BIOLOGY 2B03 Lecture 8: Lecture 8 Summary
9 Feb 2012
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Wouldn t show up in tem passed the tight junction. Donut shaped pores connect neighboring cells proteins make up the wall of the channel. Each channel made up of proteins that reside in each of the neighboring membranes. Only molecules smaller than the pore size of 2nm can flow through (certain ions, proteins, fluoresceins and camp) . Ie, fluorescein not common in the human body, but it is small enough, and secondary messengers like camp. Junctions allow cells to have stable associations between cells, and also communicate between cells. Interactions can be broken, endothelial cells (specialized epithelial cells) form inner lining of the blood vessels. Leukocytes must move out of the blood vessel into damaged or infected tissue (extravastion). Movement of leukocytes depends on precise sequence of adhesive interactions. Local infections (bacterial, viral) or injury rapidly attract white blood cells to the affected regions. Leukocytes: granulocytes toxins for killing pathogens. *neutrophil, esinophil, or basophil granulocytes: monocytes* (macrophages): phagocytosis, lymphocytes.
