EPITHELIAL TISSUE - created from Mind Map

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Tissues are groups of cells that are similar in structure and perform a commoner related function(the "fabrics" of our body)

Functions: Cover surfaces or line body cavities or form glands

Glands

Structure: Can be thin or thick depending on function (thin/simple for absorption, thick/stratified for protection), sometimes waterproof e.g. skin (keratin)

Simple (SINGLE cell layer)

Stratified (many cell layers)

Simple Squamous(flattened): A thin, flattened layer of cells that is one layer thick (disc-shaped nuclei)

Simple Cuboidal: A single layer of cells shaped like cubes (spherical nuclei)

Simple Columnar (can be ciliated) : A single layer of column shaped cells (round/oval nuclei)

Allows passages of materials by diffusion and filtration (located in lung air sacs, heart and blood and lymphatic vessel lining

Secretion and Absorption (kidney tubules,ducts and secretory parts of glands, ovary surface)

Absorption, secretion of mucus, enzymes, etc. Ciliated can propel mucus (non-ciliated lines stomach to anal canal; ciliated lines small bronchi, uterine tubes and parts of uterus

Stratified Squamous: Thick membrane made up of several cell layers. Basal cells are cuboidal or columnar (metabolically active), surface cells are squamous (flattened). Non-keratinized located in oesophagus, mouth and vagina linings; keratinised form the skin epidermis (dry membrane)

Pseudostratified (false) Ciliated Columnar: Single layer of cells of different heights which gives an illusion of it being stratified

Transitional Epithelium: Looks like both stratified squamous and stratified cuboidal; basal cells cuboidal/columnar, surface cells dome/squamous shaped

Protects tissue underneath from abrasion

Secretion and propulsion of mucus (cilia). Non-ciliated found in sperm ducts and large gland ducts; ciliated line trachea and most of upper respiratory tract)

Stretches readily and relieves tension caused by urine containment (ureter lining, urinary bladder and part of urethra)

Exocrine

Endocrine

Secrete onto surfaces via ducts (sweat glands, sebaceous (oil secreting) glands, liver, pancreas)

Secrete hormones (chemical messengers) that travel around the body in the blood (controlling homeostasis). Secrete directly into the blood and do not have ducts (pituitary gland, adrenal gland, pancreatic islets)

(can be ciliated or have microvilli for absorption)