Chr. 4 - Organization of Tissue Level Flashcards
[4.1] Define what a tissue is.
Cells having common origin in an embryo, functioning together in specialized activities.
[4.1] What are the four types of tissues?
Epithelial, connective, nervous, and muscular.
[4.2] What is a cell junction?
A contact point between the plasma membranes of tissue cells.
[4.2] What are the five important types of cell junctions?
Tight, adherens, desmosomes, hemidesmosomes, and gap.
[4.2] What is a tight junction?
Cell-cell junction formed by transmembrane proteins joining adjacent plasma membranes. These seal off passageways between adjacent cells and disallow extracellular space between the two.
[4.2] What is an adheren junction?
Cell-cell connection formed by interaction of cadherin in the extracellular space, anchored inside each cell by plaque (collection of dense protein) connecting to microfilaments.
[4.2] What is a cadherin?
Class of transmembrane glycoproteins that form the base of adheren junctions.
[4.2] What is an adhesion belt?
Extensive zones of adheren junctions usually encircling the cell.
[4.2] What is a desmosome?
Cell-cell connection formed by interaction of cadherin in the extracellular space, anchored inside each cell by plaque (collection of dense protein) connecting to intermediate filaments.
[4.2] What is a hemidesmosome?
Cell-matrix junctions that bonds a cells membrane to extracellular matrix by use of cadherins.
[4.2] What are gap junctions?
Cell-cell junctions formed by protein channels, connecting cells and allowing cytoplasm and solutes to travel between the two.
[4.4] Define epithelial tissue.
Avascular tissue consisting of cells arranged in continuous sheets, in single or multiple layers.
[4.4] What are the function of epithelial tissue?
Protection, secretion, absorption, and excretion, and forming special senses with nervous tissue.
[4.4] Define basement membrane.
Thin extracellular membrane consisting of two layers: basal lamina and reticular lamina.
[4.4] What is the basal lamina?
A layer of proteins, glycoproteins, and proteoglycans that rests adjacent to epithelial cells.
[4.4] What is the reticular lamina?
A layer of proteins in between connective tissue and basal lamina, anchoring one to another.
[4.4] What are the two categories of epithelial tissue?
- Covering and lining epithelium.
- Glandular epithelium.
[4.4] In which two ways are covering and lining epithelium classified?
- Cell arrangement.
- Cell shape.
[4.4] Name and describe each arrangement classification of epithelium.
- Simple epithelium: single-layer epithelium.
- Pseudostratified epithelium: vertically-elongated cells where nuclei lay at different levels, appearing to be stratified but without mutliple cells between apical surface and basement membrane.
- Stratified epithelium: two or more layers of cells between apical surface and basement membrane.
[4.4] Name and describe each shape classification of epithelium.
- Squamous: thin plate-like cells allowing for rapid passage of substances through them.
- Cuboidal: cube/hexagon-shaped cells.
- Columnar cells: Cells with vertical elongation - taller than they are wide.
- Transitional cells: Cells that change shape between squamous and cuboidal due to mechanical changes.
[4.4] What are the two types of epithelium?
Simple epithelium and stratified epithelium.
[4.4] What is glandular epithelium?
Epithelium specialized for secretion, and forms glands.
[4.4] What are the two types of glands?
- Endocrine gland: secrete substances into interstitial fluid/bloodstream
- Exocrine glands: secrete substances onto surfaces of covering and lining epithelium.
[4.4] What are the structural classification of exocrine glands?
- Unicellular glands: single-celled glands.
- Multicellular glands: composed of many cells.
[4.4] What are the categories of multicellular glands?
Simple gland, compound gland, tubular glands, acinar glands, tubuloacinar glands.
[4.4] What are the functional classification of exocrine glands?
- Merocrine glands: glands that release substances in secretory vesicles via exocytosis.
- Apocrine glands: accumulate substances at apical portion and release them by pinching off the section of cell that contains them.
[4.5] Define connective tissue.
A group of tissues in the body that maintain the form of organs and provide cohesion and internal support.
[4.5] What two basic elements make up connective tissue?
Extracellular matrix and cells.
[4.5] What is extracellular matrix?
Material located between widely spaced cells, consisting of protein fibers and ground substance (gel-like material surrounding cells; separate from protein fibers which are found inside).
[4.5] List the six main types of connective tissue cells.
- Fibroblasts.
- Macrophages
- Plasma Cells
- Mast Cells
- Adipocysts
- Leukocytes
[4.5] Describe ground substance.
Component of connective tissue between cells and fibers - can be fluid, semi-fluid, gelatinous, or calcified. Responsible for binding cells together, storing water, and acts as a medium for exchange between blood and cells.
[4.5] What is hyaluronic acid?
A slippery viscous substance that binds cells, lubricates joints, and maintains shape of eyeballs.
[4.5] What are the three types of fibers found in extracellular matrix?
- Collagen
- Elastic
- Reticular
[4.5] Describe collagen fibers.
Strong, resistant, flexible glycoprotein fibers achieving structural durability based on surrounding molecules.
[4.5] Describe elastic fibers.
A glycoprotein fiber conmposed of elastin and fibrillin, characterized by it’s strength and elasticity.
[4.5] Describe reticular fibers.
Fibers consisting of collagen wrapped in bundles and coated with another glycoprotein. Forms a mesh network acting as supporting framework for many organs and vessels, known as stroma.
[4.5] What are the two major classification of connective tissue?
Embryonic connective tissue and mature connective tissue.
[4.5] What are the two sub-classifications of embryonic connective tissue?
Mesenchyme and mucoid.
[4.5] What are the three classification of mature connective tissue?
Connective proper, supporting, and liquid.
[4.5] What are the classifications of connective tissue proper, and the sub-classifications of each?
Loose: areolar, adipose, reticular
Dense: dense regular, dense irregular, elastic connective.
[4.5] What are the classifcation of supporting connective tissue, and the sub-classification of each?
Cartilage: hyaline, fibrocartilage, elastic cartilage.
Bone: compact, spongy.
[4.5] What are the classification of liquid connective tissue?
Blood, lymph.
[4.5] Define mesenchyme.
immature connective tissue cells able to differentiate into different connective tissue cells.
[4.5] Define mucous connective tissue.
Ground substance composed of several irrelevant (for this course) materials, mostly seen as Wharton jelly in the umbilical cord.
Don’t stress on this one too much.
[4.5] Describe connective tissue proper.
Flexible tissue with a viscous ground substance abundant with fibers.
[4.5] Describe loose and dense connective tissue
Loose: connective tissue with less fibers present in ground substance, leading to loosely connected cells.
Dense: connective tissue with thicker, densely packed fibers connecting fewer cells.
[4.5] Describe areolar connective tissue.
Typical loose connective tissue, lower amount of fibers in ground substance.
[4.5] Describe adipose connective tissue.
Fibroblasts specalized for storage of triglycerides, often co-located with areolar connective tissue.
[4.5] Describe cartilage.
Supporting connective tissue composed of collagen fibers and elastic fibers embedded in chondroitin sulfate within ground substance.
[4.5] What are chondrocytes?
Cells of mature cartilage.
[4.5] What is the perichondrium?
A covering of dense irregular connective tissue surrounding the surface of cartilage, providing blood flow and new chondrocytes.
[4.5] What are the three types of cartilage?
Hyaline, fibrocartilage, elastic.
[4.5] Describe hyaline cartilage.
Chondrocytes surrounded by ground substance rich in collagen fibers and chondratin sulfate.
[4.5] Describe the two types of cartilage growth.
Interstitial: chondrocytes divide and produce extracellular matrix. Seen in adolescence and younger.
Appositional: Cells of the interior perichondrium differentiate into chondroblasts, producing extracellular matrix and maturing into chondrocytes.
[4.5] What is bone tissue?
Connective tissue containing a high concentration of minerals in extracellular matrix.
[4.5] What are the two classifications of bone tissue?
Compact and spongy.
[4.5] What are the basic units of compact bone? List its components.
Osteons, composed of: lamellae, lacunae, canaliculi, and central canals.
[4.5] Describe lamellae.
Concentric rings of extracellular matrix formed around central canals.
[4.5] Describe lacunae.
Small spaces between lamellae, house osteocytes.
[4.5] Describe canaliculi.
Networks of tiny channels allowing the processes of osteocytes to reach other cells for nutrient exchange.
[4.5] Define central canals.
Canals located in the center of osteons containing blood vessels and nerves.
[4.5] What is spongy bone tissue?
Bone tissue organized in columns of “trabeculae” rather than formed by osteons.
[4.5] Describe trabeculae.
Columns of bone tissue comprised of lamellae, osteocytes, lacunae, and canaliculi, but no central canal. lamellae form concentric rings with either nothing in the center, or an osteocyte.
[4.5] What is liquid connective tissue?
Any connective tissue which has an extracellular matrix of liquid consistency.
[4.5] Describe blood tissue.
Connective tissue with blood plasma making up extracellular matrix, with red blood cells, white blood cells, and platelets inhabiting the ground substance as formed elements.
[4.5] Describe blood plasma.
Pale yellow fluid consisiting of water as a solvent for nutrients, hormones, plasma proteins, ions, gases, and enzymes.
[4.5] Describe formed elements.
Red blood cells, white blood cells, and platelets suspended in blood plasma.
[4.5] What is lymph?
Liquid connective tissues composed of extracellular fluid found in lymph vessels.
[4.6] What is a membrane?
Flat sheets of tissue composed of an epithelial layer and an underlaying connective tissue layer.
[4.6] What is a mucous membrane?
A membrane composed of epithelial tissue varying depending on area of the body, and a layer of areolar connective tissue called the lamina propria. Lines body cavities that open directly to the exterior environment.
[4.6] What is the lamina propria?
Layer of connective tissue in mucous membranes, binding epithelial layer to underlaying structure and houses blood vessels.
[4.6] What is a serous membrane?
A membrane lining a body cavity that does not open directly to exterior environment. Consists of two layers of mesothelium (visceral and parietal layers) joined by a layer of loose connective tissue.
[4.6] What is a cutaneous membrane?
A membrane consisting of epidermis and dermis, forming skin.
[4.6] What are synovial membranes?
Membranes composed of a discontinuous layer of cells known as synoviocytes and loose connective tissue, and are lacking an epithelium layer.
[4.7] What is muscular tissue?
Tissue consisting of muscle fibers (myocytes), classified as skeletal, caridac, and smooth.
[4.8] What is nervous tissue?
Tissue composed of neurons and neuroglia.
[4.9] What are excitable cells?
Cells that are able to respond to stimul by poducing electrical signals known as action potentials.
