Chapter 3 Flashcards
Tissues
A group of cells that have similar structure and function together as a unit = form organs
Histology
The study of tissues
Epithelial Tissue
Covers exposed surfaces, lines internal passageways and chambers, and forms glands
Connective Tissue
Fills internal spaces, provides structural support for other tissues, transports materials within the body, and stores energy
Muscle Tissue
Specialized for contraction, including skeletal muscle, cardiac muscle, and smooth muscle
Nervous Tissue
Carries information from one part of the body to another in the form of electrical impulses
Epithelia
Layers of cells covering internal or external surfaces
Glands
Structures that produce fluid secretions
Physical Protection
One of the essential functions of epithelial tissue, protecting from abrasion and destruction by chemical/biological agents
Control Permeability
Any substance that enters or leaves the body must cross an epithelium
Provide Sensation
Epithelial tissue is sensitive to stimulation because it has a large sensory nervous supply
Produce Specialized Secretions
Epithelial tissue produces secretions, also known as glands
Polarity
Presence of structural and functional differences between the exposed surface (apical) and attached surface (basal)
Cellularity
Interconnections that bind epithelial cells closely together
Attachment
Epithelial cells adhere to the basal surface and underlying tissues to establish cell border and resist stretching
Avascularity
Epithelial tissue lacks blood supply; nutrients are obtained by diffusion or absorption
Regeneration
Epithelial tissue is continuously replaced through stem cell division, with a higher rate of cell division than other tissues
Apical Surface
The part of the epithelial cell exposed to an internal or external environment
Basolateral Surface
The base (basal surface) where the cell attaches to underlying cells and the sides (lateral surfaces) where the cell contacts its neighbors
Intercellular Connections
Support and communication between epithelial cells
Cell Adhesion Molecules (CAMs)
Transmembrane proteins that bind epithelial plasma membranes to each other and to extracellular materials
Gap Junctions
Allow rapid communication and passageway for small molecules and ions to pass from cell to cell
Tight Junctions
Encircle the apical regions of epithelial cells, acting as a barrier to maintain structure and permeability
Desmosomes
Provide anchorage sites for intermediate filaments and maintain tissue architecture
Basement Membrane
A two-part structure that epithelial cells must attach to, consisting of basal lamina and reticular lamina
Basal Lamina
Restricts movement of proteins and other large molecules from the underlying connective tissue to the epithelium
Reticular Lamina
The deeper portion of the basement membrane that provides strength and acts as a filter
Classification of Epithelia
Based on shape: Squamous (thin and flat), Cuboidal (square shaped), Columnar (tall, slender); based on layers: Simple (single layer), Stratified (several layers)
Squamous
Thin and flat - like scales
Cuboidal
Square shaped - little boxes
Columnar
Tall, slender rectangles
Simple epithelium
Single layer of cells
Stratified epithelium
Several layers of cells
Simple squamous epithelium
Body’s most delicate type of epithelium, located where absorption or diffusion takes place or slick surface reduces friction
Mesothelium
Lines body cavities: enclosing lungs, heart, abdominal organs
Endothelium
Inner surface of heart and all blood vessels
Stratified squamous epithelium
Located where mechanical stresses are severe, such as the surface of skin, lining of the mouth, esophagus
Simple cuboidal epithelium
Secretion and absorption found in glands and portions of kidney tubules
Stratified cuboidal epithelium
Located in ducts of sweat glands and mammary glands
Transitional epithelia
Unusual stratified epithelium because it can change between being squamous and cuboidal in shape
Simple columnar epithelium
Absorption and secretion found in stomach, small intestine, large intestine
Pseudostratified columnar epithelium
Appears to be layered or stratified, typically have cilia, found in nasal cavity, trachea, bronchi
Stratified columnar epithelium
Provides protection in pharynx, anus, urethra
Glandular epithelia
Epithelia that contain gland cells
Gland
Organ that makes substances such as hormones, digestive juices, sweat, tears, saliva, milk
Endocrine glands
Release substances that enter bloodstream, have no ducts
Exocrine glands
Release substances into a duct that opens onto an epithelial surface
Unicellular glands
Individual secretory cells called goblet cells found in epithelia of large and small intestines
Multicellular exocrine glands
Classified by structure of the duct, shape of secretory portion, and relationship between ducts and glandular areas
Merocrine secretion
Released by secretory vesicles (exocytosis), vesicle formed in the cell fuses with and becomes part of the plasma membrane
Apocrine secretion
Released by shedding cytoplasm
Holocrine secretion
Method of secretion involving the entire cell
Sebaceous glands
Example of holocrine secretion in skin.
Serous glands
Produce watery secretions, e.g., parotid glands.
Mucous glands
Secrete mucins, e.g., sublingual glands.
Mixed exocrine glands
Produce both serous and mucous secretions.
Connective tissue
Supports, connects, and protects body structures.
Extracellular matrix
Composed of fibers and ground substance.
Fibroblasts
Most abundant cells in connective tissue proper.
Adipocytes
Fat cells storing large fat droplets.
Macrophages
Phagocytic cells engulfing pathogens and debris.
Mast cells
Release histamine and heparin during inflammation.
Lymphocytes
White blood cells producing antibodies.
Collagen fibers
Strong fibers resisting force in one direction.
Elastic fibers
Branched fibers returning to original length.
Reticular fibers
Form networks stabilizing blood vessels and nerves.
Ground substance
Viscous fluid filling spaces in connective tissue.
Loose connective tissue
Fills spaces, cushions organs, supports epithelia.
Areolar tissue
Beneath skin, allows movement and supports organs.
Adipose tissue
Stores energy, insulates, and cushions organs.
White fat
Common fat type, stores energy and insulates.
Brown fat
Found in infants, generates heat via metabolism.
Mesenchymal cells
Stem cells differentiating into various connective cells.
Microphages
Small phagocytic blood cells responding to signals.
Stem cells
Undifferentiated cells replacing lost tissue.
Connective tissue proper
Connects and protects; includes loose and dense types.
Fluid connective tissues
Transport substances, e.g., blood and lymph.
Supporting connective tissues
Provide structural strength, e.g., cartilage and bone.
Adipose Tissue
Connective tissue storing energy and insulating body.
Reticular Tissue
Connective tissue providing a 3D framework for organs.
Reticular Fibers
Thin fibers forming a supportive network in tissues.
Dense Connective Tissue
Tissue with high collagen fiber density for strength.
Dense Regular Connective Tissue
Tightly packed collagen fibers aligned in one direction.
Tendons
Connective tissue attaching muscles to bones.
Ligaments
Connective tissue connecting bones to other bones.
Aponeuroses
Broad, flat tendinous sheets connecting muscles.
Elastic Tissue
Dense tissue with elastic fibers for flexibility.
Elastic Ligaments
Ligaments allowing expansion and contraction of organs.
Dense Irregular Connective Tissue
Collagen fibers arranged in multiple directions for strength.
Fasciae
Connective tissue layers supporting and surrounding organs.
Superficial Fascia
Layer separating skin from underlying tissues.
Deep Fascia
Dense connective tissue forming internal frameworks.
Subserous Fascia
Tissue between serous membranes and deep fascia.
Blood
Fluid connective tissue transporting cells and materials.
Plasma
Liquid matrix of blood containing dissolved substances.
Erythrocytes
Red blood cells transporting oxygen in blood.
Leukocytes
White blood cells defending against infections.
Platelets
Cell fragments aiding in blood clotting.
Lymph
Colorless fluid containing white blood cells.
Chondrocytes
Cartilage cells located in lacunae.
Hyaline Cartilage
Most common cartilage reducing friction between bones.
Elastic Cartilage
Flexible cartilage found in ear and epiglottis.
Fibrocartilage
Cartilage providing tough support and shock absorption.
Avascular
Describes tissues with poor blood supply and healing.
Stroma
Supporting framework of reticular tissue.
Matrix
Extracellular material providing structure to tissues.
Bone (Osseous Tissue)
Calcified matrix providing strength and structure.
Osteocytes
Bone cells located in lacunae within the matrix.
Canaliculi
Small channels for material exchange in bone.
Periosteum
Covers bone with fibrous and cellular layers.
Tissue Membranes
Physical barriers lining or covering body surfaces.
Mucous Membranes
Line passages with external connections; must stay moist.
Serous Membranes
Line cavities not open to the outside; reduce friction.
Cutaneous Membrane
Skin; thick, waterproof, and dry covering the body.
Synovial Membranes
Line joint cavities and produce synovial fluid.
Skeletal Muscle Tissue
Striated, voluntary muscle responsible for body movement.
Cardiac Muscle Tissue
Striated, involuntary muscle found only in the heart.
Smooth Muscle Tissue
Nonstriated, involuntary muscle in hollow organs.
Neurons
Cells specialized for conducting electrical impulses.
Neuroglia
Supporting cells that maintain and repair nervous tissue.
Dendrites
Short branches receiving signals in a neuron.
Axon
Long extension carrying outgoing signals from neuron.
Inflammation
Initial tissue response characterized by swelling and pain.
Fibrous Matrix
Dense connective tissue providing support in fibrocartilage.
Striations
Banding pattern in skeletal and cardiac muscle.
Pacemaker Cells
Regulate heart contractions in cardiac muscle.
Intercalated Discs
Connect cardiac muscle cells for synchronized contraction.
Myosatellite Cells
Stem cells that repair skeletal muscle fibers.
Serous Fluid
Reduces friction between serous membranes.
Epithelial Surfaces
Moist surfaces in mucous membranes for absorption.
