Chapter 4 Tissue Level Flashcards
Epithelial tissue
Covers body surfaces and lines hollow organs, cavities, and ducts. Also forms glands.
Allows body to interact with internal and external environment
Is avascular.
Connective tissue
Protects and supports the body and its organs. Binds organs together, stores energy reserves, provides immunity
Muscular tissue
Composed of cells specialized for contraction and generation of force. Generates heat.
Nervous tissue
Detects changes inside and outside the body. Activates muscular contractions and glandular secretions.
Tight junctions
Transmembrane proteins that fuse the outer surfaces of adjacent plasma membranes. Seals off pathways between adjacent cells.
Inhibits passage between cells, prevent organ contents from leaking
Adhering junctions
Contain plaque. Attached to membrane proteins and microfilaments. Cadherins join the cells. Forms zones called adhesion belts.
Resists separations during contraction
Desmosomes
Contain plaque and cadherins. Attaches to intermediate filament. Prevent separation during contraction. Common among epidermis.
Hemidesmosomes
Do not link adjacent cells. Contains transmembrane glycoproteins called integrins.
Anchors cells to a basement membrane.
Gap junctions
Contains proteins called connexins. Form tunnels called connexons which allows passage of small molecules between different cells.
Common in nervous system, GI tract, uterus, heart.
Epithelial tissue cellular arrangements
Cells in continuous sheets in either single or multiple layers.
2 general types:
Surface epithelium
Glandular epithelium
Surface epithelium
Forms outer covering of skin and some internal organs. Forms inner lining of blood vessels, ducts, body cavities, respiratory, digestive, urinary, genital systems.
Glandular epithelium
Makes up secreting portion of glands, such as thyroid, adrenal, sweat, and digestive glands.
Apical surface
Faces the body surface, body cavity, lumen, or tubular duct that receives cell secretions.
Epithelial lateral surface
Faces adjacent cells on either side. May contain tight junction, adhering junction, desmosomes, or gap junctions.
Epithelial basal surface
Surfaces the deepest layer of epithelial cells. Adheres to extracellular materials such as basement membrane.
Basement membrane
Commonly consists of the basal lamina and the reticular lamina. Forms a surface for epithelial cells to migrate, restricts passage of larger molecules, participates in filtration.
Basal lamina
Closer to and secreted by epithelial cells. Adheres to integrins in hemidesmosomes and attaches epithelial cells to basement membrane.
Reticular lamina
Closer to underlying connective tissue. Contains collagen.
2 types of surface epithelial tissues
Simple epithelium
Stratified epithelium.
Simple epithelium
Single layer of cells functioning in secretion or absorption.
Simple squamous, cuboidal, columnar, psuedostratified.
Pseudostratified epithelium
Appears to have multiple layers of cells. Not all cells reach the apical surface. All cells rest on the basement membrane. May contain cilia or secrete mucus.
Stratified epithelium
2 or more layers of cells that protect underlying tissues.
Stratified squamous, cuboidal, columnar.
Epithelial cell shapes
Squamous
Cuboidal
Columnar
Transitional
Squamous epithelial cells
Thin cells which allow rapid passage of substances through them.
Cuboidal epithelial cells
Shaped like cubes or hexagons. May have microvilli. Function in secretion or absorption
Columnar epithelial cells
Taller than they are wide. Protect underlying tissues. May have cilia or microvilli. Specialized for secretion and absorption
Transitional epithelial cells
Change shape from squamous to cuboidal and back as organs distend and collapse.
Glandular epithelium
Secretes substances into ducts, onto a surface, or eventually into the blood.
Endocrine glands
Secrete hormones into interstitial fluid which diffuses into the blood without flowing through a duct.
Exocrine glands
Secrete products into ducts that empty onto an epithelium that covers or lines a surface.
Classified as unicellular or multicellular.
Unicellular glands
Single called glands. Goblet cells are most important unicellular glands which secrete mucus directly onto apical surface of a lining epithelium
Multicellular glands
Composed of many cells that form a distinctive microscopic structure or macroscopic organ. Example includes sweat glands, sebaceous glands, salivary glands.
Simple tubular multicellular glands
Secretory part is straight and attaches to a single unbranched duct.
Simple branched tubular multicellular gland
Secretory part is branched and attaches to a single unbranched duct.
Simple coiled tubular multicellular gland
Coiled and attaches to a single unbranched duct.
Simple acinar multicellular gland
Secretory portion is rounded, attaches to a single unbranched duct.
Simple branched acinar multicellular gland
Rounded secretory part branches and attaches to single unbranched duct.
Compound tubular multicellular gland
Secretory portion is tubular and attached to a branched duct
Compound acinar multicellular gland
Secretory portion is rounded and attached to a branched duct.
Compound tubuloacinar multicellular gland
Secretory portion is both tubular and rounded and attached to a branched duct.
Merocrine glands
Secretions are synthesized on ribosomes attached to rough ER. Processed, sorted, and packaged by Golgi and then released via exocytosis.
Apocrine sweat glands
Accumulate secretory product at the apical surface of the secreting cell. Portion pinches off from rest of cell due to exocytosis. Cell repairs itself and repeats the process.
Holocrine glands
Accumulate secretory product in cytosol. Cell ruptures as it matures and becomes the secretion.
Extracellular matrix
Consists of protein fibres and ground substance.
Connective tissue cells
Fibroblasts
Macrophages
Plasmocytes
Mast cells
Adipocytes
Leukocytes
Ground substance
Connective tissue between cells and fibres. Supports cells, binds them together, stores water, provides a medium to exchange substances.
Ground substance contents
Water, large molecules, glycosaminoglycans, proteoglycans.
Hyaluronic acid
Viscous, slippery substance that binds cells together, lubricates joints, and helps maintain the shape of the eyeball.
Chondroitin sulfate
Provides support and adhesion in cartilage, bone, skin, blood vessels
Dermatan sulfate
Contained in skin, tendons, blood vessels, heart valves.
Keratan sulfate
Present in bone, cartilage, and the cornea.
Fibronectin
The main adhesion protein of connective tissues.
3 main types of fibres in extracellular matrix
Collagen
Elastic
Reticular
Collagen fibres
Very strong. Resist pulling or stretching. Allows for stretching.
Elastic fibres
Form a fibrous network within connective tissue. Consist of elastin surrounded by fibrillin.
Strong and can be stretched. Returns to original shape.
Reticular fibres
Consist of collagen arranged in fine bundles with a coating of glycoprotein. Provide support and strength.
2 types of embryonic connective tissue
Mesenchyme
Mucoid.
Mesenchyme
Present primarily in the embryo, developing from fertilization through the first 2 months of pregnancy.
Mucoid connective tissue
Found in fetus. Develops from 3rd month of pregnancy.
Connective tissue proper
Mature connective tissue. Flexible with viscous ground substance.
Loose connective tissue
Dense connective tissue.
Supporting connective tissue
Mature. Includes cartilage and bone. Does not have blood supply.
Contains cells called chondrocytes.
Perichondrium
Surrounds the surface of most cartilage and contains blood vessels, nerves, and is the source of new cartilage cells.
3 types of cartilage
Hyaline
Fibrous
Elastic
Interstitial growth
Growth from within the tissue. Chondrocytes divide, produce new matrix, and become pushed away from each other
Appositional growth
Growth at the outer surface of the tissue. Cells at the inner layer of the perichondrium differentiate.
Bone tissue
Stores calcium, phosphorus, house red bone marrow, yellow bone marrow.
Classified as either spongy or compact.
Compact bone
Osteon system. Contains bone lamellae, lacunae, canaliculi, and osteonic canal.
Lamellae give bone hardness
Lacunae contain osteocytes
Canaliculi provide routes for nutrients
Osteonic canal contain blood vessel
Spongy bone
Lacks osteons. Consists of bone trabeculae. Spaces between bone trabeculae contain red bone marrow.
Blood tissue
Liquid connective tissue. Extracellular matrix called plasma.
Lymph plasma
Lymphatic liquid connective tissue. Similar to blood plasma but contains less proteins.
Mucous membranes
Mucosa. Lines a body cavity that opens directly to the exterior. Usually contains tight junctions. Lines lungs, urinary tract, digestive canal, genital tracts
Lamina propria
Supports mucosa, binding it to underlying structures. Holds blood vessels in place, acts as vascular source for overlying epithelium.
Serous membrane
Lines a body cavity that does not open directly to the exterior. Covers organs within a cavity. Consist of areolar connective tissue covered by mesothelium.
Cutaneous membrane
Covers surface of the body. Consists of epidermis and dermis.
Synovial membrane
Line the cavities of partially or freely moving joints. Lacks epithelium. Composed of synoviocytes which secrete synovial fluid.
Tissue repair
Replacement of work out, damaged, or dead cells. Originate by cell division from the stroma (supporting connective tissue) or the parenchyma (functional part of the tissue).