Chapter Five Flashcards
Tissues (define)
Groups of similar cells with a common function
Histology (define)
The study of tissues
Major Types of Tissues in the Body
Epithelial tissue
Connective tissue
Muscle tissue
Nervous tissue
Epithelial Tissue (describe)
Covers organs and body surface
Lines cavities and hollow organs
Makes up glands
Types of Epithelial Tissue
Simple squamous Simple cuboidal Simple columnar Stratified squamous Stratified cuboidal Stratified columnar
Simple Squamous (describe)
Single layer of thin, flat cells
Substances pass easily through
Thin & delicate, can be damaged. Found in diffusion & filtration sites
Lines air sacs (alveoli) & capillaries; lines blood & lymphatic vessels
Simple Cuboidal (describe)
Single layer of cube-shaped cells
Secretion and absorption
Lines kidney tubules, thyroid follicles
Covers ovaries; lines ducts of some glands
Stratified Squamous (describe)
Many cell layers; thick protective layer
Outermost cells are flat; deeper cells are cuboidal
New cells form, push older cells toward free surface
Outer layer of skin (keratinized); lines oral cavity, vagina, anal canal
Stratified Cuboidal (describe)
2-3 layers of cube-shaped cells; more protection than 1 layer
Lines ducts of mammary, sweat and salivary glands, and pancreas
Stratified Columnar (describe)
Top layer of elongated cells; cube-shaped cells in deeper layers
Lines part of male urethra, ducts of exocrine glands
Transitional (uroepithelium) (describe):
Many cell layers; cube-shaped and elongated cells
Changes shape with increased tension; stretches
Line urinary bladder, ureters, and part of urethra
Glandular Epithelium (describe):
Composed of cells that produce and secrete substances into ducts, blood or tissue fluids
Types of Glandular Epithelium
Endocrine glands
Exocrine glands
Endocrine Glands (describe)
Secrete into tissue fluid or blood
Exocrine Glands (describe)
Secrete into ducts that open onto surface
Types of Exocrine Glands
Unicellular
Multicellular
Unicellular Exocrine Glands
Composed of one cell, such as a goblet cell (secretes mucus)
Multicellular Exocrine Glands
Composed of many cells
Sweat glands, salivary glands, etc.
Types of Glandular Secretion
Merocrine Glands
Apocrine Glands
Holocrine Glands
Merocrine Glands (describe)
Secrete fluid products by exocytosis: salivary & sweat glands, pancreas
Apocrine Glands (describe)
Lose small part of cell during secretion: mammary and ceruminous glands
Holocrine Glands (describe)
Release entire cells filled with product: sebaceous glands
Types of Intercellular Joints
Tight joints
Desmosomes
Gap joints
Tight Joints (describe)
Membranes between cells merge and fuse
Located among cells that form linings, sheetlike layers
Blood-brain barrier
Desmosomes (describe)
Form “spot welds” between cells
Structural reinforcement
Located among outer skin cells
Gap Junctions (describe)
Tubular channels between cells
Molecules can move between cells
Located in cardiac muscle cells
Connective Tissue (describe)
Most abundant tissue type. Extracellular matrix consists of protein fibers and ground substance; consistency varies from fluid to semisolid to solid
Cells are farther apart than epithelial cells; contain matrix between cells
Functions include: bind structures together, provide support and protection, serve as frameworks, fill spaces, store fat
Major Cell Types of Connective Tissue
Fibroblasts
Macrophages (Histiocytes)
Mast Cells
Fibroblasts (describe)
Most common fixed cell
Large star-shaped cell
Secrete fibers into extracellular matrix
Macrophages (Histiocytes) (describe)
Usually attached to fibers, but can detach and wander
Conduct phagocytosis
Defend against infection
Mast Cells (describe)
Large, fixed cells
Release heparin to prevent blood clotting
Release histamine, which causes inflammatory response
Fibroblasts
Types of fibers in connective tissue
Collagen fibers
Elastic fibers
Reticular fibers
Fibroblasts
Collagen Fibers (describe):
Thick threads of collagen, the body’s main structural protein
Great tensile strength and flexible, slightly elastic
Found in ligaments and tendons
Fibroblasts
Elastic Fibers (describe):
Composed of elastin protein; branching
Can stretch and return to original shape
Not as strong as collagen fibers
Found in vocal cords, respiratory air passages
Fibroblasts
Reticular Fibers (describe):
Thin, branching fibers of collagen
Form delicate, supporting networks
Found in spleen, liver
Types of Connective Tissue
Loose
Dense
Specialized
Types of Loose Connective Tissue
Areolar
Adipose
Reticular
Types of Dense Connective Tissue
Dense Regular
Dense Irregular
Elastic
Examples of Specialized Connective Tissue
Cartilage
Bone
Blood
Loose Connective Tissue
Areolar Connective Tissue (describe)
Forms thin, delicate membranes
Cells are mainly fibroblasts
Gel-like ground substance; collagenous & elastic fibers
In subcutaneous layer; beneath most epithelia, where it nourishes nearby epithelial cells
Loose Connective Tissue
Adipose Tissue (describe)
Adipocytes store fat
Push their nuclei to one side; crowd out other cell types
Cushions and insulates. Beneath skin (subcutaneous layer); behind eyeballs
Spaces between muscles; around kidneys and heart
Loose Connective Tissue
Reticular Tissue (describe)
Composed of thin reticular fibers
Supports walls of internal organs; walls of liver, spleen
Dense Connective Tissue
Dense Regular (describe)
Closely packed collagenous fibers; fine network of elastic fibers
Most cells are fibroblasts
Very strong, withstands pulling
Binds body parts together; tendons, ligaments, dermis
Poor blood supply; slow to heal
Specialized Connective Tissue
Cartilage (describe)
A rigid, specialized connective tissue; support, framework, attachments
Protection of underlying tissue; models for developing bone
Matrix contains collagen in gel-like ground substance
Covered by perichondrium (connective tissue), which provides some nutrients to the cartilage
Lacks blood supply; heals slowly
Types of Cartilage
Hyaline
Elastic
Fibrocartilage
Fibrocartilage (describe)
Very tough, due to many collagenous fibers; shock absorber
Intervertebral discs; pads of knee and pelvic girdle
Specialized Connective Tissue
Bone (describe)
Most rigid connective tissue
Solid matrix, composed of mineral (Ca) salts & collagen
Supports structures; protects vital structures
Produces blood cells
Attachment sites for muscles
Forms skeleton
Types of Bone
Compact
Spongy
Compact Bone (describe)
Osteoblasts deposit matrix in lamellae (layers)
Lamellae occur in rings around central canals
Osteocytes + matrix + central canal form cylindrical units called osteons
Osteons are cemented together to form compact bone
Central canals contain blood vessels; bone is well-nourished, heals more quickly than cartilage
Specialized Connective Tissue
Blood (describe)
Cells suspended in fluid matrix called plasma
Red blood cells transport gases; white blood cells defend again infection
Platelets help in blood clotting
Transports substances around body
Membranes (describe)
Membranes are sheets of cells
Epithelial Membranes (describe)
Composed of epithelial and connective tissue; cover body surfaces and line cavities
Types of Epithelial Membranes
Serous
Mucous
Cutaneous
Epithelial Membrane
Serous Membranes (describe)
Line body cavities that do not open to outside of body (cover organs); inner linings of thorax and abdomen
Simple squamous epithelium + areolar connective tissue
Secrete serous fluid for lubrication, reducing friction
Epithelial Membrane
Mucous Membranes (describe)
Line cavities and tubes that open to the outside of body; lining of digestive, respiratory, urinary, and reproductive tracts
Epithelium + areolar connective tissue
Goblet cells secrete mucus
Epithelial Membrane
Cutaneous Membranes (describe)
Covers body surface; commonly called skin
Part of integumentary system
Epithelial Membrane
Synovial Membrane (describe)
Different from epithelial membranes
Composed entirely of connective tissue
Line joint cavities
Muscle Tissue (describe)
Muscle cells are also called muscle fibers
Contractile; can shorten and thicken
Types of Muscle Tissue
Skeletal
Cardiac
Smooth
Skeletal Muscle Tissue (describe)
Attached to bones
Striated; voluntary
Multinucleated cells; long cylindrical cells
Stimulated by nerve cells
Smooth Muscle Tissue (describe)
Walls of hollow organs; walls of blood vessels
Spindle-shaped fibers
Non-striated; involuntary
Cardiac Muscle Tissue (describe)
Only in wall of heart
Branching cells; intercalated discs
Involuntary; striated
Nervous Tissue (describe)
Found in brain, spinal cord, peripheral nerves
Main cells are neurons
Neurons (describe)
Specialized for communication, via conduction of nerve impulses (sensory reception, motor control)
Neurons coordinate, integrate, and regulate body functions
Neuroglia (describe)
Cells that support and nourish neurons
