Musculoskeletal System Assignment
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Added on 2020-11-02
Musculoskeletal System Assignment
Added on 2020-11-02
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Musculoskeletal system:Made up of: tendon, muscle, bone, joint, cartilageLigaments: Bands of flexible fibrous connective tissue in one direction to resist force. Limit normal and prevent abnormal movement. Connects two bones together to stabilize a joint. Cartilage: a smooth elastic rubber like tissue that acts as padding on the ends of long bones at the joint Tendon: strong fibrous collagen tissue that attaches muscle to a boneJoint: junctions between two or more bones, allow for different types of movement.Muscle: produce force and motion, maintaining and changing posture, locomotion.Bone: support the body structurally, protect vital organs, enable movement, house bone marrow and store minerals (importantly calcium)Bone marrow: a spongey tissue in the very inner layer of some bones, containing stem cells that develop into RBC’s, WBC’s and platelets. Bones form the axial and appendicular skeleton; they articulate at joints and enable skeletal muscle to provide force for movement at joints under the control of the nervous systemAxial: skull, vertebral column, ribs, sternum and joints between. Function to maintain upright posture, protect vital organs (brain, spinal cord, heart lungs and thoracic abdominal organs and reproductive organs) and transfer body weight to the ground through hips.Appendicular: bones that support appendages and pelvis.Bone tissue:-Bone is a connective tissue, formation and remodelling happens continuously.-Cells are supported by protein fibres; collagen. Hydroxyapatite.Spongey bone: inner layer = resist forces and protects bone marrowCompact bone: outer layer = protection and strength of bonesEpiphysis: end of long bonesOsteon: is a cylindrical structure that holds mineral matrix and osteocytes and a central canal housing blood vessels called the haversian canal, situated in the middle of the osteon. Lamellae are layers that surround the central canal containing mature bone. The fibres orientate in different ways = withstand tensile strength and compressionPeriosteum: dense layer surrounding bone, where the nerve supply is.Bone development:-Has to develop from another tissueJoints:Fibrous: bone ends are separated by strong fibrous material preventing movement betweenthe bones. Found between bones of axial skeletonCartilaginous: bone ends separated by flexible cartilage, allowing small amount of movement. Found between bones of axial skeleton: intervertebral discs, costochondral joints and public symphysis. Cartilage much more flexible than fibre
Synovial: found between bones of appendicular skeleton, designed for mobility. Much more common for injury, have a cavity between bone ends lined by synovial capsule = freely moveable. Mobility is determined by; presence of ligaments, shape of bony surface and arrangement of muscle around the joints.Articular capsule: capsule surrounding a synovial joint, containing 2 parts: outer fibrous membrane and inner synovial layer. Synovial membrane: connective tissue that lines the inner layer of capsules of synovial jointsArticular cartilage: fluid filled, like kitchen sponge for shock absorption and protection of bone ends.Joint cavity: refers to the space between the joints, is filled with synovial fluid that lubricatesjoints = reducing friction between bones and allowing for greater movementNeuromuscular system:Skeletal muscles are controlled by somatic nervous systemMuscle belly: skeletal muscle portion of all muscle fibres of a given muscle. Muscle cells exist in groups and separated by connective tissue layers (fascial = a group) therefore, a muscle is made of many fascicle.Endomysium: layer surrounding each individual fibre within fascicle.Perimysium: surrounds the bundles of muscle fibresEpimysium: connective tissue layered around the whole muscleFascia: even stronger connective tissue layered around the epimysiumSkeletal muscle cells:What allows them to contract/shorten:Myofibrils: muscle cells are made up of subunits of proteinsMyofilaments: smaller cells in myofibrils, are categorised into -Myosin: thick-Actin: thinThese have a regular pattern causing a striped appearance and can overlap on top of each other to shorten = contractionContraction: is controlled by a nerve. Skeletal muscle is controlled by 2 neuron pathways:1.UMN: starts in primary motor cortex and travels to the brain stem and spinal cord2.LMN: travels to skeletal muscle in peripheral nervesThe level of movement in a muscle is determined by the number of muscle cells controlled by the lower motor neuron (motor unit).Atrophy: lack of neural stimulation in skeletal muscle causing reduced size.Control of skeletal muscle/ process of movement:1.Sensory input: seeing soccer ball moving towards you, sensory signals sent to brain.2.Integration: brain receives integrates the sensory input and sends the signals for an appropriate motor response. (message travels from brain down spinal cord)
3.Motor output: the muscles needing to be used receive motor signals sent and contract to move and kick the ball.The motor unit: the number of muscle cells controlled by a single motor neuron.-Larger motor unit = less control-Smaller motor unit = more controlSynapse with effector organ cells: (synapse = a structure permitting a neuron to pass an electrical or chemical signal to anotherneuron or target effector cell)Lower motor neuron synapses with effector organ (muscle cell) at neuromuscular junction. Damage to motor pathway: -can cause paralysis (inability to voluntarily contract muscle)Types of paralysis: flaccid – LMN damage (floppy) & spastic: UMN damage (caused by increase in tone)-paresis: slight ability to voluntarily contract/ weakness-paraesthesia: abnormal sensation-anaesthesia: loss of sensationNeuropathy: atrophy due to nerve damage Adaptive changes to muscle:disuse atrophy: causes fewer myofibrilsendurance training: more mitochondria and increased blood supplyresistance training: develops more myofibrilsChanges due to inactivity/ older age causes a decrease in muscle bulk, strength and ROM due to loss/atrophy of skeletal muscle.Caused by: -decreased activity-decreased nerve supply (dementia)-nutritional deficiency (not enough protein)-menopause (drop in bone density due to falling levels of oestrogen which helps protect bone strength.Osteoporosis, lecture 1Metabolic injury to boneOssification/ osteogenesis: process of remodelling via laying down of new bone materialOrganic componentCells: -Osteoblasts: bone forming - deposition-Osteocytes: maintaining mature bone-Osteoclasts: remodelling - resorbed
This process happens continuouslyAlso, - collagen fibres and proteins, help bone resist distortion Inorganic component:Calcium (85%) stored in our bone, and prosperous saltsBone is constantly being remodelled to:-Restore serum levels-Ensure if inadequate intake serum calcium is reabsorbed from body stores-Maintain osteoblastic activity / processesHypocalcaemia: low calcium in blood.Calcium: -Nerve conduction-Iron transportation-Muscle contraction -Bone depositionSerum calcium levels: 2.1-2.6 Mmol/L or KG.-50% floating free in plasma-40% binded to protein like albumin-10% bound to other ionsSerum levels affected by:-Supplementation-Hormone and renal function-Diet and absorption Endocrine control Parathyroid gland:-Secreted parathyroid hormone which stimulate increase in serum calcium levels-GUT, kidney and bones can be used to increase calciumThyroid gland:-Calcitonin – tones down calcium levels-Does so by inhibiting osteoclasts which break down bonesVitamin D:Vitamin d stimulates calcium absorption in the gutInhibits parathyroid productionInvolved in production of boneStimulates immune system – t cellsInactive d (7-dehydrocholesterol) synthesized in sebatious glands and secreted on the skin surface and converted by UV like to cholecalciferol vitamin d, goes to liver then kidney and is now active form calciferol
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