1. List 3 major muscle pairs. What are muscle pairs?
Muscles commonly occur in groups of two, called muscle pairs. As one muscle in the pair contracts the other one relaxes, creating movement. The human body is made up of many different muscle pairs, though some are more important than others. Examples of three major muscle pairs are the biceps and triceps for bending and straightening the elbow, the quadriceps and hamstrings for bending and straightening of the knee, as well as the deltoids and lattisimus dorsi for lifting the arm and lowering the arm.
2. Describe the structure of skeletal muscles. What do muscle fibers consist of?
A skeletal muscle is a type of striated muscle connected to the skeleton. There purpose is to create movement by applying force to bones and joints. Skeletal muscles are made up of many smaller units called muscle fascicles, and those are made up of even smaller units called muscle fibres. A muscle fibre is a single cell that contracts when stimulated. It is made up of bundles of myofibrils, thick and thin filaments arranged in sacromeres.
Skeletal muscles vary considerably in size, shape and the arrangement of these muscle fibres.
3. Describe the sliding filament theory of muscle contraction. How is movement created?
The sliding filament theory of muscle contraction is a theory that describes how muscles contract to produce force. In muscles there are both thick and thin muscle filaments within the sacromere. The thin filament slides over the thick filament to create tension in the muscle, shortening the sacromere’s length.
4. Define types (fast twitch/slow twitch) of muscle fibres and list their characteristics. Which muscle fiber type has a better ability to use oxygen?
Muscle fibres can be categorized into two different types, fast twitch and slow twitch. On average we have about 50% slow twitch and 50% fast twitch fibres in most muscles used for movement though the percentage of each type of muscle fibre depends on a variety of factors such as muscle function, training and genetics. Slow twitch fibres are most efficient at using oxygen to generate fuel for continuous, extended muscle contractions over a long time. As a result, this fibre type is best suited for endurance activities such as marathons or long distance cycling. In contrast, fast twitch fibres are best suited for generating short bursts of strength or speed, but fatigue more quickly.
One of the most important muscles in both a mink and a human are those of the arms and shoulders because of their involvement with movement. One of the primal movers of arm abduction along the frontal plane is the deltoid muscle found in both minks and humans. In both species, deltoid muscles allow for the abduction of the humerus. The next two muscles are the biceps brachii and its opposing muscle the triceps brachii. The biceps brachii consists of two heads, which arise from the scapula and join to form a single muscle that ends upon the upper forearm. The most important functions of the biceps brachii are the supination of the forearm and the flexing of the elbow. The triceps brachii on the other hand extends the forearm in both minks and humans and has three heads as opposed to two in its antagonist biceps brachii (Scott). The origin of the triceps brachii is also from the scapula like the biceps brachii. In a mink, the extensor digitorium originates on the lateral epicondyle of the humerus yet in humans it is present in the posterior forearm and is responsible for extending the phalanges, wrist, and elbow in both species. Anothier muscle with similar functions to the extensor digitorium is the flexor carpi ulnaris but instead it is soley responsible for flexin...
In the beginning phases of muscle contraction, a “cocked” motor neuron in the spinal cord is activated to form a neuromuscular junction with each muscle fiber when it begins branching out to each cell. An action potential is passed down the nerve, releasing calcium, which simultaneously stimulates the release of acetylcholine onto the sarcolemma. As long as calcium and ATP are present, the contraction will continue. Acetylcholine then initiates the resting potential’s change under the motor end plate, stimulates the action potential, and passes along both directions on the surface of the muscle fiber. Sodium ions rush into the cell through the open channels to depolarize the sarcolemma. The depolarization spreads. The potassium channels open while the sodium channels close off, which repolarizes the entire cell. The action potential is dispersed throughout the cell through the transverse tubule, causing the sarcoplasmic reticulum to release
...st the sacrolemma will depolarized, thus activation potentials along the T-tubules. This signal will transmit from along the T-tubules to sarcroplasmic reticulum's terminal sacs. Next, sarcoplasmic reticulum will release the calcium into the sarcroplasm leading to the next second event called contraction. The released calcium ions will now bind to troponin. This will cause the inhibition of actin and mysoin interaction to be released. The crossbridge of myosin filaments that are attached to the actin filaments, thus causing tension to be exerted and the muscles will shorten by sliding filament mechanism. The last event is called Relaxation. After the sliding of the filament mechanism, the calcium will be slowly pumped back into the scaroplasmic reticulum. The crossbridges will detach from the filaments. The inhibition of the actin and myosin will go back to normal.
Within skeletal muscle there are extremely small structures that form the muscle and allow contractions and movement to occur (epimysium, perimysium, endomysium, fascicles, fiber, sarcomere, sarcoplasmic reticulum and t tubules). These structures all play a role in protecting, connecting and transporting substances throughout the muscle fibers. They are also the main contributors to movement.
The musculoskeletal system offers support and stability for your body so we can properly function and move around. Different types of muscle within the muscular system include cardiac, skeletal, and smooth. The reason our bodies are capable of producing movement is because of the way our muscles contract. Our adult skeletal structure is made up of 206 bones that all differ in shapes and sizes. The composing parts that make up the system include the bones, joints, and muscles that all connect so we’re capable of moving. These components allow for our bodies to maintain a stable structure that can keep us upright. The axial skeleton refers to the skull, the vertebral column which supports the spinal cord, ribs, and sternum. It offers protections
As we have learned through our reading, most all bodies skeletal muscles are made up of primarily three types of skeletal muscle fibers, but their proportion differs depending on what action the muscles is doing. For example, type I fibers such as muscles of the neck, back, and leg have a higher proportion. According to Quinn (2014), type I muscles are slower and more effective, they tend fire a lot slower than fast twitch fibers and they fatigue at a much slower rate. Hence, slower twitch fibers are pronounced at helping athletes run marathons and bicycle for hours. Shoulder and arm muscles are not always active but are intermittent in their use; these muscles tend to have a larger amount of tension for uses in throwing and lifting. These muscles have a combination of both type I and type II B fibers. These fast twitch fibers use anaerobic metabolism to create energy and are the "classic" fast twitch muscle fibers that excel at producing quick, powerful bursts of speed. These muscles are used in events such as 100m sprint, basketball, soccer and football. Since this muscle fiber fires at such a high rate of contraction it will fatigue much faster and will not last long before needing to rest.
The surfaces of the joint are organised to allow only back and forth motion such as bending and straightening. This type of joint can be found between your upper arm and your lower arm, in the elbow. This type of joint is incredibly important as it allows an up and down movement, without this type of joint, we wouldn’t be able to move our arm up and down. Muscles are attached to this type of joint by tendons to allow it to contract and relax and be able to move the bone within this joint. Ligaments attach the bones in a hinge joint together, for example, the humerus and the tibia are joined by ligaments but they also have antagonist muscle pairs attached to them by tendons which allow the bone to move by contraction and relaxation of the muscles.
Skeletal, smooth, and cardiac muscles play a vital role in the everyday processes that allow the human body to function. Without these muscles, everyday tasks and functions could not be conducted. Injury to these muscles could cause serious problems, however, these muscles have the ability to regenerate, repair, and fix multiple problems all by themselves. Repair and regeneration of a muscle are two similar, yet different things. Repair restores muscle continuity so that it can continue to function in the same way as before injury, but does not completely restore the pre-injury structure like regeneration (Huijbregts, 2001). Muscle repair and regeneration take place after an injury, after surgery, after atrophy, and even after working out.
The skeletal system assists the muscular system to provide movement for the body. Certain muscles that are attached to bones contract and pull on the bones resulting in movement.
The muscular system is the set of all the muscles that make up the human body. It is an extensive system of muscles and nervous tissue, which is distributed all through the body. In total, the human body consists of approximately 650 muscles. The muscular system is divided into three types of muscle: cardiac muscle, smooth muscle, and skeletal muscle.
The musculoskeletal system is made up of bones, muscles, cartilage, tendons, ligaments, joints and other connective tissue that supports and binds tissue and other organs together. Each muscle is a discreet organ constructed of skeletal muscle tissue, blood vessels, and nerves. Did you know there are roughly 600 organs that make up the muscular system? They include the cardiac muscles, smooth muscles, and skeletal muscles to name a few. The heart is the cardiac muscle. Smooth muscle are the tissues that line blood vessels and organs, such as the stomach and intestines. The skeletal muscles, which are the most well known and familiar of the muscle organ system, helps hold the skeletal frame work together. They make up bout 40 percent of the
The soleus, gastrocnemius and tibialis anterior contract isometrically to keep the ankle stable at 90 degrees (Teachpe.com n.d.) (The previous reference was used to identify key joint types and muscles throughout my analysis). The knee joint is extended when in the standing position, to stabilize this joint the biceps femoris, semi-mebranosus, semi-tendonosus (hamstrings) and the rectus femoris, vastus lateralis, vastus transcriptis and vastus medialis (quadriceps) co-contract isometrically. The vertebral column of the body remains stable due to the isometric co-contraction of the erector spinae, rectus abdominus and the external and internal obliques.... ...
The sarcomere is found in structures called myofibrils which make up skeletal muscle fibres. Within the sarcomere there are various different proteins. One of the most significant, myosin is found in the thick filaments of the sarcomere. Although both cells contain myosin, it is important to highlight that smooth muscle cells contain a much lower percentage of myosin compared to skeletal muscle cells. Despite this, myosin filaments in smooth muscle cells bind to actin filaments in a manner similar to that in skeletal muscle cells; although there are some differences. For instance, myosin filaments in smooth muscle cells are saturated with myosin heads so that myosin can glide over bound actin filaments over longer distances, enabling smooth muscle cells to stretch further, whilst in skeleta...
The three functions of the skeletal system are to support, to allow movement, and to protect. The skeleton is the framework of the body and also cradles its soft organs, with it the body would be just a jelly mass it wouldn’t have no definite shape and would just collapse. It supports the softer tissues and provides points of attachment for more skeletal muscles to hold all of the parts of the body upright. For example, the bones of the legs as pillars to support the body trunk we stand up. It also supports the body against the pull of gravity. The skeletal allows movement. The skeletal muscle attached to the bones by tendons and uses the bones as a simple mechanical lever system to move the body and its parts. All together with the muscles
Muscle tissues grow by means of physical activity in the same way they are able to become more well-defined (with regards to physical