tissues Flashcards
what are tissues
groups of cells that are similar in structure and work together to perform specific functions
cells are joined together by intercellular membranes?
yes or loosely grouped
what are the 4 types of tissue
nervous, muscle, epithelial and connective
what does epithelial tissues do
forms boundaries between different environments, protects, secretes, absorbs, filters. it has a high regeneration rate
where is epithelial tissue found
in the lining of GI tract organs and other hollow organs and on the skin surface
what does nervous tissue do
used for internal communication
where is nervous tissue found
brain, spinal cord and nerves
what does muscle tissue do
contracts to cause movement
where is muscle tissue found
on muscles attached to the bone (skeletal), muscles of the heart (cardiac) and muscles of walls of hollow organs (smooth)
what does connective tissue do
supports, protects, binds other tissues together
where is connective tissue found
bones, tendons, fat and other soft padding tissues, under epithelial cells
what tissues are joined by tight junctions and desmosomes
epithelial
what tissue is supported by a basement membrane
epithelial
what are the three surfaces of epithelial cells
basal, apical and lateral
do epithelial cells have blood supply
no, but they have a nerve supply
cells with one layer is called
simple
cells with multiple layers is called
stratified
what are the three types of cell shapes
squamous, cuboidal and columnar
what are the two other types of epithelium tissues
transitional epithelium- found in structures that need to stretch to accomodate increases in volume
pseudo stratified epithelium- cells are attached to the basement membrane below
what is a gland
one or more specialised cells that make and secrete a particular product called secretion
what are the two types of glands
endocrine glands- secrete hormones into the bloodstream
exocrine glands- secrete their substance to the external environment e.g the surface of the skin
examples of endocrine glands
pituitary gland (in brain), thyroid gland (in neck), adrenal gland (on kidneys) and gonads (testicle)
examples of exocrine glands
sweat glands, salivary glands, oil glands, mucous cells, liver, mammary glands
what are the 2 types of exocrine glands
merocrine glands- secreted via exocytosis e.g. salivary glands
holocrine glands- secretes via rupture of the cell. only type in the human body is sebaceous glands (oil)
where is a basement membrane found
in all types of epithelium
what is the most abundant tissue
connective tissue
what is connective tissue made of
cells and extracellular matrix (ECM)
what is ECM made of
ground substance and fibers (collagen, elastic, reticular)
is connective tissue suspended within ECM and not connected to each other
true
what is the main type of connective tissue in the body
CT proper
what are the 4 types of connective tissue
blood and lymph, CT proper, cartilage and bone
what are the 6 sub types of CT proper
areolar, adipose, reticular (loose)
dense regular, dense irregular and elastic (dense)
areolar loose CT
most widely distributed, supports epithelium and glands, surrounds small blood vessels and nerves
adipose (fat) loose CT
composed mostly of adipose cells, store lipid nutrients and provides insulation, mostly found in subcutaneous tissue, around kidneys, eyeballs, abdomen and hips
reticular loose CT
found only in the liver, kidneys, lymph nodes, spleen and bone marrow. contains a complex network of reticular fibres which support white macrophages (white blood cells) and fibroblasts (cells that make fibers of ECM)
regular dense CT
packaged bundles of collagen fibers arranged parallel to each other, provide great resistance to undirectional pulling forces and is found in tendons, ligaments and fascia
irregular dense CT
collaged fibers in an irregular arrangement, provides resistance to tension forces from numerous directions and found in the dermis of the skin, joint capsules and fibrous coverings surrounding some organs
elastic dense CT
has lots of elastic fibers which allow stretch and recoil. found in a few ligaments, large blood vessels and bronchi of the lungs
cartilage
tough, flexible CT composed of firm ECM. the three types are hyaline, elastic, fibrocartilage
what are membranes
structures composed of epithelial and CT proper which line the body cavities and cover body organs
three types of membranes
cutaneous- covers the body
serous- lines the major body cavities and body spaces that are completely internal and has 2 layers (parietal and visceral) a special type is synovial membranes which form a single layer lining the inside of joint cavities
mucous- lines areas exposed to exterior lining of the upper respiratory tract, digestive tract and lower urogenital tracts.
steps of tissue repair
inflammation, organisation, regeneration and fibrosis
inflammation stage
damaged blood vessels bleed and inflammatory chemicals are released, capillaries become permeable, allowing white blood cells and clotting factors to seep into the injured area. blood clotting occurs. there is redness and swelling and heat
organisation stage
blood clot is replaced by connective tissue which contains capillaries that re establish blood supply. fibroblasts produce collagen fibers fill in gaps in the tissue. microphages remove dead and dying tissues
regeneration and fibrosis
the fibrosed area matures and contracts, condensing the area of damage. tissue cells regenerate to replace fibrous tissue or. the fibrous tissue remains, in which case it becomes scar tissue. the amount of regenerated tissue compared to the fibrous/ scar tissue will depend on the tissue type and severity of damage
