| Question | Answer |
| Epithelial tissue | -Protection, secretion, absorption, excretion
-Cover body surface, cover and line internal organs, compose glands
-Lack blood vessels, cells readily divide, cells are tightly packed |
| Connective tissue | -Bind, support, protect, fill spaces, store fat, produce blood cells
-Widely distributed throughout the body
-Mostly have good blood supply, cells are farther apart than epithelial cells, with extracellular matrix in between |
| Muscle tissue | -Movement
-Attached to bones, in the walls of hollow internal organs, heart
-Able to contract in response to specific stimuli |
| Nervous tissue | Conduct impulses for coordination, regulation, integration, and sensory reception |
| Tight junctions: | -Membranes of adjacent cells merge and fuse.
-Located among cells that form linings, sheet-like layers.
-Blood-brain barrier. |
| Desmosomes: | -Form “spot welds” between cells.
-Structural reinforcement.
-Located among outer skin cells. |
| Gap junctions: | -Tubular channels between cells.
-Molecules can move between cells.
-Located in cardiac muscle cells. |
| Epithelial tissue classification and shapes | Classified according to cell shape and cell layers
Shapes: squamous, cuboidal, columnar
Layers: simple (one layer of cells), stratified (2 or more layer of cells), or pseudostratified (appears layered, but is not). |
| Simple squamous: | -Single layer of thin, flat cells
-Substances pass easily through air sacs (alveoli) & capillaries.
-Thin & delicate, can be damaged.
-Found in diffusion & filtration sites.
-Lines air sacs (alveoli) & capillaries.
-Lines blood & lymphatic vessels. |
| Simple cuboidal: | -Single layer of cube-shaped cells.
-Secretion and absorption.
-Lines kidney tubules, thyroid follicles.
-Covers ovaries.
-Lines ducts of some glands. |
| Simple columnar: | -Single layer of elongated cells.
-Nuclei usually at same level, near basement membrane.
-Sometimes have cilia.
-Sometimes have microvilli.
-Sometimes have goblet cells (secrete mucus).
-Secretion and absorption.
-Lines uterus, stomach, intestines |
| Pseudostratified columnar: | -Single layer, but appears layered.
-Nuclei at 2 or more levels.
-Cells vary in shape.
-Often has cilia, goblet cells.
-Protection from infection.
-Lines respiratory passageways. |
| Stratified squamous: | -Many cell layers; thick.
-Protective layer.
-Outermost cells are flat.
-Deeper cells are cuboidal.
-New cells form, push older cell toward free surface.
-Outer layer of skin (keratinized).
-Lines oral cavity, vagina, anal canal. |
| Stratified cuboidal: | -2 to 3 layers of cube-shaped cells.
-More protection than 1 layer.
-Lines ducts of mammary, sweat, & salivary glands, and pancreas. |
| Stratified columnar: | -Top layer of elongated cells.
-Cube-shaped cells in deeper layers.
-Lines part of male urethra, ducts of exocrine glands. |
| Transitional (uroepithelium): | -Many cell layers.
-Cube-shaped and elongated cells.
-Changes shape with increased tension; stretches.
-Line urinary bladder, ureters, and part of urethra. |
| Glandular Epithelium | Composed of cells that produce and secrete substances into ducts or body fluids |
| There are 2 types of glands | Endocrine glands
Exocrine glands |
| Endocrine glands | secrete into tissue fluid or blood. |
| Exocrine glands | secrete into ducts that open onto surface. |
| 2 structural types of exocrine glands: | Unicellular
Multicellular |
| Unicellular exocrine gland | Composed of one cell, such as a goblet cell (secretes mucus). |
| Multicellular exocrine gland | -Composed of many cells.
-Sweat glands, salivary glands, etc.
-Simple or compound. |
| Simple structure Exocrine gland | duct does not branch |
| Compound structure Exocrine gland | duct branches before it reaches secretory portion |
| Tubular structure Exocine gland | consist of epithelial-lined tubes |
| Aveolar structure Exocrine gland | terminal portions form sac-like dilations |
| Merocrine glands: | Secrete fluid products by exocytosis; salivary & sweat glands, pancreas |
| Apocrine glands: | Lose small part of cell during secretion; mammary & ceruminous glands |
| Holocrine glands: | Release entire cells filled with product; sebaceous glands |
| Fibroblasts: | -Major cell type of Connective tissue
-Most common fixed cell.
-Large star-shaped cell.
-Secrete fibers into extracellular matrix. |
| Macrophages (Histiocytes): | -Major cell type of Connective tissue
-Usually attached to fibers, but can detach and wander
-Conduct phagocytosis.
-Defend against infection. |
| Mast Cells: | -Major cell type of Connective tissue
-Large cells.
-Release heparin to prevent blood clotting.
-Release histamine, which causes inflammatory response. |
| Fibroblasts produce 3 types of fibers in connective tissue | Collagen fibers
Elastic (yellow) fibers
Reticular fibers |
| Collagen Fibers: | -Thick threads of collagen, the body’s main structural protein.
-Great tensile strength and flexible, slightly elastic.
-Found in ligaments and tendons. |
| Elastic (Yellow) Fibers: | -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. |
| Reticular Fibers: | -Thin, branching fibers of collagen.
-Form delicate, supporting networks.
-Found in spleen, liver. |
| Connective Tissue Proper: | Loose connective tissues
Dense connective tissues |
| Dense connective tissues | Dense Regular.
Dense Irregular.
Elastic. |
| Loose connective tissues: | Areolar.
Adipose.
Reticular. |
| Specialized connective tissues: | Cartilage
Bone
Blood |
| Areolar Connective Tissue: | -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. |
| Adipose Tissue: | -Adipocytes store fat.
-Push their nuclei to one side.
-Crowd out other cell types.
-Cushions and insulates.
-Beneath skin (subcutaneous layer).
-Behind eyeballs.
-Around kidneys and heart.
-Spaces between muscles |
| Reticular Connective Tissue: | -Composed of thin reticular fibers.
-Supports walls of internal organs.
-Walls of liver, spleen. |
| Dense Regular Connective Tissue: | -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. |
| Dense Irregular Connective Tissue: | -Randomly organized, thick, interwoven collagenous fibers.
-Can withstand tension exerted from different directions.
-Dermis of skin.
-Around skeletal muscles. |
| Elastic Connective Tissue: | -Abundant yellow elastic fibers.
-Some collagenous fibers.
-Fibroblasts.
-Attachments between bones of spinal column.
-Walls of hollow organs, such as large arteries, airways.
-Parts of heart.
-Elastic quality, stretches. |
| Cartilage: | Rigid specialized connective tissue
Support&framework
Lack blood supply
Matrix contains collagen in gel-like substance
Chondrocytes in lacunae surround by matrix
Covered by perichondrium which provides some nutrients to cartilage |
| 3 types of cartilage: | Hyaline, Elastic, and Fibrocartilage. |
| Hyaline cartilage: | Most common type.
Fine collagen fibers.
Ends of bones in joints Nose, respiratory passages.
Embryonic skeleton. |
| Elastic cartilage: | Flexible, due to elastic fibers in matrix.
External ear, larynx. |
| Fibrocartilage: | Very tough, due to many collagenous fibers.
Shock absorber.
Intervertebral discs.
Pads of knee and pelvic girdle. |
| Bone (Osseous Tissue): | Most rigid connective tissue
Solid matrix, composed of mineral salts & collagen
Supports structures
Protects vital structures
Produces blood cells
Stores & releases C a, P
Attachment sites for muscles
Forms skeleton
Contain osteocytes in lacunae |
| 2 types of bone tissue | compact and spongy. |
| Compact Bone: | 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. |
| Blood: | 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. |
| Epithelial membranes | are composed of epithelial and connective tissue; cover body surfaces and line cavities |
| 3 types of epithelial membranes | Serous membranes
Mucous membranes
Cutaneous membran |
| Serous membranes: | Line body cavities that do not open to outside of body.
Inner linings of thorax and abdomen; covers organs.
Simple squamous epithelium + areolar connective tissue.
Secrete serous fluid for lubrication, reducing friction. |
| Mucous membranes: | 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. |
| Cutaneous membranes: | Covers body surface.
Commonly called skin.
Part of integumentary system. |
| Synovial membranes: | Different from epithelial membranes.
Composed entirely of connective tissue.
Line joint cavities. |
| Skeletal muscle tissue: | Attached to bones.
Striated.
Voluntary.
Multinucleated cells.
Long cylindrical cells.
Stimulated by nerve cells. |
| Smooth muscle tissue: | Non-striated.
Spindle-shaped fibers.
Walls of hollow organs.
Walls of blood vessels.
Involuntary. |
| Cardiac muscle tissue: | Only in wall of heart.
Branching cells.
Involuntary.
Striated.
Intercalated discs. |
| Nervous tissues: | Found in brain, spinal cord, peripheral nerves
Main cells are neurons, which are specialized for communication via conduction of nerve impulses
Neurons coordinate, integrate,®ulate body functions
Neuroglia support&nourish neurons |
