Term
| What are the three types of muscle tissue and what is the function of each? |
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Definition
| Skeletal muscle tissue moves the body by pulling on bones of the skeleton. The cardiac muscle tissue of the heart pushes blood through the arteries and veins of the cardiovascular system. Smooth muscle tissues push fluids and solids along the digestive tract. |
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Term
| What is the perimysium? What structure would be located here? |
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Definition
| the perimysium is the connective tissue partition that seperates adjacent fasciculi in a skeletal muscle. The perimysium contain blood vessel and nerves that supple each individual fascicle. |
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Term
| Describe the difference between a tendon and an aponeurosis |
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Definition
| tendons are collagenous bands that connect skeletal muscle to the skeleton. Aponeuroses are thick flattened tendinous sheets |
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Term
| What is the difference between a myoneural junction and a motor end plate? |
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Definition
| A myoneural junction (also called a neuromuscular synapse) is the site where the anxon meets the muscle sarcolemna, or cell membrane. A motor end plate is the region of the sarcolemna at the neuromuscular synapse |
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Term
| Why does skeletal mucle appear striated when viewed with a microscope? |
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Definition
| skeletal muscle appear striated when viewed under a microscope because it is composed of the microfilaments actin and myosin, which are arranged in such a way as to produce a banded appearance in the muscle. |
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Term
| What are myofibrils? Where are they found? |
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Definition
| A myofibril is a cylindrical collection of myofilaments within a cardiac or skeletal muscle cell. |
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Term
| Myofilaments consist primary of what proteins? |
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Definition
| myofilaments consist primary of actin and myosin, along with accessory proteins of the thin filament (tropomyosin and troponin) |
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Term
| What is the functional unit of skeletal muscle? |
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Definition
| The functional unti of a skeletal muscle is the sarcomere |
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Term
| What two proteins help regulate actin and myosin interaction? |
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Definition
| The proteins tropomysin and troponin help regulate the actin and myosin interactions |
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Term
| What happens to the A bands and I bands of a myofibril during a contraction? |
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Definition
| During a contraction of the A band remains the same and the I band gets smaller. |
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Term
| List the sequence of activites during a contraction? |
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Definition
| Stimulation of a motor neuron triggers the release of chemicals at the neuromuscular synapse, which alters the transmembrane potiental at the sarcolemma. This change sweeps across the surface of the sarcolemna and into the T tubles. The change in the transmembrane potiental of the T tubules triggers the release of calcium ions by the sarcoplasmic reticulum The release intitates the contraction, which proceeds as myosin heads go through repeated cycles of attach-pivot-detach-return |
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Term
| How do terminal cisternae and transverse tubules interact to cause a skeletal muscle contraction? |
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Definition
| Terminal cisternae are expanded chambers of the sarcoplasmic reticulum--they store calcium ions, which are required to intiate contractile activities within skeletal muscle cells. Transverse tubules are sandwiched brtween terminal cisternae. A transverse tubule is in a invagination of the sarcolemma, which conducts the stimulation into the interior of the cell. On arrival it causes the release of calcium ions from the terminal cisternae, and this results in a muscle contraction. |
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Term
| What is a neurotransmitter? What does it do? |
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Definition
| A neurotransmitter is a chemical compound released by one neuron to affect the transmembrane potiental of another. |
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Term
| Why does a sprinter experience muscle fatigue after a few minutes, while marathon runner can run for hours? |
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Definition
| The sprinter requires a large amount of engery for a relatively short burst of engery. To supply this demand of energy, the muscles switch to anaerobic metabolism. Anaerobic metabolism is not as efficient in producing energy as is aerobic metabolism, and the process also produces acidic waste products. The combination of less energy and the waste products contribute to fatigue. Marthon runners on the other hand, derive most of their energy from aerobic metabolism, which is more efficient and does not produce the level of waste products that anaerobic metabolism does. |
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Term
| What type of muscle fibers would you expect to predominate in large leg muscles or someone who excels at endurance activities such as cycling or long-distance running? |
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Definition
| Individuals who are naturally better at endurance types of activites such as cycling or marathon running have a higher percentage of slow-twitch muscle fibers, which are physiologically better adapted to this type of activity than the fast-twitch fibers, which are less vascular and fatigue faster |
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Term
| Why do some motor units control only a few muscle fibers whereas other control many fibers? |
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Definition
| It depends on the number of branches in the motor neurons. A lesser number of branches (collateral) results in the activation in only a few motor neurons. |
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Term
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Definition
| Recruitment is the smooth but steady increase in muscular tension produced by increasing the number of active motor units. |
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Term
| What does the flexor digitorum longus tell you about this muscle |
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Definition
| This is a long muscle that flexs the joint of the finger |
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Term
| Describe the difference between orgin and insertion of a muscle |
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Definition
| Each muscle begins at an origin, which typically remains stationary, and ends at an insertion, which is the part of the muscle that moves during a contraction |
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Term
| What type of a muscle is a synergist? |
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Definition
| A synergist contracts to assist the prime mover in performing a specific action |
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Term
| What is the difference between a major and minor designations for a muscle? |
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Definition
| Major is used to describe muscles that are bigger, wheras minor is used to describe muscles that are smaller |
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Term
| The direct energy supply produced by the skeletal muscles in order to enable them to contract is? |
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Definition
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Term
| In a pennate muscle the fibers are ? |
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Definition
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Term
| ANother name for the muscle that is the prime mover is? |
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Definition
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Term
| Interactions between actin and myosin filaments of the sarcomere are responsible for? |
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Definition
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Term
| The theory that explains muscle contraction is formally known as as the |
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Definition
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Term
| The bundle of collagen fibers at the end of a skeletal muscle that attaches the muscle to bone is called |
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Definition
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Term
| All muscle fibers controlled by a single motor neuron constitute a |
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Definition
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Term
| Name the changes that occur in the skeletal muscles is a consequence of aging?- |
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Definition
-muscle fibers become smaller in diameter
-muscle become less elastic
-the number of myosatellitte cells decrease |
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Term
| Active sites on the actin become available for binding when? |
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Definition
| calcium binds to troponin |
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Term
| The function of a neuromuscular synapse is |
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Definition
| To facilitate chemical communication between a neuron and a muscle fiber |
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Term
| To lessen the rate at which muscles fatigue during a contraction motor units are activated |
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Definition
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Term
| The ability to recover from injuries in older individuals decrease because |
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Definition
-the number of myosatellitte cells decrease with age
- the amount of fibrous tissue in the muscle increases |
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Term
In which of the following would the ratio of motor neurons to muscle fibers be the greatest?
a. large muscles of the arm
b. postural muscles of the back
c. muscles that control the eye
d. leg muscles |
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Definition
| c. muscles that control the eye |
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Term
| If a person is cold, a good way to warm up is to exercise. WHat is the mechanism of this warming? |
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Definition
| muscle contraction uses ATP, and the utilization of this energy generates heat, which helps the body |
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Term
| Names of the muscles tell you about the particular muscle so what does the name rectus tell us? |
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Definition
| rectus- means straight; these muscles are parallel muscles who fibers generally run along the long axis of the body. |
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Term
| Names of the muscles tell you about the particular muscle so what does the name externus tell us? |
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Definition
| externus- Muscles are visible at the body surface |
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Term
| Names of the muscles tell you about the particular muscle so what does the name flexor tell us? |
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Definition
| flexor- Indicates that flexion is the primary function of the muscle. |
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Term
| Names of the muscles tell you about the particular muscle so what does the name trapezius tell us? |
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Definition
| trapezius- indicates the shape of the muscle |
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Term
| Summarize ths basic sequence of events that occur at a neuromuscular synapse |
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Definition
| A nerve impulse arrives at the terminal bouton of the neuromuscular synapse and causes acetylcholine to be released into the synaptic cleft. The acetlycholine released then binds to receptors on the sarcolemma surface, intiating a change in the local transmembrane potiental. This change results in a generation of electrical signals that sweep over the surface of the sarcolemma |
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Term
| What is the role of connective tissue in the organization of skeletal muscle? |
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Definition
| Connective tissue bind and attach skeletal muscles to other structures. There are three concentric layers of connective tissue. The outer layer, or epimysium, surrounds the entire muscle. The middle layer, or perimysium, divides the muscle into a series of internal compartments, each containing a bundle of muscle fibers. Each compartment is called a fascicle. The inner layer, or endomysium, surrounds each skeletal muscle fiber and binds each fiber to its neighbors. |
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Term
| A motor unit from a skeletal muscle contains 1500 muscle fibers. Would this muscle be involved in fine, delicate movements or powerful, gross movements? explain |
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Definition
| A motor unit with 1000 fibers would be involved in powerful, gross movements. The greater the number of fibers in a motor unit, the more powerful the contraction, and the less fine control exhibited by the motor unit |
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Term
| What is the role of the zone of overlap in the production of tension in a skeletal muscle? |
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Definition
| In the zone of overlap, the thin filiments pass between the thick filaments It is in this region that interaaction between thick and thin filaments occurs to form cross-bridges so that contraction may occur and tension may be generated |
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Term
| Tom broke his leg in a soccer game, and after six weeks in a cast, the cast is finally removed. Afterwards, as he stepped down fromt he table, heloses his balance and falls why? |
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Definition
| If a muscle is not stimulated by a motor neuron on a regular basis, the muscle will lose tone and mass and become weak (atrophy) During the time that Tom's leg was immobilized, it did not recieve sufficient stimulation to maintain proper tone. It will take a while for the muscle to build back up and support weight. |
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Term
| Severl anatomy students take up weight lifting and bodybuilding. After several months they notice many physical changes including an increase in muscle mass, lean body weight, and greater muscular strength? |
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Definition
| Weight lifting requires anaerobic endurance. The students would want to develop fast fibers for short-term maximum strength. This could be achieved by engaging in activities that involve frequent, brief but intenstive workouts, such as with progressive-resistance machines. Repeated exhaustive stimulation will help the fast fibers develop more mitochondria and a higher concentration of glycolytic enzymes, as well as increase the size and strength of the muscle (hypertropy) |
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Term
| Over the last 10 years several countries have intiated the practice of taking muscle bioposies of track athletes to determine if they are sprinters or long distant runners. How do they determine this? |
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Definition
| muscle biopsies are used to determine the relative of red and white muscle has a greater chance of being a good srinter than an individual with a higher percentage of red muscle Conversely, an individual with a high percentage of red muscle has a greater chance of being a good distance runner than an individual with a higher percentage of white muscle |
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Term
| Functions of muscle system: |
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Definition
-produce movement
-maintain body posture and position
-support soft tissues
-maintains body temperature
-guard entrances and exits |
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Term
| Properties muscle systems |
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Definition
1. excitability
2. Contractility
3 Extensibility
4. Elasticity |
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Term
| List the three layers of connective tissue framework |
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Definition
epimysium
perimysium
endomysium |
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Term
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Definition
| Dense irregular CT that seperates muscle from surrounding tissue and organs and is connected to deep fascia |
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Term
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Definition
| Divides muscle into servies of internal compartments (fascicles) |
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Term
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Definition
| Surrounds each skeletal muscle fibers; binds each muscle to its neighbor. Satellite cells lie between endomysium |
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Term
| The plasma membrane of the muscle cell is called the? |
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Definition
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Term
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Definition
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Term
| describe the thin filaments? |
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Definition
Composed of actin (Pearls like), troponin and tropomyosin
troponin binds to calcium
when troponin is bound to calcium, myosin can bind to actin (cross-bridge) |
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Term
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Definition
Composed of myosin
The myosin head is what attaches to actin in the presence of calcium |
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Term
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Definition
| is the entire length of thick filaments -Stains darker |
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Term
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Definition
| is the region that only includes thin filaments stains lighter |
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Term
| Sarcomere runs from what to what? |
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Definition
| one sarcomere runs from z-line to z-line |
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Term
| Each myofibril is surrounded by? |
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Definition
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Term
The Sarcoplasmic reticulum is a storehouse for ?
What happens when the cell has a electic signal? |
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Definition
The Sarcoplasmic reticulum is a storehouse for Calcium
What happens when the cell has a electic signal--the calcium is released. |
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Term
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Definition
| cross bridge = myosin head = Actin binding |
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Term
| What happens with contraction: |
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Definition
shortening of a sacromere
Actin and myosin form a cross-bridge
during contraction myosin pulls actin (thin filament) to the center of the sacomere. This shortens the sarcomere and the muscle-creating the contraction |
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Term
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Definition
somatic motor releases acetycholine (ACH) onto muscle fibers
-ACH causes the muscle cell to generate an electric signal (action potiental) which causes the cell to release calcium and contract. |
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Term
| Describe pennate muscles? |
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Definition
| Most muscle are pennate muscles they have a centeral body called a belly, which increases in diameter with contraction. One or more tendons run through the body of the muscle |
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Term
| Describe convergent muscles? |
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Definition
| (Deltoid) have versatility by using different portions of muscle. |
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Term
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Definition
| the lines that transmit the forces generated by muscle contraction |
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Term
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Definition
| like a pulley that changes the direction of a force |
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Term
| naming a skeletal muscle by 6 ways? |
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Definition
shape
location
attachment
orientation of fibers
specific structure features
action |
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Term
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Definition
| remains stationary and is proximal to the insertion |
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Term
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Definition
| moves and is distal to the origin |
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Term
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Definition
prime mover or agonist
synergist- assist the prime mover
antagonist-action opposes that of the agonist |
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