KP222 Lecture 2: KP222 Lecture 2
Document Summary
Occluding (integal proteins that fuse adjacent cells) Forces molecule to cross the epithelial cell layer. Lumen (apical membrane) epithelial cell cytosol basolateral membrane (ecf) Found in tissue subject to mechanical stress. Link the cytosol of two adjacent cells. Ions and molecules moving between cells act as a signal. When channel is open cells act as. Form direct cytoplasmic connections between adjacent cells. Chemical messengers released by one cell act on speci c receptors on another cell. Examples: insulting released by pancreatic beta cells acts on insulin receptors in most cells to facilitate glucose uptake. Autocrine signals: act on the same cell that secretes them. Paracrine signals: are secreted by one cell and di use to adjacent cells. Most signal pathways consist of 5 steps shown. Use shapes and colours of the steps shown here to identify the pattern in later illustrations. Allow exchanges of material: icf/ecf (extracellular uid) Allow the transport of some substances, but not others.