tissues Flashcards
Define epithelium.
Epithelial tissues cover surfaces and separates compartments.
What are the 4 groups of tissues?
Epithelium, connective, muscle and nerve.
What are the 3 main types of cell-to-cell junctions?
Desmosomes (adhering junctions) for firm anchorage between cells via actin. Tight junctions (occluding) waterproof and seal intercellular spaces. Gap junctions (communicating junctions) for cell-to-cell communication. All cell-to-cell. Also cell-to-ECM hemidesmosomes.
What is the function of simple epithelium?
1 cell thick. Can be squamous (alveoli - diffusion), cuboidal (lines nephrons for secretion) or columnar (digestive tract to move mucous).
What is the function of stratified epithelium?
More than 1 cell thick. Can be squamous (epidermis - thick), cuboidal (ducts - protection) or columnar (pharynx - protection and secretion). Classified by whatever the top layer is.
Which 2 components make the basement membrane?
Basal lamina (closest to cells) and reticular lamina (anchors the BM to underlying connective tissues).
Where is transitional epithelia found?
Only in the urinary bladder. Cells are round.
What is the difference between exocrine and endocrine glands?
Exocrine have a duct coming from them eg. sweat glands. Endocrine secrete directly into a blood vessel eg. adrenal cortex.
What are glands made of?
Collections of secretory epithelial cells. Can be tubular, acinar or tubuloacinar. Mucous glands are rich in proteoglycans. Serous glands are rich in protein.
Describe the epithelial components of the liver and kidney.
Liver: parenchyma are hepatocytes arranged into rows/cords between blood vessels. Kidney: parenchyma are epithelial cells arranged into nephrons. Filter blood and partially absorb filtrate.
What are the consequences of abnormal glandular function?
Over-production: pituitary giantism. Under-production: pituitary dwarfism. Uterine tube: mucous glands can thicken secretions with STD’s like Chlamydia - infertility.
Give 3 examples of connective tissue.
Bone, blood and adipose tissue.
Where is pseudostratified epithelium found?
Trachea.
Where is dense regular connective tissue found?
Tendons.
Where is dense irregular connective tissue found?
Sebaceous glands in the skin.
