Fundamentals of Anatomy and Physiology System †MyAssignmenthelp

Question: Discuss about the Fundamentals of Anatomy and Physiology System. Answer: Introduction: The plasma membrane or cell membrane contains both lipids and proteins. Structurally, the membrane is a phospholipid bilayer, which acts as a stable barrier between two aqueous compartments, the inner and the outer surfaces of the cells. The proteins are embedded in the bilayer. These embedded proteins have different functions like selective transportation of molecules in or out of the cell and cell to cell recognition. Within this bilayer, the water loving heads of the fatty acids are oriented towards the outer surfaces, while the non-fearing tail is oriented towards the inner surface (between the two layers). Due to such an orientation of the polar heads, the bilayer can seal itself on its own, while the orientation of the non polar tails makes the membrane impermeable to water soluble molecules (Peat Nair, 2016). This is also called the fluid mosaic model of the cell membrane, where the membrane acts as a mosaic of proteins embedded in the 2 layers (Marieb Hoehn, 2016). Respiratory gases like oxygen and carbon dioxide, as well as fat soluble vitamins can move across the phospholipid bilayer of the plasma membrane by simple diffusion. The energy for the movement of the molecules across the membrane is provided by the kinetic energy of the molecules. The higher concentration of oxygen in the blood and extracellular fluid, than inside the cell, facilitates the movement of the oxygen molecules into the cell (Marieb Hoehn, 2016). This type of movement across the cell membrane is rapid as they pass right though the pores on the membrane (Peat Nair, 2016). How Sodium ions move in and out of the cell: Ions like Sodium (Na+) and Potassion (K+) are transported across the plasma membrane by the process of primary active transport. In this type of transport system, the molecules are moved against their concentration gradient, and the energy is provided by the hydrolysis of an ATP molecule, which helps to change the shape of the membrane proteins to act as a pump to drive the molecules (bound to the membrane) across the membrane. The Na+ and K+ molecules are moved by sodium-potassium pumps. Due to the action of these pumps, the extracellular concentration of Na+ can be maintained 10 times higher than the intracellular concentration, and the reverse for K+ concentration (Peat Nair, 2016). References: Marieb, E.N. Hoehn, K. (2016). Human anatomy physiology (10th global ed.). Harlow, Essex: Pearson. Peat, I., Nair, M. (Eds.). (2016). Fundamentals of Anatomy and Physiology: For Nursing and Healthcare Students (2nd Ed.). New Jersey: Wiley-Blackwell.