Muscle Tissue Flashcards
What is the function of Muscle Tissue?
Extremely specialised tissue capable of contraction. Allows body/skeleton to move and enables movement of individual structures within the body.
What is the process of Myogenesis?
Embyronic cells -> Myoblasts -> multi-nucleated fibres ‘Myotubes’ -> Myofibres
What are Muscle Fibres/Cells?
Cells that are mostly cylindrical strands of contractile proteins known as myofibrils.
What are Sarcomeres?
Myofibrils can be broken down into segments called sarcomeres, which contain bundles of parallel Actin and Myosin filaments.
How do Actin and Myosin function?
Actin and Myosin filaments slide in between each other, allowing muscle contraction and shortening of the sarcomere. All muscle cells produce a force on contraction because they contain filaments made of actin and myosin.
What are the three types of muscle cell?
Skeletal, Cardiac and Smooth
What is the structure and function of Skeletal cells?
Cylindrical in shape with multiple nuclei arranged around the outside; striated in appearance due to the arrangement of the fibres. They are attached to, support and move the skeleton through voluntary muscle.
Main function is movement of the skeleton at the joints, they work in antagonistic pairs (Actin and Myosin).
What is the structure and function of Cardiac cells?
Elongated, branching cells; one or two nuclei per cell; striations which are characterised by dark and light bands; found with excitatory and conductive muscle fibres, which conduct electrical impulses and control the heartbeat. Specialised muscles found in the heart, which are myogenic - involuntary contractions without nervous input.
Main function is contraction of heart tissue.
What is the structure and function of Smooth cells?
Cells are spindle-shaped with one nucleus. Found in the digestive system, reproductive tracts, the vascular system, bladder and bowels. Involuntary muscle.
Main function is allowing hollow organs to contract.
What are slow twitch fibres?
Slow twitch fibres are muscle fibres which contract slowly but keep going for a long time. They can work for along time without getting tired. Slow twitch fibres are red in colour as they contain many blood vessels. This is because they need a lot of oxygenated blood to contract the muscles and have a high density of mitochondria for aerobic respiration.
E.g. wolves are an example of an animal with a lot of slow twitch muscle fibre as they are long distance runners.
What are fast twitch fibres?
Fast twitch fibres are muscle fibres which contract quickly but also rapidly fatigue as they consume high amounts of energy (ATP). Fast twitch muscle fibres are lighter in colour than slow twitch muscle fibres because they have a lower density of capillaries as they do not rely on oxygen. They use anaerobic respiration to allow a rapid generation of ATP and have a low density of mitochondria.
E.g. Cheetahs are an example of an animal with a lot of fast twitch muscle fibre as they run incredibly fast distances.
Define Aerobic Respiration.
Aerobic respiration is the release of energy from the breakdown of glucose by combining with oxygen. It occurs in the mitochondria of the cells and the energy produced is used by animals to enable muscles to contract and allow movement.
Define Anaerobic Respiration.
Anaerobic respiration is the release of energy in the absence of oxygen. A short-term method of ATP production that animals use when they cannot exchange enough oxygen to carry out aerobic respiration. It happens in the cytoplasm of cells and leaves a poisonous chemical called lactic acid in the muscles.
Which is more efficient at energy production, Aerobic or Anaerobic?
Aerobic is more efficient, as it releases more ATP and does not produce a toxin like Anaerobic. Lactic acid in the muscles can cause them to stop working well and can cause pain in the animal.
What is the structure of the muscles?
Fast twitch and slow twitch muscle fibres are mixed together in a bundle. Oxygen is delivered to the muscle fibres via the blood vessels.
