Table 4.

Differences between the components of the epithelial–lymphatic barrier of adult animals and newborns.

Features	Adult Rats	Newborn Rats
Apical endocytosis	Weakly developed	Well developed
Subapical network of the endosomes	Weakly developed	Well developed
The network of the cisterns of the smooth endoplasmic network in the supranuclear zone	Well developed	Weakly developed
The contractile cuff around the finger-shaped contacts of the basolateral PM	Well developed	Weakly developed
The height of the cells	22 µm	20 µm
Mean microvillus length	1020 nm	760 nm
Tissue mosaics	Hexagons	Shifted towards pentagons
The pores in the BM	Well developed	Weakly developed
The occurrence of dendritic cells in the epithelial layer	Often	Rarely
The development of fenestra fields in endotheliocytes of blood capillaries	Well developed	Not developed
The asymmetry of the arrangement of the fenestra fields	In the capillary wall areas looking at enterocytes, the number of fenestrae was much higher	Weakly developed
The development of intravenous valves in the lymphatic capillaries is poorly expressed	Well developed	Weakly developed