Chapter 9- Muscular system
Which three characteristics are signs of aging in the muscular system?
Slow reflexes Weak contractions Atrophy
Name the invaginations of the sarcolemma that extend through the muscle fiber.
Transverse (T) tubules
Numerous openings in the sarcolemma of a muscle fiber lead down into structures called the _____.
Transverse tubules
What structures are positioned between adjacent cisternae of the sarcoplasmic reticulum?
Transverse tubules
A T-tubule and its two adjoining cisternae constitute a(n) _____.
Triad
Name the long rod-like protein that sets in the longitudinal grooves along the thin filaments.
Tropomyosin
The protein _____ holds tropomyosin in place along the thin filament.
Troponin
List the three components of thin filaments.
Troponin, Actin, Tropomyosin
What three proteins from the thin filaments of muscle myofibrils?
Troponin, Actin, Tropomyosin
True or false: Muscles tend to atrophy with age.
True
True of false: The transverse tubules are located between structures called cisternae.
True- Cisternae are enlarged (dilated) areas of the sarcoplasmic reticulum.
What are thin filaments composed of?
Two intertwined strands of actin
As indicated by its name, the quadriceps femoris has _____ origins.
4
Identify the components of a muscle triad.
A T tubule and its associated cisternae
The root word -troph means "well _____".
Fed
Due to their shape, muscle cells are also called muscle _____.
Fiber
Due to their shape, muscle cells are also called muscle _____.
Fibers
A _____-class leer has its components arranged as resistance-fulcrum-force.
First
The triceps brachii is the main muscle that causes extension of the elbow. What is the name of the role of the triceps brachii in this example?
Acts as prime mover
A muscle that functions to cause an action is referred to as the _____.
Agonist
Binding sites for the myosin heads (cross-bridges) are found on the which of the proteins found within the thin filaments?
Actin
Troponin and tropomyosin are associated with that other protein within the muscle fibers?
Actin
A muscle that opposes the action at a joint is classified as a(n) _____
Antagonist
A broad sheet of fibrous connective tissue that attaches a muscle to aonnective tissues of adjacent muscles is called a(n) _____.
Aponeuroses
Where is perimysium found?
Around individual muscle fascicles
What is the name of the network of membranous channels that surrounds each myofibril within a muscle fiber?
Sarcoplasmic reticulum
What are tendons?
Bands of dense connectie tissue that attach skeletal muscles to bones
What are tendons?
Bands of dense connective tissue that attach skeletal muscles to bones
What are myofibrils?
Bundles of proteins in a muscle cell
What root word means something inserted?
Calat-
A space enclosed in fascia containing a group of muscles and their associated blood vessels and nerves is called a(n) _____.
Compartment
Which muscle type has multinucleated cells that are cylindrical in shape?
Skeletal muscle
Differentiate between the deep fascia and the subcutaneous fascia.
Deep fascia surrounds individual muscles; subcutaneous fascia underlies the skin
What is fascia?
Dense connective tissue surrounding and separating muscles
Indicate three characteristics of skeletal muscle fibers.
Elongated cells, Multinucleated, Cylindrical shape
Name the connective tissue layer that surrounds individual muscle fibers within a muscle.
Endomysium
The layer of connective tissue that most closely surrounds an entire skeletal muscle is called the _____.
Epimysium
Correctly list, from superficial to deep, the connective tissue layers associated with a skeletal muscle.
Epimysium Perimysium Endomysium
Match the connective tissue layers with the structures they surround.
Epimysium- Entire muscle, Endomysium- Muscle fiber, Perimysium- Fascicle
What is the meaning of the word root iso- (as in isotonic)?
Equal
A bundle of skeletal muscle fibers enclosed by a perimysium forms a(n) _____ within a muscle.
Fascicles
List the arrangement of components found in a second-class lever.
Fulcrum-resistance-force
Within a sarcomere, the region within the A band that lacks thin filaments is called the _____.
H zone
What is the meaning of the root word laten- (as in latent period)?
Hidden
The prefix _____ means over or more.
Hyper-
Actin (thin) filaments are attached to a Z line, which is located in the middle of what region of the striations?
I band
The _____ region of a sarcomere is composed primarily of actin.
I band
Match each striation and with its composition.
I band (light band)- Actin (thin) filaments only A band (dark band)- Myosin and actin filaments H zone- Myosin (thick) filaments only
When a muscle contracts, its attachment point, called its _____, is pulled towards its origin.
Insertion
What root word means between?
Inter-
A simple mechanical device consisting of a rigid bar, a fulcrum, weight, and a force that is applied to some point on the bar is called a(n).______
Lever
The upper limb, as it bends at the elbow, can be viewed as a lever. For each upper limb structure, indicate what part of a lever it corresponds to.
Muscles of anterior arm- Force that supplies energy Forearm bones- Rigid bar/rod Hand holding a weight- object moved against resistance Elbow joint- Fulcrum (pivot point)
The biceps brachii is an organ of the _____ system.
Muscular
What root word means "muscle"
Myo-
Long bundles of contractile proteins found in the sarcoplasm are called _____.
Myofibrils
The thick filaments are composed of _____ proteins.
Myosin
What are the two major protein types found in myofibrils?
Myosin, actin
The end of a muscle that is fixed (relatively immovable) is called its _____.
Origin
The point of attachment for a muscle that remains relatively stationary is its _____.
Origin
Name the connective tissue layer that separates a skeletal muscle into fascicles.
Perimysium
Within a sarcomere, what is the H zone?
Region within the A band that lacks thin filaments
List the four components of a lever.
Rigid bar or rod Pivot point Object to move Force
What word root means flesh?
Sarco-
What term is used for the plasma membrane of a muscle fiber?
Sarcolemma
Within myofibrils, the area between two successive Z lines is called a(n) _____.
Sarcomere
Myofibrils are formed by many _____ positioned end-to-end.
Sarcomeres
The organization of the thin and thick filaments within a muscle cell results in the formation of what muscle feature?
Striations
What root word means "together"?
Syn-
Any muscle that assists the agonist during a movement is called a(n) _____.
Synergists
Dense connective tissue cords that anchor muscles to bone are called _____.
Tendons
What root word means stiff?
Tetan-
Which of the following best describes the M line found within sarcomeres?
The M line is in the middle of the H zone, providing an attachment point for the thick filaments.
Describe the dark bands in the striations of skeletal muscle fibers.
They are called A bands and include the area of overlap of actin and myosin.
Intertwined strands of actin make up part of the _____ filaments.
Thin
A _____-class lever has its components arranged as resistance-foce-fulcrum.
Third
The protein called _____ anchors myosin filaments to the Z lines.
Titin
When describing the roles of muscles in an action, what is the role of the agonist?
To cause an action
What is the meaning of the root word syn-?
Together
What is the meaning of the root word erg- (as in the term synergist)?
Work
Dense connective tissue cords that anchor muscles to bone are called _____.
tendons