PHIL 2130 Chapter Notes - Chapter 1.4: Paracellular Transport, Passive Transport, Small Intestine
6 May 2020
School
Department
Course
Professor
Document Summary
Small intestine, need sealed paracellular and resistance to abrasion. Gap junctions: 6 subunits form pore, provide cytosolic continuity between cells. Permits movement of ions and small molecules. Number of layers: simple (molecular transfer) vs stratified (protection) Shape of cells: squamous (flat) vs cuboidal (height = width) vs columnar (height > width) Surface specialization: microvilli vs cilia vs goblet. Simple cuboidal epithelial = secretion and absorption. Simple columnar epithelial = high rates of secretion and absorption, some protection. Pseudostratified epithelial = fake stratified, ciliated with goblet cells (respiratory tract) Stratified squamous keratinized epithial: skin, protects against dehydration. Stratified squamous non-keratinized epithelial: moist by glandular secretion, protection from abrasion and pathogens. Transitional epithelial: line surface with stretch and recoil, urinary bladder. Stretched = flat, relaxed = puff appearance. Malignant tumours metastatsize from primary tissue source to other tissues in body, latter tumors are secondaries . Sarcoma: malignant tumour arise form muscle, blood vessels, bones.
