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PHAS5001 Anatomy & Physiology Musculoskeletal System (MSK): Muscle & Bone Anatomy Dr Mariasole Da Boit [email protected]  MSK: Learning Objectives To outline the structural, mechanical and physiological features of the mus...

PHAS5001 Anatomy & Physiology Musculoskeletal System (MSK): Muscle & Bone Anatomy Dr Mariasole Da Boit [email protected]  MSK: Learning Objectives To outline the structural, mechanical and physiological features of the musculoskeletal system and relate them to their function To identify the major bones and muscle groups of the body Describe key features of MSK associated clinical conditions MSK Lecture 1: Overview of Topics Structure & function of the skeleton Types of bone, joints & connective tissue Types of muscle Structure & function of muscle Interactions of bone and skeletal muscle Associated clinical conditions Identification of major bones and muscle groups  The Musculoskeletal System What is the musculoskeletal system? Bones Muscles Joints Connective tissue: tendons, ligaments & cartilage What is its function? Support Protection Motion Haematopoiesis Storage of minerals and fat – calcium/phosphate https://study.com/academy/lesson/musculoskeletal-system-lesson-for-kids.html  The Skeleton Consists of: Bones, joints, cartilage and ligaments In adults: composed of 206 named bones Skeleton falls into two divisions: Axial skeleton – 80 bones Consists of skull, vertebral column and bony thorax Appendicular skeleton – 126 bones Consists of the limbs and © Gray’s Anatomy for  Classification of Bones 1 5 1. Flat – thin, flattened and usually curved; protection & attachment 2. Long – elongated shape: shaft plus 2 ends; locomotion -> strong quite resilient 2 due to structure 3. Sesamoid – type of short bone located in some tendons; alter direction of tendon, 4 modify pressure on a joint, reduce friction 4. Short – roughly cubed shaped, include carpal and tarsal bones; stability 5. Irregular – complicated shapes; 3 protection REMEMBER: Structure relates to function! http://library.open.oregonstate.edu/aandp/chapter/6-2-bone-classification/  Bone Components of Bone tissue is alive hence always reproducin There are two types of bone: g Cortical (compact) bone Dense, hard outer layer Appears solid, however contains nerves, blood & lymphatic vessels Trabecular (spongy) bone Porous - consists of spicules of bone – cavities containing bone marrow Lightweight, but resistant to tension Contains strong mineralised fibres Bone marrow found in the ends of long bones and in the bones of the pelvis, Bone is a LIVING ribs, vertebrae, and skull organ  Long Bone Structure Epiphy line Long bone structure: sepera epiphy Diaphysis – dense bone outside and metap and is with cavity contain vascular cartila which system contro how b Metaphysis – end of bone with growth from puber spongy bone Epiphysis - covered by articular cartilage to reduce  External Surface Features of Bone Projections, Depressions & Irregularities: Femur Found where muscles, ligaments, tendons, blood vessels, nerves etc. Insertion tendon gluteus minimus attach to during elbow flexion Insertion tendon deltoid radius bone  Tendons, Ligaments & Cartilage  Tendons and ligaments are bands of dense, fibrous connective tissue, containing collagen fibres Withstand tension and have a limited blood supply Tendons connect muscle to bone – transmit forces to enable movement Ligaments connect bone to bone – stabilize and restrict esn’t have blood supply hence injuries take long to heal joint motion Achilles Tendon  Cartilage is a resilient smooth elastic gel-like tissue Reduces friction and can withstand compressive, sheer and tensile forces Has no blood supply, nerves or lymphatic system Covers and protects long bones and provides structure to By The original uploader was Montrealais at English Wikipedia. - Transferred from en.wikipedia to Commons., Public Domain, https://commons.wikimedia.org/w/index.php?curid=2662789 many body components i.e. rib cage, vertebrae, trachea, nose fferent types of etc. Fibrous , elastic, cartilage:  The Axial Skeleton Formed from 80 named bones Consists of the skull, vertebral column and bony thorax Skull: 8 cranial, 14 facial, 6 auditory ossicles Vertebral column: ~26 bones Bony thorax/rib cage: 24 ribs, 1 sternum, 1 hyoid By Anatomography is provided by DBCLS - en:Anatomography (setting page of this image at Anatomography), CC BY-SA 2.1 jp, https://commons.wikimedia.org/w/index.php?curid=38024088  The Axial Skeleton Bones lined up to form the longitudinal axis of the body Skull, vertebral (spinal) column, hyoid, ribs and the sternum Skull: encases brain Vertebral column: encases the spinal cord Thoracic cage: surrounds the heart & lungs Thoracic Cage (Rib Cage) sternum - All ribs attach posteriorly to the thoracic vertebrae Costal 1. The true ribs 1-7 attach to the sternum cartilage via costal cartilages (hyaline). White part 2. False ribs- 8-10 indirectly attach via costal cartilage. - groups and attached to one cartilage 3. 11-12 – float – no attachment to sternum, but their costal cartilages are embedded  Thoracic Cage (Rib Cage) http://ovid.visiblebody.com/atlas  Vertebral Column con Roughly 26 irregular bones Transmits the weight of the trunk to the lower limbs concave conve Anterior and posterior longitudinal ligaments support the vertebrae, preventing hyperextension/flexion Fibrocartilage intervertebral discs act as shock absorbers and provide flexibility to the spine – S- flatten during the day shaped Physical trauma/heavy lifting may result in a herniated disc – slipped disc – resulting in © Gray’s Anatomy for Students: Richard Drake, , A. Wayne Vogl, , and Adam W. M. Mitchell  A Typical Vertebrae Vertebral body – anterior; Vertebral arch – form Vertebral arch – attachment for main weight bearing lateral & posterior walls of muscles/ ligaments; sites of component the vertebral canal articulation with adjacent vertebrae Vertebrae increase in size from Contains the spinal cord, Thoracic vertebrae have large costal c2 to l5 blood vessels, connective elements which form articulation  Vertebral Column https://commons.wikimedia.org/wiki/File:ACDF_oblique_annotated_english.svg  Skull / Cranium Human skull consists of 22 bones: 8 cranial and 14 facial (+ additional 6 inner ear ossicles) All bones are immovably joined – exception being the mandible Skull divided into : Forehead – Frontal Roof – Parietal Side – Temporal Back - Occipital By Patrick J. Lynch, medical illustrator - Patrick J. Lynch, medical illustrator, CC BY 2.5, https://commons.wikimedia.org/w/index.php?curid=1498166 https://www.thoughtco.com/types-of-joints-in-the-body-4173736 By Dr. Johannes Sobotta - Sobotta's Atlas and Text-book of Human Anatomy 1909, Public Domain, https://commons.wikimedia.org/w/index.php?curid=29771885  Appendicular Skeleton Consists of the bones of the pectoral and pelvic girdles and the upper and lower limbs Upper limb: 64 bones Pectoral girdle: Scapulae and clavicles: 4 Arms & forearms: 6 Wrist and hands: 54 Lower limb: 62 bones Pelvic girdle: 2 Thigh & lower leg: 8 Ankle & feet: 52 © Gray’s Anatomy for Students  The Pectoral (Shoulder) Girdle Both the pectoral and pelvic girdles anchor the limbs to the axial skeleton Pectoral: 4 bones: 2 clavicles and 2 scapulae Not typically weightbearing – stability sacrificed for mobility https://en.wikipedia.org/wiki/Shoulder_girdle#/media/File:Pectoral_girdle_front_diagram.svg Most mobile joint in the body, hence not very stable and can easily dislocate shoulder  Most mobile joint in the body – why? - Structurally the head of the humerus rests in the glenoid cavity of the scapula which is shallow (in comparison with other ball and socket joints) and the joint capsule is quite loose - Provides great manoeverability, however can be easily dislocated. - Rotator cuff muscles maintaining structure to help support and give  The Pelvic (Hip) Girdle Specialized for weight bearing Basin-like bony pelvis formed by hip bones, sacrum and coccyx 2 hip bones secure the lower limbs to the axial skeleton Each hip bone consists 3 fused bones (ilium, ischium  Female Male Pelvis male Pelvis female Male pelvis deep and Female pelvis, which forms narrow with larger, the birth canal, is shallow heavier bones and wide  Joints / Articulations A joint is a site where two or more bones meet Function to hold bones together and allow various levels of movement Two general categories: Synovial joints – also known as diarthrosis Enables movement © Gray’s Anatomy for Students Contains a cavity filled with synovial fluid Frictionless, load bearing & withstand  Types of Joint Cartilaginous Fibrous Synovial https://en.wikipedia.org/wiki/Joint 3 Major types of joint in the body: Cartilaginous – limited or no movement Solid joints Fibrous – virtually no movement Synovial – a variety of movement  Examples of Solid Joints - Cartilaginous Synchondrosis – allows bone growth during adolescence and eventually become ossified e.g. shaft of long bones and rib cage Symphyses – often occur in the midline, connect two bones by cartilage e.g. pubic symphyses  Examples of Solid Joints - Fibrous Sutures – thin layer of connective tissues, occur only in the skull Gomphoses – collagen fibres in the periodontal ligament secure teeth into adjacent bone Syndesmoses – two adjacent bones linked by an interosseous Types of Fibrous ligament i.e. radius Joints and ulna or tibia and fibular  General Structure of Synovial Joints Joint Cavity Articular Cartilage Synovial Fluid - Egg white consistency - Without this lubrication, rubbing of joint surface and friction could overhead and damage the tissues © Marieb. Human A&P. Pearson Types of Synovial Joints a) Pivot – allow rotation; a round bony process fit into a bony ligamentous socket b) Hinge – permit flexion & extension only c) Saddle – concave & convex joint surfaces d) Plane – permit gliding or sliding movements e) Condyloid – permit flexion & extension, abduction, adduction & circumduction f) Ball & socket – permit movement in several axes; a rounded head  Types of Synovial Joint Hinge Condyloid elbow wrist Plane Saddle between Ball- carpal- tarsal socket metacarp Pivot C1-C2 bones hip al  Types of Synovial Joint Pivot - rotation: Atlas (C1) and Axis (C2) Condyloid – most movement : wrist https://www.visiblebody.com/blog/3d-skeletal-system-atlas-axis-and-the-atlanto-axial-relationship https://makeagif.com/gif/condyloid-joint-cepWxx? Saddle – Ball & carpometacarpal: socket – thumb hip http://www.scientistcindy.com/joints.html https://makeagif.com/gif/hip-joint-range-of-movement-3d-medical-animation-abp-c-mC2VCJ  Largest and most Knee Joint complex joint in the body Formed by articulation of tibial and femoral condyles and anteriorly by the patella and patellar surface of the femur Modified hinge joint - extension, Factors Influencing Synovial Joint Stability ARTICULAR SURFACES – larger the surface and deeper the socket provides increased stability LIGAMENTS – reinforce and prevent undesirable movement MUSCLE TONE– the tone of muscles whose tendons cross the joint is the most important stabilising factor  Ageing & Degenerative Changes Adult height, skeleton changes little until middle age With old age, thinning of intervertebral discs and along with osteoporosis leads to gradual loss of height Increase risk of disk herniation Increase risk of fractures through loss of bone mass Increased rigidity of the thoracic cage promotes breathing difficulties Increased risk of rheumatoid arthritis and osteoarthritis (inflammatory and degenerative)  Osteoarthritis Osteophyt es Reduction in quality of cartilage – becomes more fragile and prone to mechanical wear Synovial fluid may leak into cracks in the bone Bony nodules form – osteophytes Deformation alters biomechanical forces, disrupting the joint and causing inflammation and pain deterioration © Gray’s Anatomy for Students  Joint Replacement © Marieb. Human A&P. Pearson © Gray’s Anatomy for  Osteoporosis A disease where bone mineral density is reduced Bone loss greater than bone growth Bones progressively weaken and fracture with minor stress Most common bones affected: neck of femur, wrist, forearm, hip and vertebrae No obvious symptoms until fractures. Often elderly suffers exhibit curved back from compression fractures of the spine Higher risk groups include: elderly; women over 50; family By James Heilman, MD - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php? curid=16911658 history; petit and thin, previous fracture; Caucasian and Asian women; certain diseases; and lifestyle  Osteoporosis Normal hip & Insufficiency fracture Well-defined neck of bone density of the neck of femur femur fracture  Osteoporosis – Bone Changes Healthy trabecular bone Architectural damage to trabecular pattern as a result of osteoporosis 10 Minute Break Muscle Specialised for generating force and motion Muscle tissue represents ~50% body mass in adult humans It can be divided into 3 types: – Skeletal muscle – Cardiac muscle – Smooth muscle Many similarities but also differ https://medlineplus.gov/ency/imagepages/ 19841.htm considerably to one another  Muscle Functions Body Movement http://www.body-cognition.org/en/body-movement-class.html Skeletal muscle contraction Body posture Continual adjustment of skeletal muscles Support and Skeletal muscles e.g. surrounding protection joints & within the abdominal wall Sphincter control Skeletal and Smooth muscle – cardiac sphincter in stomach; bladder; anus Movement of food Smooth muscle generates along GI tract peristalsis Regulation of blood Cardiac muscle pumps blood. flow Smooth muscle in vessel walls http://www.gastroconsultantsqc.com/services/diseases/motility-disorders/ regulate blood flow Temperature Skeletal muscle – shivering regulation http://www.cdc.gov/bloodpressure/about.htm Smooth muscle – erection of hairs  Design & Function & wiseGEEK.org https://simple.wikipedia.org/wiki/Peristalsis#/media/ File:Peristalsis.gif  Common Features of All Muscles Actin and myosin – generate force for contraction Calcium ions – needed for activation of http:// exchange.smarttech.co m/details.html? id=14ac310a-f789- 4c9b-97d8- 32778d779446 contraction Supply of ATP – generated via respiration: Aerobic oxidative respiration Anaerobic glycolytic respiration Stimulation – need an action potential from a neurone http://www.broughtonfc.co.uk/ http://www.nvo.com/scullari/unitii/  Muscle Characteristics EXCITABILITY – responsive to stimuli i.e. a chemical signal such as a neurotransmitter CONTRACTILITY – ability to shorten Flex forcibly when adequately stimulated EXTENSIBILITY – can extend beyond Extend their resting/relaxed length ELASTICITY – recoil and resume its Gross Skeletal Muscle Anatomy Muscle Tissue: Histology | Concise Medical Knowledge  A single = muscle cell Marieb 10th Ed. Pg301 Muscle Histology Transverse  A typical (non muscle) Micro Muscle Cell Anatomy Cell membrane – sarcolemma Cytoplasm – sarcoplasm Full of myofibrils Skeletal – actin/myosin muscle cell Many mitochondria https://opentextbc.ca/biology/chapter/19-4-muscle-contraction-and-locomotion/ Extensive endoplasmic reticulum – sarcoplasmic reticulum  Muscle Fibre Anatomy Musclefibre Myofilament: Contractile units called SARCOMERE S Striations: overlapping ACTIN & nicerweb.com Sarcomer e MYOSIN (myofilaments)  Muscle Cell Function: Contraction Actin and Myosin make up ~90% of muscle protein Thin filament Thick filament http://www.crossfitinvictus.com/blog/muscle-contraction-really-cool-protein-called-myosin/  Actin Actin subunits (“G actin”) G actin subunits polymerise into long, filamentous or “F actin” Two intertwined actin filaments Active sites to which myosin head attaches in contraction Regulatory proteins Marieb, figure 9.3 Tropomyosin  stabilise  Myosin Rod-like tail attached by flexible hinge to two globular heads Tail – two intertwined helices Globular heads link thick and thin filaments in contraction Cross bridges  motors (force) Actin and ATP-binding sites Marieb, figure 9.3 Intrinsic ATPase activity Actin and Myosin Interaction http://imgur.com/gallery/DaGwMo2/comment/378891276 Sarcomere Skeletal muscle Contraction cell https://opentextbc.ca/biology/chapter/19-4-muscle-contraction-and- locomotion/ SLIDING FILAMENT THEORY  Sarcomere Contraction Blue – Red – Myosin Actin http://biology.stackexchange.com/questions/1243/stabbing-muscles-when-flexed-and-when-relaxed  Sarcomere Components A band H Zone A band I Band I Band Myosin Actin M Z Disc Line Z Disc  The Muscular System Muscles can be classified into 3 functional groups: Agonist – the prime mover Antagonist – may stretch or be relaxed Synergist – may add extra force or prevent undesirable effects *synergists can also be known as fixators if they maintain body structure i.e. body ©Visible Body posture or positioning of a structure All muscles within a group help ensure smooth, coordinated and precise  Muscle Nomenclature Muscles are named according to multiple criteria: Location – e.g. temporalis muscle overlies the temporal bone Shape – e.g. the deltoid is roughly triangular ∆ Size – e.g. gluteus maximus; minimus; longus or brevis Direction of muscle fibres – e.g. external oblique Number or origins – e.g. biceps, triceps, quadriceps Muscle Action  Fascicle/Fibre Arrangements Circular: eyes, mouth, sphincters Convergent: broad origin and fascicles converge towards a single tendon Parallel: fascicles along the long axis Pennate: short & Muscle Origin, Insertion & Action Biceps brachii Origin: both heads of the biceps are attached to separate regions on the scapula Insertion: by common tendon on the radius Brachialis Origin: front of distal humerus Insertion: ulna and capsule Brachiali of elbow joint s What is the action of contraction of these two Head Muscles MSK Lecture 2: Overview of Topics Bone Physiology Breaks Tissue turnover Haematopoiesis Endocrine function Muscle Physiology Contraction Regeneration Metabolism and physiological function Ageing and clinical conditions  MSK Resources Visible Body - A&P and 3D atlas https://tinyurl.com/vbdmu Gray’s Anatomy for Students: Access via the PHAS5001 Bb shell ‘Resource List’ in the ‘Learning Materials’ folder Marieb – human Anatomy & Physiology, chapters 7 - 10 Any human anatomy & physiology text book