Cell Membrane (Nursing)

00:01 Today we will discuss the cellular level of organization, which is the basic functional unit of our human body.

00:11 So in this lecture we will discuss the different structures of the cell.

00:16 This can be divided into three different subdivisions.

00:19 The nucleus of the cell, the plasma membrane of the cell and the cytoplasm of the cell.

00:27 So we will work our way from the outside in starting first with the plasma membrane, which is going to separate the internal and external environments of the cell.

00:38 Then we will move into the cytoplasm where we will discuss the cytosol as well as different organelles that perform different functions in the cell.

00:46 And then finally we will conclude with the nucleus, including its chromosomes and genes, which allow for the cell to allow our body to function.

00:58 All right. So let's start with the plasma membrane.

01:00 The plasma membrane is a flexible yet sturdy barrier that's going to surround the inside of the cell.

01:09 And again it's going to provide a barrier between the external and internal environment of the cell.

01:17 When you think of the plasma membrane, even though it is a barrier, think about bubbles.

01:24 You know how a bubble is.

01:26 It's a very thin film, and it's made up of lipids.

01:31 That's exactly how our plasma membrane is made up.

01:34 It is a double lipid bilayer that's made up of phospholipids, where you have phosphates facing the outside and the inside of the cell, and then in between you have fatty acid tails facing each other.

01:50 This is actually really important for the structure of the plasma membrane because it allows it to form this barrier.

01:59 The phosphates are aqueous or hydrophilic, and they are attracted to the water in the internal and external environment, whereas the fatty acid tails hate water and are hydrophobic and therefore they point inward.

02:15 And so this double layer is there and it creates this barrier.

02:20 The plasma membrane is not a static feature of the cell.

02:24 It is extremely dynamic where the lipids are moving and flowing throughout, and as well it's studded with different structures such as different types of proteins and cholesterol and other things that allow the plasma membrane to actually perform its functions.