Notesale: Turn your study into money

Document Preview

Extracts from the notes are below, to see the PDF you'll receive please use the links above

---

Lecturer: Dr O’ Sullivan

Module: BIOM - 1010

Date: 26/10/16

Integrity and Specialisation of Epithelial Tissue
Integrity of Epithelial Tissue
o

The integrity of epithelial tissue must be strong in order to stay as a unit as opposed to singular cells
...

 Blocking junctions prevents the diffusion of molecules
between cells
 The apical membrane of the epithelial cells lining
the urinary tract have a high number of
sphingolipids
 These resist osmotic fluid movement
 Desmosomes and hemidesmosomes act as
mechanical barrier
 Stratified squamous epithelial cells undergo a process
called keratinization
 The cytoskeleton becomes tightly condensed
with other specialised proteins and forms a
resilient mass
 This leads to the death of the cell which forms a
tough, impervious layer of keratin

o

Secretory adaptations
 Some organelles develop more prominently than others due to an epithelial cells adaptation for
secretion
 Secretions include enzymes, mucins and steroids
 Ions can also be secreted
 Secretory cells have a large nucleus and lots of rough endoplasmic reticulum
 Mucin-secreting cells have an expanded Golgi system
 Steroid-secreting cells have an extensive soft endoplasmic reticulum
 Ion-pumping cells have a large surface area and lots of mitochondria
 Epithelial cells can be grouped into glands for large amounts of a certain secretion
 This may involve straight or coiled glands
 They can be divided into specialised zones
 Most glands are refined and have branching and acini
 Some glands may be:
 Part of other tissue, such as mucus glands in the respiratory tract
 Anatomically distinct, such as salivary glands
 There are two types of secretion:
 Holocrine (bottom right)
 Merocrine (bottom left)
 The following shows the difference between simple and compound alveolar/tubular structures:



---