P1 Anatomy & Physology

P1 – Anatomy & Physiology

Outline the functions of the main cell components

Cell Membrane; in the human body there are millions of cells, for every cell in the body it is surrounded with a cell membrane also known as plasma.The cell membrane separates the interior of all cells to the outside environment.
The outer layer or the cell controls the movement which goes in and out of the cell.
The cell membrane holds the cell together, but has very tiny holes to allow products to move in and out of the cell.
Proteins in the cell membrane provide structural support, form channels for passage of materials. Nucleus; The cell nucleus acts like the brain of the cell which helps control the eating, movement, and reproduction of the cell. The main function of the cell nucleus is to control gene expression and mediate the replication of DNA during the cell cycle. The nuclear envelope surrounds the nucleus and all of its contents. The nuclear envelope is a membrane similar to the cell membrane around the whole cell.
Chromosomes are gatherings of DNA.
Human cells have 46 chromosomes, 23 from each parent.

Cytoplasm; Cytoplasm is the gel-like fluid inside the cell. The cytoplasm is about 70% to 90% water and usually colourless. It provides a platform upon which other organelles can operate within the cell; all of the functions for cell expansion, growth and replication are carried out in the cytoplasm of a cell. Cytoplasmic organelles are little organs that are postponed in the cytoplasm of the cell. Each type of organelle has a certain structure and a detailed role in the function of the cell.

Organelles; The mitochondria which are rod-shaped organelles. Their main function is to produce energy that a cell can use to function. The name organelle comes from the idea that these structures are to cells what an organ is to the body.

Endoplasmic Reticulum (smooth and rough); A network of membranes that form canals in the cytoplasm that allow substances to move around the cell. The structure is categorised into two types, rough endoplasmic reticulum (RER) and smooth endoplasmic reticulum (SER).
RER (Rough endoplasmic reticulum) is mainly found in hepatocytes where protein synthesis occurs actively.
SER (Smooth endoplasmic reticulum) is a smooth network without the ribosomes. The smooth endoplasmic reticulum is concerned with lipid metabolism, carbohydrate metabolism, and detoxification.

Golgi apparatus; The Golgi apparatus or Golgi complex is found in most cells. It is another packaging organelle like the endoplasmic reticulum but they have a different function. The Golgi apparatus is the organelle that builds lysosomes (cell digestion machines). Helps to move proteins out of the cell and builds lysosomes Lysosome; A lysosome is basically a specialised vesicle that holds a variety of enzymes. The enzyme proteins are first created in the rough endoplasmic reticulum. They also help to breakdown food to be used as energy. These are described as the stomach of the cell. Lysosomes are the cell's waste disposal system and can digest some compounds. They are used for the digestion of macromolecules from phagocytosis.