Bone classification lab

Introduction of quiz focused on the skeletal system covering previous discussions.
Emphasis on the lab practical for the skeletal system beginning today.

Definition and Importance: Cartilage can withstand tension and compression due to its high water content.
Key Cell Type: Chondrocytes located in lacunae, embedded in an extracellular matrix with ground substance and fibers.
Types of Cartilage:
- Hyaline Cartilage: The most abundant type, found in the nose, ribs, larynx, and joint ends of bones, providing structural support.
- Elastic Cartilage: More flexible, found in the ear and epiglottis, the flap that covers the larynx during swallowing.
- Fibrocartilage: Highly compressible, present in areas subjected to pressure, like intervertebral discs.

Categories of Bones:
- Axial Skeleton: Comprises bones in the head and torso including the skull, vertebrae, and ribcage.
- Appendicular Skeleton: Consists of limbs (arms and legs) plus the shoulder and pelvic girdles.
Shapes of Bones:
- Long Bones: Longer than they are wide, such as those in limbs (e.g., femur, humerus).
- Short Bones: Cube-like shapes, found in wrists and ankles.
- Flat Bones: Thin, curved bones like the sternum and cranial bones.
- Irregular Bones: Complex shapes, like vertebrae and some facial bones.

Provide Support: The framework for the body; all body weight is supported by the skeletal structure.
Protection: Protect vital organs (e.g., ribs protect the heart).
Leverage: Act as levers facilitating movement when muscles contract.
Mineral Storage: Store essential minerals like calcium and phosphorus, releasing them as needed.
Energy Storage: Fat storage occurs in the yellow marrow.
Blood Cell Formation: Red marrow is involved in producing blood cells.

Types of Tissue in Bone: Bone is an organ made of multiple tissues including:
- Bone Tissue: Main component
- Nervous Tissue: Present for signaling
- Connective Tissue: Supportive framework
- Cartilage: Covering joint surfaces
- Blood Vessels: Nutrition and signaling providers.
Anatomical Structures:
- Compact Bone: Dense outer layer.
- Spongy Bone: Inner, lighter matrix filled with marrow; allows for efficient blood cell production.
- Epiphyseal Line: Thin growth line indicating the end of bone growth.
- Periosteum: Dense protective layer covering bone; connects to bone through perforating fibers.
- Endosteum: Lines inner surfaces, including marrow cavities.

Types of Bone Cells:
- Osteogenic Cells: Stem cells that produce bone matrix, found in the periosteum and endosteum.
- Osteocytes: Mature bone cells maintaining the matrix; originate from osteoblasts.
- Bone Lining Cells: Flat cells assisting with maintenance on the surface of the bone.
- Osteoclasts: Bone-resorbing cells that breakdown bone tissue, involved in releasing minerals.

Components:
- Osteons: Cylindrical units comprising compact bone featuring central canals with blood vessels.
- Lamellae: Concentric rings that make up osteons; house collagen fibers for tensile strength.
- Lacunae: Small cavities containing osteocytes.
- Canaliculi: Tiny canals connecting lacunae and enabling nutrient delivery and waste removal.

Organic Components: Cells (osteocytes, etc.) and osteoid (collagen fibers and ground substance) that help maintain flexibility and strength of bone.
Inorganic Components: Hydroxyapatites which provide hardness, mainly calcium and phosphate crystals.
Durability: Bones can withstand significant tensile and compressive forces, analogous to steel.

Endochondral Ossification: The process from hyaline cartilage to bone in long bones, occurring primarily during fetal development and continuing until bones mature in early adulthood.
Intramembranous Ossification: Formation of flat bones (e.g., skull, clavicle) from fibrous membranes during embryonic development.
Growth Plates: Zones of cartilage allowing for elongation during development; impacted by hormones (especially growth hormone).
- Post-puberty, increased hormones like estrogen/testosterone accelerate ossification processes.

Calcium's Role in the Body: Critical for physiological functions such as muscle contraction and nerve signaling.
Hormonal Regulation:
- Calcitonin: Produced by thyroid gland, lowers blood calcium levels by prompting osteoblasts to store calcium.
- Parathyroid Hormone (PTH): Produced by parathyroid glands, raises calcium levels by stimulating osteoclast activity to release calcium from bones.
Kidneys and Calcium Regulation: Control calcium excretion in urine and absorption in the intestines.

Understanding the skeletal system from structure to function is critical for quizzes and lab applications.
Familiarity with terminology and processes related to bone growth, types of bone cells, and calcium homeostasis will be crucial for assessments.