Diversity of Cells and Their Function.pdf

Diversity of Cells and Their Function 17/10/23, 7:04 PM Diversity of Cells and Their Function Haematoxylin and eosin • Haematoxylin stains acidic molecules purple • Eosin stains basic molecules pink Epithelium • Cover surfaces of the body, lines hollow organs, forms glands • Backed by a basal lam...

Diversity of Cells and Their Function 17/10/23, 7:04 PM Diversity of Cells and Their Function Haematoxylin and eosin • Haematoxylin stains acidic molecules purple • Eosin stains basic molecules pink Epithelium • Cover surfaces of the body, lines hollow organs, forms glands • Backed by a basal lamina (basement membrane) - thin layer of specialised extracellular material between the basal surface of epithelial cells and the underlying tissue • • Non-vascular Cells usually polarised - apical and basal sides differ ◦ ◦ Apical: faces the lumen of a tube or the external environment Basal: attaches to the basement membrane Functions • • • • • • Mechanical barrier Chemical barrier Absorption Secretion Containment Locomotion Classification Cell shape • • • Squamous: flattened Cuboidal: cube Columnar: tall and thin Number of layers • • • Simple: one layer Stratified: 2+ layers Pseudostratified: multiple layers, all in contact with basal lamina Cell/tissue surface specializations https://galvanized-borogovia-4fa.notion.site/Diversity-of-Cells-and-Their-Function-331bf17788fb42949ec0c02d417f7a04 Page 1 of 3 Diversity of Cells and Their Function 17/10/23, 7:04 PM • • • Microvilli Cilia Keratinized Presence of specialized cell types • e.g. goblet cells Glandular epithelia • Endocrine: product secreted towards basal end of cell and distributed by vascular system ductless • Exocrine: product secreted towards apical end of cell - ducted Connective tissue Soft connective tissue • • • Tendons, ligaments Loose: loosely packed fibres separated by ground substance Dense: densely packed bundles of collagen fibres ◦ ◦ Dense regular: fibres aligned Dense irregular: fibre bundles run in many directions Hard connective tissue • • • Strong, flexible, compressible, semi-rigid tissue 3 types of cartilage - hyaline, elastic, fibrocartilage Bone ◦ ◦ Outer shell of cortical bone makes up shaft - diaphysis Cancellous/trabecular bone occupies ends - epiphyses https://galvanized-borogovia-4fa.notion.site/Diversity-of-Cells-and-Their-Function-331bf17788fb42949ec0c02d417f7a04 Page 2 of 3 Diversity of Cells and Their Function 17/10/23, 7:04 PM Blood and lymph • Fluid connective tissues Muscle • Specialized to generate force by contraction • Force is movement of actin fibres over myosin fibres • • • Smooth muscle: involuntary, non-striated Skeletal muscle: voluntary, striated, multinucleated Cardiac: involuntary, striated, single nucleus at centre of fibre ◦ Has intercalated discs - contain many intracellular junctions for stability Nervous tissue • Consists of neurons and their supporting cells (glia) • Control function and allow for rapid communication between different parts of the body • Surrounded by connective tissue coat ◦ Meninges in CNS ◦ Epineurium in PNS Glia of the CNS • • • Astrocytes: provide support, involved in ion transport Oligodendrocytes: produce myelin Microglia: immune surveillance Glia of the PNS • Schwann cells: produce myelin and support axons https://galvanized-borogovia-4fa.notion.site/Diversity-of-Cells-and-Their-Function-331bf17788fb42949ec0c02d417f7a04 Page 3 of 3