Massachusetts Institute of Technology Harvard Medical School Brigham and Women’s Hospital VA Boston Healthcare System 2.79J/3.96J/BE.441/HST522J TISSUE TYPES M. Spector, Ph.D. and I.V. Yannas, Ph.D. The Cell and Its Membrane Molecules Viewing Histological Sections Effects of the Plane of Sectioning TISSUE CLASSIFICATION Connective Tissue Epithelia Muscle Nerve TISSUE CLASSIFICATION Connective Tissue Epithelia Muscle Nerve Matrix and cell continuous Cell continuous Cells surrounded by basal lamina (basement membrane) Connective Tissue Images removed due to copyright considerations. Sketches from AB McNaught and R Callander, Illustrated Physiology. 2 nd ed. Baltimore MD: Williams and Wilkins, 1967. Connective Tissues Image removed due to copyright considerations. See http://cal.vet.upenn.edu/histo/connective/connective.html. Loose and dense connective tissue from a cow's planum. Dense Connective Tissue Loose Connective Tissue Images removed due to copyright considerations. See Netter, F. H. The Ciba collection of medical illustrations: a compilation of pathological and anatomical paintings. Summit, N.J.: Ciba Pharmaceutical Products, 1987. Connective Tissue Adipose Tissue (Fat) Bone Images removed due to copyright considerations. Connective Tissue: Cartilage Images removed due to copyright considerations. See Netter, F. H. The Ciba collection of medical illustrations: a compilation of pathological and anatomical paintings. Summit, N.J.: Ciba Pharmaceutical Products, 1987. http://cal.vet.upenn.edu/histo/cartilage/cartilage.html Connective Tissue: Cartilage Hyaline Cartilage: Trachea Elastic Cartilage: Epiglottus Images removed due to copyright considerations. See http://cal.vet.upenn.edu/histo/cartilage/cartilage.html. Fibrocartilage Epithelia Images removed due to copyright considerations. See Netter, F. H. The Ciba collection of medical illustrations: a compilation of pathological and anatomical paintings. Summit, N.J.: Ciba Pharmaceutical Products, 1987. http://www.uoguelph.ca/zoology/devobio/210labs/epithelial1.html Simple Squamous Epithelium (chick blastodisc at about 33 hours of incubation ) Top View Cross-Sectional View Simple squamous epithelium, which generally occurs as a thin sheet-like layer allowing for minimal resistance to diffusion, is also been called "pavement” epithelium, because it can look like like paving stones as seen from above. Examples include the linings of the peritoneal, pleural and pericardial cavities. Other places simple squamous epithelium can be found include: the glomerulus of the kidney, the walls of capillaries, and the alveoli of the lungs. http://www.uoguelph.ca/zoology/devobio/210labs/epithelial1.html Simple Cuboidal Epithelium (collecting ducts in the medulla of a mammalian kidney) This type of epithelium is thicker than simple simple squamous epithelium, so it does not allow for passive diffusion as readily. http://www.uoguelph.ca/zoology/devobio/210labs/epithelial1.html Simple Columnar Epithelium (small intestine) Since columnar cells are quite thick, they do not readily allow passive diffusion. As a result, these cells use active transport to move nutrients through them from the intestine to the blood. This is what we commonly call "absorption." To help with this, they have numerous microvilli on their apical (lumenal) surface, which increases their surface area to allow for greater absorption. Simple Columnar Epithelium Image removed due to copyright considerations. See http://cal.vet.upenn.edu/histo/epithelium/epithelium.html. This is a section through the edge of a gallbladder. There is a layer of simple columnar epithelium overlying the connective tissue as indicated by the arrows. Epithelia Images removed due to copyright considerations. See Netter, F. H. The Ciba collection of medical illustrations: a compilation of pathological and anatomical paintings. Summit, N.J.: Ciba Pharmaceutical Products, 1987. Stratified Squamous Epithelium Image removed due to copyright considerations. See http://cal.vet.upenn.edu/histo/epithelium/epithelium.html. This is an example of stratified squamous epithelium from the esophagus of a cat. Arrows show nuclei of the outermost layer. This is normal for mucosa. Most stratified squamous cells in other areas, such as skin, lose their nuclei by the time they approach the outermost layers. http://www.uoguelph.ca/zoology/devobio/210labs/epithelial1.html Stratified Squamous Epithelium (epidermis) The cells of the basal layer of the epidermis (closest to the dermis) are cuboidal to columnar in shape. These cells are actively mitotic, producing new cells that get pushed upward into the overlying layers. As these cells are pushed up, they become flatter and longer taking on the typical squamous shape. When the cells reach the top, they are sloughed off and replaced by cells from below. The dermis which underlies the epidermis is composed of a dense, irregular connective tissue, which we will see again later. Muscle Images removed due to copyright considerations. 1. Smooth muscle 2. Cardiac muscle 3. Voluntary muscle fiber. See Netter, F. H. The Ciba collection of medical illustrations: a compilation of pathological and anatomical paintings. Summit, N.J.: Ciba Pharmaceutical Products, 1987. http://www.uoguelph.ca/zoology/devobio/210labs/epithelial1.html Muscle Striated (Skeletal; Vountary) MuscleSmooth (Involuntary) Muscle Cardiac Muscle Skeletal Muscle Images removed due to copyright considerations. See Netter, F. H. The Ciba collection of medical illustrations: a compilation of pathological and anatomical paintings. Summit, N.J.: Ciba Pharmaceutical Products, 1987. Nerve Images removed due to copyright considerations. See Netter, F. H. The Ciba collection of medical illustrations: a compilation of pathological and anatomical paintings. Summit, N.J.: Ciba Pharmaceutical Products, 1987. http://www.uoguelph.ca/zoology/devobio/210labs/epithelial1.html Nerve An isolated nerve cell - neuron (large arrow) - from a mammalian spinal cord showing and the nuclei of the surrounding neuroglial cells (small arrows). Note the numerous cytoplasmic extensions emanating from the neuronal cell body and the size of the neuron compared with the neuroglial cells. http://cal.vet.upenn.edu/histo/nerves/nerves.html Nerve Image removed due to copyright considerations. This is a myelinated nerve from the thoracic wall. A indicates the myelin sheath around the actual nerve fibers (B). http://www.uoguelph.ca/zoology/devobio/210labs/epithelial1.html Connective Tissue Adipose (fat) Bone Cartilage Loose Connective Tissue http://cal.vet.upenn.edu/histo/epithelium/epithelium.html Pseudostratified Columnar Epithelium Image removed due to copyright considerations. This is an example of ciliated pseudostratified columnar epithelium from the trachea. The arrows indicate the layer of cilia on the surface of the pseudostratified columnar cell layer.