Exam 1 Flashcards
What tissue are serous membranes composed of?
Simple squamous epithelial tissue
Components of cytoplasm
Cytosol, cytoskeleton, inclusions, organelles
Marker molecules
Outside of cell: cell to cell recognition
Inform immune system of “self” cell or cell type
Glycoproteins or glycolipids
Attachment proteins
Attach cells to other cells, extracellular molecules or intracellular
Basis of forming tissue (cell-cell adhesion)
Channel proteins
Involved with transportation of substances in and out of a cell
Transporter proteins
move substances (ions or molecules) from one side of the plasma membrane to the other
Channels vs transporters
Channels - proteins that form a hydrophilic pore through membrane, molecules passively diffuse
Transporters - transfer only those molecules or ions that fit into specific binding sites on the protein, can move against concentration gradient
Receptor proteins
contain binding sites that can attach to specific substances
external signals effect internal cell function
What does tissue begin as?
As pluripotent stem cells
Wandering cells
Some cells that temporarily appear in tissue
Phagocytes/other immune cells, embryonic cells involved in differentiation/growth
3 functions of junctions
Form fluid-tight seals between cells
Anchor cells together or to the matrix
Act as channels, which allow ions and molecules to pass from cell to cell in a tissue
Tight Junctions
Watertight seal between cells, plasma membrane fused with a strip of proteins
Common in cells that line GI and bladder
Adherens junctions
Hold epithelial cells together
Structural components: plaque (dense layer of proteins inside cell membrane), plaque contains microfilaments that extend into cytoplasm, cadherin proteins that connect membrane of other cell
Gap junctions
Forms tiny connection between plasma membranes of 2 cells, made of protein channels called connexons - fluid filled tunnels, cytoplasm is shared between cells
Rapid instant communication between cells
Muscle/nerve impulses, heart, smooth muscle of gut
Desmosomes
Cellular rivet - resists separation and cell disruption, similar structure to adherens junction except intermediate filaments enter cytoplasm of cell which is connected to the cytoskeleton
Cellular support of cardiac muscle
Hemidesmosome
Half a desmosome, connect cells to extracellular basement membrane
The basal lamina
Part of BM, from epithelial cells and collagen fibers
The reticular lamina
Part of BM, secreted by connective tissue cells and reticular fibers
Function of BM
Guide for cell migration during development, may become thickened due to increased collagen and laminin production
2 types of epithelium
1) Covering and lining epithelium - epidermis of skin, lining blood vessels and ducts, respiratory, reproductive, urinary, GI tract
2) Glandular epithelium -
secreting portion of glands, thyroid, adrenal, and sweat glands
Endothelium
Lines the heart and blood vessels
Mesothelium
Lines the thoracic and abdominopelvic cavities and covers the organs within them
Keratinized vs non-keratinized
Non-keratinized: stays moist, found in other mucous membranes
Keratinized: skin (epidermis), hardened protein layer is protective, prevents infection, and moisture loss
Gland
A single cell or a mass of epithelial cells adapted for secretion
Derived from epithelial cells that sank below the surface during development
2 types of exocrine glands
Unicellular glands - goblet cells
Multicellular glands - shape and structure
2 ways to classify multicellular glands
Secretory unit - determine if gland shape is tubular or aciner/alveolar
Epithelial duct - determine if gland structure is simple or compound (branches)
Merocrine glands
Secretory products discharged by exocytosis
Examples - watery (sudoriferous) sweat, salivary glands, digestive enzymes
Apocrine glands
Accumulate secretory products at the apical surface of the secreting cell
Portion of cell pinches off to form the secretion
Examples - mammary and cerumen glands
Holocrine glands
Accumulate the secretory products in the cytosol
Cell dies and its products are discharged
Examples - sebaceous and meibomian glands
What is connective tissue derived from?
Mesenchyme (embryonic connective tissue)
Macrophages
engulf bacteria and debris by phagocytosis
Plasma cells
produce antibodies that fight against foreign substances
mast cells
produce histamine that dilate small BV
components of extracellular matrix
Glycosamine glycans - slick sugary molecules
Hyaluronic acid - thick, viscous, slippery
Chondroitin sulfate - jellylike substance providing support
adhesion proteins (fibronectin) - holds collagen fibers to ground substance
Collagen fibers
Parallel bundles, the body’s main structural protein
Great tensile strength, flexible, only slightly elastic
Found in bone, cartilage, ligaments, tendons
Elastic fibers
Spring-like, some branching
Not as strong as collagen fibers, can stretch and return to original shape
Found in vocal cords, respiratory air passages, skin, blood vessels
Reticular fibers
Thin, branching, web-like fibers of collagen
Form delicate, supporting networks
Found in spleen, liver, support in the blood vessels and in lymph nodes
Areolar connective tissue
Found in the subcutaneous layer of the integument
Makes of BM of epithelial tissue
All 3 types of fibers present
Adipose connective tissue
Consists of adipocytes, deeper skin, surrounding organs, yellow marrow
Cushions and insulates, serves as energy reserve
Generates considerable heart to help maintain proper body temp
Reticular connective tissue
Contains fine interlacing reticular fibers and reticular cells
Forms the stroma (framework) of certain organs
Helps to bind together the cells of smooth muscle
Chondrocytes
Secrete matrix - ground substance and embedded fibers
What tissue provides nutrients to cartilage?
Dense irregular connective tissue