Glands Flashcards
Define a gland.
An epithelial cell/collection of cells, specialised for secretion.
What does exocrine and endocrine mean?
Exocrine- with ducts
Endocrine- ductless
Name a unicellular gland.
Goblet cell
What are the 3 methods of gland secretion?
Merocrine
Holocrine
Apocrine
Explain merocrine secretion.
Exocytosis of membrane bound molecules. Method of majority of secretions.
Explain apocrine secretion.
Exocytosis of non-membrane bound molecules, e.g. lipids. The apical membrane drapes over it so it can be released membrane bound.
In which type of secretion does the membrane become transiently smaller?
Apocrine.
Explain holocrine secretion.
Disintegration of the cell, releasing the cell content.
What does acinar (alveolar) mean?
Swelling of secretary cells at the end of a tube.
Are branched and simple ducts uni or multi cellular?
Multicellular
Explain the difference between simple and compound ducts.
Simple- ducts are not branched. However, the 1 duct may be split.
Compound- ducts are branched.
Name the 5 types of simple ducts.
1) Simple tubular 2) Simple coiled tubular
3) Simple branched tubular 4) Simple alveolar/acinar
5) Simple branched alveolar
Name the 3 types off compound ducts.
1) Compound tubular
2) Compound alveolar/acinar
3) Compound tubloalveolar
Explain endocytosis.
Engulf material from outside the cell.
Explain transepithelial transport.
Endo and exocytosis are coupled together. Material is endocytosed at 1 surface, is transported in vesicle shuttles across cytoplasm and the material is exocytosed at the opposite surface.
Name the organ which has both endocrine and exocrine functions.
Pancreas
Describe the structure of the Golgi apparatus.
Stack of disc-shaped cisternae. One side is flat and the other concave. Swellings pinch off as golgi vacuoles.
What are the four functions of the Golgi function?
Transport
Sorting
Packaging
Glycosylation (adding sugar)
Explain the process of glycosylation and why it is required.
Glycosylation produces complex shaped sugars for specific interactions in the glycocalyx (plasma membrane). Destruction of this by enzymes alters many specific properties of the cell, e.g. cell mobility, communication and adhesion of substrate.
After glycosylaion, where do the sugars go?
Majority extruded in secretory vesicles by exocytosis.
Some retained for cell use.
Some enter the glycocalyx.
State the 4 mechanisms of secretion and give examples of each.
1) Nervous, e.g. adrenaline
2) Endocrine control, e.g. ACTH
3) Neuro-endocrine control, e.g. nervous cells control ACTH release
4) Negative feedback chemical mechanism, e.g. T3 and T4
Are the parotid and submandibular glands, and goblet cells exocrine or endocrine glands?
Exocrine.
The parathyroid glands are endocrine. Explain how and what they secrete, their location and their function.
Secrete parathyroid hormone from cheif cells. Located at the back of the thyroid gland and control calcium levels.
Name the 3 layers of the adrenal cortex in order from outside to inside.
Zona glomerulosa
Zona fasciculata
Zona reticularis
