Tissue Types Tissues- a group of cells performing a similar function Epithelial Connective Muscle Nervous

Epithelial- General Characteristics Linings, coverings and glands Protection, absorption, filtration, or secretion Closely packed (no leaks, please!), often with tight junctions Apical (free) surface Lower surface-basement membrane No blood supply (avascular) Capable of regeneration

Simple Epithelium Simple squamous  thin, single layer  tightly packed  membranes that allow for transmission of a fluid, gas, nutrient  also form serous membranes

Simple Epithelium Simple Cuboidal  One layer thick, boxy cells  Glands & ducts  Walls of tubules

Simple Epithelium Simple Columnar  Single layer, column shaped cells  Often, Goblet cells are embedded within the layer  Lines entire GI tract  Mucous membranes (note spelling: mucous- adj. vs. mucus-n.)

Simple Epithelium Pseudostratified Columnar  Rest on basement membrane  Nuclei at different heights; thus it looks like layers  Absorption/excretion  Some types are ciliated

Stratified Epithelia Stratified Squamous  Most common in body  Several layers  Found where tissue might take a beating, such as esophagus, mouth, outer skin

Transitional Epithelium  Highly modified stratified epithelium  Linings of some organs of the urinary system  Lots of stretching  Basal layers cuboidal or columnar; other layers variable  When organ is full, layers flatten out and look like squamous cells

Connective Tissue Cells within a matrix Cells loosely packed, with spaces between them Matrix runs from liquid, to fibers, to rigid and hard

Bone (Osseous tissue) Bone cells sit in holes in matrix called lacunae Matrix calcified & very hard Protective, framework of body

Cartilages Hyaline  Most common  Rubbery matrix; flexible  Larynx, ribs/sternum, joints  Fetal skeleton

Fibrocartilage Compressible Intervertebral discs

Elastic Cartilage Obviously, connective tissue that needs to have flexibility Ear lobes, tip of nose

Dense Connective Tissue Also known as fibrous CT Collagen fibers for matrix Fibroblast cells Strong, ropelike Tendons & ligaments Lower dermis of skin

Loose Connective Tissue Softer; more cells & less fiber 3 types: areolar, adipose & reticular  Areolar: cushions & protects Stores water (edema) Cobweb appearance  Adipose: fat tissue Appear empty Insulate & protect

Loose CT (con’t) Reticular  Delicate network  Limited sites: lymph nodes, spleen, bone marrow  Supports free blood cells

Blood-Vascular Tissue Fluid matrix, plasma Protein molecules constitute the fibers of the matrix Atypical CT Transport of nutrients, gases, wastes, etc. RBCs, WBCs and platelets

Muscle Tissue Skeletal Voluntary, striated, attached to bone Smooth Involuntary, non-striated walls of organs, Cardiac Involuntary, striated, heart tissue

Nervous Tissue Neurons  Cell body, cell processes that can be very long  Brain, spinal cord, nerves  Neuroglia: “nurse cells” Supporting cells of the matrix

Good review web site! faculty.ircc.edu/.../histology_flash_cards.htm