9/25/21, 12:14 AMCH03 Lecture Notes: BIO-168-OA01-ML FL21 Human Anatomy and Physiology I w/ lab (P) (4 cr) - Bridget Boyle1/7CH03 Lecture NotesThe Cellular Level of OrganizationI. An Introduction to Cells1. Cell theory (Robert Hooke, 1665)Cells are the building blocks of all plants and animals.All cells come from division of preexisting cells.Cells are the smallest units that perform all vital physiological functions.Each cell maintains homeostasis at the cellular level.2. An organism maintains homeostasis through the coordination of all its cells, working individuallyand together.3. Cytology: the study of cell structure and function, a division of cell biology.4. Two classes of cells in the human body:sex cells (germ cells): reproductive cells [male sperm, female oocytes (eggs)]. Only have 1 setof chromosomessomatic cells (soma = body): all body cells except sex cells.5. Shows the general structure and typical organelles of a body cell.6. Summarizes the organelles and their functions.7. Human body cells are surrounded by a cell membrane which separates the inside (cytoplasm)from the outside (extracellular) fluid. Fluid between cells is called interstitial fluid. (interstitium =something standing between).II. The Cell Membrane1. Cell membrane or plasma membrane has 4 basic functions:1. Physical isolation: forms a physical barrier between the inside and outside of the cell. Keepsthings in or out.2. Regulate exchange with the environment: Selectively controls entry of ions and nutrients,eliminates waste, releases cellular products.
9/25/21, 12:14 AMCH03 Lecture Notes: BIO-168-OA01-ML FL21 Human Anatomy and Physiology I w/ lab (P) (4 cr) - Bridget Boyle2/73. Monitor the environment: detects changes in composition, concentration or pH of extracellularfluid. Contains receptors that respond to chemical signals. In a sense, the cell membrane isthe brain of the cell4. Structural support: keeps cells in place and stabilizes tissuesThe Organelles1. Each organelle has a specific function related to cell structure, growth, maintenance ormetabolism.2. The 6 types of nonmembranous organelles are: cytoskeleton, microvilli, centrioles, cilia,ribosomes and proteasomes.1. cytoskeleton: structural proteins for shape, strength, and some metabolic functions.2. microvilli: finger-shaped projections on the surfaces of some cells, increase surface area forabsorption, attached to cytoskeleton.3. centrioles form spindle apparatus during cell division, only found in cells that divide.4. cilia: long extensions of cell membrane move fluids across the cell surface (respiratory tract,reproductive tract).5. ribosomes: carry out orders from the nucleus for protein synthesis.