unit 2 anatomy.pdf

Unit 2 Skeletal system Support: attachment to other organs Bones, cartilage, ligaments, connective tissue Store Minerals: calcium ions 98%, phosphate ions...

Unit 2 Skeletal system Support: attachment to other organs Bones, cartilage, ligaments, connective tissue Store Minerals: calcium ions 98%, phosphate ions Blood cell Production: bone marrow makes: erythrocytes, leukocytes, platelets Leverage: muscles pull on bones, movement Protection: rib → heart , skull → brain, vertebrae→ spinal cord, pelvic bones → repro organs Osseous Tissue (Bones) osteocyte (mature) - protein + mineral content in matrix - release calcium ion from bone to blood - in LACUNAE - matrix layer is lamellae - channels from osteocyte → bone capillaries is canaliculi osteoblast (immature) - inner and outer surface of bone - make osteoid → makes matrix - makes new! bone → osteogenesis osteoclast - multinucleated - osteolysis: secrete acid that dissolve bone → release of stored calcium & phosphate ions to blood 2 types osseous tissue - conduct stress from long end to other long end (strength) compact (dense) - weak strength whens stress applied to side - osteon arrangement parallel to bone axis - solid - walls of bones - consist if osteons (haversian sys) basic functional unit of bone & has: central canal, canaliculi, osteocytes lacunae, lamellae spongy (trabecular, cancellous) Epiphysis (ends of long bones) - network of plates - red bone marrow - surround medullary cavity (bone Diaphysis (shaft/ middle of long bones) marrow) - medullary cavity of diaphysis has yellow marrow - in parallel struts - form branching plates, trabeculae → Metaphysis form open network - narrow growth zone between epiphysis and - lightweight nature of bones diaphysis E^ M D M Ev Periosteum: - outer surface of bone - isolate/protect bone from surrounding tissue - route & place for attachment for circulatory and nervous - bone growth and repair - attach bone to connective tissue network of deep fascia Endosteum - inner surface of bone - line medullary cavity - has osteoprogenitor cells - actively repair and growth Bone development and growth 2 types of ossification: 6 weeks of development, skeleton is intramembranous ossification hyaline cartilage - Development of clavicle, mandible, skull, → ossification: cartilage cells replaced face - fast, rapid process by bone cells - bone formation direct from embryonic membrane Osteogenesis: bone formation Mesenchymal cells differentiate to form Calcification: deposits of calcium ions into osteoblast→ Osteoblast secrete matrix→ bone tissue osteoblast trapped in matrix+ differentiate form osteocytes → more osteoblasts produced → blood vessels trapped in spicules endochondral ossification - limbs, vertebrae, hips - slower, yrs to complete - bone develop from hyaline cartilage model - chondrocytes near diaphysis ↑ in size - blood vessels begin to grow around cartilage - perichondrial cells form the periosteum → thin layer of compact bone form STEPS POCOS M Primary Ossification center: Cartilage cells die & replaced by Osteoblasts → begin to form spongy bone - cartilage in Metaphysis region invaded by osteoblast, ↑ in bone length, diameter SOOCB E Secondary Ossification center Osteoblast migrate to Epiphysis region - osteoblast replace Cartilage w Bone - result: pushing epiphysis away from diaphysis → longer bone Increasing diameter of developing bone Appositional growth (side to side) ↔ 4 major sets of blood vessels associated w long bones PENM  - inner layer periosteum differentiated to form osteoblasts add bone matrix to surface Periosteal vessels → forms circumferential lamellae to outer Epiphyseal vessels surface → osteons form → bone enlarge in Metaphyseal vessels diameter Nutrient vessels Epiphyseal plate - cartilage in metaphysis - cartilage near diaphysis turned to bone - width of zone narrow as we age - mark formed location of epiphyseal cartilage Interstitial growth ↕ (length) Bone Maintenance, Remodeling, Repair Remodeling of Bone - inactivity → degeneration, unstressed bones loose ⅓ of mass Injury + Repair: Fractures - Transverse: break to the long axis - Displaced: produce new and abnormal bone arrangement - Nondisplaced: retain normal alignment to bone - Compression: jammed together - Spiral: bone twist along the length - Colles: break at distal portion of radius - Pott: at ankles affect both tibia and fibula Process of bone repair 1. Bone break, induce blessing, hrs pass and - broken bone → bleeding blood clot/ fracture hematoma develops, stops - spongy bone network form bleeding out - osteoblast overly activated→ enlarged callused area + stronger/thicker than normal 2. Internal callus form → spongy bone unite bone inner edges. External callus in cartilage stabilize outer edge 3. External callus cartilage replaced by bone, spongy bone unite broken ends, fragment of dead bone removed, replaced 4. Swelling marks break point of fracture, overtime swelling goes down, many yrs. Purpose of external callus is to build back stronger to prevent from breaking again Aging - young age: osteoblast activity balance osteoclast activity - older age: osteoblast activity ↓ , but osteoclast activity maintains the same, ossification decrease = osteopenia → osteoclast activity faster than osteoblast= porous bones In women (menopause), estrogen ↓ osteoclast are overactive → porous bones and osteoporosis Bone classification / bone shapes - long bones: long, slender, epiphysis, diaphysis, marrow cavity tibia, fibula, femur - short bones: short box like carpal bones (wrist), tarsal bones (ankles) - flat bone: thin, flat bone, parallel surfaces of compact bone parietal bone - sutural bones: small, flat oddly shaped between flat bones of skull - irregular bone: complex shapes vertebrae - pneumatized bones: hollow bones, ethmoid/nasal septum - sesamoid bones: small round bones, develop in tendons, patella Bone marking (landmarks) - bones not inert, dynamic! (large) - attached to muscle - controlled via endocrine system - well vascularized Projections - digestive + excretory sys: provide calcium Depressions and phosphate for growth - Fossa - storage for calcium, phos + minerals Openings - Sinuses, canals, fissures, foramen Processes - trochanter , crest, spine, line, head, neck, condyle, trochlea (small) Chapter 5 Osteoblasts: These are specialized cells responsible for bone formation. synthesize and secrete the bone matrix and are involved in the mineralization of bone tissue. Osteoclasts: large, multinucleated cells that break down bone tissue. Help bone resorption, regulate bone density and calcium levels Osteon: Haversian system, basic structural unit of compact bone. consists of concentric layers (lamellae) of bone matrix surrounding a central canal (Haversian canal) that contains blood vessels and nerves. Trabeculae: These are small, rod-like structures found in spongy bone (cancellous bone). form a lattice-like network that provides structural support and helps reduce the weight of bones while maintaining strength. Fontanel: soft spots on a baby's skull, bones have not yet fused together. Fontanels allow for growth of the brain and skull during infancy and provide flexibility during birth. Epiphyseal Plate: = growth plate, this is a layer of cartilage found at the ends of long bones in children and adolescents. where bone growth occurs, allowing the bones to lengthen. Osteocytes: mature bone cells originate from osteoblasts. They are embedded in the bone matrix and play a role in maintaining bone tissue and communicating with other bone cells. Epiphyseal Line: This is the remnant of the epiphyseal plate in adults. Once growth in length has ceased, the cartilage of the growth plate is replaced by bone, forming the epiphyseal line, which marks where the plate was located. Components of skeletal system + structures Bones: The primary structural elements. Cartilage: Provides flexible support and cushioning at joints. Ligaments: Connect bone to bone, stabilizing joints. Tendons: Connect muscle to bone. Joints: Sites where bones meet, allowing for movement. Axial Skeleton: Comprises the skull, vertebral column, and rib cage. It supports the central axis of the body. Appendicular Skeleton: Includes the limbs and the girdles (shoulder and pelvic girdles) that attach them to the axial skeleton. It facilitates movement and manipulation of the environment. Organic Components: collagen fibers and proteins that provide flexibility and strength. Inorganic Components: Mainly hydroxyapatite (calcium phosphate), which gives bone its hardness and rigidity. Long Bones: Humerus, femur. Short Bones: Carpals (wrist bones), tarsals (ankle bones). Flat Bones: Skull bones, sternum, ribs. Irregular Bones: Vertebrae, pelvis. Sesamoid Bones: Patella (kneecap). Pneumatized Bones: Bones with air spaces, such as some bones of the skull (e.g., frontal bone). Diaphysis: The long shaft of the bone. Epiphysis: The end part of the bone. Metaphysis: The region between diaphysis and epiphysis (contains the growth plate in growing bones). Medullary Cavity: The central cavity containing marrow. Endosteum: The lining of the medullary cavity. Periosteum: A fibrous membrane covering the bone. Yellow Bone Marrow: Found in the medullary cavity of long bones; primarily stores fat and can be converted to red marrow if needed. Red Bone Marrow: Found in the epiphyses and the cavities of spongy bone; responsible for blood cell production (hematopoiesis). Compact Bone: outer layer of the bone and provides strength. Spongy Bone: in the epiphyses, porous structure that supports and houses red marrow. Osteon: The basic structural unit of compact bone, consisting of concentric lamellae surrounding a central (Haversian) canal. Function of Perforating and Central Canals: Central Canal: Contains blood vessels and nerves supplying the bone. Perforating Canals: Allow blood vessels and nerves to enter and connect with the central canals, facilitating nutrient flow. Location of Osteocytes: Located in small spaces called lacunae between the lamellae. Nutrient Supply to Osteocytes: Nutrients reach osteocytes through tiny channels called canaliculi that connect lacunae to the central canal, allowing for communication and nutrient exchange. Function of Perforating (Sharpey's) Fibers Perforating fibers, also known as Sharpey's fibers, are bundles of collagen fibers that attach the periosteum to the underlying bone. Their main functions include: Anchoring the Periosteum: They secure the periosteum firmly to the bone surface, ensuring stability and protection. Transmitting Forces: They help distribute the mechanical forces exerted on the bone, particularly during muscle contractions, which contributes to overall bone strength and integrity. Three Different Types of Lamellae in Bone 1. Concentric Lamellae: These are the layers of bone matrix that form the osteons (Haversian systems) in compact bone. Each lamella surrounds the central canal and is arranged concentrically. 2. Circumferential Lamellae: These are layers of bone that encircle the entire outer and inner surfaces of the bone. They provide additional strength and support to the bone structure. 3. Interstitial Lamellae: These are remnants of old osteons that have been partially resorbed. They fill the spaces between the osteons in compact bone and contribute to its overall structural integrity. Intramembranous Ossification Definition: This process involves the direct formation of bone from mesenchymal tissue (a type of connective tissue). Process: 1. Mesenchymal cells differentiate into osteoblasts. 2. Osteoblasts begin to secrete bone matrix, forming ossification centers. 3. As matrix is secreted, osteoblasts become trapped and mature into osteocytes. 4. The developing bone forms trabeculae, which fuse to create spongy bone. 5. Compact bone forms on the surface, with the periosteum developing from the surrounding mesenchyme. Examples of Bones Formed: Flat bones of the skull (e.g., parietal bone), the mandible, and the clavicle. Endochondral Ossification  Definition: This process involves the replacement of hyaline cartilage with bone, typically in long bones. Process: 1. Mesenchymal cells differentiate into chondrocytes, forming a cartilage model. 2. Chondrocytes enlarge and then die, creating spaces. 3. Blood vessels invade, bringing osteoblasts that replace the cartilage with bone. 4. The primary ossification center forms in the diaphysis, while secondary ossification centers form in the epiphyses after birth. 5. The epiphyseal plate remains for growth until adulthood, at which point it becomes the epiphyseal line. Examples of Bones Formed: Long bones (e.g., femur, humerus), vertebrae, and ribs. Ossification Tracings For both processes, visual tracings would illustrate the stages of differentiation from mesenchyme or cartilage to mature bone, showing key changes such as the formation of ossification centers and the replacement of cartilage. Types of Bone Fractures 1. Transverse Fracture: A straight fracture line across the bone. 2. Displaced Fracture: Bone fragments are out of alignment; may require realignment (reduction). 3. Nondisplaced Fracture: Bone remains in its normal alignment despite the fracture. 4. Compression Fracture: Bone is crushed, often occurring in vertebrae; common in osteoporosis. 5. Spiral Fracture: A twisting force causes the fracture, resulting in a spiral-shaped break. Process of Bone Remodeling/Repair 1. Hematoma Formation: Following a fracture, blood vessels rupture, leading to a hematoma (blood clot) at the fracture site. 2. Fibrocartilaginous Callus Formation: Capillaries grow into the hematoma, and fibroblasts and chondroblasts produce a soft callus of collagen and cartilage. 3. Bony Callus Formation: Osteoblasts replace the fibrocartilaginous callus with a bony callus made of spongy bone. 4. Bone Remodeling: The bony callus is remodeled over time, restoring the bone to its original shape and structure through the action of osteoclasts and osteoblasts. Ch 6 1. Bone Terminology: Cranium: The skull, particularly the part enclosing the brain. Epicondyle: A raised area on or above a condyle, typically for ligament attachment. Foramen: An opening or hole in a bone, allowing passage for nerves or blood vessels. Suture: A seam-like immovable joint between two bones, particularly in the skull. Fissure: A narrow, slit-like opening between bones for nerves and blood vessels. Fontanel: Soft spots on an infant's skull where the bones haven't fully fused. Canal: A passageway through bone. Meatus: A canal or passageway in a bone (e.g., external auditory meatus in the ear). Fossa: A shallow depression or hollow in a bone. Process: A bony projection or outgrowth. Condyle: A rounded articular projection at the end of a bone. Trochanter: A large, blunt projection on a bone (found in the femur). Tubercle: A small rounded projection on a bone. Tuberosity: A large, roughened area on a bone, typically where muscles attach. Spine: A sharp, slender projection. Ridge: A raised elongated area on a bone. Ramus: A branch or arm-like extension of a bone. Crest: A prominent ridge or elongated projection. 2. Bones or Bony Features: Orbit of the Eye: ○ The bones forming the orbit include the frontal, zygomatic, maxilla, sphenoid, ethmoid, lacrimal, and palatine bones. Cheek Bone: ○ The zygomatic bone forms the cheekbone. It articulates with the maxilla, temporal, frontal, and sphenoid bones. Hard Palate: ○ Formed by the palatine processes of the maxilla and the horizontal plates of the palatine bones. Nasal Septum and Nose: ○ The nasal septum is formed by the vomer and the perpendicular plate of the ethmoid bone, as well as cartilage. The external structure of the nose is supported by nasal bones. 3. Nasal Conchae Bones: Location: The nasal conchae are thin, scroll-like bones that protrude into the nasal cavity from the lateral walls. There are three pairs: superior, middle, and inferior conchae. The superior and middle conchae are part of the ethmoid bone, while the inferior conchae are separate bones.  Function: They increase the surface area of the nasal cavity, aiding in warming, humidifying, and filtering the air as it is inhaled. Why Called Turbinate Bones: They are called turbinate bones because their scroll-like shape helps create turbulence in the airflow, enhancing contact with the mucous membranes for conditioning the air. 4. Sella Turcica: Location: The sella turcica is a saddle-shaped depression in the sphenoid bone. Function: It houses and protects the pituitary gland, which is crucial for hormone regulation in the body. 5. Articulations: Mandible and Temporal Bones: ○ The mandibular condyle of the mandible articulates with the mandibular fossa of the temporal bone, forming the temporomandibular joint (TMJ). Skull and Vertebral Column: ○ The occipital condyles of the occipital bone articulate with the atlas (the first cervical vertebra), forming the atlanto-occipital joint. 6. Chart 1. Functions of the Vertebral Column and Thoracic Cage: Vertebral Column: ○ Support: It provides the main structural support for the body, allowing us to stand upright and bear weight. ○ Protection: It encases and protects the spinal cord. ○ Movement: The vertebral column allows for a wide range of motion (flexion, extension, lateral bending, and rotation). ○ Attachment Points: It provides attachment for muscles and ligaments. ○ Shock Absorption: The intervertebral discs act as shock absorbers. Thoracic Cage: ○ Protection: It protects vital organs such as the heart and lungs. ○ Support: It supports the shoulder girdle and upper limbs. ○ Respiration: The ribs and intercostal muscles assist in breathing by expanding and contracting the thoracic cavity. ○ Muscle Attachment: Provides attachment points for muscles involved in respiration, posture, and movements of the upper limbs. 2. Assigned Features on the Vertebrae:  Body: The large, weight-bearing portion of the vertebra. Spinous Process: The bony projection from the posterior of the vertebra, which serves as a point of muscle attachment. Transverse Process: The lateral projections on either side of the vertebra, also important for muscle and ligament attachment. Vertebral Foramen: The opening in each vertebra through which the spinal cord passes. Superior and Inferior Articular Processes: These form joints with adjacent vertebrae to allow movement. Intervertebral Foramen: The space between adjacent vertebrae where spinal nerves exit. 3. Types of Vertebrae: Cervical Vertebrae: ○ Number: 7 (C1-C7) ○ Features: Small body, transverse foramen, bifid (split) spinous processes, large vertebral foramen. Atlas (C1) and Axis (C2) are specialized for rotation of the head. Thoracic Vertebrae: ○ Number: 12 (T1-T12) ○ Features: Medium-sized body, long spinous process angled downward, costal facets for rib articulation, smaller vertebral foramen. Lumbar Vertebrae: ○ Number: 5 (L1-L5) ○ Features: Large, thick body, short and blunt spinous process, large transverse processes, large vertebral foramen. Sacral Vertebrae: ○ Number: 5 (fused into the sacrum) ○ Features: The sacrum is a triangular bone at the base of the spine that connects the spine to the pelvis. Coccygeal Vertebrae: ○ Number: 4 (fused into the coccyx or tailbone) ○ Features: Small, fused vertebrae at the base of the sacrum. 4. Functions of Vertebral Features: Intervertebral Foramina: Openings between adjacent vertebrae that allow the passage of spinal nerves. Intervertebral Discs: Cartilaginous discs between vertebrae that cushion the spine and absorb shock, providing flexibility. Vertebral Foramen: The large central opening in each vertebra through which the spinal cord passes.  Transverse Foramen (Cervical Vertebrae Only): Openings in the transverse processes of cervical vertebrae that allow the passage of the vertebral arteries and veins. 5. Parts of the Thoracic Cage and Sternum: Thoracic Cage: ○ Ribs: 12 pairs of ribs. ○ Sternum: Consists of three parts: 1. Manubrium: The upper portion of the sternum. 2. Body: The main central part of the sternum. 3. Xiphoid Process: The small cartilaginous tip at the bottom of the sternum. ○ Costal Cartilage: The cartilage that connects ribs to the sternum. 6. Features of a Typical Rib: Head: The rounded end of the rib that articulates with the thoracic vertebrae. Neck: The narrow area between the head and the tubercle. Tubercle: A small bump near the neck that articulates with the transverse process of a vertebra. Body (Shaft): The long, curved part of the rib. Costal Groove: A groove on the underside of the rib that houses blood vessels and nerves. 7. Types and Numbers of Ribs: True Ribs (Vertebrosternal Ribs): ○ Number: 7 pairs (ribs 1–7) ○ Features: They attach directly to the sternum via costal cartilage. False Ribs (Vertebrochondral Ribs): ○ Number: 3 pairs (ribs 8–10) ○ Features: They attach to the cartilage of the rib above, not directly to the sternum. Floating Ribs: ○ Number: 2 pairs (ribs 11–12) ○ Features: They do not attach to the sternum at all, and their anterior ends are free. 1. Bones and Bony Features Outlined in the Lab Activities: Pectoral Girdle: Clavicle, scapula (acromion, coracoid process, glenoid cavity, spine of scapula). Pelvic Girdle: Ilium (iliac crest, greater sciatic notch), ischium (ischial tuberosity, ischial spine), pubis (pubic symphysis), acetabulum (hip socket). Arm Bones: Humerus (head, greater and lesser tubercles, deltoid tuberosity), radius, ulna (olecranon, styloid processes). Leg Bones: Femur (head, greater trochanter, lesser trochanter, medial and lateral condyles), tibia (tibial tuberosity, medial malleolus), fibula (lateral malleolus). Hands and Feet: Phalanges, metacarpals, metatarsals, carpal bones (scaphoid, lunate, etc.), tarsal bones (talus, calcaneus, etc.). 2. Numerical Sequence of the Digits in the Hand and Foot: Hand: ○ The digits are numbered 1–5, starting from the thumb (pollex) to the pinky finger. 1. Thumb (pollex) 2. Index finger 3. Middle finger 4. Ring finger 5. Pinky finger Foot: ○ The digits are also numbered 1–5, starting from the big toe (hallux) to the small toe. 1. Big toe (hallux) 2. Second toe 3. Middle toe 4. Fourth toe 5. Little toe 3. Bones of the Pectoral and Pelvic Girdle: Pectoral Girdle: ○ Composed of the clavicle and scapula. Pelvic Girdle: ○ Formed by the two hip bones (os coxae), which are each made up of three fused bones: the ilium, ischium, and pubis. 4. Comparison of Pectoral and Pelvic Girdle:  Which Girdle Has the Greatest Flexibility? ○ The pectoral girdle has the greatest flexibility. It allows a wide range of motion in the shoulder joint due to the loose attachment of the scapula and clavicle to the axial skeleton. Which Girdle Forms the Strongest Joint? ○ The pelvic girdle forms the strongest joint. The sacroiliac joint is a strong, weight-bearing joint that connects the pelvis to the axial skeleton, providing stability for the lower limbs and supporting body weight. Bones that Articulate to Form the Pectoral Girdle: ○ Clavicle articulates with the sternum at the sternoclavicular joint and with the scapula at the acromioclavicular joint. Bones that Articulate to Form the Pelvic Girdle: ○ Each os coxae (hip bone) articulates with the sacrum at the sacroiliac joint and the femur at the acetabulum (hip joint). 5. Difference Between the True and False Pelvis: True Pelvis: ○ The space below the pelvic brim (lesser pelvis), containing the pelvic organs (bladder, rectum, reproductive organs). It forms the birth canal. False Pelvis: ○ The area above the pelvic brim (greater pelvis), between the iliac crests, which supports the abdominal organs. 6. Difference Between the Pelvic Inlet and Outlet: Pelvic Inlet: ○ The opening bounded by the pelvic brim (superior part of the pelvis). It is the entrance to the true pelvis. Pelvic Outlet: ○ The inferior opening of the true pelvis, defined by the coccyx, ischial spines, and pubic symphysis. It is the exit of the birth canal. 7. Differences Between Male and Female Pelvis: Shape: ○ Male Pelvis: Narrower, deeper, and more heart-shaped. ○ Female Pelvis: Wider, shallower, and more oval-shaped to accommodate childbirth. Subpubic Angle: ○ Male Pelvis: Narrower, typically less than 90 degrees. ○ Female Pelvis: Wider, typically greater than 90 degrees. Pelvic Inlet and Outlet: ○ Male Pelvis: Smaller, more obstructed pelvic inlet and outlet.  ○ Female Pelvis: Larger pelvic inlet and outlet, providing more space for childbirth. Sacrum: ○ Male Pelvis: Longer and more curved. ○ Female Pelvis: Shorter and less curved. Ischial Spines: ○ Male Pelvis: More prominent, projecting inward. ○ Female Pelvis: Less prominent, allowing more room in the pelvic outlet.