Fundamentals of Anatomy & Physiology - Chapter 4: Tissue Level of Organization

Flashcards based on lecture notes about the Tissue Level of Organization.

Tissues

Collections of specialized cells and cell products that perform specific functions.

Histology

The study of tissues.

Epithelial Tissue

Covers exposed surfaces, lines internal passageways, and forms glands.

Connective Tissue

Fills internal spaces, supports other tissues, transports materials, and stores energy.

Muscle Tissue

Specialized for contraction; includes skeletal, heart, and smooth muscle.

Nervous Tissue

Carries electrical signals from one part of the body to another.

Epithelia

Layers of cells covering internal or external surfaces.

Glands

Structures that produce fluid secretions.

Microvilli

Increase absorption or secretion on the apical surface of epithelial cells.

Cilia

Move fluids on a ciliated epithelium.

Cell adhesion molecules (CAMs)

Transmembrane proteins that support and allow communication between cells.

Proteoglycans

Intercellular cement containing glycosaminoglycans such as hyaluronan.

Gap junctions

Cell junctions that allow rapid communication via interlocking transmembrane proteins (connexons).

Tight junctions

Cell junctions between two plasma membranes that prevent passage of water and solutes.

Desmosomes

Cell junctions that link opposing plasma membranes with CAMs and proteoglycans.

Basal lamina

Closest to the epithelium and part of the basement membrane.

Reticular lamina

Deeper portion of basement membrane that provides strength.

Stem cells

Epithelial cells are replaced by continual division of these cells near the basement membrane.

Squamous

Thin and flat epithelial cell shape.

Cuboidal

Square-shaped epithelial cell shape.

Columnar

Tall, slender rectangle epithelial cell shape.

Simple epithelium

Single layer of cells.

Stratified epithelium

Several layers of cells.

Mesothelium

Lines body cavities.

Endothelium

Forms inner lining of heart and blood vessels.

Keratin

Adds strength and water resistance to stratified squamous epithelia.

Transitional epithelia

Epithelium that tolerates repeated cycles of stretching without damage and is found in the urinary bladder.

Glands

Collections of epithelial cells that produce secretions.

Endocrine glands

Release hormones that enter the bloodstream and have no ducts.

Exocrine glands

Produce exocrine secretions and discharge secretions through ducts onto epithelial surfaces.

Goblet cells

Unicellular exocrine glands that secrete mucin, which mixes with water to form mucus.

Merocrine secretion

Released by secretory vesicles (exocytosis).

Apocrine secretion

Released by shedding cytoplasm.

Holocrine secretion

Released by cells bursting, killing gland cells.

Serous glands

Glands with watery secretions.

Mucous glands

Glands that secrete mucins.

Mixed exocrine glands

Glands with both serous and mucous secretions.

Matrix

Extracellular components of connective tissue (fibers and ground substance).

Connective tissue proper

Connective tissue category that connects and protects.

Fluid connective tissues

Connective tissue category that transports.

Supporting connective tissues

Connective tissue category that provides structural strength.

Loose connective tissue

More ground substance, fewer fibers; e.g., fat (adipose tissue).

Dense connective tissue

More fibers, less ground substance; e.g., tendons.

Fibroblasts

Most abundant cell type in connective tissue proper; secretes proteins and hyaluronan.

Fibrocytes

Maintain connective tissue fibers.

Adipocytes

Fat cells; store a single, large fat droplet.

Mesenchymal cells

Stem cells that respond to injury or infection and differentiate into fibroblasts, macrophages, etc.

Melanocytes

Synthesize and store the brown pigment melanin.

Macrophages

Large phagocytic cells of the immune system; engulf pathogens and damaged cells.

Mast cells

Stimulate inflammation after injury or infection; release histamine and heparin.

Lymphocytes

Migrate throughout the body; may develop into plasma cells, which produce antibodies.

Microphages

Phagocytic blood cells (neutrophils, eosinophils) attracted to signals from macrophages and mast cells.

Collagen fibers

Most common fibers in connective tissue proper; strong and flexible; resist force in one direction.

Reticular fibers

Form a network of interwoven fibers (stroma); strong and flexible; resist forces in many directions.

Elastic fibers

Contain elastin; branched and wavy; return to original length after stretching.

Ground substance

Clear, colorless, and viscous; fills spaces between cells and slows pathogen movement.

Mesenchyme

Embryonic connective tissue; first connective tissue in embryos.

Mucous connective tissue

Loose embryonic connective tissue.

Areolar tissue

Least specialized loose connective tissue; open framework; viscous ground substance; elastic fibers.

Adipose tissue

Loose connective tissue containing many adipocytes (fat cells).

Reticular tissue

Loose connective tissue that provides support; reticular fibers form a complex, three-dimensional stroma.

Dense regular connective tissue

Dense connective tissue that is tightly packed, with parallel collagen fibers.

Dense irregular connective tissue

Dense connective tissue with an interwoven network of collagen fibers.

Elastic tissue

Dense connective tissue made of elastic fibers.

Fasciae

Connective tissue layers and wrappings that support and surround organs.

Fluid connective tissues

Includes blood and lymph.

Plasma

Watery matrix in blood.

Formed elements

Cells and cell fragments in blood (red blood cells, white blood cells, platelets).

Lymph

Interstitial fluid that enters lymphatic vessels.

Cartilage

Provides shock absorption and protection; matrix is a firm gel.

Chondroitin sulfates

Polysaccharide derivatives in cartilage matrix.

Chondrocytes

Cells in cartilage matrix in chambers called lacunae.

Perichondrium

Outer, fibrous layer (for support and protection) and inner, cellular layer (for growth and maintenance) of cartilage.

Hyaline cartilage

Most common type of cartilage; tough and somewhat flexible.

Elastic cartilage

Supportive cartilage that bends easily.

Fibrocartilage

Very durable and tough cartilage; limits movement; prevents bone-to-bone contact.

Interstitial growth

Enlarges cartilage from within.

Appositional growth

Growth at outer surface of cartilage.

Osseous tissue

Bone tissue; for weight support; calcified.

Osteocytes

Bone cells that lie in lacunae.

Periosteum

Covers bone; fibrous (outer) and cellular (inner) layers.

Tissue membranes

Physical barriers that line or cover body surfaces.

Mucous membranes (mucosae)

Line passageways that have external connections; epithelial surfaces must be moist; e.g., digestive, respiratory tracts.

Lamina propria

Areolar tissue in mucous membranes.

Serous membranes

Line cavities that do not open to the outside; thin but strong; e.g., peritoneum, pleura, pericardium.

Cutaneous membrane

Skin that covers the body; thick, relatively waterproof, and usually dry.

Synovial membranes

Line synovial joint cavities; movement stimulates production of synovial fluid for lubrication; lack a true epithelium.

Muscle tissue

Specialized for contraction.

Skeletal muscle

Large muscles responsible for body movement; striated voluntary muscle.

Cardiac muscle

Found only in the heart; striated involuntary muscle.

Smooth muscle

Found in walls of hollow, contracting organs; nonstriated involuntary muscle.

Muscle fibers

Long, thin cells that make up skeletal muscle tissue.

Cardiac muscle tissue cells

Cells that form branching networks connected at intercalated discs in cardiac muscle tissue.

Nervous tissue

Specialized for conducting electrical impulses; concentrated in the brain and spinal cord.

Neurons

Types of cells in nervous tissue.

Neuroglia

Supporting cells in nervous tissue.

Cell body

Contains the nucleus and nucleolus of a neuron.

Dendrites

Short branches extending from cell body of neuron; receive incoming signals.

Axon (nerve fiber)

Long, thin extension of the cell body of a neuron; carries outgoing electrical signals to their destination.

Inflammation and Regeneration

Tissues respond to injury in these two stages.