Connective Tissue and Muscle Quiz

Connective Tissues

• Mesenchyme: Embryonic tissue, precursor to all connective tissues, including cartilage, bone, and blood vessels.
• Reticular Connective Tissue: Provides supportive framework for soft organs like lymph nodes, spleen, and bone marrow.
• Adipose Tissue: Stores energy as fat, insulates the body and cushions organs. Located in subcutaneous tissue, around organs, and in bone marrow.
• Pigmented Connective Tissue: Found in parts of the eye (iris and choroid), protecting from UV light and contributing to visual processing.
• Loose Connective Tissue: Supports blood vessels, nerves, and epithelial layers, allowing nutrient and waste diffusion. Surrounds these structures.
• Dense Regular Connective Tissue: Resistant to tension, found in tendons, ligaments, and aponeuroses.
• Dense Irregular Connective Tissue: Resists stress in multiple directions, located in the dermis, fibrous organ capsules, and fascia.
• Hyaline Cartilage: Supports and reduces friction, found in trachea, nose, costal cartilage, and articular surfaces of joints.
• Elastic Cartilage: Maintains shape while allowing flexibility, present in the external ear, epiglottis, and auditory tubes.
• Fibrocartilage: Strong, resists compression, found in intervertebral discs, pubic symphysis, and menisci of the knee.
• Bone: Provides structural support, protects organs, enables movement, and stores minerals. Located in the skeletal system.
• Intramembranous Ossification: Forms flat bones (e.g., skull, clavicle) directly from mesenchyme.
• Endochondral Ossification: Forms long bones (e.g., femur, humerus) by replacing cartilage with bone.
• Blood (Mammalian): Transports oxygen, nutrients, hormones, and waste. Plays a role in immunity and clotting.

Other Connective Tissues

• Bird Blood: Similar to mammalian blood, but nucleated red blood cells. Transports oxygen and nutrients.
• Smooth Muscle Tissue: Located in the walls of hollow organs (intestines, blood vessels, uterus). Involuntary contractions move substances.
• Skeletal Muscle Tissue: Attaches to bones, responsible for voluntary movement, posture, and heat production.
• Cardiac Muscle Tissue: Found in the heart walls, responsible for involuntary contractions that pump blood throughout the circulatory system.

General Connective Tissue Features

• Composition: Cells, fibers (collagen, elastin, reticular), and extracellular matrix (ECM).
• Function: Support, strength, elasticity, protection, and nutrient/waste exchange.
• Diversity: Ranges from rigid bone to flexible adipose tissue.

Connective Tissue Cells

• Fibroblasts: Produce fibers and ground substance.
• Adipocytes: Store fat.
• Macrophages: Immune cells, phagocytize pathogens.
• Mast Cells: Release histamine during allergic responses.
• Chondrocytes/Osteocytes: Specialized for cartilage and bone respectively.
• Mesenchymal Cells: Stem cells, differentiate into other connective tissue types.

Ground Substance

• Gel-like material between cells and fibers.
• Composed of water, glycosaminoglycans (GAGs), proteoglycans, and adhesive glycoproteins.
• Aids in hydration, nutrient diffusion, and resistance to compression.

Blood Supply and Innervation

• Most connective tissues are vascularized (except cartilage, which is avascular).
• Nerve supply varies: cartilage has no direct innervation.

Other Functions

• Metabolism: Adipose tissue stores and releases energy.
• Immunity: Reticular tissue forms the framework of lymphoid organs.
• Healing: Fibroblasts vital in wound repair and fibrosis.

Pathological Conditions

• Inflammation: Connective tissue cells (macrophages, mast cells) involved.
• Fibrosis: Excessive fibrous tissue formation can impair function.

Development and Growth

• Mesenchyme: Embryonic connective tissue.
• Bone growth: Involves connective tissue processes (e.g., ossification).
• Wound healing: Connective tissue's reparative capacity crucial.

Connective Tissue Fibers

• Collagen: Tensile strength.
• Elastic: Stretch and recoil.
• Reticular: Supportive networks.