Find study materials for any course. Check these out:
Browse by school
Make your own
To login with Google, please enable popups
To login with Google, please enable popups
Don’t have an account?
To signup with Google, please enable popups
To signup with Google, please enable popups
Sign up withor
What are the three major types of muscle tissue? What are their functions?
1. Skeletal: movement
2. Cardiac: Contracts in time (found in heart)
3. Smooth: Moves food through digestive tract, blood vessels, lung passages, uterine contractions.
Identify the common properties shared by muscle tissues.
Identify the primary functions of skeletal muscle.
1. Producing Movement
2. Maintaining Posture and Body
3. Supporting soft tissues
4. Guarding Body Entrances and Exits
5. Maintaining Body Temperature
6. Storing Nutrients
Describe the three connective tissue layers associated with skeletal muscle tissue
1. Epimysium: Surrounds entire muscle.
2. Perimysium: Surrounds Musle Fascicles
3. Endomysium: Surrounds Muscle Fibers
How would serving the tendon attached to a muscle affect the muscles ability to move a body part?
Where they contact the bone, collagen fibers extend into the bone matrix, providing a firm attachment. because of this, any contraction of the muscle pulls on the attached bone.
Describe the Components of sarcomere
A Bands= Dark Bands; Contain Thick Myosin and Thin Actin Filaments.
I Bands = Light Bands; Contains only Thin Filament
M Line = Middle; center of the A Band
H Band = lighter region on either side of M Line; Contains thick filaments only.
Why do skeletal muscle fibers appear striated when viewed through a microscope?
Because of the precise arrangements of thin (actin) & thick myosin filaments.
Where would you expect to find the greatest concentration of Ca2+ in a resting skeletal muscle fiber?
In the terminal cisternae of the sarcoplasmic reticulum
Describe the structure of the neuromuscular junction.
The neuromuscular junction contains the nerve ending, the synaptic cleft which is the space between the nerve ending and motor end plate, and finally the motor end plate which is folded in shape and is part of the sarcolemma with receptors for Ach.
How would a drug that blocks ACh release affect muscle contraction
ACh is necessary because it serves as the first step in the process, enabling cross-bridge formation. Blocking it would interfere w/ formation and prevent muscle contraction
What would happen to a resting skeletal muscle if the sarcolemma suddenly became very permeable to Ca2+?
The intracellular concentration of Ca2+ would increase, and the muscle would contract. In addition, because the amount of Ca2+ ions in the intracellular fluid must decrease for relaxation to occur, the muscle may not be able to completely relax.
Predict what would happen to a muscle if the motor end plate failed to produce acetylcholinesterase?
Without acetlycholinesterase, the motor end plate would be continuously stimulated by acetylcholine, locking the muscle in a state of contraction
Why does a muscle that has been over stretched produce minimal tension
An increase in sarcomere length reduces the tension produced by reducing the zoned overlap and the number of cross bridges
Can a skeletal muscle contract without shortening?
Yes. The muscle can shorten(isotonic, concentric), elongate (isotonic, eccentric) or remain the same length (isometric) depending on the relationship bt the load (resistance) and the tension produced by the actin- myosin interactions.
How do muscle cells continuously synthesize ATP?
Muscle cells synthesize ATP continuously by utilizing creatine phosphate (CP) and metabolizing glycogen and fats. Most cells generate ATP through aerobic metabolism in the mitochondria and through glycolysis in the cytoplasm
The amount of oxygen consumed during recovery from exercise, above that ordinarily consumed at rest in the same time period. There is a rapid component (alactacid) and a slow component (lactacid).
Structural Characteristics of Smooth Muscle Tissue
Nonstriated tissue; Different internal organization of actin and myosin; Different functional characteristics;
Which type of muscle tissue is least affected by changes in extracellular Ca2+ concentration during contraction?
Why can a smooth muscle contract over a wider range of resting lengths than a skeletal muscle can?
The looser organization of actin and myosin filaments in the smooth muscle allows smooth muscle to contract over a wider range of resting lengths.
Identify the three types of skeletal muscle fibers
Describe Muscle Fatigue
When it can no longer perform at the required level of activity
1. Depletion of metabolic reserves
2. Damage to the sarcolemma and sarcoplasmic reticulum
3. a decline in pH within the muscle fibers and the muscle as a whole.
Describe age-related effects on skeletal muscle tissue
-skeletal muscle fibers become smaller in diameter- decrease in myofibrils, small ATP and glycogen reserves, decrease in blood flow
-skeletal muscles become less elastic- increase in fibrosis (loss of flexibility)
-tolerance of exercise decreases
Why would a sprinter experience muscle fatigue before a marathon runner would?
Because a sprinter's muscles rely on Anaerobic metabolism
Which activity would be more likely to create an oxygen debt: swimming laps or lifting weights
Activities that require short periods of strenuous activity - lifting weights
Which type of muscle fibers would you expect to predominate in the large leg muscles of someone who excels at endurance activ
Slow fibers are better adapted to endurance activities than are fast fibers.
Compare and contrast Skeletal, Cardiac, and Smooth muscle tissue. (Define all 3)
Skeletal - Striated appearance cylindrical shaped, creates movement
Cardiac - Striated appearance, branching cylindrical shaped, found only in the heart, has intercolated disks, involuntary
Smooth - spindle shaped, no striations, involuntary, found
How does cardiac muscle tissue act as a functional syncytium?
All cells work together at once because they’re connected by intercalated discs, allowing AP to propagate from one cell to another
The connective tissue coverings of a skeletal muscle, listed from superficial to deep are
The signal to contract is distributed deep into a muscle fiber by the?
The detachment of the myosin cross bridges is directly triggered by
The hydrolysis of ATP
A muscle producing near peak tension during rapid cycles of contraction and relaxation is said to be in
The type of contraction where the tension rises, but the load does not move is?
An action potential can travel quickly from one cardiac muscle cell to another because of the presence of
Gap junctions and intercalated discs
What are the 3 types of muscle tissue in the body
What are the three layers of connective tissue surrounding a muscle?
Epimysium: surrounds entire muscle
Perimysium: surrounds fascicles
Endomysium: surrounds individual muscle fibers
The _____ contains vesicles filled with the acetylcholine
What structure feature of a skeletal muscle fiber propagates action potentials into the interior of the cell
What five interlocking steps are involved in the contraction process?
Exposure of active sites, attachment of cross bridges, pivoting of myosin head (power stroke), detachment of cross-bridges, activation of myosin heads (cocking)
what 2 factors affect the amount of tension produced when a skeletal muscle contracts?
1. the frequency of motor stimulation
2. the number of motor units involved
What forms of energy reserves do resting skeletal muscle fibers contain?
ATP, creatine phosphate, glycogen
what two processes are used to generate ATP from glucose in muscle cells?
aerobic metabolism & glycolysis generate ATP from glucose in muscle cells
What is the calcium binding protein in smooth muscle
An activity that would require anaerobic endurance is?
Levels of the body where you would not expect to find slow fibers
Eye and hand
during relaxation muscles return to their original length because of all the follwing XCept
actin and myosin actively psuhing away from one another
According to the length tension relationship
-the greater the zone of overlap in the sarcomere the greater the tension the muscle can develop
-there is an optimum range of actin and myosin overlap that will produce the greatest amount of tension
What are the events (in order) for each portion of a myogram tracing a twitch in a stimulated calf muscle fiber?
1. Initial latent
2. Contraction phase
What three processes are involved in repaying the oxygen debt during a muscle's recovery period?
1. O2 by liver cells
2. O2 by skeletal muscle fibers
3. O2 in blood and tissues
How does cardiac muscle tissue contract without neural stimulation?
Cardiac muscle tissue has the property of automaticity The concentrations are timed by pacemaker cells, specialized in cardiac muscle fibers
Explain why a murder victim's time of death can be estimated according to the flexibility or rigidity of the body.
Due to rigor mortis
Which of the following activities would employ isometric contractions?
Maintaining an upright posture
Sign up for free and study better.
Get started today!