Topic 3 - Muscle Structure Flashcards
What are the three types of muscle?
- Smooth Muscle
- Cardiac Muscle
- Skeletal Muscle
Describe Smooth muscle
- Contracts without conscious control
- Found in the walls of internal organs (apart from the heart)
Describe Cardiac muscle
- Contracts without conscious control
- Only found in the heart
Describe skeletal muscle
- The type of muscle you use to move
- They are attached to bone by tendons
- Pairs of skeletal muscles contract and relax to move bones at a joint
- The bones of the skeleton are incompressible so they act as levers, giving the muscles something to pull against
What are antagonistic pairs?
Muscles that work together to move a bone
What are the contracting muscles in an antagonistic pair called?
The agonist
What are the relaxing muscles in an antagonistic pair called?
The antagonist
What is a myofibril?
A long, cylindrical organelle within a muscle fibre thats highly specialised for contraction
Why do muscle cells have lots of mitochondria?
To provide enough ATP for muscle contraction
What is the sarcoplasmic reticulum?
A network of internal membranes that runs through the sarcoplasm. It stores and releases calcium ions that are needed for muscle contraction
What is actin?
The thin myofilament protein in muscle fibres
What is myosin?
The protein that makes up the thick myofilaments in myofibrils
What is a sarcomere?
A short contractile unit thats part of a myofibril, made up of overlapping myosin and actin filaments
What is the sliding filament theory?
The theory that myosin and actin filaments slide over one another to make sarcomeres contract
