Ch 6 bone anatomy and physiology
Page 1: Skeletal Components
C-Maxilla: Bone of the upper jaw.
Humerus: The long bone in the upper arm.
Mandible: The lower jawbone.
Phalanx: Bones of the fingers and toes.
Clavicle: Collarbone.
Ribs: Series of curved bones forming the ribcage, protecting the thoracic cavity.
Carpus: Group of bones forming the wrist.
Radius & Ulna: Long bones of the forearm.
Pelvic Bones: Include the pubis and ischium.
Femur: The thigh bone.
Patella: Knee cap.
Tibia & Fibula: Bones of the lower leg.
Tarsus: Ankle bones.
Metatarsals: Bones of the foot.
Page 2: Functions of the Skeletal System
Support: Provides a framework for the body.
Protection: Shields vital organs from injury.
Movement: Acts as levers for the muscles.
Mineral Storage: Stores minerals such as calcium and phosphorus.
Blood Cell Formation: Hematopoiesis occurs in the red marrow cavities.
Triglyceride Storage: Stores fats in yellow marrow.
Page 3: General Anatomy
Connective Tissue: Bone is a type of connective tissue.
Associated Tissues: Includes cartilage, blood, and fat.
Types of Bone:
Spongy Bone: 20% of bone, has a network with open spaces.
Compact Bone: 80% of bone, appears solid.
Page 4: Types of Bone
Long Bones: Longer than wide (e.g., arm and leg bones).
Sesamoid Bones: Develop within tendons (e.g., patella).
Flat Bones: Thin and curved (e.g., skull, ribs).
Irregular Bones: Complex shapes (e.g., vertebrae).
Page 5: Long Bones Classification
Characteristics:
Longer than wide.
Diaphysis (shaft) and epiphysis (ends).
External surface: compact bone; internal: spongy bone.
Examples: Most appendicular bones.
Page 6: Short Bones Classification
Characteristics:
Cube-shaped.
Thin exterior of compact bone; spongy interior.
Examples: Carpals, tarsals.
Page 7: Flat Bones Classification
Characteristics:
Thin, flat structure.
External compact bone coating; internal spongy bone.
Examples: Skull, sternum.
Page 8: Irregular Bones Classification
Characteristics:
Any bone that does not fit other categories.
Example: Vertebrae.
Page 9: Check Your Understanding
Four Classifications of Bone Types:
Long, Short, Flat, Irregular with examples.
Page 10: Gross Anatomy of Long Bones
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Diaphysis: Shaft containing yellow marrow cavity.
Epiphysis: Ends containing external compact bone, internal spongy bone, and red marrow.
Articular Cartilage: Cushions the ends of bones.
Epiphyseal Plate: Site for ossification during growth.
Periosteum: Covers external surfaces; contains osteogenic cells.
Endosteum: Covers inner surfaces; composed of osteogenic cells.
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Page 11: Flat Bone Anatomy
Structure:
Outer compact bone.
Middle spongy bone (diploe).
Inner compact bone.
Page 12: Microscopic Anatomy
Bone Cells:
Osteogenic Cells: Stem cells.
Osteoblasts: Build new bone.
Page 13: Bone Cells Continued
Osteocytes: Mature bone cells maintaining matrix in lacunae.
Osteoclasts: Cells that resorb and break down bone matrix.
Page 14: Microscopic Anatomy of Compact Bone
Structure:
Made of osteons (Haversian systems).
Lamellae: Layers of collagen fibers in a calcified matrix.
Lacunae: Spaces housing osteocytes.
Volkmann's canals: Connective vessels between periosteum and central canals.
Page 15: Compact Bone Connections
Canaliculi: Small canals connecting lacunae.
Function: Nutrient and waste exchange among osteocytes.
Page 16: Microscopic Anatomy of Spongy Bone
Structure:
No osteons; instead, it has a framework of trabeculae.
Contains lacunae and canaliculi with osteocytes.
Page 17: Check Understanding
Questions about osteocytes, canaliculi and lamellae functionalities.
Page 18: Osteogenesis (Bone Formation)
Begins early (5-6 weeks of embryo development).
Processes:
Intramembranous Ossification: Formation of flat bones.
Endochondral Ossification: Formation of most bones, especially long bones.
Page 19: Intramembranous Ossification
Involves mesenchyme cells differentiating into osteoblasts.
Osteoblasts secrete bone matrix and develop canaliculi.
Page 20: Continued Intramembranous Ossification
Trabeculae formation associates with blood vessels, developing red marrow.
Periosteum forms around new bone; move to compact bone.
Page 21: Endochondral Ossification
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Process:
Hyaline cartilage is replaced by bone.
Enlarge chondrocytes; calcified matrix.
Page 22: Continued Endochondral Ossification
Development follows specific stages: formation of bone collar, cavitation, and ossification centers.
Page 23: Fetal Development of Bone
Diagram of primary ossification centers in several fetal bones.
Page 24: Interstitial Growth of Long Bones
Growth occurs at epiphyseal plate; includes phases such as proliferation, hypertrophy, calcification, ossification.
Page 25: Epiphyseal Plate Closure
Occurs in late teens; frequency of cell division reduces leading to closure.
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Page 26: Continued Epiphyseal Plate Closure
Observations of epiphyseal scars in bones post-closure.
Page 27: Appositional Growth
Adjustments during bone lengthening to maintain shape.
Controlled by osteoblasts and osteoclasts for thickness and cavity diameter.
Page 28: Bone Remodeling
Continuous replacement of bone to maintain strength and adapt to stress.
Requires specific minerals and vitamins; involves osteoclasts and osteoblasts.
Page 29: Check Understanding
Questions focused on interstitial and appositional growth.
Page 30: Blood Calcium Homeostasis
Calcitonin: Released in response to high calcium levels.
PTH: Released in response to low calcium levels, stimulates osteoblasts.
Page 31: Types of Bone Fractures
Categories include: Nondisplaced, Displaced, Complete, Incomplete, Linear, etc.
Page 32: Common Types of Fractures
Comminuted Fracture: Bone breaks into multiple pieces.
Compression Fracture: Bone is crushed.
Page 33: Further Types of Fractures
Spiral Fracture: Ragged break due to twisting forces.
Epiphyseal Fracture: Separation along the epiphyseal plate.
Page 34: Additional Types of Fractures
Depressed Fracture: Bone portion is pressed inward.
Greenstick Fracture: Incomplete break typical in children.
Page 35: Healing Process of Bone Fracture
Hematoma formation.
Fibrocartilaginous callus formation.
Bony callus formation.
Bone remodeling.
Page 36: Bone Disorders
Osteoporosis: Imbalance in bone resorption and deposition, leading to fragile bones.
Page 37: Osteoporosis Risk Factors
Factors include genetics, lifestyle, and hormonal changes.
Page 38: Achondroplastic Dwarfism
Genetic condition causing halted long bone growth.
Page 39: Humor
"What do you call a funny bone? A humerus."
Skeletal Components
The skeletal system comprises various components including the maxilla, which is the bone of the upper jaw; the humerus, the long bone in the upper arm; and the mandible, the lower jawbone. Additionally, it includes phalanx bones that make up the fingers and toes, the clavicle or collarbone, and a series of ribs that form a curved structure protecting the thoracic cavity. The carpus refers to a group of bones in the wrist, while the radius and ulna are the long bones of the forearm. The pelvic bones consist of the pubis and ischium, and further down the body, the femur serves as the thigh bone, with the patella functioning as the knee cap. The tibia and fibula are the bones of the lower leg, leading to the tarsus, which comprises the ankle bones, followed by the metatarsals of the foot.
Functions of the Skeletal System
The skeletal system serves various vital functions for the body. It provides structural support, acting as a framework that maintains the shape and form of the body. Additionally, it offers protection to vital organs from injury and facilitates movement by acting as levers for muscles. The system is also critical for mineral storage, particularly calcium and phosphorus, and plays a significant role in blood cell formation through hematopoiesis in the red marrow cavities. Furthermore, it stores triglycerides in the yellow marrow.
General Anatomy
Bone is classified as a type of connective tissue and is associated with other tissues such as cartilage, blood, and fat. There are two main types of bone: spongy bone, which accounts for 20% of total bone, characterized by a network with open spaces, and compact bone, which constitutes 80% of bone mass and appears solid.
Types of Bone
Bones can be categorized into four main types: long bones, which are longer than wide (examples include arm and leg bones); short bones, which are cube-shaped with a thin exterior of compact bone and a spongy interior (exemplified by carpals and tarsals); flat bones, which are thin and curved in shape, such as the skull and ribs; and irregular bones that have complex shapes, like the vertebrae.
Gross Anatomy of Long Bones
In examining long bones, they typically possess a diaphysis, or shaft, containing a yellow marrow cavity, and an epiphysis, or ends, which consist of external compact bone, internal spongy bone, and red marrow. Important components include the articular cartilage, which cushions the ends of the bones; the epiphyseal plate, a site for ossification during growth; the periosteum, which covers the external surfaces and contains osteogenic cells; and the endosteum, which lines the inner surfaces and is also made up of osteogenic cells.
Bone Cells
Bone is constituted of various cells: osteogenic cells that act as stem cells; osteoblasts that are responsible for building new bone; osteocytes, which are mature bone cells maintaining the matrix in lacunae; and osteoclasts, those that resorb and break down bone matrix. Compact bone is structured of osteons (Haversian systems) arranged in a specific manner with lamellae, lacunae, and Volkmann's canals facilitating vascular connections. Spongy bone, conversely, lacks osteons but has a network of trabeculae along with lacunae and canaliculi housing osteocytes.
Bone Formation
Bone formation, or osteogenesis, begins as early as 5-6 weeks in embryo development. It primarily occurs through two processes: intramembranous ossification, which refers to the formation of flat bones, and endochondral ossification, which involves the replacement of hyaline cartilage by bone for most others, particularly long bones. The growth of bones continues at the epiphyseal plate during childhood and adolescence and involves several phases and adjustments in bone length and thickness. Bone remodeling is a continuous process for maintaining strength and adapting to stress, requiring specific minerals and vitamins.