Lecture 5 Flashcards
What is a gland?
An epithelial cell or aggregate of epithelial cells specialised for secretion.
In what circumstance is trans epithelial transport very important?
When molecules are too big to penetrate membranes.
What is a myoepithelial cell?
Ancontractile epithelial cell found in tubuloacinar glands that contract to help secrete a water substance that assists in the release of the mucus. E.g breast milk ducts and submandibular salivary gland.
What is a neoplasm?
A new and abnormal growth of tissue in a part of the body, especially as a characteristic of cancer.
What is an adenocarcinoma?
Malignant neoplasm from glandular epithelium.
What is secretion?
Production and release of material from cells or an aggregate of cells
How are glands classified?
Structure and how products released?
How are glands generated?
Growth signal is received
Extracellular protein enzymes produced
Epithelial cells invade space
In exocrine glands canicularisation occurs to make a duct
In endocrine gland angiogenesis occurs and link to surface broken through apoptosis
What is the difference between an acinar and alveolar duct?
There is no difference , they meant the same thing
Merocrine , apocrine, holocrine and cytocrine gland examples
Merocrine is hornmones eg insulin
Apocrine is mammary glands
Holocrine is sebaceous glands in skin
Cytocrine is where the whole cell is lost e.g sperm
What are the two pathways of merocrine secretion?
Regulated by calcium and constitutive. Rekulated requires energy and so is a form of active transport.
Give an example of regulated secretion
Insulin
What is glycosylation?
The covalent attachment of sugars by enzymes to proteins and lipids to form glycoproteins and glycolipids
What is the purpose of glycosylation?
AIDS protein folding
Prevents protein digestion by intracellular proteases and lipids by lipases
What is the difference between phagocytosis and pinocytosis?
Phagocytosis is used by phagocytes which ingest or engulf other cells or particles whereas pinocytosis is the process in which liquid droplets are ingested into cells.
Pinocytosis can be used by cells to sample the environment, especially smooth muscle cells.
