Page 48 - PRE-U STPM BIOLOGY TERM 1

Biology Term 1 STPM Chapter 2 Structure of Cells and Organelles

• The proximal convoluted tubules allows absorption of
filtrate molecules back into blood capillaries. The distal
convoluted tubules and collecting ducts are affected by
ADH to reabsorb back water in the kidneys.

Basement membrane
2

Longitudinal section
Cross section
Figure 2.38 Simple cuboidal epithelium
• Simple columnar epithelium. This epithelium is found
lining the innermost layer of the intestines and stomachs.
• The epithelia in stomach and small intestine can be
modified to form glands to produce mucus and digestive
enzymes.
• The epithelia in small intestine can absorb digested food
molecules. In the large intestine, the epithelium can
absorb water beside producing mucus.
Epithelial lining

Vilus
Capillary

Lacteal
Vertical section of a simple
columnar epithelium

Crypt of
Lieberkuhn
Venule
Arteriole
Lymph vessel
Figure 2.39 Simple columnar epithelium
• Stratified squamous epitelium. This epithelium is found
in the epidermis of skin, lining the innermost layer of the
oesophagus. The epithelium top layer keeps worning off
while the cells at the bottom divide and grow to replace
the loss. It’s function therefore is more for protection.
• Stratified cuboidal epithelium. This epithelium is found Vertical section
in the excretory ducts of sweat glands. Therefore, the Figure 2.40 Stratified
ducts are to channel sweat out. squamous epithelium

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