Chapter 4 - Tissue Level of Organization Flashcards
Cell junctions
contact points between plasma membranes of tissue cells
Tight junctions
web like proteins, sew cells together, prevent leakage
Types of cell junctions
tight junctions, adherens, desmosomes, hemidesmosomes, gap junctions
Gap junctions
connexons (tunnels) connect neighboring cells, cells separated by intercellular gap (common in cardiac muscle tissue)
Tissue
group of similar cells that perform specific functions
Tissue types
epithelial, connective, muscular, nervous
Epithelial tissue
located on surface of skin, free surfaces on body
Epithelium
closely packed cells arranged in continuous sheets, avascular/own nerve supply, reproduce readily
Basement membrane
basal lumina and reticular lumina
Covering and lining epithelium
forms outer covering of body, lines body cavities and some internal organs
Simple (single layer) functions
diffusion, osmosis, secretion, excretion, absorption, filtration
Stratified (multiple layer) function
protection
Shape of cells
squamous (thin, flat cells), cuboidal, columnar
Glandular epithelium
cells lie in clusters deep to covering and lining epithelium, produce secretions
Endocrine gland
secretions (hormones) enter interstitial fluid and diffuse directly into bloodstream without flowing into a duct
Exocrine gland
cells produce a secretion into a duct system that empties directly on surface of body or into a cavity
Structural classification of exocrine glands
unicellular/multicellular, simple vs. compound (duct branched), tubular vs. acinar (round), vs. tubuloacinar
Merocrine
vesicles, most glands of this type
Apocrine
pinched off portion of cell is secretion
Holocrine
mature cells die/become secretions
Connective tissue
most abundant tissue, derived from mesenchyme, vascular/good nerve supply
Functions of connective tissue
protection, support and binding, insulation, transportation
Connective tissue composition
cells and extracellular matrix
Extracellular matrix
composed of ground substance and fibers, what cell bathes in
Osteoblast
immature cell (make ECM)
Osteocyte
mature cells
Fibroblasts
secretes substances of extracellular matrix
Defensive cells
macrophages, white blood cells, most cells, plasma cells
Adipocytes
fat cells, store energy through triglycerides
Ground substance
supports cells and binds them together, stores water, proteins, and carbohydrates
Fibers
strengthen and support matrix
Collagen
strength, lack in collagen can lead to Ehlers Danlos Syndrome
Elastic
elasticity/stretch
Reticular
support, lymph nodes and spleen
Types of mature connective tissue
loose connective tissue, dense connective tissue, cartilage
Loose connective tissue
areolar, adipose, reticular
Dense connective tissue
regular (same order), irregular (different directions), elastic (lungs, arteries)
Cartilage
avascular/no nerves, chondrocytes in lacunae, ground substance of chondroitin sulfate, perichondrium covers surface
Types of cartilage
hyaline, elastic, fibrocartilage
Hyaline
most abundant, support, reduces friction, absorbs shock, weakest
Elastic
strength and elasticity
Fibrocartilage
strongest, lacks perichondrium
Types of muscle tissue
skeletal, cardiac, smooth
Skeletal muscle
voluntary, striated, multinucleated, attached to bone
Cardiac muscle
involuntary, striated, uninucleated, intercalated discs, heart
Smooth muscle
involuntary, no striations, uninucleated, spindle-shaped cells, found in walls of hallow organs
Intercalated discs
part of gap junction, allow spreading of electricity fast
Neurons
nerve cells, cannot reproduce
Neuroglia
“mother” of neurons, can reproduce/multiply
Neuronal cell structure
cell body, axon, dendrites
