CHAPTER 2 ANATOMY

• Cytology is the study of cells
• The cell is the most basic structural and functional unit of life, and play a vital role in our structure and function
• Diseases begin at the cellular level
• Living things are made of 50 to 70 trillion cells
• Cell theory states that cells are the building blocks of life, cells are made when pre-existing cells divide, and cells are the smallest unit that perform all vital functions
• The type of cells are sex and somatic cells
• Sex cells (germ Gametes) are used for reproduction and include the sperm and the egg
• Somatic cells are all the other cells that are not reproductive, meaning the rest of the cells
• Extracellular fluid is outside of the cell and include things such as nutrients, glucose, gasses, hormones, waste products and oxygen
• Intracellular fluids are inside of the cell and is the cytoplasm
• Extracellular fluid is usually watery but is not always fluid, creating a matrix of connective tissue. Between these some tissues is a little space between cells that provides a way for nutrients and gasses to travel
• The plasma membrane isolates cell contents from the extracellular fluid and is able to adapt to changes outside of the cell. It is able to create support for the cell and regulate exchange of materials between cell and extracellular fluid
• Phospholipid molecules are made of phosphate heads and lipid tails and make up the plasma membrane
• Phosphate heads are hydrophilic and love water
• Lipid tails are hydrophobic and fear water, so they avoid water inside and outside of the cell
• Small non-polar things are able to pass through the phospholipid molecules of the plasma membrane
• There is a 50:50 ratio by weight of proteins and lipids in a cell membrane
• Integral proteins span the membrane from outside to inside to form pores and channels
• Peripheral proteins attach to the inner or outer surface of the cell and anchors the cytoskeleton and forms gates
• Water soluble solutes are able to pass through proteins in the plasma membrane
• Cholesterol makes the phospholipid bilayer more impermeable to water soluble substances and helps the plasma membranes fluidity and structure
• Glycoproteins and glycolipids help in cell identification (fingerprint) and "sugar coating" meaning the cell coat that helps bind (glycocalyx)
• Moving substances across the plasma membrane can be through passive process and active process
• Passive processes do not use ATP and substances move from high to low concentration
• Active processes uses ATP and is not concentration dependent
• Diffusion is a passive process in which substances move from higher to lower concentration with kinetic energy (heat)
• Facilitated diffusion is a passive process that uses protein to move substances
• Osmosis is a passive process of water moving from high to low concentration
• Filtration is a passive process that uses gravity of hydrostatic pressure and dissolved solutes move across membranes through external mechanical forces. The kidneys use this
• Active transport is an active process in which substances are moved through the membrane carrier protein usually against a concentration gradient
• Endocytosis is an active process in which the cell membrane engulfs a molecule or organism and is brought into the cell, forming a vesicle
• • Exocytosis
  • Substances transported view vesicle, it fuses to membrane and opens to outside independent of concentration gradient
• Non-membranous organelles are made of tubules and consist of the microvilli, cilia, flagella, cytoskeleton, ribosomes, and centrioles
• Microvilli are used in absorption and increase surface area
• Cilia are longer than microvilli and beat rhythmically to move particles along cell surface
• Flagella are similar to cilia but are longer. They are used for movement and are found in bacteria
• The Cytoskeleton is the bones and muscles of cells and provides structure. In consists of microfilaments, intermediate filaments and microtubules
• Ribosomes are responsible for protein synthesis and can be either free or fixed to the rough ER
• Centrioles are used for cell division and causes movement of chromosomes
• Membrane bound organelles include the nucleus, mitochondria, endoplasmic reticulum, golgi apparatus, lysosomes, and peroxisomes