Tissue Types

Tissue Types

1. Connective

   • found everywhere in the body
   • provides protection, binds body tissues together, and supports the body
   • some are well-vascularized, some have poor blood supply. some are avascular
   • extracellular matrix- non-living material
   • types:
     • dense regular CT
       • fibroblast, has no lacunae, attaches bone to bone and bone to muscle, resists pulling forces from a single direction, found in ligaments and tendons
     • dense irregular CT
       • fibroblast, fibers are in bundles, provides strength, can withstand pulling forces from any direction,found in dermis of skin
       • elastic CT
         • provides elasticity, found in the aorta
     • cartilage
       • hyaline
         • chondrocyte, LACK OF FIBROUS APPEARANCE, functions: structural support,, cushions joints, found in articulating ends of long bones, nose, trachea, and ends of ribs
       • fibrocartilage
         • chondrocytes, HAS LACUNAE, USUALLY BLUE IN COLOR, resists compressive forces, found in intervertebral disks, pubic symphysis, menisci of knee joint
       • elastic cartilage
         • chondrocyte, often paired lacunae, extensive dark elastic fibers, functions: flexibility, bendability, found in ear lobe and epiglottis
     • loose CT
       • areolar CT
         • fibroblast, wraps, cushions, holds defensive cells, holds fluids
       • adipose tissue
         • adipocyte, has a nucleus, functions: energy storage, cushioning, insulation, found under skin, breasts, surrounds eyes and kidney
       • reticular CT
         • fibroblast, forms scaffolding to upport other cells, found in spleen, bone marrow, and lymph nodes
     • bone
       • osteocytes, HAS RINGS, functions: support, protection, act as levers, mineral storage, found in bones
     • blood
       • erythrocytes (may have leucocytes) ROUND, transports nutrients, gases, waste, etc., found within the circulatory system

2. nervous

   • neurons, IRREGULAR BODY, DARK NUCLEUS, DARKER NUCLEOLUS, SUPPORTING GLIAL CELLS, communication, found all over the human body

3. epithelial

   • simple
     • simp. squamous
       • single layer of flat cells, lines air sacs of lungs, forms walls of capillaries, form serous membrane that line and cover organs in ventral cavity,
       • functions: diffusion, filtration, secretion
     • simp. cuboidal
       • single layer of cube-like cells, common in glands and their ducts, forms walls of kidney tubules, covers the surface of ovaries
       • secretion, absorption, ciliated types propel mucus or reproductive cells
     • simp. columnar
       • single layer of tall cells (goblet cell- secretes mucus) lines digestive tract from stomach to anus, mucous membrane body cavities opening up to the exterior
   • pseudostratified columnar
     • single layer but looks like multiple layer, found in respiratory tract, absorption and secretion
   • stratified
     • strat, squamous
       • mult, layers of flat cells, found in skin, mouth, and esophagus, is a protective covering where firction is common
     • strat. cuboidal
       • at least two layers of cuboidal cells, protection, found in ducts of glands,very rare
     • strat. columnar
       • very rare, found in ducts of large glands
   • transitional
     • composed of modified stratified squamous epithelium, shape of cells depends on the amount of stretching, function: stretching and ability to return back to its shape

4. muscle

   • skeletal
     • multiple nuclei, CONTAIN STRIATIONS AND NUCLEI ARE PUSHED TO THE EDGE OF THE FIBERS, voluntary, found skeletal muscles
   • cardiac
     • faint striations, multiple nuclei, INTERCALATED DISK, involuntary, found in the muscle of the heart
   • smooth
     • LACKS STRIATIONS, multiple nuclei, involuntary, found surrounding most hollow organs