Types of muscle and muscle fibre types Flashcards
What are the three types of muscle?
Cardiac muscle, smooth muscle and skeletal muscle.
What is cardiac muscle?
Cardiac muscle is specialised muscle that forms the walls of the heart chambers. It is an involuntary muscle as it contracts without conscious thoughts or effort and never fatigues (healthy heart). The cardiac muscle has its own blood supply via the carotid artery.
What is smooth muscle?
Smooth muscle is an involuntary muscle that is controlled by the nervous system and can be found in and around organs such as the digestive stem and around blood vessels. It moves substances around the body and keeps cells supplied with nutrients and oxygen.
What is skeletal muscle?
Skeletal muscles are straited or striped, voluntary muscles which are connected to the skeletal system with tendons. They are responsible for movement so they do fatigue but some fibres fatigue quicker than others.
What is skeletal muscle made of?
Skeletal muscle is made up of thousands of muscle fibres and each fibre contains smaller units called myofibrils; these run the length of the muscle and give it its stripy appearance.
What are the four parts of skeletal muscle?
Epimysium, Perimysium, Fascicle and Endomysium.
What is the epimysium?
The epimysium is the outer layer of connective tissue that holds the muscle fibres in place and protects them from friction of other muscles and bones.
What is the perimysium?
The perimysium is the connective tissue that surrounds each fascicle.
What is a fascicle?
The fascicle is a bundle of muscle fibres.
What is the endomysium?
The endomysium is a layer of strong connective tissue that acts as an insulator and covers the surface of each muscle fibre.
What are the three muscle fibre types?
Type I, Type IIa and Type IIx
What is muscle fibre type I?
Type I are slow twitch muscles which contract slowly with low force and contain a rich supply of blood. They fatigue at a slow rate due to aerobic respiration and use mitochondria to create energy (ATP).
What is muscle fibre type IIa?
Type IIa are fast oxidative twitch muscles that contract quickly with large force which utilise the energy already found within the muscles. These muscles are less dependent on oxygen than type I but they fatigue at a quicker rate.
What is muscle fibre type IIx?
Type IIx are fast glycolitic twitch muscles which have the fastest contraction with the largest force which require no oxygen or blood supply. These muscles use the energy from glycogen in the muscles and fatigue rapidly due to anaerobic respiration.
What is mitochondria?
Mitochondria are the organelles within muscle cells that are responsible for turning oxygen into energy (ATP) using the Krebs cycle and the Electron transport chain.
