Locomotor

Question 1

Use anatomical terms to correctly describe the position or orientation of parts of the body.

Answer 1

○ Abaxial – away from longitudinal axis
○ Axial – towards longitudinal axis

○ Palmer – rear surface of forepaw
○ Plantar – rear surface of hind paw

○ Medial – towards median plane
○ Lateral – away from median plane

○ Rostral – towards nose
○ Cranial – towards head
○ Caudal – towards tail

○ Distal – away from body
○ Proximal – closer to body

○ Dorsal – towards the spine/top (up)
○ Ventral – towards the tummy/ground (down)

Question 2

Use appropriate terminology to describe the view of an Anatomical Terminology photograph or medical image (e.g. X ray, CT scan).

Answer 2

○ Median/Mid-sagittal – symmetrical left & right

○ Sagittal/parasagittal/paramedian – unsymmetrical left & right

○ Transverse – divides cranial/caudal OR distal/proximal (cross section)

Question 3

Describe how bipedal and quadrupedal animals are adapted for posture and movement.

Answer 3

○ Quadrupeds
§ Stability (large base of support)
§ Differentiate function (forelimbs manoeuvrability, hindlimbs power)

○ Bipedal
§ Free thoracic forelimbs (flight, prehension, brachiation)
○ Large feet (wide base of support)

Question 4

Explain major similarities and differences in body form between bipeds and quadrupeds.

Answer 4

○ Quadrupeds
§ Elbows & knees oppositely orientated (homologous joints)
§ Larger proximal mass & springier in hindlimb
§ Forelimb uprightness

○ Bipedal
§ Walking – long HL & short FL, plantigrade, upright spine (centre of mass)
§ Jumping – crouched limbs, proximal muscle mass, thin distal limbs
§ Flight – HL perch body weight & catch prey, FL wings

Question 5

Discuss anatomical adaptations of animals for specific functions.

Answer 5

○ Cheetah (Carnivore) – powerful psoas muscles, HL bone long (longer strides)

○ Horse (Ungulate) – long limbs (long distance), distal limb low mass (stride rate), limb elongation (stride length)

○ Capybara (Rodent) – HL soleus muscle for water propulsion, semi aquatic

Question 6

What the major patterns and processes in evolution are

Answer 6

○ Patterns
§ Anagenesis – gradual linear transformation of 1 species into another
§ Cladogenesis – rapid branching of species (2+ spit at each node)

○ Processes
§ Sources of variation (prodigy produced)
□ Mutation, recombination, phenotypic plasticity & constraints
§ Modifiers of variation (next gen prodigy)
○ Natura selection, sexual selection, genetic drift

Question 7

How a phylogeny is used

Answer 7

○ Diversification of lineages through evolution

○ Computer algorithms find pattern (phylogeny) that represents best estimate of evolutionary patterns

○ Shared novel traits (not primitive traits)

○ Track pattern of trait evolution at any scale

○ Test convergent evolution

Question 8

What adaptation is, and what about evolution is non-adaptive

Answer 8

○ A trait that enhances fitness and that arose historically as a result of natural selection for its current biological role.

○ Key innovators lead to adaptive radiation (explosion of speciation at a lineage) = phenotypical & ecological diversification

○ Non-adaptive forces are primarily random & not influenced by environment (mutation, genetic drift, and recombination)

Question 9

Why evolution is relevant to vet students

Answer 9

○ host parasite, drug disease arms races

○ phylogeny similarity - similar treatments work better on closely related species

○ Harnessed by humans for breeding artificial selection (health problems arise when animal experience environments they did not evolve in)

Question 10

Classify bone according to shape (e.g. long bones, flat bones), and giving examples explain how shape relates to function.

Answer 10

Long - Cylinder (longer than wide), Leverage, e.g. Femur, tibia, fibula

Short - Cube (approx. equal lengths), Stability, support & some motion, e.g. Carpels & tarsals

Flat - Thin and curved, Points for muscle attachment & protect internal organs e.g. Ribs, cranial bones

Irregular - Complex shapes, Protect internal organs, Vertebrae & facial bones

Sesamoid - Small & round (embedded in tendons), Protect tendons from compressive forces, e.g. Patellae

Question 11

Describe the macroscopic architecture of bone and explain how this organisation relates to function

Answer 11

○ Periosteum – thin layer of connective tissue lining outside of bone

○ Cartilage – flexible material at bone edges to absorb impact

○ Epiphysis – next to cartilage at bone end, houses red bone marrow (RBC produced)

○ Epiphysis plate – next to epiphysis, extra bone produced to elongate pre-puberty

○ Metaphysis – contain epiphysis plate, expands neck region

○ Diaphysis – in main bone shaft, house bone marrow, site of ossification

Question 12

Recount the anatomical relationship between bone and peri- and endosteum. Describe the functions of these tissues.

Answer 12

○ bone is an organ and therefore subject to continual adaptation processes.

○ Bone Function
§ Cortical (compact) bone – thick, dense & stiff
§ Trabecular (spongy) bone – cobweb, less dense , handle loads in loco

○ Periosteum/Endosteum Function
§ Peri – blood supply, bone rescaling & maintenance, lines outside
○ Endo – lines inside cavity in long bones outside the medullary cavity

Question 13

(part 1) Describe gross skeletal muscle and tendon structure and how muscle and tendon are arranged in the locomotor system

Answer 13

○ Gross Skeletal Muscle Structure
§ Origin – where muscle directly attaches to bone (top)
§ Muscle belly – thick fleshy central part & tapers at each end (proximal)
§ Connective tissues – between muscle fibres
§ Tendon – attaches muscle to bone in insertion site (distal)
§ Aponeurosis – bridge between muscle/tendon
○ Insertion – site on bone where tendon attaches

Question 14

(part 2) Describe gross skeletal muscle and tendon structure and how muscle and tendon are arranged in the locomotor system

Answer 14

○ Skeletal Muscle Arrangement (striated)
§ Aponeurosis – bridge between muscle/bone OR muscle/tendon
§ Epimysium – thin connective tissue that binds muscle belly together
§ Muscle belly – thick fleshy central part & tapers at each end
§ Perimysium – connective tissue binding each fascicle
§ Fascicle – bundle of muscle fibre subunits
§ Endomysium – surround muscle fibres
§ Sarcolemma – cell membrane around muscle fibres
§ Muscle fibre – primary muscle cell unit
□ Sarcomas – series of myofilaments between z lines
□ Myofibril – multiple peripheral nuclei
○ Contractor proteins – actin & myosin

Question 15

(part 3) Describe gross skeletal muscle and tendon structure and how muscle and tendon are arranged in the locomotor system

Answer 15

Tendon Structure
○ Proximal – short & fat
○ Distal – long & thin

○ Triple helix - 3 polypeptide chains
○ Collagen fibril – multiple triple helices
○ Collagen fibre – multiple fibrils
○ Subfascicles – multiple fibres

Question 16

Discuss the roles/functions of muscle in the body and particularly in locomotion & compare and contrast the structure of skeletal, smooth and cardiac muscle

Answer 16

○ Muscle roles
§ Tendon – minimise distal limb mass, elastic energy storage, direct join
muscle power to bone
§ Skeletal – joint movement & stabilisation, posture control, shivering
§ Smooth – mastication, swallowing, digestion, birthing, dilation/constriction
§ Cardiac – maintain cardiac rhythm

○ Muscle Structure
§ Tendon – triple helix strands creating collaged fibres
§ Skeletal – myofibril fibres containing contractor proteins actin & myosin
(striated)
§ Smooth – un-striated, involuntary, long spindle-shaped cells, surrounding
connective tissue bind cells into sheets/layers
○ Cardiac – striated & cylindrical, involuntary, cells branch & create fibrous network

Question 17

Explain how tendon contributes to locomotion

Answer 17

○ Tendon springs – store & release elastic energy = economical distal limb

○ Power amplifiers – stretched tendon recoils faster than muscle = higher power output

○ Minimise distal limb mass (horses) – swing efficiently

○ Joins muscle direct to bone – muscle forces transmit to skeleton efficiently

Question 18

Describe muscle architectural design and explain how this influences muscle function

Answer 18

○ Pennate muscles
§ feather-like fibre arrangement
§ short fibres orientated towards muscle axis
§ able to pack in more sarcomere contractile units = increase muscle PCSA &
force (economical)
§ e.g. serratus ventralis – attaches scapula to trunk

○ Parallel muscles
§ Fibres run directly parallel to muscle axis
§ More sarcomeres in series = higher muscle fibre shortening
§ Moves joints in a greater range of motion
§ E.g. pectoral muscle – retract limb

Question 19

Describe the basic structure of a synovial joint and the tissues of which a synovial joint is composed & explain how joint tissue and structure facilitate effective joint function

Answer 19

○ Ligament – stabilise joint (outside & inside joint)

○ Joint cavity – synovial fluid filled space that surrounds whole joint & separates the two bones

○ Fibrous tissue layer – protects joint cavity

○ Synovial membrane – lines joint cavity & secretes synovial fluid

○ Synovial fluid – lubricates joint & provides nutrition for hyaline articular cartilage ends of the bones

○ Articular hyaline cartilage – bone interface at synovial joint, low friction, no nerves/blood vessels

○ Menisci – increase range of movement & shock absorbers (2 in stifle joint)

○ Bursae – synovial fluid sacs (found in other joint types), reduce friction

Question 20

Classify synovial joints according to their action. Give examples of types of synovial joints in the body.

Answer 20

Planar - Gliding, Slide bony surface over another, Between rows of carpal/tarsal bones

Hinge - Uniaxial, Movement in 1 plane, Humeroulnar

Pivot - Uniaxial, Peg in ring (rotation), Atlantoaxial joint

Condylar - Biaxial, Convex surface sitting on concave surface, Tarsus/hock & femorotibial (stifle)

Saddle - Biaxial, Convex & concave surfaces @ right angle, Distal interphalangeal (dog claw flex & extend)

Ball & Socket - Triaxial, Big movement range, Hip and shoulder

Question 21

List the molecular components of the Extracellular Matrix (ECM) and discuss their structural and mechanical properties.

Answer 21

○ Network of secreted macromolecules – maintains integrity, protection, cell communication

○ Elastin – allows deformation, coiled when relaxed, cross linked when stretched

○ Collagen – triple helix = high tensile strength (microfibrils –> fibrils –> fibres)

○ Glycosaminoglycans (GAGs) – anti-compressive hydrophilic, lubricant e.g. synovial fluid

○ Proteoglycans = Gag + protein, anti-compressive e.g. keratin sulfate & chondroitin sulfate

Question 22

Describe and compare the macro and microscopic structure of different musculoskeletal tissues (bone, tendon, ligament, cartilage, muscle).

Answer 22

○ Bone, tendon, muscle, ligament see previous answers

○ Cartilage structure
§ Superficial tangential zone = 85% collagen to resist tension by shearing
§ Middle transitional zone = mostly proteoglycans, oblique arranged collagen,
transition from shearing to compressive forces
○ Deep radial zone = collagen fibres vertical to resist compression forces

Question 23

Explain how the gross structure and molecular and cellular composition of musculoskeletal tissues relate to their function and mechanical properties.

Answer 23

○ Cell types (blasts, clasts & cytes) & functions
§ Tendon (TENO) = store & release elastic energy, economical locomotion
§ Ligaments (FIBRO) = stabilise joints
§ Cartilage (CHONDRO) = mechanical joint loading, resist tension produced
by shearing
§ Bone (OSTEO) = cytes support/maintain structure, blasts synthesise matrix,
clasts absorb bone

○ Cellular composition
§ Tendon – collagen type 1 (86%), proteoglycan (15%), elastin (2%), water
§ Ligament – collagen type 1 (75%), proteoglycan (15+%)
§ Cartilage – collagen type 2 (90%), proteoglycan (10-20%), water (68%)
○ Bone – collagen type 1 (90% of 30% organic component), hydroxyapetite
(organic)

Question 24

Describe the influence of mechanical loading on ECM turnover and tissue adaptation processes.

Answer 24

○ ECM constant turn over due to mechanical loading
§ - cytes = transmits forces to cells
§ – blasts = experience force & build more tissue or will signal
§ – clasts = receive signal & produce response

○ Tissue adaptation
§ Mesenchymal cells – undifferentiated stem cells
§ Cells differentiate under mechanical loads
§ Tendons & ligaments – pulled unidirectional
○ Cartilage – compressed one side & pulled the other (omnidirectional)

Question 25

Specify the cellular and molecular composition of bone tissue

Answer 25

○ Osteocytes = support/maintain structure

○ Osteoblasts = synthesise matrix

○ Osteoclasts = absorb bone

Question 26

Describe the process of bone formation in the developing animal

Answer 26

○ Intramembranous ossification
§ Flat bone – osteoblasts lay down between 2 layers of fibrous connective
tissue with no cartilage template

○ Endochondral ossification
§ Bone collar formation around hyaline cartilage model
§ Primary ossification centre in diaphysis bone region
□ Mesenchymal tissue excrete pre-mineralised ECM (osteoid) = bone
precursor tissue
§ Cartilage replaced with bone via osteoblasts & extends to bone edges
§ Secondary centre of ossification at epiphysis region
§ Osteoclasts remove bone rom centre of diaphysis to form medullary cavity
○ Artery invasion & blood vessel formation (vascularise tissue)

Question 27

Describe the process of bone growth in the young animal

Answer 27

○ Epiphysial growth plate allows bone to lengthen while animal grows

○ LHS EGP high number of chondrocytes

○ Cells increase in number & size (hypertrophy) & elongates from LHS across diaphysis region

○ Final size – EGP becomes a line & changes function

Question 28

Discuss nutritional and hormonal factors that can affect bone growth

Answer 28

○ Nutritional factors
§ Dietary calcium & phosphate salts
§ E.g. Vitamin A, B12, C, D, K
§ Absorption depends on calcitriol (hormone in vitamin D presence)

○ Hormonal factors
§ Calcitonin & parathyroid hormone calcium = regulate metabolism
§ Insulin, growth hormone & thyroxine = bone growth
○ Oestrogen = growth plate closure & osteoblast activity (ossify cartilage)

Question 29

Describe the process of bone remodelling and explain why it occurs

Answer 29

○ Cyclical process
§ Osteoclasts form & attach to bone matrix
§ Reabsorption - osteoclasts secrete breaking bone down enzyme &
apoptose themselves
§ Reversal – area is populated by osteoblasts
§ Formation – osteoblasts synthesise organic matrix & regulate its
mineralisation, entomb selves into matrix = become osteocytes
§ Forms lamellar bone (strong & slow production) or woven bone (weak &
rapid production)

○ Why it occurs
§ Maintains mechanical strength from microfractures
○ Mineral homeostasis – stores calcium & phosphorus

Question 30

Discuss the trade-offs between locomotor performance and risk of injury.

Answer 30

○ Performance – HL muscle mass, thick long tendons, fast twitch, anaerobic resp, remodelling (support load change)

○ Risk of injury – traumatic single event or repetitive cyclic stress, micro-ruptures to bone fractures

Question 31

Discuss the relationships among loading, use/disuse, tissue damage and repair, and how disruption of the balance among these leads to injury.

Answer 31

○ Loading – overloading stress from a traumatic event overcomes safety factor of structure

○ Repetitive use – cyclic stress induced damage overcomes adjustment/repair capacity

○ Tissue damage & repair – woven bone (quick & weak)

Question 32

Explain the concept of safety factors, and why some structures have lower safety factors than others.

Answer 32

○ Safety factor - limb bones have a capacity to withstand greater loads than they usually experience

○ Lower/higher factors depend on the kind of mechanical load placed upon them

Question 33

Describe the cellular and molecular mechanisms involved in muscle contraction.

Answer 33

○ Calcium ions diffuse from sarcoplasmic reticulum into myofibrils

○ Calcium binds to troponin molecule & changes shape

○ Myosin-binding site on actin now free for ADP + P head

○ Actin & myosin filaments slide over each other

○ cross-bridges form between heads of actin & myosin filaments

○ cross-bridges swing through an arc (pull thin filament past thick ones) = sarcomere shortens

○ binding of ATP onto myosin head = cross-bridges detach from thin filament
release of energy allows myosin head to reattach further away (move back)

Question 34

Describe why skeletal muscle contraction requires energy, and discuss possible sources of this energy.

Answer 34

○ energy needed to produce contractions
○ energy sources
§ 1. Phosphorylation of ADP by creaine phosphate (short duration only)
§ 2. Phosphorylation of ADP in cytosol (anaerobic) (2ATP for every glucose)
○ 3. Oxidative phosphorylation of ADP in mitochondria (aerobic) (34 ATP)

Question 35

Compare the properties of the main types of skeletal muscle fibre.

Answer 35

○ Slow oxidative muscle cells (type 1)
§ Weaker than faster muscle cells but are fatigue resistant
§ Use aerobic respiration (high oxidative capacity)
§ Contract & twitch slower, but sustain forces for a longer duration

○ Fast glycolytic (Type IIb)
§ Twitch very quickly (high ATPase activity)
§ ATP responsible for causing the muscle myosin head to reset
(quicker reset = twitch/move quicker)
§ Good at producing glycolysis (high glycolytic pathway)
§ Large, strong, high force, run out of energy quickly

○ Fast oxidative glycolytic
§ Uses oxidative & glycolytic pathways
§ quicker than type 1 but slower than type2b
§ Decent capacity for oxidative phosphorylation & glycolytic pathway
(aerobic & anaerobic)

Question 36

Name and describe the types of muscle contraction and give examples of when each might be used in a standing or moving animal.

Answer 36

○ Isometric – muscle contract (not shorten) e.g. horse standing stationary

○ Concentric – force exceeds load e.g. pick up leg

○ Eccentric – load exceeds force e.g. place leg back down

Question 37

Recall the basic layout of the nervous system

Answer 37

○ 1. Central (CNS)
§ Brain & spinal cord

○ 2. Peripheral (PNS)
§ Efferent (Motor) - outgoing signals, trigger muscles to contract
□ Somatic (Skeletal muscle) - aware of
□ Autonomic (Cardiac/ smooth muscle, exocrine glands)
§ Afferent (Sensory)
□ Somatic (awareness of)
○ Visceral (unaware of)

Question 38

Describe the structure of a neuromuscular junction

Answer 38

1. Axon - of motor neuron w/ myelin sheath
2. Axon terminal – where axon ends & bulb begins
3. Pre-Synaptic bulb – contains terminal buttons, voltage-gated calcium channels and vesicles of neurotransmitters
4. Synaptic cleft – gap where neurotransmitter is released into
5. Motor end plate – neurotransmitter gated channels, voltage gated potassium channels, acetylcholinesterase

Question 39

(part 1) Discuss the basic mechanism of synaptic communication and the events at a NMJ that lead to an action potential in a skeletal muscle fibre

Answer 39

○ Pre-synaptic axon
o An action protentional (voltage) will come down motor neuron axon
o The action potential jumps down axon due to insulated myelin sheaths
o Reaches axon terminal
· Voltage-gated calcium channels
· Action potential triggers calcium channel proteins to reconfigure &
allow calcium to enter from extracellular matrix into the axon
· Calcium in axon will bond to proteins as it moves to the internal
surface of the axon terminal membrane (towards synapse)
· Calcium & proteins grab vesicles & fuse the vesicles to the membrane
& release their contents into the synaptic gap in high density

○ Synaptic gap
· Passive stage - waiting for red acetylcholine molecules within the vesicles
to float down & interact with sarcolemma
§ Importance of large surface area & a short gap - diffusion
distance across does slow it down

○ Fast animal movements = short gap, many acetylcholine molecules released, large surface area & many receptors to receive the acetylcholine

Question 40

(part 2) Discuss the basic mechanism of synaptic communication and the events at a NMJ that lead to an action potential in a skeletal muscle fibre

Answer 40

○ Post-synaptic
· Acetylcholine bonds to ligand-gated channels (respond to interaction with
other molecules)
· Ligand-gated channels allows
§ large amounts of sodium into the muscle cells
§ Small amounts of potassium out of muscle cells
· After sodium enters the cells, a new voltage potential is produced across
cell membrane
§ which stimulates voltage-gated sodium channels
· This allows more sodium in & action potential will travel rapidly &
propagate across cell until it completes
§ Causes muscle cells to be depolarised

○ Acetylcholinesterase protein
§ Mechanism to stop passively diffusing acetylcholine from bonding to ligand-gated sodium-potassium channels
§ Enters extracellular matrix, bonds to sporadic acetylcholine & breaks them down to stop stimulating ligand-gated channels

Question 41

Explain the mechanism of excitation contraction coupling

Answer 41

○ Muscle action potential propagates an voltage differential into T tubule along cell membrane

○ Depolarisation of T-tubule causes opening of calcium channels between myosin & S.R.

○ Calcium released from Sarcoplasmic Reticulum

○ Calcium binds to troponin C

○ Affects tropomyosin & allow myosin start bonding to the actin & begin walking along actin strand pulling tropomyosin filaments together causing muscle contraction

Question 42

Appreciate the concept of a skeletal muscle motor unit

Answer 42

○ how the nervous system controls the force generating capacity of muscles

○ Array of muscle fibres innervated by multiple different motor units

○ ratio of number of muscle fibres being triggered by each motor units determine how fine of an actuation is

Question 43

Describe the role of the forelimb in locomotion

Answer 43

○ Roles – manoeuvrability, weightbearing, support & stability

○ Thoracic limb has evolved into a supporting structure of locomotor system

○ Thoracic girdle is reduced in cursors

○ Scapula slides on rib cage

○ Humerus large and robust

○ Radio ulnar articulation reduced/absent

Question 44

Discuss differences in forelimb anatomical structure between the major veterinary species and how this relates to their locomotor behaviour

Answer 44

○ Distal forelimb
Horse – minimise mass, store & release elastic energy, less requirement to control loss of digits

○ Tendon & ligaments
Horse – long, elastic flexor tendons (deep digital & superficial digital)
Dog – coupled with large proximal muscles (muscle control over digits)

○ Interosseus muscle
Horse – none (only one digit)
Dog – possess a lot to allow for individual movement of each digit

○ Foot & digits
Horse – hoof (keratin) = ungulate
Dog – digitigrade (bears weight on digits), metacarpal pads

Question 45

Describe the role of the pelvic limb in locomotion

Answer 45

○ Pelvic limb = fixed to trunk via sacroiliac joint

○ Proximal pelvic limb robust = Enable to withstand loads imposed on them

○ Thoracic limb = Support weight and turning and breaking

Question 46

Discuss differences in pelvic limb anatomical structure between the major veterinary species and how this relates to their locomotor behaviour.

Answer 46

○ Equine hindlimb
· Huge propulsive muscles (gluteals and hamstrings)
· Patella locking
· Reciprocal apparatus
· Reduced number of bones
· Increased tendons distally
· angular proximal limb, short robust femur, long & upright distal limb

○ Canine hindlimb
	· joint stops to take more angulation
	· weight based solely on digits
	· calcaneus for weight support
	· More RoM at ankle and foot = more muscles

○ Plantigrade hindlimb
· hind foot fully contact with ground
. long non-angular upper limb bones

Question 47

Describe the kinetics and kinematics of fore and hind limbs during the stride cycle

Answer 47

○ Forces (kinetics) – GFR (support animal weight), muscle forces (limb movement), joint contract forces

○ Stance phase – high GRF, stabilise joint, resist over-extension of distal joint

○ Swing phase – no GRF, protract limb, clear foot off ground, prepare for stance

Question 48

Know which muscle groups contribute to the various stages of the stride cycle

Answer 48

○ Hamstring group (hindlimb) – extend hip & flex stifle (main forward thrust)

○ Pectoral group (forelimb) – protracts, retracts & abducts forelimb

Question 49

Compare the basic differences between gaits based on i) footfall patterns and ii) biomechanical principles

Answer 49

○ Walking
· FF – RH,RF,LH,LF
· Biomechanics – out of phase kinetic & potential energy

○ Trotting
· FF – alternately balanced on diagonally opposite feet (LF/RH then RF/LH)
· Biomechanics – in phase kinetic & potential energy (due to elasticity)

○ Canter/Gallop
· FF – floating phase underneath body
. Biomechanics – minimise collision forces

Question 50

Explain why animals might chose to use particular gaits

Answer 50

○ Minimise GFR - reduce fatigue & musculoskeletal tissue impact

○ Energy efficient – change when oxygen consumption becomes costly

Question 51

Appreciate how gait may differ from the norm due to injury/pathology

Answer 51

○ Forelimb lameness – nods head when non-lame leg impacts the ground

○ Hindlimb lameness – asymmetry vertical movement

Question 52

Explain how the musculoskeletal system is arranged in animals adapted for terrestrial locomotion.

Answer 52

○ Bones, joints, cartilage, tendons, ligaments & muscles (See previous answers)

Question 53

Explain the role of tendon in locomotion and how it interacts with muscle to enhance efficiency and power output.

Answer 53

○ minimise distal limb mass

○ elastic energy storage

○ attached to muscle and bone – enhances muscle power to bone

Question 54

Discuss difference in limb morphology between different classes of mammal.

Answer 54

○ Plantigrade - surface of the whole foot touches the ground during locomotion

○ Digitigrade – only phalanges touch the ground

○ Unguligrade – singular toe touches ground

Question 55

Relate cost of locomotion to mode of transport, body mass and morphology.

Answer 55

○ Swimming – lowest cost (energetically cheap)

○ Flying – energetically expensive but fast

○ Running – most expensive, moving centre of mass not smooth, support body weight (slows down)

○ Body mass – smaller the animal, more costly the locomotion