ANAT2012 definitions Flashcards Preview

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Flashcards in ANAT2012 definitions Deck (112):
1

cleavage

rapid mitotic division of zygote

2

blastomere

mitotic cleavage product of zygote

3

morula

precursor of blastocyst

4

blastocyst

structure containing embryoblast, walled by trophoblast

5

trophoblast

part of blastocyst which forms placenta

6

embryoblast

part of blastocyst which forms embryo

7

conception

implantation (7-10 days after fertilisation)

8

stress

force/area

9

strain

extension/original length

10

Young's modulus/modulus of elasticity

stress/strain

11

parathyroid

enhances Ca2+ release from bone
indirectly stimulates osteoclast activity

12

calcitonin

inhibits Ca2+ absorption in intestines
inhibits osteoclast activity

13

elasticity

the ability of a solid to recover its shape when deforming forces are removed

14

viscoelasticity

materials for which the relationship between stress and strain depends on time

15

creep

if the stress is held constant the strain increases with time

16

stress relaxation

if the strain is held constant, the stress decreases with time

17

cyclic loading

application of repeated stress or strains

18

mechanotransduction

bone remodelling process due to stressors applied

19

anisotropy

the property of being directionally dependent

20

windlass mechanism

winding of the plantar fascia shortens the distance between the calcaneus and metatarsals to elevate the medial longitudinal arch

21

hysteresis

the energy put into the tissue is more than that recovered (lost as heat)

22

complex joint

contains intracapsular disc, labrum or meniscus

23

osteokinematics

movement of bones (not joints)

24

arthrokinematics

movement of joints (no reference to forces)

25

anatomical axis

related to structure (eg. longitudinally through long bone)

26

mechanical axis

related to joint (perpendicular to joint surfaces)

27

spin

mechanical axis is centre of rotation

28

slide

orientation of mechanical axis does not change, position does

29

roll

orientation of mechanical axis constantly changing

30

chondral-apophyseal enthesis

more zones
small attachment sites

31

periosteal-diaphyseal enthesis

less zones
large attachment sites

32

mechanobiology

mechanical load influencing the structure of MSK tissue

33

tribology

the science of interacting surfaces in relative motion

34

boundary layer lubrication

few molecules thick
relies on chemical properties

35

fluid film lubrication

finite thickness
relies on physical properties

36

medial and ventral motorneuron pools

proximal limb

37

dorsal and lateral motorneuron pools

distal limb

38

central pattern generator

a flexible network of interneurons than can produce purposeful movement in response to stimulus

39

inhibatory neurotransmitter

GABA
glycine

40

excitatory neurotransmitter

glutamatergic

41

pacemaker cell

triggers rhythmic activity of non-pacemaker cells

42

V0 interneuron

left-right alternations

43

V1 interneuron

locomotor rhythm regulation

44

V2a interneuron

left-right alternations
rhythm robustness

45

V3 interneuron

rhythm robustness

46

Hb9 interneuron

rhythm generation

47

mesencephalic locomotor region

controls intensity of locomotion
influences CPG via reticular formation and reticulospinal tract

48

supraspinal structures and CPG

activate, modulate and silence CPG

49

motor unit recruitment order

type I > type IIa > type IIb

50

effect of firing frequency

increased firing frequency, increased force

51

effect of motor unit synchronisation

enhanced rate of force development (explosive strength)

52

muscle-tendon unit components

contractile component (muscle)
series elastic component (tendon)
parallel elastic component (connective tissue)

53

stretch-shortening cycle

successive combination of concentric and eccentric contractions --> greater force and power

54

utilisation of stored elastic energy

energy stored in series elastic component used to increase mechanical energy in next concentric contraction

55

autogenic inhibition

reduction in excitability of a contracting or stretched muscle (used in contract-relax)

56

reciprocal inhibition

contraction of opposing muscles reduces activation of target muscles --> descending commands excite inhibitory interneurons of target muscles (used in hold-relax)

57

superficial layer of hyaline cartilage

type II collagen parallel to surface
reduces friction

58

middle layer of hyaline cartilage

collagen in lattice
permits deformation

59

deep layer of hyaline cartilage

collagen perpendicular to surface
anchors to bone

60

hemorrhagic phase of tendon/ligament healing

1st phase
gap fills with blood clot
lymphocytes and leukocytes increase inflammatory response

61

inflammatory phase of tendon/ligament healing

2nd phase
macrophages predominant cell type
induces vascularisation and granulation

62

proliferative phase of tendon/ligament healing

3rd phase
fibroblasts produce collagen

63

remodelling and maturation phase of tendon/ligament healing

4th phase
decreased cellularity
tissue becomes more dense and longitudinally orientated

64

enthesis

joint between hard and soft surfaces

65

enthesis organ

a collection of tissues at and near enthesis which serve to dissipate stress

66

multi-enthesis organ

two or more neighbouring tendons/ligaments share and enthesis (eg. popliteus and LCL)

67

enthesopathy

overuse injury of enthesis

68

instantaneous centre of rotation

COR moves throughout movement due to ovoid joint surfaces

69

helical axis of motion

the movement of a joint's axis of rotation in 3D space

70

compound joint

more than one joint within a joint capsule (eg. elbow)

71

simple joint

one pair of articulating surfaces

72

toe region

straightening of crimped ligament fibres

73

elastic region

tissue will return to original shape

74

yield point

point of permanent deformation (between elastic and plastic regions

75

plastic region

tissue is permanently deformed

76

ultimate stress

point of failure

77

ultimate strain

breaking point

78

toughness

amount of energy per volume a material can absorb before failure (area under curve)

79

brittle break

linear stress/strain curve, no yield until ultimate stress

80

ductile break

gradual yield before failure

81

stiffness

ability to resist deformation

82

compliance

undergoing elastic deformation in response to force

83

stiffness/toughness trade-off

the more stiff a material becomes, the more brittle it becomes (less tough) --> ie bone

84

safety factor

how much stronger a material is compared to its intended load
SF = max force/applied force x 100%

85

mechanocoupling (1st step mechanotransduction)

force causes physical perturbation of cells

86

cell-cell communcation (2nd step mechanotransduction)

perturbation transformed to chemical signal which is communicated to distant cells

87

effector cell response (3rd step mechanotransduction)

tissue remodels in response to stimulus

88

endoderm

forms epithelial linings of digestive and respiratory tracts

89

ectoderm

forms skin epidermis, nervous system, hair, nails

90

mesoderm

forms connective tissue, bones, muscle, blood vessels, cartilage

91

somite

a segment of mesoderm arranged along the neural tube of an embryo

92

sclerotome

part of somite giving rise to skeletal tissue

93

dermatome

part of somite giving rise to connective tissue of skin

94

myotome

part of somite giving rise to skeletal muscle

95

differentiation

to become more specialised

96

modulation

adaptation of a cell to its environment

97

induction

specific change of shape of an embryo

98

notochord

a cylindrical cord of cells marking the longitudinal axis (signalling centre)

99

apical ectodermal cells

signalling centre at distal end of each limb bud

100

fibrous joint development

mesenchyme between developing bones differentiates into fibrous connective tissue

101

cartilaginous joint development

mesenchyme between developing bones differentiates into hyaline cartilage or fibrocartilage

102

synovial joint development

peripherally, mesenchyme gives rise to capsule and ligaments (DRCT)
centrally, mesenchyme disappears creating joint space
on articular surfaces and capsular surfaces mesenchyme forms synovial membrane --> worn away on articular surfaces due to movement

103

vertebral segmental defects

vertebrae fuse together, either partially or fully

104

vertebral formation defects

vertebrae do not fully form, creating wedging or contouring of spine

105

spina bifida occulta

no spinous process formed

106

spina bifida meningocele

meningeal sac squeezes through spine, causing cyst

107

spina bifida meningomyelocele

spinal cord goes into meningeal cyst, stretching nerve roots

108

spina bifida myelocele

secretion of CSF out of spine

109

spina bifida syringomyelocele

spinal cord goes into meningeal cyst and does not develop properly

110

mechanisms of congenital scoliosis

failure of segmentation
failure of formation

111

mechanisms of congenital kyphosis

failure of segmentation
failure of formation
dislocation of spine due to rotation

112

mechanisms of congenital lordosis

failure of segmentation posteriorly