Week 5 Bones and Skeletal Tissues PDF

Bones and Skeletal Tissues  What is the skeletal system made off The skeletal system is the body's internal framework, made up of  Support. Bones provide a framework that Bones supports the body and cradles its soft organs. perform minerals,...

Bones and Skeletal Tissues  What is the skeletal system made off The skeletal system is the body's internal framework, made up of  Support. Bones provide a framework that Bones supports the body and cradles its soft organs. perform minerals, Mineral storage. Bone is a reservoir for phosphate. most importantly calcium and several Blood cell formation. hematopoiesis occurs in importan the red marrow of certain bones t Protection. The fused bones of the skull protect the brain functions bones Anchorage. Skeletal muscles, which attach to by tendons, use bones as levers the body and its parts. The Skeletal System The skeleton has 206 bones Classification of bones Bones are classified by their Shape Short BONES Generally, cube-shape Contain mostly of spongy bone tissue Examples: Carpals, tarsals Bones are classified by their Shape FLAT BONES Thin and flattened Usually curved Thin layers of compact bone around a layer of spongy bone Examples: Skull, ribs, sternum Bones are classified by their Shape Irregular bones Complex shapes Do not fit into other bone classification categories Vary in the amount of spongy and compact bone present Example: Vertebrae and hip Bones are classified by their Shape sesamoid bone Small nodules of bone that are found in certain tendons where they rub over bony surfaces Function: To reduce friction on the tendon; Can alter the direction of pull of a tendon Patella – largest sesamoid bone; located in the tendon of the Bones are classified by their Shape LONG BONES Greater length than width Have a shaft with heads at both ends Slightly curved for strength Contain mostly of compact bone tissue Examples: Femur, humerus Structure of Short, Irregular, and Flat Bones all consist of thin plates of spongy bone (diploe) covered by compact bone. Thin plates of periosteum covered compact bone on the outside Endosteum –covered spongy bone on the inside No diaphysis or epiphysis Bone marrow between trabeculae Parts of a long bone Diaphysis The tubular shaft of a long bone, made of dense cortical bone. The diaphysis has a hollow medullary cavity filled with yellow bone marrow. Epiphysis The rounded ends of a long bone, made of spongy bone filled with red marrow. The epiphysis is the main source of red marrow in long bones and is where the bone grows in length. Metaphysis The area between the diaphysis and epiphysis, made of cancellous bone. In children, the metaphysis contains the epiphyseal plate, which is responsible for linear bone growth. Parts of a long bone Articular cartilage A thin layer of connective tissue that provides a smooth surface for articulation and helps transmit loads to the underlying bone. Endosteal membrane A membrane that covers the Haversian and Volkman's canals Epiphyseal line A remnant of the area that contained hyaline cartilage during childhood. Periosteum The thin outer layer of a long bone that contains nerves and blood vessels. The periosteum is especially sensitive to tearing or tension. Two layers Fibrous layer – outer thin layer of dense connective tissue containing fibroblasts Osteogenic later – contains osteogenic cells and rich with blood supply Microscopic Anatomy of Compact Bone Haversian System (Osteon) Makes up the bulk of the compact bone Consists of several bone lamellae arranged concentrically around a canal Microscopic Anatomy of Compact Bone Haversian canal Channels containing blood vessels and nerves Lined by endosteum o Cement line Mineralized matrix ad collagen fibers osteon boundaries o Volkmann’s canal Transverse vascular channels Connect haversian canals with each other and with blood vessels in the medullary cavity and periosteum Microscopic Anatomy of Compact Bone Lamellae: Concentric rings of calcified matrix that surround the central canal of each osteon. Lacunae: Spaces between the lamellae where bone cells, or osteocytes, are located. Canaliculi: Small channels that radiate from the lacunae to the central canal, providing passageways for nutrients to reach the osteocytes and wastes to be removed. Cement line: The boundary of an osteon. Bone Resorption & Bone Deposition Bone marrow Bone marrow is a general term for soft tissue that occupies the marrow cavity of a long bone, the spaces amid the trabeculae of spongy bone, and the larger central canals. Clinical cases Achondroplastic Dwarfism is a condition in which the long bones of the limbs stop growing in childhood, while the growth of other bones is unaffected. It is a failure of cartilage growth— specifically, failure of the chondrocytes in zones 2 and 3 of the metaphysis to multiply and enlarge. Pituitary dwarfism a deficiency of growth hormone stunts the growth of all of the bones, and a person has short stature but normal proportions throughout the skeletal system Microscopic Anatomy of Bone Microscopic Anatomy of Bone Microscopic Anatomy of Bone Meme to remember it  Bone ossification also known as osteogenesis It is the process of bone formation that begins in the embryo and continues until about age 25 CLASSIFICATION OF BONES: EMBRYONIC/ DEVELOPMENTAL ORIGIN CLASSIFICATION OF BONES: EMBRYONIC/ DEVELOPMENTAL ORIGIN MEMBRANOUS CARTILAGINOU (Inter- S membranous (Endochondral ossification) ossification)  Intramembranous ossification is a process that directly converts connective tissue into bone, forming flat bones like the skull, clavicles, and most of the cranial bones. Timing: Begins in utero, continues through adolescence. Birth: Skull and clavicles are incompletely ossified. Sutures: Open at birth, allowing for deformation during childbirth. Facial bones: Last to ossify, reaching adult size in adolescence. Endochondral ossification is the process of bone development that replaces hyaline cartilage with bone. It's responsible for the formation of most bones in the body, with the exception of the flat bones Endochondral ossification Mesenchyme forms a cartilage model that in turn, ossifies The long bones of the limbs are developed by endochondral ossification, a slow process that is not completed until the 18th to 20th year or later. Examples are bones of the upper and lower extremities and the thoracic cage Epiphyseal Plate: Location: Between diaphysis and epiphysis. Function: Enables bone growth in length. Zones: Reserve zone: Contains inactive chondrocytes, securing the plate. Proliferative zone: Chondrocytes divide and produce matrix. Hypertrophic zone: Chondrocytes enlarge. Calcification zone: Cartilage matrix calcifies. Ossification zone: Calcified cartilage is replaced by bone. Appositional Growth: Increasing Bone Diameter Process: Bone is added to the surface, increasing diameter. Locations: Endosteum (inner layer) and periosteum (outer layer). Mechanism: Osteoclasts resorb old bone, osteoblasts produce new bone. Result: Increases diaphysis and medullary cavity diameter. Remodeling: Continuous process throughout life, essential for maintaining bone health. What is a Cartilage consists primarily of water. It is very resilient-it has the ability to spring back to its original shape after being compressed contains no nerves or blood vessel dense irregular connective tissue perichondrium acts as reinforcement to resist outward expansion when the cartilage is compressed. Contains blood vessels that nourish the cartilage cells. Growth of Cartilage Appositional growth Is produced by the activity of chondroblast in the inner chondrogenic layer It leads to increase in width Interstitial growth Is produced by division and activity of mature chondrocytes It leads to increase in length  Hyaline, elastic, and fibrocartilage help form the skeleton Type of cartilage Hyaline(most Elastic cartilages Fibrocartilages abundant) contain more stretchy elastic Highly Provide support fibers and so are compressible with with flexibility and better able to stand great tensile resilience up to repeated strength, bending padlike cartilages Nasal cartilages, external ear and (menisci) of the Costed cartilages the epiglottis knee and the discs between vertebrae Bones are classified by their location Bones are classified by their location Axial skeleton Functions as a protection to vital organs Located at the center of the axis Three Parts: oSkull o Vertebral Column o Bony Thorax  Skull The skull is one of the most vital bony structures of the human body, as it houses and protects the most important organs, including the brain. There are 29 bones (including the hyoid and middle ear bones) that comprise the skull and give shape to the head. Axial bone – Skull Sutures of the Skull Sutures are a unique type of fibrous joint that connect the skull bones. These joints allow for movement during infancy, so the brain and skull can grow. These joints fuse and become immovable around the age of 22-24.  Important Foramina Foramen magnum in the occipital bone – the spinal cord Optic nerve canal in the sphenoid bone (the optic foramen is the opening to this canal) – Optic nerve and ophthalmic artery Foramen ovale in the sphenoid bone – Mandibular nerve (trigeminal nerve branch) Foramen rotundum in the sphenoid bone – Maxillary nerve (trigeminal nerve branch) Foramina spinosum in the sphenoid bone – Middle meningeal artery  Important Foramina Cribriform plate in the ethmoid bone – Olfactory nerve Supraorbital and infraorbital foramina in the maxilla – Supraorbital and infraorbital nerves Mental foramina in the maxilla – Incisive and mental nerves and mental artery Supraorbital foramen in the frontal bone – Supraorbital nerve Name this. Name this bone. Name this bone. Name this bone. Name this bone. Name this bone. Name this bone. Name this bone. Name this bone. Name these bones. Name this. Name this bone. Name this bone. Name this. Name this bone. Name this bone. Name this bone. Name this. Name this bone. Name this. Name this bone. Name this. This the Hyoid bone  Humans have 25 bones in the chest that together protects several vital organs and provide shape and structure to the upper body. These bones collectively form the thorax, one of the most critical structures in the human body.  Sternum (1): Also known as the breastbone, the sternum is a flat bone located in the middle of the chest. Its primary function is protecting the heart. The bone has three parts – the manubrium, body, and xiphoid process. The sternum is the attachment point for the costal cartilage, which connects it directly to the first seven pairs of ribs. It is also where the shoulder or pectoral girdle joins with the axial skeleton via an articulation with the clavicles.  sternal clavicular notch notch manubrium sternal angle body intercostal space xiphoid process Sternum  1 True True Ribs Ribs 2 False Ribs (7 (7 pairs) pairs) 3 (2 pairs) 4 5 6 7 (2) 4 1 Floating 5 2 3 Thorax costal groove shaft tubercle Rib neck head Vertebral column is a flexible hollow structure through which the spinal cord runs. It comprises 33 small bones called vertebrae, which remain separated by cartilaginous intervertebral discs Vertebral arch ✓ Pedicle ✓ Laminae ✓ Spinous process ✓ Articular process  Functions Protects: Spinal cord, cerebrospinal fluid, nerve roots, vital organs Supports: Body weight, head, shoulders, chest Attachment point: Muscles, tendons, ligaments Allows movement: Twisting, bending, flexing, extending, rotating  transverse process costal facet (thoracic only) Superior facets vertebral body foramen Inferior facets spinous process Vertebral Parts  bifid Dens process transverse foramen (odontoid process) Vertebral arch Atlas (C1) Axis (C2) Cervical Vertebrae  lumbar vertebrae thoracic vertebrae Thoracic & Lumbar Vertebrae  intervertebral disk intervertebral foramen Vertebral Column sacral canal median sacral crest sacral foramen sacral hiatus Articular surface (SI joint) Transverse ridge Sacrum (5 fused vertebrae)  Articular surface (sacroiliac joint) Coccyx Coccyx  INTERVERTEBRAL DISC Lies between adjacent vertebrae in the vertebral column Forms a fibrocartilaginous joint (symphysis) to allow slight movement of the vertebral column Acts as ligament to hold the vertebras together The more active you are, the more you lose water on the intervertebral disc Water diminishes on intervertebral disc as you age because of loss of water content – may result to Osteoporosis Intervertebral length – Constitute 25% of intervertebral column Clinical Notes: LUMBAR TAP/ SPINAL TAP Spinal needle is inserted between the 3rd and 4th lumbar vertebrae (usual) or 4th and 5th lumbar vertebrae WHY? Spinal cord ends at L1 or L2 Landmark: Highest point of ileum (above it would be L3 or L4) Aims to obtain Bones are classified by their location APPENDICULAR SKELETON Located at the sides of the body, appended to axial skeleton Responsible in bringing about movement in the organism Scapula – Shoulder Blade ⎯Flat triangular bone that lies on the posterior chest wall between the second and seventh rib ⎯ Convex posterior surface has two depressions: o Supraspinous fossa o Infraspinous fossa Clavicle ✓ First membranous bone that ossified ✓ Most frequently fractured bone during difficult delivery ✓ Irregular bone ✓ Acromial end – articulates with acronium; somewhat flat and irregular ✓ Sternal end – articulates with sternum; thicker and somewhat round  Humerus Articulates with the scapula at the shoulder and the radius and ulna at the elbow Distal end has multiple features: Epicondyles – For the attachment of muscles and ligaments Capitulum – For the articulation with the head of the radius Trochlea – For articulation with the trochlear notch of the ulna Deltoid tuberosity- is a prominent feature for muscle attachment Radial groove- houses the radial nerve and deep artery of the arm  Humerus Olecranon fossa -Accommodates the olecranon of the ulna during full extension of the elbow Coronoid fossa - Receives the coronoid process of the ulna during full flexion of the elbow Radial fossa -Accommodates the edge of the head of the radius when the arm is fully flexed Surgical neck is a common fracture site https://cdn.britannica.com/15/99115-050- 2F721419/radius-ulna-supination.jpg?w=300  Composed of three pairs of fused bones: Pelvis o Ilium o Ischium o Pubis Where the total weight of the upper body rests Protects several organs: o Reproductive organs o Urinary bladder o Part of the large intestine Forms the body connection between the trunk (sacrum) and lower limb (femur) Birth o Three separate primary bones (joined by hyaline cartilage) Puberty o Three primary bones are still separated by Yshaped triradiate cartilage centered in the acetabulum Pubic Symphysis Femur ⎯Thigh bone ⎯Longest and strongest bone in the body ⎯Head of the Femur o Articulates with the acetabulum Indication where the neck joins the femoral body  Type of Joints Fibrous joints – a joint made of dense connective tissue that doesn’t allow movement between bones that form the joint Suture Gomphosis Syndesmosis ▪ The fibrous later of Takes the form of a peg The 2 bones entering into periosteum on the outer fitting into a hole and the joint are typically and inner surfaces of the held by connective tissue separated by a space but articulating bones bridge Tooth and socket joints united by fibrous tissue the gap between the that bridges this space bones and constitute the oMiddle radioulnar joint main bond between them & Inferior radioulnar joint No movement is possible Suture Spheno-vomerine joint (schindylesis) Type of Joints Cartilaginous joints – joints in which the union of bones is by means of cartilage Symphysis binding element is a fibrocartilage, which allows limited but important amount of movement Example -Midline intervertebral joint and Sacrococcygeal joint Synchondrosis united by cartilage as seen in developing bone, where the bony epiphysis and bony body of a single bone are united by epiphyseal cartilage Epiphysio-diaphyseal joint (growing bone) Type of Joints Synovial joints – refers to the fluid in the joint; characterized by the presence of joint cavity filled with synovial fluid  Activity of the day Make an infographics about different Bone related illness: For each disorder, include: A brief description of the disorder. Key facts or statistics (e.g., prevalence, genetic inheritance). Common symptoms or manifestations. Diagnostic methods. Treatment options or management strategies. Citations APA No repetitions to your classmates References https://www.slideshare.net/adityasamantaray50/ossifica tion-124056450 https://www.theskeletalsystem.net/leg-bone