Week 3 Flashcards
1
Q
How many bones are in the human wrist?
A
27 in each wrist
2
Q
How many carpals are there?
A
8 in each hand
3
Q
Name the bones here
A
4
Q
How many metacarpals in each hand?
A
5
5
Q
How many phalanges in each hand? Distrbution?
A
14
3 in each digit, 2 in thumb
6
Q
Name the different joints in the hand
A
Carpometacarpal joint
Metacarpalphalangeal joint
Interphalangeal joint
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
8
Q
Function of fascia in hand?
A
Hold tendons, nerves and Blood vessels close to bones
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
10
Q
Which retinaculum covers anterior carpal bones? What passes under this?
A
Flexor retinaculum
FLexor tendons and median nerves pass under (carpal tunnel)
11
Q
Which retinaculum covers dorsal carpals? What passes under here?
A
Extensor retinaculum
Extensor tendons of hand and digits pass under
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
13
Q
What is the roof of the carpal tunnel made from? Attached to?
A
Flexor retinaculum
Scaphoid, trapezium, pisiform, hamate
14
Q
Contents of carpal tunnel?
A
9 flexor tendons
vascular synovium
median nerve (superficial to tendons)
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
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
17
Q
Prehensile movements of the hand?
A
Grasp and grip
Fundamental movements
Depends on positioning of fingers and thumb
18
Q
2 types of grip?
A
Power and precision
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
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
21
Q
What is between carpals and ulna?
A
Articular disc
22
Q
What bones are involved at metacarpophalangeal joints? Movements?
A
Metacarpals and proximal phalanges
Flexion/extension = waving bye
Abduction/adduction = move fingers apart
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
24
Q
Name each of these movements
A
25
What are thumb movements between?
Trapezium and 1st metacarpal
26
Where are instrinsic muscle bellies? Muscles included in intrinsic category? What movements do instrinsic muscles allow?
Belly inside palm
Lumbricals and interossei
Instrinsic movements and precision grip
27
Where are extrinsic muscle bellies found? Muscles involved in this category? Important when? Where do tendons enter hand? Where is transverse digit found?
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
28
2 superficial flexors of fingers (extrinsic)? Arise from where? Where do they pass? Supplied by, exception?
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
29
Flexor carpi ulnaris nerve supply?
Ulnar nerve
30
What is the common flexor origin?
Medial epicondyle of humerus
31
Palmaris Longus:
- Origin?
- Insertion?
- Movements?
- Innervation?
Medial epicondyle
Flexor retinaculum of wrist
Flexion at the wrist weakly
Median nerve
Absent in 15% population
32
Flexor Digitorum Superficialis
- Origin?
- Insertion?
- Actions?
- Innervation?
- Deepest of?
- Where is belly found?
- 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
33
2 deep extrinsic flexors of the fingers? Arise from?
Flexor digitorum profundus and flexor pollicus longus
Arise from radius and ulna bone
34
Flexor Digitorum Profundus
- Origin?
- Insertion?
- Movements?
- Innervation?
- Deep to?
- 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
35
Flexor pollicus longus origin and attachments? Actions? Innervation?
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
36
Superficial extrinsic extensors of fingers? Arise from?
Extensor digitorum and extensor digiti minimi
Common extensor origin
37
What is the common extensor origin?
Lateral epicondyle of humerus
38
Extensor digitorum attachments and insertion? Actions? Innervation?
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
39
Extensor digiti minimi attachments and insertion? Actions? Innervation?
Originates from common extensor origin
Attaches to distal and middle interpahlangeal joints
Extends little finger
Radial nerve
40
Deep extrinsic extensors of the hand? Function? Arise from? INserts on? Innervation?
Extensor indicis
Extends digit 2
Arises from posterior ulna
Inserts on extensor expansion of digit 2
Innervated by deep radial nerve
41
What is the extensor expansion/hood?
Proximal to metacarpophalangeal joint
All extensor tendons join triangular expansion to form hood over joint
42
4 extrinsic muscles of the thumb? Anetior or posteiror?
Flexor pollicus longus = ant
Extensor pollicus longus = post
Extensor pollicus brevis = post
Abductor pollicus longus = post
43
Flexor pollicus longus origin and insertion?
Origin: deep muscle, radius and interosseus membrane
Inserts on base of distal phalanx
44
Extensor pollicus longus origin and insertion?
Origin: deep muscle, ulna and interosseus membrane
Insertion: base of distal phalanx
45
eXTENSOR pollicus brevis origin and insertion? Forms?
Origin: deep muscle, posterior radius and interosseus membrane
Insertion: base of proximal phalanx
Forms border of snuff box
46
Abductor pollicus longus origin and insertion ? Forms?
Origin: posterior surface ulna and radius and interosseus membrane
Inserts on base of first metacarpal
Forms border of snuffbox
Sits most laterally
47
What is flexor pollicus longus the same plane as?
Flexor digitorum profundus
48
4 intrinsic mucles of fingers? Nerve supply?
Thenar, hypothenar, lumcricals, interossei
Radial and ulnar nerves
49
3 muscles of hypothenar eminence? Attachments? Act on? Nerve supply?
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
50
3 muscles of thenar eminence? Attach to? Insert on? Nerve supply?
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
51
What are lumbricals? Innervation? Arise from? Insert on?
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
52
Interossei origin? Funnction?
Originate between metacarpal bones deeply
Abduct/adduct digits
53
3 palmar interossei muscles function? Innervation? Arise from? Insertion?
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
54
4 dorsal iinterossei movement? Innervation? Arise from?
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
55
What is any movement of middle finger known as? Impact of this?
Abduction - dorsal interossei on both sides
56
Why are there only 4 dorsal interossei if middle finger has 2?
Pinky finger has abductor digiti minimi
57
What is the anatomical snuffbox? What forms floor of it? Name originates from? Landmark for?
Triangular deepening on radial dorsal hand
Scaphoid and trapezium bones form florr
Where placed sniffed powdered tobacco
Landmark for physical exam of wrist
58
What is the anatomical snuffbox bounded by?
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
59
How is the metabolism generally regulated?
Skeletal muscle
60
How much skeletal muscle in men vs women?
30% body weight in women
40% in men
61
What does skeletal muscle affect metabolically?
Affects metabolic rate
Blood glucose: soaks up glucose after a meal
Lipid profiles
Cardiovascular risk - more muscle = less risk of CV disease
62
When do muscle characteristics change? What does this affect?
Usage
Age
Disease
Affects metabolic regulation of glucose, lipids etc, mobility, work capacity, daily routine
63
Principle function of muscle?
Contracting/shortening distance between bones
Skeletal muscle moves bones attached to it by tendons
64
What movement happens when muscle contracts?
Insertion pulled towards origin
65
How can a muscle contraction have more force?
More complete activation of one muscle
More activation of agonist muscles
More inactivation of antagonist muscles
66
Where do muscle fibre strength come from?
Bundling fibres together
67
What is a fascicle?
Bundles of cells surrounded by connective tissues
68
Hierarchy of muscle composition?
Muscle
Bundles/fascicles
Cells
Fibrils
69
Where is the majority of sensory innervation in muscles?
Connective tissue around muscle cells, not muscle cells themselves
70
What is a motor unit?
Single motor neurone and all the muscle fibres it innervates
71
How many motor units may be in a muscle? What do motor units contain?
Muscle may have hundreds of motor units
Each motor unit may contain hundreds of muscle fibres
72
What happens to axons from peripheral nerve when they get close to skeletal muscle? What is each muscle fibre innervated by?
They branch
Single neuron
73
Big axon vs small axon branching?
Big axons will branch a lot, supply larger group of muscle fibres
Smaller axons branch less, supply smaller group of muscle fibres
74
What happens to muscle fibres when one axon is activated?
All muscle fibres innervated by same axon will contract at once
75
What do size of motor units depend on?
Function of muscle
Extraocular muscles have smaller motor units for precise movements
76
Difference in muscle fibres in larger vs smaller animals?
Smaller animal muscles will contract faster than larger animals
77
Slower vs faster contracting muscle? Distribution of motor units in this?
Slower: soleus. Mainly slow motor units, some fast
Faster: gastrocnemius, mainly fast motor units, some are slow
78
Mechanical classifications of motor units?
Twitch responses:
speed
force
rate of fatigue
79
Histological classifications of motor units?
Metabolic profile: oxidative, glycolytic (aerobic/anaerobic)
80
Motor neuron properties?
cell body size
axon diameter
synaptic inputs
axon branching
81
Colour and use of motor neurons?
Red/white
Phasic (less energy output) tonic (more output)
82
3 main types of muscle fibres?
Slow aka type 1
Fast fatigue resistant 2a
Fast fatiguing 2b
83
Type 2b vs type 1 muscle fibres?
2b: large and quick force, faster rise, faster fatigue
type 1: smaller force/twitch, slower rise, slower fatigue
84
Differents observed generally with training?
Muscle size change increase or decrease
Strength and endurance change
85
Changes observed in strength training?
Early changes
Better motor unit activation
Less antagonist activation
Improved glycolytic metabolism
2b fibre hypertrophy
86
Changes observed in endurance training?
Enhanced oxidative metabolic profile
More mitochondria
Improved o2 supply
More myoglobin
Type 1 and type 2a fibre hypertrophy
87
Untrained person muscle fibre type distribution?
55% type I and 45% type II
88
High force output associated with what type of fibre? E.g. weights
Type II
89
Good endurance output is associated with what type of fiber? E.g. running
Type I fibre
90
Sprinter fibre predominance?
Type II e.g. 60-75% type 2
91
Marathoner fibre predominance?
Type one 55-65%
92
What happens to muscle fibres in different types of training?
Hypertrophy of certain types of fibre, not changes in fibre
93
Skeletal muscle activation steps? Fatigue affects which of these stages? Effect of this?
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
What is muscle fatigue?
Failure to produce desired/expected force in short/long term
95
What is gastrulation?
Process of cell division and migration resulting in formation of 3 germ layers
96
3 germ layers?
Ectoderm
Mesoderm
Endoderm
97
Name derivatives of each germ layer
98
What is the building block of muscle?
Mesoderm
99
Name parts of mesoderm from medial to lateral?
Notochord
Paraxial mesoderm
Intermediate mesoderm
Lateral plate mesoderm
Extraembryonic mesoderm
100
When does the mesoderm differentiate?
Days 17-21
101
3 parts of mesoderm?
Paraxial mesoderm
Intermediate mesoderm
Lateral plate mesoderm
102
What is paraxial mesoderm formed from? What does it lie adjacent to? Function?
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
What does the intermediate mesoderm form?
Genitourinary system
104
What is lateral plate split by? 2 layers formed?
Intraemryonic coelom splits it into two layers
Parietal and visceral layers
105
Where does skeletal muscle form from?
Paraxial mesoderm
106
Where is smooth muscle (gut/derivates) formed from?
Visceral layer of lateral plate mesoderm
107
Where does smooth muscle e.g. pupil/mammary/sweat glands form from?
Ectoderm
108
Where does cardiac muscle form from?
Visceral layer of lateral plate mesoderm
109
What happens in somitogenesis aka what is a somite?
Paraxial mesoderm gets organised into segments
110
What do somites form alongside? From when?
Form alongside developing neural tube
Craniocaudal sequence over time from day 20
111
How and when are somites form? What can this help determine?
3 pairs a day until end of wk5
Determine age of embryo by counting number of pairs
112
What is presomitic mesoderm?
Unsegmented mesoderm
113
What molecular factors affect patterning of pre somitic mesoderm aka somitogenesis?
FGF family
Wnt
Notch
114
Which structure influences somite formation?
Notochord
115
What transition happens in somitogenesis?
Mesenchymal to epithelial transition
116
What does clock and wave mechanism control?
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
What is clock gene expression factor?
Notch
118
What happens in somatogenesis when cells are in correct permissive state?
They express notch allowing them to react with the wave
119
What factor is in wave in somatogenesis? When will it have effect? Role of wnt in this?
Wave of FGF8 is washing up the somites
Only has effect if mesoderm is at right time and expressing notch
Wnt helps this
120
How many somite pairs are present at end of 5th week? WHat do they form?
42-44 pairs
Form axial skeleton
121
What happens in somite epithelialisation?
Segmented blocks of paraxial mesoderm are transformed into spheres
Epithelial cells around a lumen
122
What do formed somites differentiate into after epithelialsiation?
Cells in ventral/medial area: epithelial to mesenchymal transition to become SCLEROTOME, forming vertebrae/ribs
Dorsal half: form DERMOMYOTOME
123
What does dermomyotome split into?
Dermatome: dermis of back
Myotome: muscles
124
Give an overview of what develops from paraxial mesoderm
Somites
Sclerotome/dermomyotome
Sclerotome = ribs/vertebrae
Dermomyotome = dermatome/myotome
Dermatome = dermis/connective tissue
Myotome = muscle
125
Give an overview of what develops from intermediate mesoderm
Urogenital structures
126
Give an overview of what develops from lateral plate mesoderm
Parietal/visceral layer
Parietal = body wall, connective tissue, boens
Visceral = wall of gut tube, serous memrbanes
127
What are myocytes? What are they made from?
Mature muscle cells
Made from myoblasts (muscle cell precursors)
128
What are myoblasts?
Muscle cell precursors
129
How do myoblasts become muscle cells?
Undergo cell division under influence of growth factors
Align into chains and fuse, cell membranes dissapear
Multinucleated myotubes (primary myotubes)
130
What happens when growth factors are depleted (myoblasts)?
Myoblasts stop dividing
Secrete fibronectin onto ECM, bind to it via an integrin
131
What mediates myoblast differentiation?
Myogenin
132
MYOD/MYF5 function?
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
How is MYOD activated? where?
WNT proteins (activating)
BMP (inhibitory)
Combine to activate MYOD in dermomyotome
Create group of muscle cell precursors expressing MYF5
134
Where and what induces sclerotome formation?
Sonic hedgehog and noggin induce sclerotome formation in notocord
135
What activates MYOD/MYF5 in lateral plate mesoderm?
WNT and BMP
136
What is required for myoblast formation?
Myoblast formation
137
What happens when loss of function mutation affects MYF5 / MYOD1?
Complete lack of skeletal muscle formation
138
Where is smooth muscle found?
GI tract walls
Artery/vein walls
Around glands
139
Where is skeletal muscle attached and how?
To bones via tendons
140
What is cardiac muscle the bulk of? What is foudn in it?
Bulk of hearts mass
Intercalated discs
141
How is skeletal muscle formed?
Myoblasts fuse to form long multinucleated fibres aka myotubes
142
What are myotubes?
Long multinucleated muscle fibres
143
What do striated skeletal muscle contain>
Many mitochondria
144
What genes control skeletal muscle formation?
MYOD
MYF5
Myogenin
145
WHere are tendons derived from?
From sclerotome under control of scleraxis
146
What is scleraxis?
Transcription factor
147
Where does smooth muscle originate from? Except?
Visceral mesoderm
Ciliary muscle (eye), spincter pupillae of eye (Ectoderm)
148
What is responsible for smooth muscle cell differentiation? What is this upregulated by? What enhances its activity?
Serum response factor
Upregulated by kinase phosphorylation pathways
Myocardin/myocardin related transcription factors enhance SRF activity
149
Where does cardiac muscle derive from?
Visceral mesoderm around developing heart tube
150
Splanchnic vs somatic?
Splanchnic = visceral
Somatic = parietal
151
How does cardiac muscle form?
Myoblasts adhere to each other via intercalated discs
152
What factor specifically isnt involved in cardiac muscle development?
MYOD
153
What is tinman? What does lack of tinman or mutatuons in it cause?
Homeobox gene responsible for specification of cardiac muscle in drosophilia
Causes many congenital heart defects
154
What is the wnt family?
Family of signalling molecules
Control biological/development processes
Body axis patterning, cell fate specification, cell proliferation/migration
155
What are BMPs? Disregulation of this causes?
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
Sonic hedgehod function?
Signalling pathway family belonging
Acts as morphogen: diffuses to form concentration gradient
Has effects on cells of embryo depending on conc
157
What is notch?
Family of transmembrane proteins controlling cell fate decisions
158
What are FGFs?
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
Fatigue definition?
Inability to maintain power output,
Reversible by rest
160
Effects of fatigue?
Reduces force and power, velocity, relaxation rate
161
Power = ?
Power = force x velocity
162
What does recovery time depend on?
Nature of fatigue
Could be seconds or weeks
163
What is peripheral fatigue? What is it a failure of?
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
WHat is central fatigue?
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
How can sites of fatigue be identified?
External stimulation
If direct muscle stimulation delivers smaller forces, fatigue is peripheral
If muscle stimulation delivers normal forces then fatigue is central
166
3 ways to test central and peripheral fatigue?
Stimulate muscle nerves
Stimulate motor paths at cervical cord
Stimulate motor cortex with electromagnetic coil
167
What are metaboreceptors?
In peripheral muscle
Finely myelinated sensory fibres that are sensitive to metabolites inside muscle
168
Mechanoreceptos function?
Sensory receptor responding to movement/force
169
What is the ergoflex composed of?
Muscle mechano and metaboreceptors
170
Where do fibres from ergoflex travel to? What happens?
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
When is excitation failure most likely to happen? Why? Recovery?
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
When does central fatigue usually occur? Symptoms? When is it not a factor?
Occupational work and recreational sport
Fatigue, discomfort, due to lack of motivation
Not a factor in elite sport as there is high motivation
173
What happens if ATP runs out?
Muscle goes into rigor, not fatigue
174
What increases in fatigue? Effect of this?
ADP, Pi, Hydrogen ions
Impair Ca fluxes and impair force delivery at cross bridges
175
Name the 5 latin names for fingers starting with thumb
Pollex
Index forefinger
Digitus medius
Ring annularis
Little minimus
176
What does atp become when broken down?
ADP + Pi + H+
177
What happens at an ATPase site when ADP/Pi/H+ accumulates?
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
What happens to ATP in activties of short duration and high power?
Regenerated by breakdown of creatine phosphate
179
What is a lohmann reaction?
Reversible reaction in muscle fibres
ATP and creatine are formed from ADP and phosphocreatine
180
What happens in activities of moderate duration and low power e,g, football? Problem?
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
What happens in long duration exercise?
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
What happens when carbohydrates are completely depleted? e.g. long distance exercise
Slows rephosphorylation of ADP by krebs cycle and leads to severe fatigue
Slow recovery
183
What fibres are used in long duration exercise?
Low power
Type 1 fibres
Uses aerobic
Uses carbohydrate and lipid metabolsim
Lose weight for this aka activate type 1 fibres
184
What is used in moderate duration exercise? e.g. tennis
Higher power
Uses type 1 and 2a FFR fibres
Aerobic
Uses more carbohydrate
185
What is used in short duratione exercise? e.g. weightlifting
Very high power
All units active
Aerobic and anaerobic
Carbohydrate dependent
Inneficeint glycolytic metabolism
186
What does training for strnegth endurance require?
Multiple repititions of exercise concerned
187
How to train for strength?
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
What to do when endurance training?
Large numbers of repetivie low force contractions
Can reduce muscle mass
189
What muscles enlarge in strength training?
2a and 2b
190
What happens to fibres in endurance training?
type 1 enlarge
2a smaller
Lose fat and muscle mass
191
2 phases of muscle strength gain?
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
What happens to the body in endurance training?
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
How does hypertrophy of muscle begin in strength training?
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
Type 1 fibers?
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
Type 2a fibres?
Produce ATP aerobically
Not a lot of myoglobin appear pink
Walking, football
Fatigue resistant
196
Type 2b fibres?
Anaerobic glycolysis
High glycogen levels
No myoglobin/mitochondria
Rapid forceful contractions
Short period e.g. weightlifting
Appear white
197
Myoglobin function?
Improves delivery of oxygen
