Muscle Physiology Flashcards
What are the 3 types of muscle?
Like the tissues
- skeletal
- cardiac
- smooth
What are the defining characteristics of skeletal muscle?
- attached to bone
- cannot initiate without motor neuron
- striated
What are the defining characteristics of cardiac muscle?
- in heart
- branched cells
- visible striations
- spontaneously active
What are the defining characteristics of smooth muscle?
- internal structures
- no striations
- spontaneously active
What muscle is this?
Skeletal
What muscle is this?
Cardiac
What muscle is this?
smooth
What type of skeletal muscle is this?
Slow twitch
More pink = more oxygen = doesnt fatigue
What type of skeletal muscle is this?
Fast twitch
Less pink = Less oxygen = fatigue
Why do fast/slow twitch muscle fibres behave differently?
- The ‘pink’ is the myoglobin
- more myoglobin = more O2 stored
- more O2 = less fatigued
What is this?
Skeletal muscle
What is this?
Tendon
What is this?
Connective Tissue
What is this?
Nerve and blood vessels
What is this?
Bundle of muscle fibres
What is this?
A muscle fibre
What is this?
Nucleus
Where is calcium stored in the muscle fibres?
In the sarcoplasmic reticulum
(SR)
What causes the visible striations in muscles?
When thick and thin filament meet
What is myofibril?
Long contractile fibres run through muscle cells
What is the role of T-tubules?
- “pathway” to deep centre of cell
- Which is where the SR is
What is this?
Nucleus
What is this?
Sarcoplasmic Retriculum, SR
What is this?
Mitrochondria
What is this?
Thick and thin filaments
What is this?
Myofibril
What is this?
T-Tubules
What is this?
Sarcolemma
What is the result of having more fibrils?
More force and strength
What protein makes up thin filaments?
Actin
several g actin monomers
What protein makes up thick filaments?
myosin
What are the regulatory proteins and their functions?
- Tropomyosin
- Troponin
They control when muscles contract
What are the accessory proteins and their functions?
- Titin
- Nebulin
They provide elasticity and structure
What type of filament is this?
Thick
What type of filament is this?
Thin
Fill the blank
Myosin
What is this?
Actin
Whats going on here?
What is a sacromere?
Building block of striations
What is this?
Sacromere
What are the 6 steps that lead to muscle contraction?
- myosin attached to actin
- ATP binds to myosin, causing it to move away from actin
- ATP breaks down to ADP and Pi
- Myosin attaches to next actin molecule
- Pi is released, moving the actin molecule forward
- Myosin releases ADP and resumes step (1)
What is the role of tropomyosin and troponin?
- They prevent muscle contractions when they shouldnt occur
- Tropomyosin covers actin, preventing myosin binding
What is the role of calcium in muscles?
- Binds to troponin
- Which moves tropomyosin out of myosin’s way
What is an iostonic contraction?
- When muscle contracts and shortens
- Moves the load
What is an isometric contraction?
- When muslc e contracts but doesnt shorten
- Cannot move load
Why does a small bicep contraction have a (relatively) larger impact on the hand’s movements?
- Bicep inserts near fulcrum so it has lever advantage
