Muscular System Overview
About how many muscles are in the Muscular System?
>600 (~640)
What is the difference between fascia and tendon?
Fascia connects muscles to other structures
Which model describes the mechanism of muscle contraction, what are the names of the 4 phases in order
Sliding Filament Model
1. Excitation
2. Cross Bridge formation
3. Power Stroke
4. Relaxation
What are the names of the 2 primary attachment points in muscle on bone, and how are they different?
Origin - attaches to the bone it's not moving
Insertion - attaches to the bone that it is moving
Slide 1
(From left to right)
Tendon
Epimysium
Perimysium
Endomysium
What are the three types of muscle tissue, and define which are voluntary and which are involuntary
Involuntary = smooth and cardiac muscle
Voluntary = skeletal muscle
What are the 3 connective tissues that make up muscle? What does each connective tissue surround?
Epimysium = surrounds entire muscle
Perimysium = surrounds a fascicle
Endomysium = surrounds a muscle fiber
Describe what happens during phase 1 of contraction? Include the following terms; Neuron, neuromuscular junction, action potential, receptors, acetylcholine (ACh), sarcolemma, t-tubule, calcium
Action potential travels through the neuron and arrives at the neuromuscular junction. The neuron releases ACh across the junction and binds to receptors on the sarcolemma. The ACh "excites" the t-tubule in the muscle fiber, and releases calcium.
What is the difference between the agonist and antagonist? What is an example of an agonist and antagonist relationship?
Agonist = prime mover; the main muscle involved with a movement
Antagonist = reverses the movement of an agonist
examples varies
Slide 2
(From left to right)
Entire Muscle
Fascicle
Muscle Fiber
Myofibril
What are 3 functions of the skeletal muscles? What makes those functions possible?
1. Support
2. Movement
3. Stabilization of Joints
4. Generate Heat
5. Protect internal organs
Made possible by contraction
What is a fascicle, and how does it contribute to the structure of muscle?
Fascicles are a bundle of muscle fibers within a muscle. Muscles are composed of multiple fascicles, and each fascicle contains individual muscle fibers. The arrangement of fascicles within a muscle contributes to it's contractile capabilities
Describe what happens during phase 2 of contraction? Include the following terms; calcium, sarcomere troponin, actin binding site, actin, shape, myosin head, ATP
Calcium binds to troponin causing it to change its shape, exposing the actin binding site on actin. Myosin heads then bind to actin using ATP
True or false - The agonist and antagonist can switch roles (the agonist in one movement, could be an antagonist in another movement)
True
Slide 3
look for two z-lines for the boundary of the sarcomere
Actin are thin blue filaments extending from the z-line.
Myosin are the thick red lines between the actin
What is the contractile unit of muscle
Sarcomere
What is the correct order, from largest to smallest, of the structures mentioned below;
Myofibrils, Muscle Fiber, Muscle, Sarcomere, Myofilaments, Fascicle.
Muscle --> Fascicle --> Muscle Fiber --> Myofibrils --> Sarcomere --> Myofilaments
Describe what happens during phase 3 of contraction. Include the following terms; actin, myosin heads, ATP, m-line
Actin is pulled by myosin heads toward the m-line of the sarcomere. ATP is released
What is the name of the two structures that assist an agonist, and how do they assist?
Synergist - helps the agonist move
Fixator - stabilizes the origin of the agonist
Slide 4
(from left to right)
Z-line, Myosin, Actin
What are the two primary myofilaments involved with contraction? Which one is moving and which one is not moving during contraction?
Actin = moving
Myosin = not moving
Double Jeopardy
What is a sarcomere? How is it generally organized? Include the following terms: M-line, A-band, I-band, Z-line, M-line, H-zone, actin, and myosin
A sarcomere is the contractile unit of muscle.The Z-lines marks its edges and attaches actin. The I-band has only actin and shortens during contraction. The A-band has both filaments and remains constant. The H-zone in the A-band has only myosin and narrows during contraction. The M-line at the sarcomere center stabilizes myosin.
Describe what happens during phase 4 of contraction. Include the following terms; actin, myosin head, ATP, cocked-position, shape, actin binding site, troponin
Another ATP binds to the myosin head causing it to release from the actin and return to a "cocked-position." The troponin returns to its original shape covering the actin binding site.
What does the muscle do to a bone to produce movement? Include the type of attachment point.
The muscle pulls on the bone from it's insertion
Slide 5
(starting at the top, then bottom left to right)
M-line, H-zone, I-band