Muscles Flashcards
What are the three kinds of muscle?
Skeletal, Smooth, and Cardiac.
How do muscles work? How do they work with other muscles when joints are involved? (Antagonistic Pairs)
Muscles work by shortening when they are flexed, and lengthening when they are relaxed. In order for certain movements, a muscle needs to contract and another muscle needs to relax. (Biceps relax when triceps flex)
What makes up a muscle?
Parallel bundles make up muscles, which are bundles of single fibres containing nuclei.
What is sarcolemma?
A membrane that encloses the fibres.
What are fibres?
Involved in the composition of muscles, fibres are tiny myofilaments bundled together.
what are myofibrils?
Made of two types of myofilaments that overlap each other:
- Thin filaments composed of the actin protein.
- Thick filaments composed of the Myosin protein.
What is the sliding filament model?
The sliding of actin past myosin during muscle contraction. The myosin head needs to attach to an actin molecule, and push it down further and re-attach itself onto an actin molecule further down the strain.
When muscles are relaxed, what protein blocks the sites where myosin heads are attached to actin strands? What protein binds with (___) in order to allow contraction?
Tropomyosin. Troponin binds with calcium to move Tropomyosin out of the way.
Where is calcium stored? When does it get released? What happens after?
Calcium is stored is the Sarcoplasmic Reticulum, and is only released when a nerve stimulates the muscle fiber to contract. Calcium returns to the Sarcoplasmic Reticulum by active transport.
What is the role of Tropomyosin?
Tropomyosin blocks off the Myosin head from connecting to Actin sites while your body is at rest.
What is the role of calcium in the muscles?
Calcium needs to bind with Troponin in order to allow for active sites on the Actin filament. If there was no calcium, Tropomyosin would be blocking off these active sites.
What is the role of nerves and blood vessels that surround the bundles of fibers in muscles?
Blood vessels: Supply muscles with glucose and oxygen, carry away wastes.
Nerves: Trigger and control muscle contractions.
When energy from ATP is out, how else does the body receive energy?
- Breakdown of Creatine Phosphate: 8 Seconds of energy, not restored until rest.
- Aerobic & Anaerobic Respiration: Glucose > ATP. Fermentation.
What is Atrophy?
The shrinking or loss of muscle fibres due to a variety of things. This includes lack of stimulation, aging, injury, etc…
What is Hypertrophy?
The enlargement or growth of muscle fibres due to intense and heavy movements. Muscle fibres are torn and re healed with more tissue, leading to mass gain.
