Topic 5 Part 1 (muscle) Flashcards
What are muscles?
Tissue that can contract (shorten)
What are 3 types of muscle?
- Cardiac muscle (heart)
- Skeletal muscle (bones)
- Smooth muscle (organs)
What is the smooth muscle?
-have one nucleus
-long and tapered at the ends
-arranged in parallel lines forming sheets
-contract voluntarily
-form walls of internal organs
What is the cardiac muscle?
-only found in walls of the heart
-have light and dark bands (striated)
-are tubular and have a branched structure
- one nucleus
-contract involuntarily
What is striated?
marked with long, thin parallel streaks.
What is the skeletal muscle
-are tubular and striated
-can be very long
-many nucleus
-contract voluntarily (controlled by the nervous system)
-attached to bones
-referred to as fiberz
What are the 3 types of skeletal muscle?
- Slow twitch
- Fast twitch
- Intermediate twitch
What is slow twitch?
They don’t produce a lot of power, but they’re also resistant to fatigue and can contract for a long time. Slow-twitch muscle fibers help with a lot of your daily movements, like walking, cleaning your house, or sitting upright in a chair.
-marathon runners
What is fast twitch
The muscle cells responsible for short, powerful movements. They can produce a lot more force and power for a short time, but they get fatigued fast.
What is intermediate twitch ?
Similar to fast twitch divers but are more resistant to fatigue
How are muscles controlled?
By electrical impulses from the nervous system
-each muscle fibre has a minimum voltage require to cause it to contract
What is the all or none response?
If the minimum voltage threshold is reached, the fibre will contact.
-it will not contact “harder” or “faster” if there is more voltage
What is the contraction in relation to all or none reponse called?
Muscle twitch
What are the 3 periods muscle twitches are divided into?
- Latent period
- Contraction period
- Relaxation period
What is the latent period?
Period of time between stimulation and initiation contraction
What is the contraction period?
When the muscle shortens
What is the relaxation period?
When the muscle returns to its original length
What happens when muscles contract?
They shorten
-producing a pull on the joint
How do muscles move joints?
In moving pairs
Myo Greek word meaning?
Muscle
Sacro Greek word meaning?
Flesh
What do connective tissues do for muscles?
Protect muscle from friction
What are myofibrils?
Cylindrical subunits of muscle that are made of myofilaments
What are the two different myofilaments?
- Actin
- Myosin
What is the actin?
Thin myofilament
-two strands of globular (round) protein molecules wrapped around each other
What is the mysoin?
Tick filament
-two strands of protein molecules wrapped around eachother
-10x bigger than actin and diff shape
-bundled so that half of molecules head are facing one way and other half the opposite.
What is a sarcomere?
basic unit of striated or skeletal muscle.
what is the z-line?
junction between 2 sarcomeres
what is the m-line?
centre of the myosin filament
what is the l-band?
actin only
what is the h-zone?
myosin only
what is the a-band?
where myosin & actin overlap
What is summation?
More than 1 nerve stimulation on muscle before the relaxation phase is complete
What is tetanus?
Constant muscle contraction
What is the energy source for muscles?
ATP
