Chapter 8: Muscular System Flashcards
What are intercalated disks?
Intercalated discs are unique structural formations found between the myocardial cells of the heart.
What is Fascia?
It’s the loose connective tissue outside the muscle organs that forms a flexible, sticky “packing material” between muscles, bones, and the skin.
The muscle’s attachment to this more stationary bone is called its _____.
Origin.
Its attachment to the more movable bone is called the muscle’s _____.
Insertion.
The muscle fiber’s internal framework is organized into many long cylinders, each made up of two kinds of thread-like microfilaments called ____ and ___ myofilaments.
Thin and Thick
The thick myofilaments are formed from a protein called ____.
Myosin
The thin myofilaments are composed mainly of the protein ____.
Actin
Explain the Sliding Filament Model.
According to this model, during contraction the thick and thin myofilaments in a muscle fiber first attach to one another by forming crossbridges that then act as levers to ratchet or pull the myofilaments past each other.
The connecting bridges between the myofilaments form only if _____ is present.
calcium
What is a tendon?
Tendons are dense, fibrous connective tissue that anchor muscles firmly to bones.
What is the basic contractile unit of muscle?
Sarcomere
The repeating units, or sarcomeres, are separated from each other by dark bands called _____.
Z Lines
Of all the muscles contracting simultaneously, the one that is mainly responsible for producing a particular movement is called the _____ _____ for that movement.
prime mover
What is it called when muscles help the prime mover produce a given movement?
Synergist muscle
What is it called when a muscle opposes the action of a prime mover in a given movement?
Antagonist muscle
We are able to maintain our body position because of a continuous, low-strength muscle contraction called muscle tone or ___ ____.
Tonic Contraction
What is Oxygen Debt?
The amount of extra oxygen needed by muscle tissue to oxidise lactic acid following exercise.
What are the three primary functions of the muscular system?
1) Movement 2) Posture 3) Heat Production
How would you define the term posture?
Muscle tone, or tonic contraction, holds muscles in position. In other words, muscle tone maintains posture.
How does muscle function affect body temperature?
The contraction of muscle fibers produces most of the heat required to maintain body temperature.
Muscle fibers are stimulated by a nerve cell called a ____ ____.
Motor Neuron
The point of contact between the nerve ending and the muscle fiber is called a ____ _____.
neuromuscular junction (NMJ)
Define Motor Unit.
Combination of a motor neuron with the muscle fibers it controls
What is a Twitch Contraction?
A twitch is a quick, jerky response to a stimulus. Twitch contractions can be seen in isolated muscles during research but play a minimal role in normal muscle activity.
