Muscle(1) Flashcards
What are the 3 different types of muscle?
Smooth
Cardiac
Skeletal
What is the structure of smooth muscle?
Long and slender cells
Cells arranged along, across and obliquely across the length of tubes
Irregularly shaped
Create a narrowing of tubes
Where is smooth muscle found?
Surrounding all tubes in the body
E,g blood vessels, digestive system, reproductive system and respiratory system
What is smooth muscle?
Involuntary muscle stimulated by the autonomic nervous system
Where is cardiac muscle found?
In there heart
What is the structure of cardiac muscle?
Strained in appearance
All or nothing contraction
How is the cardiac muscle stimulated ?
Has no nervous input
Intrinsically activates through the Sino atrial (SA) node -> AV node -> purkinje fibres
What is skeletal muscle?
Brings about movement to the skeleton
Voluntary muscle
What is the structure of skeletal muscle?
Striated and rectangular arrangement
Fibres contract and shorten along their length
Describe the components of the skeletal muscle outer sheaths
Endomyosium
Perimysium
Epimysium
What is the structure of skeletal muscle fibres?
Muscle fibre -> fascicles -> muscle
Briefly describe sliding filament theory?
- Myosin heads hydrolyse ATP and become reorientated and energised
- Myosin heads bind to the actin filaments creating cross bridges
- Myosin heads rotate towards the centre of the sarcomere = THE POWER STROKE
- As myosin heads bond ATP, the cross bridges attach from the actin
Describe the Excitation-Contraction Process?
- Nerve impulse - action potential
- Sacroplasmic reticulum excitation
- Calcium release
- Contraction Phase
- ATP-ADP hydrolysis (breakdown)
- Actin and Myosin cross bridges
What are slow twitch fibres?
Type 1
What are fast twitch fibres?
Type 2
What is type 2a?
Fast oxidative glycolytic
What is type 2b?
Fast glycolytic
What energy system does type 1 use?
Aerobic
Fat source
Describe type 1 fibres?
Slow to contract
Low/moderate tension/force
Small in diameter
Can sustain contraction over extended periods (resistant to fatigue) aka endurance
Describe the structure of type 1 fibres?
Good supply of capillaries Red in colour O2 available for ATP resynthesis Mitochondria can be increased in size by endurance training Have a high myoglobin store
Describe type 2 a fibres?
Using the glycolytic/anaerobic energy system
Glucose as an energy source
What force does type 2a exert?
High muscular force
Less resistant to fatigue
Can resynthesises ATP aerobically and anaerobically
What are 2 b fibres?
Using the ATP-PC energy system
ATP as an energy source
What are 2 b fibres good at?
Rapid speed of contraction
Low myoglobin content
Not good at endurance
Weight lifting, sprinting etc
Describe the structure of 2b fibres?
Large cross sectional diameter
Low myoglobin content
