Anatomy Block 2 Lecture 1 PDF

1. Recall the components of bone that provide strength and flexibility.​ Bone Composition and Function: Organic Components (living): 100% ON THE EXAM - Flexibility - Cells, osteoid, collagen fibers - Hemopoiesis (produce WBC and RBC) - Storage Ca2+ - Muscle contra...

1. Recall the components of bone that provide strength and flexibility.​ Bone Composition and Function: Organic Components (living): 100% ON THE EXAM - Flexibility - Cells, osteoid, collagen fibers - Hemopoiesis (produce WBC and RBC) - Storage Ca2+ - Muscle contraction, blood clotting, impulse transmission - Storage of Phosphates - APT utilization - Lipids - In yellow bone marrow, a potential energy source Inorganic Components: - Strength - Hydroxyapatite crystals - Support, Protection, and Movement Bone classification - Long bones - tubular, elongated with expanded ends - Site for Hematopoiesis - Flat bones - provide protection for underlying soft tissue - Hematopoiesis during growth - Short bones - cuboidal bones of ankle and wrist - Irregular bones - complex shapes - Sesamoid bones - develop in tendons throughout life, ex: knee caps Anatomical makeup of bone - Ratio of compact to spongy bone will be related to function - Example: - Femur: strength, thick cortical bone, organized trabecular architecture to support - Ribs: protect organs, lots of trabecular, made to absorb impact - Compact/cortical: Outer layer that provides strength - Trabecular/cancellous: Inner bone composed of flat or needle-like trabeculae (spongy) Movement: Origin site: fixed on bone Insertion site: moves Predict muscle action: origin site, insertion site, and direction of muscle fibers Efferent nervous system: movement and reflexes controlled by motor neurons Isotonic contraction: muscle length changes Concentric: muscle fibers shorten Eccentric: controlled lengthening Stability: Isometric contraction: contraction without change in muscle length, joint stabilization, posture, proprioception Communication muscles: facial muscles convey mood, speech, hearing 2. Describe the gross anatomical structure of bone including the variety of shapes, components of long bones, and organizational types.​ Long Bone Anatomy Diaphysis: long section of bone Metaphysis: present only during development, linear growth to proximal and distal ends Epiphysis: at the ends of the bone, covered in hyaline cartilage Epiphyseal line/plate: marks the end of growth in the bone Marrow Cavity: exists in the diaphysis of long bone, consists of Red and Yellow BM Red BM: blood cell and platelet formation  Yellow BM: fatty Nutrient Foramen: opening in diaphysis for vessels and nerves Compact Bone Anatomy Osteons: haversian system, long cylinders within bone with their own blood supply Central Canal: holds blood vessels and nerves for osteons Concentric Lamellae: parallel layers/rings of bone matrix inside newer osteons Lacunae: spaces between lamellae that hold osteocytes Canaliculi: hold cellular extensions of osteocytes, allow for communication Osteocytes: sit inside lacunae Perforating Canals: connect central canals Circumferential lamellae: adjacent to peri- and endosteum Interstitial lamellae: fill gaps/left over from remodeled osteons Trabecular Bone Location: deep to compact bone Composition: needle-like trabeculae and lamellae with no central canals Canaliculi: source of nutrients that connect to capillaries in the endosteum surrounding trabeculae Related Tissue Periosteum: two layered CT membrane outside Fibrous outer layer: dense irregular CT, anchors tendons/ligaments Osteogenic inner layer: osteogenic cells, contains/create bone cells, attached to bone via sharpeys fibers Endosteum: internal CT membrane lining the medullary cavity 3. Recall the microscopic organization of bone including the cells and tissues that support it and their functions.​ Bone Cells Osteogenic (osteoprogenitor) cells: - Mitotically active stem cells in both tissue layers - Can differentiate into osteoblasts (osteocytes) or bone lining cells Osteoblasts - Bone building cells on bone surface - Synthesize and secrete osteoid bone matrix Osteocytes - Osteoblasts that are located in lacunae and adhered to bone matrix - maintains bone tissue - React to mechanical stress and stimulate osteoblasts/osteoclasts - Connect and communicate with other bone cells via projections Osteoclasts - Bone eating cells, reabsorb bone and enzymes break down bone matrix - Large, motile, multinucleated Bone lining cells - Flat cells on bone surface, maintain matrix when bone is not remodeling 4. Visually identify bone, cartilage, and their related structures histologically.​ 5. List the components and characteristics of cartilage and the attributes of each type to relate them to their location and function in the body. Cartilage Components: gelatinous extracellular matrix (ECM) and abundant fibers Chondrocytes: within lacunae in the ECM Perichondrium: dense CT covering supplies nutrients via diffusion Functions: - Flexibility, smooth, low friction gliding surface Characteristics: - Avascular, lacks nerves 3 Cartilage Types 1. Hyaline - movement and support 2. Elastic - flexibility and stretching 3. Fibrocartilage - strength and cushioning Hyaline - Most common, collagen fibers and sparse chondrocytes - Juvenile: Forms scaffolding for developing bone, allows for longitudinal bone growth - Adults: Ends of bones in many joints, respiratory tract, and connects ribs to sternum Elastic - Ear, epiglottis in the upper respiratory tract - More elastin fibers compared to hyaline Fibrocartilage - Intervertebral discs, and menisci of knee, pelvic girdle - Organized rows of chondrocytes between rows of collagen fibers 6. Recall the microscopic organization of skeletal muscle based on their connective tissue components​ Muscle Tissue - Surrounded by CT that carries nerve and vessels and binds them into fascicles (bundles) Muscle Fibers: long and narrow contractile muscle cells Categorized by: - Voluntary or involuntary - Smooth or striated - Somatic (body walls/limbs) or visceral (hollow organs/vessels) 3 types of muscles: Skeletal muscle: voluntary, somatic, striated Cardiac muscle: involuntary, visceral, striated Smooth muscle: involuntary, visceral, smooth Skeletal muscle - One or more contractile portions (bellies) - Associated tendons, noncontractile CT linking muscle to bone Attach: bone, cartilage, ligaments, fascia Functions: movement, support, form, heat Muscle organization - Thin layers of CT surround and organize muscle tissue Epimysium - surrounds entire muscle, Dense irregular CT, carries nerves/vessels Perimysium - Thin, Surrounds each fascicle (bundle), Nerves and vessels penetrate to supply each fascicle Endomysium - Very thin, delicate CT of reticular fibers and fibroblasts, Surrounds external lamina of each muscle fiber (cell), Nerve fibers and capillaries penetrate 7. Describe muscle contraction by comparing the types of contraction, motor units, and origin and insertion sites​ Skeletal muscles always pull, never push Muscles contract: shorten Attachment sites of muscles: - provide movement information - move joints they cross - Flex, extend, abduct, adduct 3 types of muscle contraction ​1. Tonic contraction - Muscle tone: slight contraction while relaxed - Does not produce movement or active resistance - Joint stability, maintain posture, at-the-ready 2. Reflexive contraction - Automatic contractions due to stimulus - E.g., myotatic reflex, movement of diaphragm 3. Phasic (active) contraction - Isotonic contraction: muscles changes in length, movement Concentric contraction: muscle shortening Eccentric contraction: controlled muscle lengthening - Isometric contraction: no change in length, increased force Resist gravity or antagonistic force Motor Unit: motor neurons and muscle fibers that it controls Prime mover: muscle responsible for movement Synergist: complements prime mover Antagonist: opposes action of another muscle Fixator: steadies/stabilizes Shunt muscle: contracts to resist dislocating forces at joints Spurt muscle: capable of rapid and effective movement 8. Recall muscle categories, linking their names to the direction of their fibers, function, and/or shape​ Skeletal Muscle Shape - Muscle shape depends on: arrangement of muscles fibers, associated CT - Most muscles are named for their: function, the bone they attach, position, length, or shape Circular (sphincteral): controlled opening and closing of opening or orifice Fusiform: spindle shape, tendinous attachments Flat: parallel fibers with aponeurosis; stabilizers Pennate: feather like, diagonal fibers Quadrate: 4 equal sides Convergent: cover broad areas but form single tendon Multiheaded or multibellies