Week 2 Anatomy PDF

Week #2 Thursday, January 16, 2025 9:57 AM Tissue Types - Epithelium - Connective Tissue ○ Cartilage ○ Bone ○ Joints Connective Tissues - Never exposed to environment outside of body - Contain 3 basic components ○ Specialized cells ○ Extracell...

Week #2 Thursday, January 16, 2025 9:57 AM Tissue Types - Epithelium - Connective Tissue ○ Cartilage ○ Bone ○ Joints Connective Tissues - Never exposed to environment outside of body - Contain 3 basic components ○ Specialized cells ○ Extracellular proteins ○ Ground substance (Fluid) ○ These all make up the matrix - Functions ○ Transport fluid and dissolved materials ○ Makes the structural framework for the body ○ Supports, surrounds, and connects other tissues ○ Defends the body from microorganisms ○ Protect organs ○ Stores energy Types of Connective Tissue - Connective tissue ○ Connective tissue proper (How loose or dense the fibers are) § Lose § Dense ○ Fluid Connective tissue § Blood  ○ Connective tissue proper (How loose or dense the fibers are) § Lose § Dense ○ Fluid Connective tissue § Blood § Lymph ○ Supporting connective tissues § Cartilage § Bone Connective Tissue Proper - Collagen Fibers ○ Long and thick ○ Strong but provide some flexibility - Elastic Fibers ○ Thinner ○ Provide more flexibility ○ More elastic tissue means more flexible - Reticular Fibers ○ Really small ○ More flexible than collagen - Fixed cells stay in place - Wondering cells can be recruited to come to a certain tissue Fixed Cells - Melanocytes ○ Provide pigment - Macrophage ○ Engulf something that shouldn’t be in the body like an infection - Adipocytes ○ Fats cells ○ They provide energy - Fibroblasts ○ Cells that can grow into fibers - Fibrocytes ○ Help to maintain fibers - Mesenchymal Cells ○ Kind of like stem cells ○ Can grow into different types of cells  - Fibrocytes ○ Help to maintain fibers - Mesenchymal Cells ○ Kind of like stem cells ○ Can grow into different types of cells Wondering Cells - Mast Cells - Macrophages - Lymphocytes - Any immune cells can be recruited to this tissue Cartilage and Bone - Main Function ○ Provide framework for the body ○ Matrix = many fibers - Cartilage ○ Functions § Support - soft tissues (Respiratory) § Smooth sliding surface (joints) § Model (For future bones) § Growth § Intervertebral cushioning How Cartilage Grows - Appositional Growth ○ Chondrocytes § Cells that make up cartilage ○ Chondroblasts § immature chondrocytes ○ Perichondrium § Where cells divide 1. Cells in the perichondrium differentiate into chondroblasts 2. Chondroblasts secrete new matrix 3. New matrix enlarges and chondroblasts differentiate into chondrocytes - Interstitial Growth ○ Grows from within  2. Chondroblasts secrete new matrix 3. New matrix enlarges and chondroblasts differentiate into chondrocytes - Interstitial Growth ○ Grows from within § Chondrocytes divide in a lacuna surrounded by matrix § Daughter cells secrete matrix. Cells move apart creating cartilage from within Types of Cartilage - Hyaline Cartilage ○ Functions § Stiff flexible support § Reduces friction between boney surfaces ○ Examples § Between tips of tibs and bones of sternum § Covering bone surfaces at synovial joints § Supporting the larynx, trachea and bronchi § Part of the nasal septum - Elastic Cartilage ○ Functions § Provides support, tolerates distortion and returns to original shape ○ Examples § Auricle of external ear § Auditory canal § Epiglottis § Larynx - Fibrous Cartilage ○ Functions § Resist compression § Prevents bone-to-bone contact § Limits relative movement  - Fibrous Cartilage ○ Functions § Resist compression § Prevents bone-to-bone contact § Limits relative movement ○ Locations § Pads within knee joint § Between pubic bines of pelvis § Intervertebral discs Bones - Functions ○ Support - structural support ○ Hematopoiesis - blood cell production ○ Storage of minerals - calcium and phosphate ○ Protection ○ Leverage - levers working with muscles - Cells of Bone ○ Osteocyte § Canaliculi allows matrix to receive oxygen ○ Osteoblast § Build bone § Release osteoid ○ Osteoprogenitor cell § Stem cell like § Grows into osteoblast ○ Osteoclast § Breakdown Two Types of Osseous Tissue - Compact bone ○ Dense and solid, forms the walls of bone ○ Consists of osteons (Functional unit in bone) - Spongy Bone ○ Open network of plates, lightweight ○ Surrounds the medullary cavity (bone marrow)  ○ Consists of osteons (Functional unit in bone) - Spongy Bone ○ Open network of plates, lightweight ○ Surrounds the medullary cavity (bone marrow) ○ Arranged in parallel struts, form trabeculae (open network) Osteon - Osteocytes arrange in circular layers around a central canal Bone development and Growth - Ossification: Process of replacing other tissues with bone - Osteogenesis: Bone formation - Calcification: Deposition of calcium ions into the bone tissue Ossification - Intramembranous ○ Mesenchymal cell § Stem cells ○ Endochondral § From cartilage Intramembranous Ossification 1. Differentiation of mesenchymal cells to osteoblast a. Osteoblast cluster and secrete matrix (Osteoid) b. Osteoid mineralizes and ossification begins (Ossification center) 2. Differentiation to osteocytes and formation of spicules a. Osteoblasts surrounds osteoid become osteocytes b. Ossification centers how outward in small struts 3. Entrapment of blood vessels  of spicules a. Osteoblasts surrounds osteoid become osteocytes b. Ossification centers how outward in small struts 3. Entrapment of blood vessels a. Blood vessels grow between spicules b. Spicules connect and trap vessels 4. Formation of spongy bone a. Osteoblasts continue to deposit bone and create boney plates b. Plates fuse together Note: This makes up the flat bones Endochondral Ossification 1. Chondrocytes enlarge a. Matrix begins to calcify b. Chondrocytes die leaving cavities in the cartilage 2. Blood vessels grow around cartilage a. Perichondrium cells differentiate to osteoblasts --> Periosteum b. Inner layer produces bone collar c. Bone collar = thin layer of compact bone around the shaft of the cartilage 3. Increase in blood supply a. Calcified matrix is replaced with spongy bone by osteoblast b. Capillaries and osteoblasts migrate to centre 4. Shaft fills with spongy bone a. Shaft becomes thicker b. Osteoblasts move to metaphysis c. Osteoclasts create medullary cavity Note: Creates Long bones Further growth involves 2 processes 1. Increase in length (longitudinal growth) 2. Enlargement in diameter (appositional growth) Further growth involves 2 processes 1. Increase in length (longitudinal growth) 2. Enlargement in diameter (appositional growth) Longitudinal Growth 1. Capillaries and osteoblast migrate into the centers of the epiphyses 2. Epiphyseal cartilage / plate a. Epiphyses fills with spongy bone b. Osteoblasts in the plate replace cartilage with bone c. Plate enlarges and pushes the epiphysis away from the diaphysis 3. Epiphyseal Closure a. Decreased rate of epiphyseal cartilage growth b. Increased osteoblast activity c. Epiphyseal cartilage becomes epiphyseal line Appositional Growth 1. Ridges form parallel to a blood vessel 2. Rides create a pocket 3. Ridges meet, fuse, and trap the vessel in the bone 4. Bone deposition continues inward towards the vessel, creating and osteon 5. Circumferential lamellae are deposited increasing diameter 6. Osteon is complete Factors Regulating Bone Growth 1. Nutrition - Calcium and phosphate salts, magnesium, sodium ions, vitamins A, C, D 2. Hormones a. Osteoclasts and osteoblast activity  1. Nutrition - Calcium and phosphate salts, magnesium, sodium ions, vitamins A, C, D 2. Hormones a. Osteoclasts and osteoblast activity b. Increase calcium absorption small intestine c. Decrease calcium loss in urine d. Growth hormone, estrogen and testosterone 3. Exercise Categories of Bones - Long Bone - Short Bone - Sutural Bone - Flat Bone - Irregular Bone - Sesamoid Bone - Pneumatized Bone Axial Skeleton - Skull - Thoracic cage - Vertebral column Appendicular Skeleton - Everything else Articulations / Joints - Classification of joints ○ Based on their function ○ Based on their structure Diarthroses/Synovial Joints - Free movement - Typically found at the ends of long bones Examples Shoulder joint  Diarthroses/Synovial Joints - Free movement - Typically found at the ends of long bones Examples Shoulder joint Elbow joint Hip joint Knee joint Characteristics 1. A joint capsule 2. Articular cartilage 3. A joint cavity with synovial fluid 4. A synovial membrane 5. Accessory structures 6. Sensory nerves and blood vessels Different Synovial Joints 1. Gliding joint (planar Joint) a. Nonaxial (Glide in only one direction) b. Multiaxial (Glide in multiple directions) 2. Hinge Joints a. Flexion and extension 3. Pivot Joints a. Rotational movements 4. Condylar/Ellipsoid Joints a. Oval articular surface on one bone articulates with a depression on another bone b. Example is wrist joints 5. Saddle Joints a. Biaxial joints that allow for some circumduction b. Example is thumb 6. Ball and socket a. Triaxial joints, allow for the most movement b. Example is shoulder With more movement comes less stability With less movement comes with more stability