Anatomy and Physiology I Final Exam Study Guide From Exam 1: Lesson 2 (slides 3-18, 21-31, 35-52)

Anatomy and Physiology I Final Exam Study Guide From Exam 1: Lesson 2 (slides 3-18, 21-31, 35-52) Introduction • 1665 Robert Hooke inspected thin slices of cork and found they consisted of millions of small, irregular units • This research produced the cell theory o Cells are building blocks of all plants and animals o All cells come from division of preexisting cells o Cells are smallest units that perform all vital physiological functions o Each cell maintains homeostasis at cellular level • Cytology- the study of cellular structure and function; part of cell biology- integrates aspects of biology, chemistry and physics • Two general classes of cells: o Sex cells (germ/reproductive cells)-are either the sperm of males or oocytes of females o Somatic cells- include all other cells in human body 3-1 • Plasma membrane- outer boundary of a cell, also called cell membrane o Physical isolation-physical barrier that separates inside of cell from surrounding extracellular fluid o Regulation of exchange with environment- plasma membrane controls entry of ions and nutrients, eliminations of wastes and release of secretions o Sensitivity to environment- first part of the cell affected by changes in the composition, concentration or pH of extracellular fluid ▪ Contain receptors that allow cell to recognize and respond to specific molecules in its environment o Structural support- specialized connections between plasma membrane, or between membranes and extracellular materials give tissues stability • Plasma membrane is extremely thin and contains lipids, proteins and carbohydrates • Membrane lipids-form most of the surface area of the plasma membrane but only make up 42% of its weight o Plasma membrane is called the Phospholipid bilayer-phospholipid molecules in it form two layers o Has hydrophilic end (phosphate portion) and hydrophobic end (lipid portion) o In each half of bilayer, lie with hydrophilic heads at membrane surface and hydrophobic tails in inside o Also contains cholesterol and small quantities of other lipids o Water and solutes cannot cross the lipid portion of the plasma membrane • Membrane proteins-account for about 55% of weight of plasma membrane o Integral proteins-part of membrane structure and cannot be removed with damaging/destroying the membrane ▪ Most span the width of the membrane one or more times, therefore known as transmembrane proteins ▪ Greatly