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Foundations in Sports Science 1 Functional anatomy Check your understanding answers 1 Describe the axial and appendicular skeleton, making reference to the names, types of bones and their function. The axial skeleton forms the upright axis of the body and consists of the following: Cranium which consists of the parietal, temporal, frontal, occipital, ethmoid and sphenoid bones, these are all flat bones and their function is to provide protection to the brain. Facial bones consisting of maxilla, zygomatic, mandible, nasal, palatine, inferior nasal concha, lacrimal and vomer bones. These are composed of irregular and flat bones, their function is to protect, provide support and shape, as well as attachment of facial and head muscles. Hyoid bone, which is a U shaped bone located in the neck. Vertebral column consisting of the cervical, thoracic and lumbar vertebrae, as well as the scrum and coccyx. These are irregular bones which provide support, and attachment for muscles. Thoracic cage consisting of the sternum and ribs. These are flat bones which provide protection for the heart and lungs, as well as attachment for muscles. Auditory ossicles consisting of the malleus, incus and stapes found in the inner ear. The appendicular skeleton consists of all the bones which attach to the axial skeleton, and can be divided into six regions: Each arm and forearm consists of humerous, ulna, and radius. These are long bones which provide attachment sites for muscles. They provide the lever in order for movement to occur. Each hand consists of 8 carpals, 5 metacarpals, 5 proximal phalanges, 4 middle phalanges, 5 distal phalanges and 2 sesamoid. These are short bones Each pectoral girdle consists of 2 clavicles and 2 scapulae. These are flat bones and provide protection for the heart and lungs. The pelvis consists of left and right os coxae, which are formed by the fusion of the illium, ischium and pubis. Comprised of irregular and flat bones, providing protection for the reproductive organs. Each leg consists of a femur, tibia, patella and fibula. These are long bones. © Pearson Education Ltd 2012 1 Foundations in Sports Science Each foot contains 7 tarsals, 5 metatarsals, 5 proximal phalanges, 4 middle phalanges, 5 distal phalanges and 2 sesamoid bones. These are short bones. Whilst flat bones’ main function if to provide protection, the entire skeleton system provides attachments for skeletal muscles via tendons, and for ligament attachment. The skeletal system therefore provides a lever system in order to create joint motion and movement. Support is provided giving the body a supportive framework for the soft tissue, and providing shape. Bone is a source of red blood cell production. The red bone marrow found within the bone produces red blood cells, white blood cells and platelets. Bone also provides storage for minerals such as calcium, phosphate (a stored form of phosphorus) and magnesium, which are essential for growth and bone health. Minerals are released into the bloodstream as the body requires them. The yellow bone marrow stores fat. 2 Briefly describe the three classifications of joints. There are three classifications of joints Synarthrosis (Fibrous/Fixed), Amphiarthrosis (Cartilaginous/Slightly moveable) and Diarthrosis (Synovial/Freely moveable). Synarthrosis Theses bones articulate at fibrous joints and are connected via fibrous connective tissue. Movement is not available at these joints. They are further divided into 3 categories: Suture(s) example – found between the cranial bones Gomphosis (-es) example – tooth in its socket Syndesmosis (-es) example – Inferior tibiofibular joint Amphiarthrosis These bones articulate at cartilaginous joints and are connected by either hyaline (articular) cartilage forming a primary joint (first sternoclavicular joint), or secondary joint formed from fibrocartilage (intervertebral disc), which may contain an internal cavity or nucleus. Movement permitted is greater than at fibrous joints. Diarthrosis Synovial joints are unique and allow a greater degree of movement than fibrous and cartilaginous. Articular cartilage encases the end of bones that articulate at the joint, allowing freedom of movement and reduction of friction. The joint is surrounded by a strong fibrous capsule, which is lined with a synovial membrane (synovium) providing lubrication and nourishment to the articular cartilage. The ligaments attach bone to bone and further strengthen the fibrous capsule. Ligaments are located internally and externally to the capsule, and further supported by the surrounding muscles and strong tendons. Ligaments’ function is to provide joint stability and thus preventing dislocation. If excessive movement occurs ligaments may become damaged. 3 Describe the gross structure of a muscle. The cell membrane of a muscle fibre is called the sarcolemma. Individual muscle fibres are covered with connective tissue called the endomysium. Muscle fibres are © Pearson Education Ltd 2012 2 Foundations in Sports Science bundled together into fascicles encased by connective tissue called the perimysium. All the fascicles are collated together and encased by connective tissue called the epimysium, which surrounds the whole muscle. The endomysium, perimysium and epimysium all extend from the deep fascia into a tendon. 4 Describe the micro structure of a muscle. A muscle fibre is made up of myofibrils which are the length of the muscle fibre. Myofibrils are made up of sarcomeres, which are units repeated along the length of the myofibril. Each sarcomere contains actin and myosin, which are in an overlapping formation. When the muscle receives a stimulus (nerve impulse), actin and myosin do not change in length, but slide across each other, therefore the sarcomere shortens. As a resultant factor the myofibrils contract. The relaxation phase is a passive process, where the cross bridges relax, actin and myosin return to their original position, thus the sarcomere, and myofilament lengthen to their original position. The nerve impulse is based on the ‘all or nothing law’. Each fibre is capable of either contracting or not contracting, there is no in between. As the athlete begins to fatigue it is the strength of the contraction which may decrease. 5 Differentiate between the function of a ligament and a tendon. Endomysium, perimysium and epimysium extend beyond the length of the muscle to form a tendon. Tendons are strong and have some elastic properties similar to a muscle. Ligaments connect bone to bone and prevent any unwanted movements at a joint. 6 Describe lordosis, and the effect on the muscular system. Lordosis is caused through an exaggeration of the lumbar curve, resulting in an increased anterior tilt of the pelvis. Hamstrings group and abdominals are lengthened and need strengthening to facilitate shortening. Erector spinae and iliopsoas, rectus femoris, sartorius and tensor fascia latae are all shortened and need lengthening through flexibility exercises such as stretches or yoga. 7 Describe kyphosis and explain which sports may predispose an athlete to this condition. Kyphosis is caused through an exaggerated curve in the thoracic vertebrae. The muscles on the upper back are lengthened such as trapezius, rhomboids and posterior deltoid and need strengthening to facilitate shortening. Chest muscles such as pectoralis major and minor, and anterior deltoid are shortened and need, lengthening through flexibility exercises such as stretches or yoga. 8 Observe a rugby player performing a squat and complete the following table for the up and down phase. © Pearson Education Ltd 2012 3 Foundations in Sports Science Up Phase Joint Hip Action Extension Knee Extension Ankle Plantar flexion Muscles Gluteus maximus, Semimembranosus, Semitendinosus and the Biceps femoris Rectus femoris, Vastus medialis, Vastus intermedius and the Vastus lateralis Gastrocnemius, Soleus, Tibialis posterior, Flexor hallucis longus, Flexor digitorum, Peroneus longus and the Peroneus brevis Contraction Concentric Concentric Concentric Down Phase During the down phase the muscles which contract concentrically during the upward phase, contract eccentrically during the down phase. Joint Action Muscle Contraction Hip Flexion Eccentric Gluteus maximus, Semimembranosus, Semitendinosus and the Biceps femoris Knee Flexion Rectus femoris, Vastus medialis, Vastus intermedius and the Vastus lateralis Eccentric Ankle Dorsiflexion Gastrocnemius, Soleus, Tibialis posterior, Flexor Hallucis longus, Flexor digitorum, Peroneus longus and the Peroneus brevis Eccentric © Pearson Education Ltd 2012 4