ITEC A&p (Muscular System) Q&a

The correct answer is three (cardiac, smooth and skeletal) because these are the three main types of muscles found in the human body. Cardiac muscles are found in the walls of the heart and are responsible for its contractions. Smooth muscles are found in various organs and blood vessels, and they control involuntary movements. Skeletal muscles are attached to bones and are responsible for voluntary movements. Therefore, these three types of muscles cover the major muscle groups in the body.

Abduction refers to the movement of a bone away from the midline of the body or limb. This means that the bone is being moved in a direction that is away from the center of the body or limb. It is the opposite of adduction, which is the movement of a bone towards the midline. Therefore, the correct answer is "movement of the bone away from the midline."

The gluteus maximus is the largest muscle in the buttocks and is responsible for extending and lifting the trunk after sitting. It is involved in movements such as standing up from a seated position or straightening the body while sitting. The gluteus maximus works in conjunction with other muscles to provide stability and power during these movements.

The flexor carpi digitorum is a muscle of the lower arm and hand. It is responsible for flexing the wrist and fingers. The other options listed (tibialis anterior, soleus, and peroneus longus) are muscles of the lower leg and foot, not the lower arm and hand.

The muscular system is controlled by the nervous system. The nervous system is responsible for transmitting signals from the brain to the muscles, allowing them to contract and relax. This control is necessary for voluntary movements and coordination of muscle activity. The cardiovascular system is responsible for pumping blood and delivering oxygen to the muscles, while the integumentary system is responsible for protecting the body and regulating temperature. Therefore, neither of these systems directly control the muscular system.

The opposing relaxing muscle is known as the antagonist because it works in opposition to the agonist muscle. While the agonist muscle contracts to produce a movement, the antagonist muscle relaxes to allow that movement to occur smoothly. This relationship between the agonist and antagonist muscles is essential for coordinated and balanced movement.

Plantarflexion refers to the movement of pointing the toes downward. This movement is achieved by contraction of the muscles on the back of the lower leg, specifically the calf muscles. When the toes are pointed downward, the foot is flexed at the ankle joint, allowing for actions such as walking, running, and standing on tiptoes. Therefore, the correct answer is "point toes down".

The bladder is an example of smooth muscle. Smooth muscle is found in the walls of organs and structures such as blood vessels, the digestive system, and the urinary system. It is involuntary muscle tissue that contracts and relaxes to facilitate the movement of substances through these organs. The bladder is a hollow organ that stores urine and its smooth muscle allows it to expand and contract to accommodate varying amounts of urine.

Striated muscle tissue, also known as skeletal muscle tissue, is responsible for supporting and facilitating movement in the body. This type of muscle tissue is attached to bones and helps to generate force and movement through contractions. It is under voluntary control, meaning that it can be consciously activated and controlled by the individual. This allows for the execution of various movements such as walking, running, and lifting objects. Therefore, the function of striated muscle tissue is to support the body's structure and enable movement.

Triangularis is a muscle located in the corner of the mouth. It is responsible for pulling the corners of the mouth downward, which creates a frowning or sad expression. This muscle works in opposition to the zygomaticus muscles, which pull the corners of the mouth upward to create a smiling or happy expression. Therefore, the correct answer is corner of mouth.

The correct answer is Peroneus longus. Peroneus longus is a muscle located in the lower leg and foot. It is responsible for plantarflexion and eversion of the foot, as well as providing stability to the ankle joint. It also helps in maintaining balance and stability during walking and running.

The action of the levator labii superioris is to lift the upper lip. This muscle is responsible for elevating the upper lip, which can be seen when smiling or showing the upper teeth. It is involved in facial expressions and helps in various functions such as speaking, eating, and expressing emotions.

Skeletal muscle is classified as voluntary because it is under conscious control, meaning we can choose to contract or relax these muscles. Additionally, skeletal muscle is striated, which means it has a striped appearance due to the arrangement of its contractile proteins. This striation is a result of the organized arrangement of actin and myosin filaments within the muscle fibers.

Cardiac muscle is involuntary and striated. Involuntary means that it is not under conscious control, meaning we cannot control its contractions consciously. Striated refers to the presence of alternating light and dark bands, which give the muscle a striped appearance. Cardiac muscle is found in the walls of the heart and is responsible for the pumping action of the heart. Its involuntary nature allows for the continuous and rhythmic contractions necessary for the heart to function properly. The presence of striations is due to the arrangement of contractile proteins within the muscle cells, giving it the ability to contract forcefully.

Skeletal muscle cells are multinucleated, meaning they have multiple nuclei within a single cell. This is because skeletal muscles are large and require a significant amount of energy and protein synthesis to function properly. The multiple nuclei allow for efficient gene expression and protein production, contributing to the strength and contractile abilities of skeletal muscles. Cardiac and smooth muscle cells, on the other hand, are mononucleated, meaning they have only one nucleus per cell.

The tendon of Achilles, also known as the Achilles tendon, is formed by the combination of the soleus and gastrocnemius muscles. These two muscles merge together at the lower part of the calf and form a strong tendon that attaches to the back of the heel bone. This tendon is responsible for transmitting the force generated by the calf muscles to the foot, allowing for movements such as walking, running, and jumping.

The biceps femoris is a muscle located in the back of the thigh. Its main action is to extend the hip joint, which means it helps to move the thigh backward. Additionally, it flexes the knee joint, which means it helps to bend the leg at the knee. Therefore, the correct answer is "Extend the hip, flex the knee."

Each myosin filament is surrounded by six actin filaments. This is because in muscle contraction, myosin filaments interact with actin filaments to generate force. The myosin heads bind to the actin filaments, forming cross-bridges. The arrangement of six actin filaments surrounding a myosin filament allows for optimal interaction and force generation during muscle contraction.

The action of the rhomboids is to adduct the scapula. This means that they bring the scapula closer to the midline of the body.

The gluteus medius muscle is responsible for abducting and medially rotating the femur. This means that it helps to move the leg away from the midline of the body and rotate it inward. This action is important for maintaining balance and stability during activities such as walking, running, and standing on one leg.

The biceps femoris is a muscle located in the back of the thigh. Its primary action is to extend the hip joint, which means it helps to move the leg backward. Additionally, it also flexes the knee joint, which means it helps to bend the leg at the knee. Therefore, the correct answer is "Extends hip and flexes knee."

The peroneus longus muscle is responsible for everting the foot and plantarflexing the ankle. This muscle is located on the outer side of the lower leg and plays a crucial role in stabilizing the ankle during walking and running. When the peroneus longus contracts, it pulls the foot outward (eversion) and points the toes downward (plantarflexion). This movement helps in maintaining balance and stability while walking on uneven surfaces.

The Splenius Capitis muscle extends the head. It is a deep muscle located in the back of the neck and upper back. When it contracts, it helps to tilt and rotate the head, allowing for extension of the neck. The Sternocleidomastoid muscle is responsible for flexing the head and neck, the Erector Spinae muscles help to maintain posture and extend the spine, and the Trapezius muscle is involved in shoulder movement and stability.

Smooth muscle is involuntary and spindle-shaped. Involuntary means that it is not under conscious control, meaning we cannot control its contractions consciously. Smooth muscle is found in the walls of organs and blood vessels and helps with involuntary movements such as digestion and blood flow. The term "spindle-shaped" refers to the elongated shape of smooth muscle cells, which allows them to contract and relax in a coordinated manner. Smooth muscle is different from skeletal muscle, which is voluntary and striated, meaning it is under conscious control and has a striped appearance under a microscope.

The action of the orbicularis oris muscle is to close the mouth. This muscle, located around the lips, is primarily responsible for puckering the lips, closing the mouth tightly, and aiding in various facial expressions such as smiling, kissing, and speaking. It works by contracting, which brings the lips together, creating a seal to close the mouth. Additionally, the orbicularis oris muscle helps in controlling the movements of the lips during speech and eating. Overall, its main function is to facilitate the closure and shaping of the mouth, making it an essential muscle for various everyday activities involving facial expressions and oral functions.

The pectoralis major is the muscle responsible for rotating the arm medially. This muscle is located in the chest area and is responsible for movements such as adduction and internal rotation of the arm. When the pectoralis major contracts, it pulls the arm inward and rotates it towards the midline of the body. This allows for movements such as throwing a punch or hugging someone.

The serratus anterior muscle is responsible for drawing the shoulder forward and rotating the scapula. It is located on the side of the chest and connects the scapula to the rib cage. When this muscle contracts, it pulls the scapula forward and helps to rotate it, allowing for movement of the shoulder joint. The other muscles listed (rhomboid major, trapezius, and latissimus dorsi) have different functions and do not specifically draw the shoulder forward and rotate the scapula.

The teres minor muscle is responsible for adducting the arm and medially rotating the humerus. It is one of the four muscles that make up the rotator cuff in the shoulder joint. The teres minor works in conjunction with the other rotator cuff muscles to stabilize and control movements of the shoulder joint.

The action of the subscapularis muscle is to adduct the arm. Adduction refers to moving the arm towards the midline of the body. The subscapularis muscle is located on the anterior side of the shoulder joint and plays a role in stabilizing and rotating the arm. It helps in various movements, including adduction, internal rotation, and stabilization of the shoulder joint. Therefore, the correct answer is to adduct the arm.