Plasma Membrane and Cellular Transportation

The assignment details the anatomy of the plasma membrane, its phospholipid bilayer structure, and embedded proteins that facilitate selective molecule transportation. It also explores how oxygen diffuses into cells and how sodium ions are transported across the membrane via primary active transport using ATP molecules. The document references Marieb and Hoehn's Human Anatomy & Physiology (10th global ed.) and Peat and Nair's Fundamentals of Anatomy and Physiology (2nd Ed.).

Running head: Nursing Assignment
Plasma Membrane and Cellular Transportation of Oxygen and Na+ ion
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1Nursing Assignment
Anatomy of the Plasma Membrane
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).
How Oxygen moves into the cell:
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:

2Nursing Assignment
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).

3Nursing Assignment
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.