Cell Physiology

Cell Types Could use istock 35534112, and remove the Human Stem Cell Applications, arrows, and stem cells(center of graphic) Although there are a lot of different types of cells in the human body with vastly different functions, they all have the same basic parts. Take a microscopic look at a muscle cell, a red or white blood cell, a nerve or a sperm cell and it becomes very apparent that not all cells are the same. But the function of each cell is basically the same—it performs its functions to help the larger organism continue to live and grow. To do this, a cell must be able to move substances from one place to another.

Transportation of Substances Passive Diffusion Dialysis Osmosis Facilitated diffusion Filtration Active Endocytosis Exocytosis Transportation of substances includes both passive (diffusion, dialysis, osmosis, facilitated diffusion, and filtration) and active transport processes (active transport, endocytosis, and exocytosis).

Passive Transport Embed link to video: https://evolve.elsevier.com/objects/elr/Patton/AP8e/animations/Module_3_11/

Knowledge Check 1 Passive Transport Movement of ions or molecules from an area of higher  to an area of lower concentration. Simple Diffusion Natural movement of a substance, usually from area of highest to lowest concentration down a concentration gradient. Facilitated Diffusion Spontaneous passage of molecules or ions across a biological membrane passing through specific transmembrane integral proteins. Filtration Movement of water and solute molecules across the cell membrane due to hydrostatic pressure generated by the cardiovascular system. Osmosis Movement of water molecules across a selectively permeable membrane.

This could be a debriefing slide set up as a tabbed interaction This could be a debriefing slide set up as a tabbed interaction. Use terms and definitions from Notes pane. Passive Transport A kind of transport by which ions or molecules move along a concentration gradient, which means  from an area of higher concentration to an area of lower concentration. Since the movement of substances is by passive transport, this process does not require chemical energy (in contrast to active transport). In moving substances across a biological membrane, a passive transport may or may not need the assistance of a membrane protein. Simple Diffusion Simple diffusion is basically the natural movement of a substance usually from area of highest to lowest concentration down a concentration gradient. This is the most basic form of transport and is considered passive because it does not require the use of ATP (energy). Simple diffusion in water is known as osmosis and is indirectly proportional to solute concentration.   Facilitate Diffusion Also known as facilitated transport or passive-mediated transport. Is a process of passive transport, facilitated by integral proteins. Facilitated diffusion is the spontaneous passage of molecules or ions across a biological membrane passing through specific transmembrane integral proteins. Filtration Filtration is movement of water and solute molecules across the cell membrane due to hydrostatic pressure generated by the cardiovascular system. Depending on the size of the membrane pores, only solutes of a certain size may pass through it. For example, the membrane pores of the Bowman's capsule in the kidneys are very small, and only albumins, the smallest of the proteins, have any chance of being filtered through. On the other hand, the membrane pores of  liver cells are extremely large, to allow a variety of solutes to pass through and be metabolized. Osmosis Osmosis is the diffusion of water molecules across a selectively permeable membrane. The net movement of water molecules through a partially permeable membrane from a solution of high water potential to an area of low water potential. A cell with a less negative water potential will draw in water but this depends on other factors as well such as solute potential (pressure in the cell e.g. solute molecules) and pressure potential (external pressure e.g. cell wall).

Active Transport Embed link to video https://evolve.elsevier.com/objects/elr/Patton/AP8e/animations/Module_3_1/

Knowledge Check 2 Active Transport Movement of ions or molecules across a cell membrane in the direction opposite that of diffusion. Endocytosis Energy-using process by which cells absorb molecules (such as proteins) by engulfing them. Exocytosis Energy-consuming process by which a cell directs the contents of secretory vesicles out of the cell membrane and into the extracellular space.

Another tabbed feedback slide Active Transport The movement of ions or molecules across a cell membrane in the direction opposite that of diffusion; that is, from an area of lower concentration to one of higher concentration. Active transport requires the assistance of a type of protein called a carrier protein, using energy supplied by ATP.  Endocytosis  Is an energy-using process by which cells absorb molecules (such as proteins) by engulfing them. It is used by all cells of the body because most substances important to them are large polar molecules that cannot pass through the hydrophobic plasma or cell membrane. The opposite process is exocytosis.  Exocytosis Is the durable, energy-consuming process by which a cell directs the contents of secretory vesicles out of the cell membrane and into the extracellular space. These membrane-bound vesicles contain soluble proteins to be secreted to the extracellular environment, as well as membrane proteins and lipids that are sent to become components of the cell membrane.

Cellular Physiology and Radiography Why is cellular physiology important to radiographers? As a radiographer, you use ionizing radiation to produce images of the inside of the body. Radiation-induced ionizations may act directly on the cellular component molecules or indirectly on water molecules, causing water-derived radicals. Radicals react with nearby molecules in a very short time, resulting in breakage of chemical bonds or oxidation (addition of oxygen atoms) of the affected molecules. The major effect in cells is DNA breaks. Since DNA consists of a pair of complementary double strands, breaks of either a single strand or both strands can occur. However, the latter is believed to be much more important biologically. Most single-strand breaks can be repaired normally thanks to the double-stranded nature of the DNA molecule (the two strands complement each other, so that an intact strand can serve as a template for repair of its damaged, opposite strand). In the case of double-strand breaks, however, repair is more difficult and erroneous rejoining of broken ends may occur. These so-called misrepairs result in induction of mutations, chromosome aberrations, or cell death. It again comes back to radiation protection to minimize the exposure to radiosensitive cells, tissues, organs or systems of the body. It is important to know the cellular structure and function of the cells to best protect the normal function of the cell to eliminate or reduce possible mutations in the cell.