Tissues Definition? Histology- study of tissues within the body systems Classified based on: – Embryonic development – Intercellular space Four Tissue Types

EPITHELIAL TISSUE  Very Little intercellular space material  Derived from all three embryonic layers  Regeneration??  Arranged in sheets with a basement membrane  Exposed surface (internal or external)  Function  Protection  Cover internal and external surfaces  Secretion and absorbtion (Glands)  Classified by shape of cells and number of layers

EPITHELIAL TISSUE SIMPLE SQUAMOUS  Single layer  Squamous shape  Lining of body cavity, lungs, blood vessels

EPITHELIAL TISSUE SIMPLE CUBOIDAL  Single layer  Cuboidal shaped  Kidney tubules, glands

EPITHELIAL TISSUE SIMPLE COLUMNAR  Single layer  Columnar shape  Lining of digestive tract  Modified by presence of cilia

EPITHELIAL TISSUE STRATIFIED SQUAMOUS  Multi layer  Outer most layer- squamous cells  Inner- cuboidal or columnar  Lining of mouth, esophagus, skin

EPITHELIAL TISSUE PSEUDOSTRATIFIED COLUMNAR  One layer  Appears stratified  Respiratory tract

Glands One cell or a group of specialized epithelial cells to secrete substances into ducts, the surfaces or blood – Exocrine Example- sweat or salivary glands – Endocrine Example- hormones

CONNECTIVE TISSUE  Abundant extracellular material  Derived from the mesoderm  Matrix (dominant part)  Fiber, cells in liquid, gel, or solid matrix  Highly vascular  Function  Bind and/or support other tissue  Store nutrients

CONNECTIVE TISSUE Tendons  Dense fiberous  Abundant, well organized fiber

CONNECTIVE TISSUE ADIPOSE TISSUE  Loose connective  Semisolid matrix  Store large droplets of fat BLOOD  Lymph  Liquid, fluid matrix  Sometimes in different category  RBC- Red Blood Cells  WBC- White Blood Cells

CONNECTIVE TISSUE CARTILAGE  Chondrocytes  Small cavities- lacunae  Dense, solid elastic matrix  Ear, nose

CONNECTIVE TISSUE BONE  Osteocytes  Solid, rigid matrix  Hardest CT  Impregnated w/ calcium salts

MUSCLE TISSUE  Derived from mesoderm  Little intercellular matrix, fibers close together  Cells have ability to contract  Function  Locomotion  Other body movement Pg ,162; slides 161

MUSCLE TISSUE SKELETAL  Voluntary movement  Typically attach to bone  Long and cylindrical  Transverse striation  Each fiber is multi-nuclear

MUSCLE TISSUE SMOOTH  Involuntary movement  Nonstriated  Predominant  Long, spindle shape  Single nucleus  Internal organs

MUSCLE TISSUE CARDIAC  Striations  Involuntary  One nucleus  Deep center  Heart muscle

NERVE TISSUE  Derived from ectoderm  Little intercellular matrix  Cells very high ability to  Respond to stimuli  Transmit impulses  Two types:  Neurons and Neuroglia

NERVE TISSUE NEURON  Cell Body(3)  Dendrites (5)  Axon(1)

List of intercellular matrix Least to most – Epithelial – Muscular – Nervous – connective