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Phase 2 Limbs & Back > Week 3 > Flashcards

Week 3 Flashcards

1
Q

How many bones are in the human wrist?

A

27 in each wrist

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2
Q

How many carpals are there?

A

8 in each hand

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3
Q

Name the bones here

A
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4
Q

How many metacarpals in each hand?

A

5

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5
Q

How many phalanges in each hand? Distrbution?

A

14
3 in each digit, 2 in thumb

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6
Q

Name the different joints in the hand

A

Carpometacarpal joint
Metacarpalphalangeal joint
Interphalangeal joint

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7
Q

What do proximal carpal bones form? What do they articulate with?

A

Proximal carpal bones form convex surface
Articulate with concave surface of radius and articular disc NOT ulna

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8
Q

Function of fascia in hand?

A

Hold tendons, nerves and Blood vessels close to bones

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9
Q

Name of fascia in hand? Function? Structure? prevents?

A

Retinacula
Thick deep fibrous band of connective tissue
Holds tendons down and prevents bowstringing during flexion and extension

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10
Q

Which retinaculum covers anterior carpal bones? What passes under this?

A

Flexor retinaculum
FLexor tendons and median nerves pass under (carpal tunnel)

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11
Q

Which retinaculum covers dorsal carpals? What passes under here?

A

Extensor retinaculum
Extensor tendons of hand and digits pass under

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12
Q

What is the floor of the carpal tunnel made from? Covered by?

A

Concave arch of carpal bones
Covered by extrinsic palmar ligaments

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13
Q

What is the roof of the carpal tunnel made from? Attached to?

A

Flexor retinaculum
Scaphoid, trapezium, pisiform, hamate

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14
Q

Contents of carpal tunnel?

A

9 flexor tendons
vascular synovium
median nerve (superficial to tendons)

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15
Q

Which flexor tendons are in the carpal tunnel?

A

Flexor pollicus longus tendon
4 flexor digitorum profundus tendons from forearm and attaches to fingers
4 flexor digitorum superficialis tendons to fingers

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16
Q

Non prehensile movements of the hand? Meaning of this?

A

Not specialised for humans e.g. chimps can do it too
Pushing
Hitting with flat hand

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17
Q

Prehensile movements of the hand?

A

Grasp and grip
Fundamental movements
Depends on positioning of fingers and thumb

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18
Q

2 types of grip?

A

Power and precision

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19
Q

What is a power grip? Allows? Strong or weak? Muscles involved? Wrist position?

A

Grasp in palm of hand
Allows holding of tool or punching with fist
Strong
Long extrinsic flexors of fingers and intrinsic muscles in palm
Wrist extended for strength, allows tendon strength

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20
Q

What is a precision grip? Between what? Muscles involved?

A

Fine control of manipulative movements - holding pen
Grips between tips of fingers and thumb (opposition)
Often between thumb and index finger, may involve middle e.g. holding pen
Holding of pen: extrinsic flexors and extensors
Precision from intrinsic muscles

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21
Q

What is between carpals and ulna?

A

Articular disc

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22
Q

What bones are involved at metacarpophalangeal joints? Movements?

A

Metacarpals and proximal phalanges
Flexion/extension = waving bye
Abduction/adduction = move fingers apart

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23
Q

What bones are involved at interphalangeal joint? Movements?

A

Proximal = proximal and middle
Distal = middle and distal
Flexion/extension = curl and straighten digits

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24
Q

Name each of these movements

A
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25
Q

What are thumb movements between?

A

Trapezium and 1st metacarpal

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26
Q

Where are instrinsic muscle bellies? Muscles included in intrinsic category? What movements do instrinsic muscles allow?

A

Belly inside palm
Lumbricals and interossei
Instrinsic movements and precision grip

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27
Q

Where are extrinsic muscle bellies found? Muscles involved in this category? Important when? Where do tendons enter hand? Where is transverse digit found?

A

Belly outside hand, in forearm
Long flexors and extensors
Important for power grip due to being larger than intrinsic muscles
Tendons enter hand deep to retinaculi
Transverse digit in fibrous sheath

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28
Q

2 superficial flexors of fingers (extrinsic)? Arise from where? Where do they pass? Supplied by, exception?

A

Palmaris longus and flexor digitorum superficialis
Arise from common flexor origin
Some also attach to ulna coranoid process
Pass anterior to elbow
Supplied by median nerve except flexor carpi ulnaris

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29
Q

Flexor carpi ulnaris nerve supply?

A

Ulnar nerve

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30
Q

What is the common flexor origin?

A

Medial epicondyle of humerus

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31
Q

Palmaris Longus:
- Origin?
- Insertion?
- Movements?
- Innervation?

A

Medial epicondyle
Flexor retinaculum of wrist
Flexion at the wrist weakly
Median nerve
Absent in 15% population

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32
Q

Flexor Digitorum Superficialis
- Origin?
- Insertion?
- Actions?
- Innervation?
- Deepest of?
- Where is belly found?

A
  • Common flexor origin
  • Splits into four tendons at wrist, pass through carpal tunnel and attach to proximal phalange bones, not thumb
    Median nerve
    Flexion at proximal IP joint and Metacarpal phalangeal joint
    Deepest of superficial flexors
    Belly in anterior forearm
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33
Q

2 deep extrinsic flexors of the fingers? Arise from?

A

Flexor digitorum profundus and flexor pollicus longus
Arise from radius and ulna bone

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34
Q

Flexor Digitorum Profundus
- Origin?
- Insertion?
- Movements?
- Innervation?
- Deep to?

A
  • Ulna and interosseus membrane
  • Splits into 4 tendons at wrist, passes through carpal tunnel, attaches to distal phalanges of each digit
  • Flexion at distal IP joints
  • Median (middle/index) and ulnar nerve (little/ring)
    Deep to FDS
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35
Q

Flexor pollicus longus origin and attachments? Actions? Innervation?

A

Originates from anterior surface of radius and interosseus membrane
Passes through carpal tunnel and attaches to base of distal phalange of thumb
Flexes interphalangeal and metacarpophalangeal joint of thumb
Innervated by median nerve

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36
Q

Superficial extrinsic extensors of fingers? Arise from?

A

Extensor digitorum and extensor digiti minimi
Common extensor origin

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37
Q

What is the common extensor origin?

A

Lateral epicondyle of humerus

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38
Q

Extensor digitorum attachments and insertion? Actions? Innervation?

A

Originates from lateral epicondyle of humerus.
Tendon divides into four in distal forearm and inserts into distal and middle phalanges of each digit
Extension of digits at interphalangeal and metacarpophalangeal joints
Innervated by radial nerve
On posterior of hand

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39
Q

Extensor digiti minimi attachments and insertion? Actions? Innervation?

A

Originates from common extensor origin
Attaches to distal and middle interpahlangeal joints
Extends little finger
Radial nerve

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40
Q

Deep extrinsic extensors of the hand? Function? Arise from? INserts on? Innervation?

A

Extensor indicis
Extends digit 2
Arises from posterior ulna
Inserts on extensor expansion of digit 2
Innervated by deep radial nerve

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41
Q

What is the extensor expansion/hood?

A

Proximal to metacarpophalangeal joint
All extensor tendons join triangular expansion to form hood over joint

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42
Q

4 extrinsic muscles of the thumb? Anetior or posteiror?

A

Flexor pollicus longus = ant
Extensor pollicus longus = post
Extensor pollicus brevis = post
Abductor pollicus longus = post

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43
Q

Flexor pollicus longus origin and insertion?

A

Origin: deep muscle, radius and interosseus membrane
Inserts on base of distal phalanx

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44
Q

Extensor pollicus longus origin and insertion?

A

Origin: deep muscle, ulna and interosseus membrane
Insertion: base of distal phalanx

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45
Q

eXTENSOR pollicus brevis origin and insertion? Forms?

A

Origin: deep muscle, posterior radius and interosseus membrane
Insertion: base of proximal phalanx
Forms border of snuff box

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46
Q

Abductor pollicus longus origin and insertion ? Forms?

A

Origin: posterior surface ulna and radius and interosseus membrane
Inserts on base of first metacarpal
Forms border of snuffbox
Sits most laterally

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47
Q

What is flexor pollicus longus the same plane as?

A

Flexor digitorum profundus

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48
Q

4 intrinsic mucles of fingers? Nerve supply?

A

Thenar, hypothenar, lumcricals, interossei
Radial and ulnar nerves

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49
Q

3 muscles of hypothenar eminence? Attachments? Act on? Nerve supply?

A

Abductor digiti minimi
Flexor digiti minimi
Opponens digiti minimi
Attach to pisiform, hamate and flexor retinaculum
Act on digit 5 aka little finger
Ulnar nerve

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50
Q

3 muscles of thenar eminence? Attach to? Insert on? Nerve supply?

A

Abductor pollicus brevis (superficial and lateral, abducts thumb)
Flexor pollicus brevis (deep and medial to abductor, draws thumb across palm)
Opponens pollicus (deepest, sits under APB, opposition)
Attach to trapezium, scaphoid, lateral flexor retinaculum
Supplied by median nerve
Insert on phalanges of thumb

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51
Q

What are lumbricals? Innervation? Arise from? Insert on?

A

4 deep muscles sitting in palm of hand
Median and ulnar nerve
Arise from tendons of FDP (no bony origin)
Insert on extensor expansions of digits 2-5
Flex digits at MP joints and extend IP joints
Puppet muscles

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52
Q

Interossei origin? Funnction?

A

Originate between metacarpal bones deeply
Abduct/adduct digits

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53
Q

3 palmar interossei muscles function? Innervation? Arise from? Insertion?

A

Adduction
Ulnar nerve
Arise from metacarpals 2,4,5
Insert on proximal phalanges of 2,4,5 on middle finger sides
No palmar interossei on middle finger as there is movement towards middle finger in adduction

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54
Q

4 dorsal iinterossei movement? Innervation? Arise from?

A

Abduction
Ulnar nerve
Larger than palmar
Arise from 2 adjacent metacarpals
Insert on exterior expansion and proximal phalanges 2-4
Abduct fingers and flex MP joints, extend IP joints

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55
Q

What is any movement of middle finger known as? Impact of this?

A

Abduction - dorsal interossei on both sides

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56
Q

Why are there only 4 dorsal interossei if middle finger has 2?

A

Pinky finger has abductor digiti minimi

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57
Q

What is the anatomical snuffbox? What forms floor of it? Name originates from? Landmark for?

A

Triangular deepening on radial dorsal hand
Scaphoid and trapezium bones form florr
Where placed sniffed powdered tobacco
Landmark for physical exam of wrist

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58
Q

What is the anatomical snuffbox bounded by?

A

Tendon of extensor pollicus longus medially
Tendons of extensor pollicus previs and abductor pollicus longus muscles laterally
Radial styloid process proximally
1st cmc joint distally

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59
Q

How is the metabolism generally regulated?

A

Skeletal muscle

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60
Q

How much skeletal muscle in men vs women?

A

30% body weight in women
40% in men

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61
Q

What does skeletal muscle affect metabolically?

A

Affects metabolic rate
Blood glucose: soaks up glucose after a meal
Lipid profiles
Cardiovascular risk - more muscle = less risk of CV disease

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62
Q

When do muscle characteristics change? What does this affect?

A

Usage
Age
Disease
Affects metabolic regulation of glucose, lipids etc, mobility, work capacity, daily routine

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63
Q

Principle function of muscle?

A

Contracting/shortening distance between bones
Skeletal muscle moves bones attached to it by tendons

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64
Q

What movement happens when muscle contracts?

A

Insertion pulled towards origin

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65
Q

How can a muscle contraction have more force?

A

More complete activation of one muscle
More activation of agonist muscles
More inactivation of antagonist muscles

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66
Q

Where do muscle fibre strength come from?

A

Bundling fibres together

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67
Q

What is a fascicle?

A

Bundles of cells surrounded by connective tissues

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68
Q

Hierarchy of muscle composition?

A

Muscle
Bundles/fascicles
Cells
Fibrils

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69
Q

Where is the majority of sensory innervation in muscles?

A

Connective tissue around muscle cells, not muscle cells themselves

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70
Q

What is a motor unit?

A

Single motor neurone and all the muscle fibres it innervates

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71
Q

How many motor units may be in a muscle? What do motor units contain?

A

Muscle may have hundreds of motor units
Each motor unit may contain hundreds of muscle fibres

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72
Q

What happens to axons from peripheral nerve when they get close to skeletal muscle? What is each muscle fibre innervated by?

A

They branch
Single neuron

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73
Q

Big axon vs small axon branching?

A

Big axons will branch a lot, supply larger group of muscle fibres
Smaller axons branch less, supply smaller group of muscle fibres

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74
Q

What happens to muscle fibres when one axon is activated?

A

All muscle fibres innervated by same axon will contract at once

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75
Q

What do size of motor units depend on?

A

Function of muscle
Extraocular muscles have smaller motor units for precise movements

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76
Q

Difference in muscle fibres in larger vs smaller animals?

A

Smaller animal muscles will contract faster than larger animals

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77
Q

Slower vs faster contracting muscle? Distribution of motor units in this?

A

Slower: soleus. Mainly slow motor units, some fast
Faster: gastrocnemius, mainly fast motor units, some are slow

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78
Q

Mechanical classifications of motor units?

A

Twitch responses:
speed
force
rate of fatigue

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79
Q

Histological classifications of motor units?

A

Metabolic profile: oxidative, glycolytic (aerobic/anaerobic)

80
Q

Motor neuron properties?

A

cell body size
axon diameter
synaptic inputs
axon branching

81
Q

Colour and use of motor neurons?

A

Red/white
Phasic (less energy output) tonic (more output)

82
Q

3 main types of muscle fibres?

A

Slow aka type 1
Fast fatigue resistant 2a
Fast fatiguing 2b

83
Q

Type 2b vs type 1 muscle fibres?

A

2b: large and quick force, faster rise, faster fatigue
type 1: smaller force/twitch, slower rise, slower fatigue

84
Q

Differents observed generally with training?

A

Muscle size change increase or decrease
Strength and endurance change

85
Q

Changes observed in strength training?

A

Early changes
Better motor unit activation
Less antagonist activation
Improved glycolytic metabolism
2b fibre hypertrophy

86
Q

Changes observed in endurance training?

A

Enhanced oxidative metabolic profile
More mitochondria
Improved o2 supply
More myoglobin
Type 1 and type 2a fibre hypertrophy

87
Q

Untrained person muscle fibre type distribution?

A

55% type I and 45% type II

88
Q

High force output associated with what type of fibre? E.g. weights

A

Type II

89
Q

Good endurance output is associated with what type of fiber? E.g. running

A

Type I fibre

90
Q

Sprinter fibre predominance?

A

Type II e.g. 60-75% type 2

91
Q

Marathoner fibre predominance?

A

Type one 55-65%

92
Q

What happens to muscle fibres in different types of training?

A

Hypertrophy of certain types of fibre, not changes in fibre

93
Q

Skeletal muscle activation steps? Fatigue affects which of these stages? Effect of this?

A
  1. AP in nerve axon terminal opens channels that permit influx of Ca into nerve ending
  2. synaptic vesicles release Ach into synaptic cleft. Ach diffuses and binds to receptors opening ion-conducting channels
  3. influx of sodium depolarises the post synaptic membrane generating an AP that propogates over the sarcolemma and T tubules
  4. T tubule activation leads to SR activation and release of Ca into myoplasm
  5. Ca activates actin/myosin complex, ATP consumed and force is generated
  6. Ca is pumped back into SR, to allow relaxation

Fatigue affects 4/5/6
Less powerful force is generated

94
Q

What is muscle fatigue?

A

Failure to produce desired/expected force in short/long term

95
Q

What is gastrulation?

A

Process of cell division and migration resulting in formation of 3 germ layers

96
Q

3 germ layers?

A

Ectoderm
Mesoderm
Endoderm

97
Q

Name derivatives of each germ layer

A
98
Q

What is the building block of muscle?

A

Mesoderm

99
Q

Name parts of mesoderm from medial to lateral?

A

Notochord
Paraxial mesoderm
Intermediate mesoderm
Lateral plate mesoderm
Extraembryonic mesoderm

100
Q

When does the mesoderm differentiate?

A

Days 17-21

101
Q

3 parts of mesoderm?

A

Paraxial mesoderm
Intermediate mesoderm
Lateral plate mesoderm

102
Q

What is paraxial mesoderm formed from? What does it lie adjacent to? Function?

A

Formed from cells moving bilaterally and cranially from the primitive streak
Lies adjacent to notochord and neural tube
Forms the somites in the embryo

103
Q

What does the intermediate mesoderm form?

A

Genitourinary system

104
Q

What is lateral plate split by? 2 layers formed?

A

Intraemryonic coelom splits it into two layers
Parietal and visceral layers

105
Q

Where does skeletal muscle form from?

A

Paraxial mesoderm

106
Q

Where is smooth muscle (gut/derivates) formed from?

A

Visceral layer of lateral plate mesoderm

107
Q

Where does smooth muscle e.g. pupil/mammary/sweat glands form from?

A

Ectoderm

108
Q

Where does cardiac muscle form from?

A

Visceral layer of lateral plate mesoderm

109
Q

What happens in somitogenesis aka what is a somite?

A

Paraxial mesoderm gets organised into segments

110
Q

What do somites form alongside? From when?

A

Form alongside developing neural tube
Craniocaudal sequence over time from day 20

111
Q

How and when are somites form? What can this help determine?

A

3 pairs a day until end of wk5
Determine age of embryo by counting number of pairs

112
Q

What is presomitic mesoderm?

A

Unsegmented mesoderm

113
Q

What molecular factors affect patterning of pre somitic mesoderm aka somitogenesis?

A

FGF family
Wnt
Notch

114
Q

Which structure influences somite formation?

A

Notochord

115
Q

What transition happens in somitogenesis?

A

Mesenchymal to epithelial transition

116
Q

What does clock and wave mechanism control?

A

Tells cells to switch between permissive and non permissive state in constantly timed fashion
Wave of factors sweeps along length of embryo and interacts with cells that are permissive in right time and right area

117
Q

What is clock gene expression factor?

A

Notch

118
Q

What happens in somatogenesis when cells are in correct permissive state?

A

They express notch allowing them to react with the wave

119
Q

What factor is in wave in somatogenesis? When will it have effect? Role of wnt in this?

A

Wave of FGF8 is washing up the somites
Only has effect if mesoderm is at right time and expressing notch
Wnt helps this

120
Q

How many somite pairs are present at end of 5th week? WHat do they form?

A

42-44 pairs
Form axial skeleton

121
Q

What happens in somite epithelialisation?

A

Segmented blocks of paraxial mesoderm are transformed into spheres
Epithelial cells around a lumen

122
Q

What do formed somites differentiate into after epithelialsiation?

A

Cells in ventral/medial area: epithelial to mesenchymal transition to become SCLEROTOME, forming vertebrae/ribs
Dorsal half: form DERMOMYOTOME

123
Q

What does dermomyotome split into?

A

Dermatome: dermis of back
Myotome: muscles

124
Q

Give an overview of what develops from paraxial mesoderm

A

Somites
Sclerotome/dermomyotome
Sclerotome = ribs/vertebrae
Dermomyotome = dermatome/myotome
Dermatome = dermis/connective tissue
Myotome = muscle

125
Q

Give an overview of what develops from intermediate mesoderm

A

Urogenital structures

126
Q

Give an overview of what develops from lateral plate mesoderm

A

Parietal/visceral layer
Parietal = body wall, connective tissue, boens
Visceral = wall of gut tube, serous memrbanes

127
Q

What are myocytes? What are they made from?

A

Mature muscle cells
Made from myoblasts (muscle cell precursors)

128
Q

What are myoblasts?

A

Muscle cell precursors

129
Q

How do myoblasts become muscle cells?

A

Undergo cell division under influence of growth factors
Align into chains and fuse, cell membranes dissapear
Multinucleated myotubes (primary myotubes)

130
Q

What happens when growth factors are depleted (myoblasts)?

A

Myoblasts stop dividing
Secrete fibronectin onto ECM, bind to it via an integrin

131
Q

What mediates myoblast differentiation?

A

Myogenin

132
Q

MYOD/MYF5 function?

A

Transcription factors
Activate muscle specific genes
Enable differentiation of myogenic precursor cells in dermatome into myoblasts
Can convert non muscle cells e.g. fibroblasts, adipocytes into cells expressing all muscle proteins e.g. muscle cells

133
Q

How is MYOD activated? where?

A

WNT proteins (activating)
BMP (inhibitory)
Combine to activate MYOD in dermomyotome
Create group of muscle cell precursors expressing MYF5

134
Q

Where and what induces sclerotome formation?

A

Sonic hedgehog and noggin induce sclerotome formation in notocord

135
Q

What activates MYOD/MYF5 in lateral plate mesoderm?

A

WNT and BMP

136
Q

What is required for myoblast formation?

A

Myoblast formation

137
Q

What happens when loss of function mutation affects MYF5 / MYOD1?

A

Complete lack of skeletal muscle formation

138
Q

Where is smooth muscle found?

A

GI tract walls
Artery/vein walls
Around glands

139
Q

Where is skeletal muscle attached and how?

A

To bones via tendons

140
Q

What is cardiac muscle the bulk of? What is foudn in it?

A

Bulk of hearts mass
Intercalated discs

141
Q

How is skeletal muscle formed?

A

Myoblasts fuse to form long multinucleated fibres aka myotubes

142
Q

What are myotubes?

A

Long multinucleated muscle fibres

143
Q

What do striated skeletal muscle contain>

A

Many mitochondria

144
Q

What genes control skeletal muscle formation?

A

MYOD
MYF5
Myogenin

145
Q

WHere are tendons derived from?

A

From sclerotome under control of scleraxis

146
Q

What is scleraxis?

A

Transcription factor

147
Q

Where does smooth muscle originate from? Except?

A

Visceral mesoderm
Ciliary muscle (eye), spincter pupillae of eye (Ectoderm)

148
Q

What is responsible for smooth muscle cell differentiation? What is this upregulated by? What enhances its activity?

A

Serum response factor
Upregulated by kinase phosphorylation pathways
Myocardin/myocardin related transcription factors enhance SRF activity

149
Q

Where does cardiac muscle derive from?

A

Visceral mesoderm around developing heart tube

150
Q

Splanchnic vs somatic?

A

Splanchnic = visceral
Somatic = parietal

151
Q

How does cardiac muscle form?

A

Myoblasts adhere to each other via intercalated discs

152
Q

What factor specifically isnt involved in cardiac muscle development?

A

MYOD

153
Q

What is tinman? What does lack of tinman or mutatuons in it cause?

A

Homeobox gene responsible for specification of cardiac muscle in drosophilia
Causes many congenital heart defects

154
Q

What is the wnt family?

A

Family of signalling molecules
Control biological/development processes
Body axis patterning, cell fate specification, cell proliferation/migration

155
Q

What are BMPs? Disregulation of this causes?

A

Growth factor/cytokine family
Control tissue arcitechture throughout body
Induce bone/cartilage formation in development
Disregulated signalling of this leads to many pathological processes e.g. cancer

156
Q

Sonic hedgehod function?

A

Signalling pathway family belonging
Acts as morphogen: diffuses to form concentration gradient
Has effects on cells of embryo depending on conc

157
Q

What is notch?

A

Family of transmembrane proteins controlling cell fate decisions

158
Q

What are FGFs?

A

Family of cell signalling growth factors activating cell surface receptors
Act as mitogens - encourages cells to commence cell division
In development stimulate wnt signalling
Mesoderm induction, limb development

159
Q

Fatigue definition?

A

Inability to maintain power output,
Reversible by rest

160
Q

Effects of fatigue?

A

Reduces force and power, velocity, relaxation rate

161
Q

Power = ?

A

Power = force x velocity

162
Q

What does recovery time depend on?

A

Nature of fatigue
Could be seconds or weeks

163
Q

What is peripheral fatigue? What is it a failure of?

A

Within muscle fibres
Failure of excitation-contraction coupling (mostly) as a result of failure T tubule action potential, SR activation, Ca release
Failure of force generation at cross bridges due to reduced Ca release
Failure of ATP generation by depletion of energy stores

164
Q

WHat is central fatigue?

A

Within nervous system: loss of excitability of motor cortex
Probable reflex inputs from metabo-receptors in muscle
Can also include failure of transmission in peripheral nerve and neuromuscular junctions
Probably due to disease e.g. MS

165
Q

How can sites of fatigue be identified?

A

External stimulation
If direct muscle stimulation delivers smaller forces, fatigue is peripheral
If muscle stimulation delivers normal forces then fatigue is central

166
Q

3 ways to test central and peripheral fatigue?

A

Stimulate muscle nerves
Stimulate motor paths at cervical cord
Stimulate motor cortex with electromagnetic coil

167
Q

What are metaboreceptors?

A

In peripheral muscle
Finely myelinated sensory fibres that are sensitive to metabolites inside muscle

168
Q

Mechanoreceptos function?

A

Sensory receptor responding to movement/force

169
Q

What is the ergoflex composed of?

A

Muscle mechano and metaboreceptors

170
Q

Where do fibres from ergoflex travel to? What happens?

A

Go up spinal cord, through midbrain and project to cortex
Tell you how hard muscle has been working
Send signals to heart and respiratory reflex
Accellerate heart rate, change breathing pattern
Sympathetic nervous system activated to release adrenaline/cortisol

171
Q

When is excitation failure most likely to happen? Why? Recovery?

A

Short, high intensity exercisee
High AP firing rate leads to extracellular accumulation of potassium
Causes most T tubules to become inexcitable and impair excitation contraction coupling
Rapid recovery as potassium concentrations are restored by ion pumping/diffusion

172
Q

When does central fatigue usually occur? Symptoms? When is it not a factor?

A

Occupational work and recreational sport
Fatigue, discomfort, due to lack of motivation
Not a factor in elite sport as there is high motivation

173
Q

What happens if ATP runs out?

A

Muscle goes into rigor, not fatigue

174
Q

What increases in fatigue? Effect of this?

A

ADP, Pi, Hydrogen ions
Impair Ca fluxes and impair force delivery at cross bridges

175
Q

Name the 5 latin names for fingers starting with thumb

A

Pollex
Index forefinger
Digitus medius
Ring annularis
Little minimus

176
Q

What does atp become when broken down?

A

ADP + Pi + H+

177
Q

What happens at an ATPase site when ADP/Pi/H+ accumulates?

A

Inhibits enzyme function
Mostly Pi, then ADP
Inhibit CA release and limit Ca reuptake into SR
Affects force and speed of shortening/relaxation
H+ competes with Ca for troponin binding

178
Q

What happens to ATP in activties of short duration and high power?

A

Regenerated by breakdown of creatine phosphate

179
Q

What is a lohmann reaction?

A

Reversible reaction in muscle fibres
ATP and creatine are formed from ADP and phosphocreatine

180
Q

What happens in activities of moderate duration and low power e,g, football? Problem?

A

Depletion of glycogen is a problem e.g. ater 1-3 hours of activity
Marathon runners try to add more carbohydrates to diet before racing for more energy
Dont have enough carbohydrate to last over 2 hours e.g. cycling

181
Q

What happens in long duration exercise?

A

Switch from glycogen (carbohydrate) metabolism to lipid metabolism
Lipids come from adipocytes and intramuscular stores
E.g. 14 hours of cycling
Long duration utilise lipids almost entirely = 35 days

182
Q

What happens when carbohydrates are completely depleted? e.g. long distance exercise

A

Slows rephosphorylation of ADP by krebs cycle and leads to severe fatigue
Slow recovery

183
Q

What fibres are used in long duration exercise?

A

Low power
Type 1 fibres
Uses aerobic
Uses carbohydrate and lipid metabolsim
Lose weight for this aka activate type 1 fibres

184
Q

What is used in moderate duration exercise? e.g. tennis

A

Higher power
Uses type 1 and 2a FFR fibres
Aerobic
Uses more carbohydrate

185
Q

What is used in short duratione exercise? e.g. weightlifting

A

Very high power
All units active
Aerobic and anaerobic
Carbohydrate dependent
Inneficeint glycolytic metabolism

186
Q

What does training for strnegth endurance require?

A

Multiple repititions of exercise concerned

187
Q

How to train for strength?

A

Small numbers of repetitive high force contractions
Use loads close to max
Use 10-30 contractions in a session
Increases muscle mass
Remember to warm up and stretch
90 percent of biggest weight manageable
Need 2-3 days recovery

188
Q

What to do when endurance training?

A

Large numbers of repetivie low force contractions
Can reduce muscle mass

189
Q

What muscles enlarge in strength training?

A

2a and 2b

190
Q

What happens to fibres in endurance training?

A

type 1 enlarge
2a smaller
Lose fat and muscle mass

191
Q

2 phases of muscle strength gain?

A

First 4-6 weeks neural as activation of motor units improvs = big difference in strength
Early strength changes are neurological
Then hypertrophic phase as large motor units grow
Connective tissue also strengthens

192
Q

What happens to the body in endurance training?

A

Enhanced aerobic metabolism
Improved cardiovascular performance
Improved oxygen delivery: cardiac output better, higher capillary densrity, blood volume
Improved metabolic performance: improved enzyme concs, improved mitochondrial density, better substrate storage
Selective hypertrophy of S and FFR fibres

193
Q

How does hypertrophy of muscle begin in strength training?

A

Development of new contractile filaments added laterally to existing myofibrils
Fibril splitting
Most enlarged fibrils divide longitudinally - painful and slow
Fibrils become more numerous

194
Q

Type 1 fibers?

A

High concentration of myoglobin so appear red
Rich capillary supply/numerous mitochondria
Function for long periods without fatiguing
Good for long distance sport/isometric contraction
Aerobic

195
Q

Type 2a fibres?

A

Produce ATP aerobically
Not a lot of myoglobin appear pink
Walking, football
Fatigue resistant

196
Q

Type 2b fibres?

A

Anaerobic glycolysis
High glycogen levels
No myoglobin/mitochondria
Rapid forceful contractions
Short period e.g. weightlifting
Appear white

197
Q

Myoglobin function?

A

Improves delivery of oxygen

Phase 2 Limbs & Back (5 decks)

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