Muscular System 1 Flashcards
What are the three types of muscle tissue?
Skeletal muscle, cardiac muscle, smooth muscle
These muscle types have distinct characteristics and functions.
What distinguishes skeletal muscle tissue?
Striations, voluntary control, multinucleate fibers
Skeletal muscle can contract rapidly but fatigues easily.
Where is cardiac muscle tissue found?
In the walls of the heart
Cardiac muscle is striated and involuntary.
What is the shape and nucleus count of smooth muscle cells?
Fusiform shape, one nucleus
Smooth muscle is found in the walls of hollow visceral organs.
What are the four special characteristics of muscle tissue?
- Excitability
- Contractility
- Extensibility
- Elasticity
These characteristics enable muscles to perform optimally.
What is the primary function of skeletal muscles?
Produce movement, maintain posture, generate heat
Skeletal muscles also stabilize joints.
What is the innermost connective tissue covering of a muscle fiber called?
Endomysium
It surrounds individual muscle fibers.
What is the layer surrounding a fascicle of muscle fibers?
Perimysium
This layer is made of dense irregular connective tissue.
What is the outermost connective tissue covering of a whole muscle called?
Epimysium
It may blend with fascia surrounding muscles.
What are the origin and insertion points of a muscle?
Origin: less movable bone; Insertion: more movable bone
The origin is typically more proximal and the insertion more distal.
How are skeletal muscles named?
Based on shape, size, location, direction of fibers, number of origins, or action
Examples include Orbicularis Oris (shape) and gluteus maximus (size).
What is flexion?
Reduction of the angle between two bones
It is a common body movement.
What is the role of the agonist in muscle action?
Muscle that performs the action
The prime mover is the agonist most responsible for the movement.
What is the antagonist’s role in muscle action?
Opposes the action of the agonist
Antagonists are typically located in the opposite compartment.
What are synergists?
Muscles that work together to perform the same task
They are generally located in the same compartment.
What does the term ‘fixators’ refer to?
Synergists that stabilize a joint
They help maintain posture during movements.
What is myology?
The study of the structure, arrangement, and action of muscles
It includes understanding muscle actions relative to joints.
What is the function of the biceps brachii during elbow flexion?
Agonist for elbow flexion
It contracts to cause the elbow to flex.
What muscle acts as the antagonist to elbow flexion?
Triceps brachii
It is located in the posterior compartment.
What is the shape of the muscle fibers in smooth muscle?
Fusiform
These fibers are larger in the middle and tapered at both ends.
What is the primary role of skeletal muscle contraction?
To produce movement and maintain posture
It also generates heat.
What is extension in terms of joint movement?
Increase in the angle between two bones
It is the opposite of flexion.
What is the difference in nucleus count between skeletal and cardiac muscle cells?
Skeletal: multinucleate; Cardiac: uninucleate or binucleate
This reflects their different functional roles.
