobic, oxidative), few in Type IIB (anaerobic, glycolytic).

Question 13

Describe the 3 main types of muscle contractions. Which contraction type generates highest forces?

Answer 13

Concentric: muscle shortens
Eccentric: muscle lengthens
Isometric: muscle remains same length

Eccentric produces most force, followed by isometric, then concentric.

Question 14

Describe the physiological process of muscle contraction.

Answer 14

• AP travels down a motor neuron
• Acetylcholine is released at the neuromuscular junction
• AP runs through the sarcolemma of muscle
• AP travels down the T tubules
• Ca2+ released from sarcoplasmic reticulum
• Ca2+ causes actin and myosin to bind
• Sarcomeres shorten
• Muscle contracts

Question 15

Name 4 functions of skeletal muscle.

Answer 15

Produce movement
Maintain posture and body position
Stabilise joints
Generate heat

Question 16

Explain the structural and functional differences between parallel and pennate muscles.

Answer 16

Parallel muscles: Long (straight) muscle fascicles, allows for larger range of motion at joints, but less force production capability.

Pennate muscles: Short (angled) fascicles, smaller range of motion and more force production capability

Question 17

Name and describe the 3 structural classifications of joints.

Answer 17

Structural classification: type of material binding bones together & whether a joint cavity is present
Fibrous joints are connected by fibrous tissue (collagen), do not have a joint cavity and provide little to no movement.
Cartilaginous joints are connected by cartilage, do not have a joint cavity and provide very little movement.
Synovial joints have articulating bones separated by fluid filled joint cavity and provide lots of movement.

Question 18

Explain the factors that influence the stability of synovial joints.

Answer 18

Shape of the articulating surface: how well two bones fit together affects stability.
Menisci/articular discs: improve the ‘fit’ of bone ends within a joint cavity.
Ligaments: hold joint in place and prevent extreme movements, the more ligaments the more stability.
Muscle/tendon tension: if tendons that cross a joint are kept under tension by their muscle contracting, then the joint
is more stable.

Question 19

What are 3 common joint injuries?

Answer 19

Sprains (stretched or torn ligaments)
Dislocations (bones forced out of alignment)
Cartilage tears (compression and shear stress)

Question 20

Differentiate between osteoarthritis and rheumatoid arthritis.

Answer 20

Osteoarthritis is chronic and degenerative, due to ‘wear and tear’. Cartilage is destroyed more than is replaced.
Rheumatoid is chronic and inflammatory, is autoimmune. Results in inflammation of synovial membrane, erosion of
cartilage and scar tissue formation

Question 21

Classify the shoulder (glenohumeral joint, GHJ) and elbow joints both structurally and functionally.

Answer 21

GHJ: Structural classification is synovial ball and socket, Functional classification is multiaxial diarthrosis.
Elbow: Structural classification is synovial hinge, Functional classification is uniaxial diarthrosis.

Question 22

Name the muscles that move the pectoral girdle.

Answer 22

Pectoralis minor, serratus anterior, trapezius, levator scapulae, rhomboid major and minor.

Question 23

Name the muscles that comprise the rotator cuff group.

Answer 23

Supraspinatus, infraspinatus, subscapularis, teres minor.

Question 24

What are the four muscular compartments of the upper limb? What functional groups of muscles do they (primarily) contain and name some muscles in each group.

Answer 24

Anterior arm, flexors, e.g., biceps brachii, brachialis.
Posterior arm, extensors, e.g., triceps brachii, anconeus.
Anteromedial forearm, flexors, e.g., flexor carpi ulnaris and radialis.
Posterolateral forearm, extensors, e.g., extensor pollicis longus and brevis

Question 25

Classify the hip and knee joints both structurally and functionally.

Answer 25

Hip: Structural classification is synovial ball and socket, Functional classification is
multiaxial diarthrosis.
Knee: Structural classification is synovial hinge, Functional classification is uniaxial
diarthrosis.

Question 26

What are the three compartments of the thigh? Name the muscles in each. How does each compartment (in general) move the knee joint?

Answer 26

Medial (Adduction): Adductor longus, adductor brevis, adductor magnus, gracilis,
pectineus.
Anterior (Extension): Sartorius, rectus femoris, vastus lateralis, vastus medialis, vastus
intermedius.
Posterior (Flexion): Biceps femoris, semitendinosus, semimembranosus

Question 27

What are the three compartments of the leg? Name the muscles in each.

Answer 27

Anterior: Tibialis anterior, extensor digitorum longus, extensor hallucis longus,
fibularis tertius.
Lateral: Fibularis longus, fibularis brevis.
Posterior: Gastrocnemius, soleus, plantaris, tibialis posterior, flexor digitorum longus,
flexor hallucis longus, popliteus.

Question 28

Describe the actions of some muscles of facial expression.

Answer 28

Occipitofrontalis: raise eyebrows and wrinkle forehead
Orbicularis oculi: close eyelids/blinking
Orbicularis oris: close mouth
Buccinator: compress cheeks

Question 29

Name the muscles of mastication. What joint do they act at?

Answer 29

Masseter, temporalis, medial pterygoid, lateral pterygoid. They move the temporomandibular joint (TMJ).

Question 30

Name the muscles that comprise the erector spinae muscle group.

Answer 30

Longissimus, Iliocostalis, Spinalis

Question 31

Name and describe the actions of the intercostal muscles.

Answer 31

External intercostals; elevate ribs during (resting) inspiration.
Internal intercostals: depress ribs during (forced) exhalation.